Appendix A. Contributed Scripts

These scripts, while not fitting into the text of this document, do illustrate some interesting shell programming techniques. They are useful, too. Have fun analyzing and running them.

Example A-1. mailformat: Formatting an e-mail message

#!/bin/bash # mail-format.sh (ver. 1.1): Format e-mail messages. # Gets rid of carets, tabs, and also folds excessively long lines. # ================================================================= # Standard Check for Script Argument(s) ARGS=1 E_BADARGS=65 E_NOFILE=66 if [ $# -ne $ARGS ] # Correct number of arguments passed to script? then echo "Usage: `basename $0` filename" exit $E_BADARGS fi if [ -f "$1" ] # Check if file exists. then file_name=$1 else echo "File \"$1\" does not exist." exit $E_NOFILE fi # ================================================================= MAXWIDTH=70 # Width to fold excessively long lines to. # --------------------------------- # A variable can hold a sed script. sedscript='s/^>// s/^ *>// s/^ *// s/ *//' # --------------------------------- # Delete carets and tabs at beginning of lines, #+ then fold lines to $MAXWIDTH characters. sed "$sedscript" $1 | fold -s --width=$MAXWIDTH # -s option to "fold" #+ breaks lines at whitespace, if possible. # This script was inspired by an article in a well-known trade journal #+ extolling a 164K MS Windows utility with similar functionality. # # An nice set of text processing utilities and an efficient #+ scripting language provide an alternative to bloated executables. exit

Example A-2. rn: A simple-minded file renaming utility

This script is a modification of Example 15-22.

#! /bin/bash # # Very simpleminded filename "rename" utility (based on "lowercase.sh"). # # The "ren" utility, by Vladimir Lanin (lanin@csd2.nyu.edu), #+ does a much better job of this. ARGS=2 E_BADARGS=65 ONE=1 # For getting singular/plural right (see below). if [ $# -ne "$ARGS" ] then echo "Usage: `basename $0` old-pattern new-pattern" # As in "rn gif jpg", which renames all gif files in working directory to jpg. exit $E_BADARGS fi number=0 # Keeps track of how many files actually renamed. for filename in *$1* #Traverse all matching files in directory. do if [ -f "$filename" ] # If finds match... then fname=`basename $filename` # Strip off path. n=`echo $fname | sed -e "s/$1/$2/"` # Substitute new for old in filename. mv $fname $n # Rename. let "number += 1" fi done if [ "$number" -eq "$ONE" ] # For correct grammar. then echo "$number file renamed." else echo "$number files renamed." fi exit 0 # Exercises: # --------- # What type of files will this not work on? # How can this be fixed? # # Rewrite this script to process all the files in a directory #+ containing spaces in their names, and to rename them, #+ substituting an underscore for each space.

Example A-3. blank-rename: Renames filenames containing blanks

This is an even simpler-minded version of previous script.

#! /bin/bash # blank-rename.sh # # Substitutes underscores for blanks in all the filenames in a directory. ONE=1 # For getting singular/plural right (see below). number=0 # Keeps track of how many files actually renamed. FOUND=0 # Successful return value. for filename in aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html #Traverse all files in directory. do echo "$filename" | grep -q " " # Check whether filename if [ $? -eq $FOUND ] #+ contains space(s). then fname=$filename # Yes, this filename needs work. n=`echo $fname | sed -e "s/ /_/g"` # Substitute underscore for blank. mv "$fname" "$n" # Do the actual renaming. let "number += 1" fi done if [ "$number" -eq "$ONE" ] # For correct grammar. then echo "$number file renamed." else echo "$number files renamed." fi exit 0

Example A-4. encryptedpw: Uploading to an ftp site, using a locally encrypted password

#!/bin/bash # Example "ex72.sh" modified to use encrypted password. # Note that this is still rather insecure, #+ since the decrypted password is sent in the clear. # Use something like "ssh" if this is a concern. E_BADARGS=65 if [ -z "$1" ] then echo "Usage: `basename $0` filename" exit $E_BADARGS fi Username=bozo # Change to suit. pword=/home/bozo/secret/password_encrypted.file # File containing encrypted password. Filename=`basename $1` # Strips pathname out of file name. Server="XXX" Directory="YYY" # Change above to actual server name & directory. Password=`cruft <$pword` # Decrypt password. # Uses the author's own "cruft" file encryption package, #+ based on the classic "onetime pad" algorithm, #+ and obtainable from: #+ Primary-site: ftp://ibiblio.org/pub/Linux/utils/file #+ cruft-0.2.tar.gz [16k] ftp -n $Server <<End-Of-Session user $Username $Password binary bell cd $Directory put $Filename bye End-Of-Session # -n option to "ftp" disables auto-logon. # Note that "bell" rings 'bell' after each file transfer. exit 0

Example A-5. copy-cd: Copying a data CD

#!/bin/bash # copy-cd.sh: copying a data CD CDROM=/dev/cdrom # CD ROM device OF=/home/bozo/projects/cdimage.iso # output file # /xxxx/xxxxxxx/ Change to suit your system. BLOCKSIZE=2048 SPEED=2 # May use higher speed if supported. DEVICE=cdrom # DEVICE="0,0" on older versions of cdrecord. echo; echo "Insert source CD, but do authorsnote.html endnotes.html mount it." echo "Press ENTER when ready. " read ready # Wait for input, $ready not used. echo; echo "Copying the source CD to $OF." echo "This may take a while. Please be patient." dd if=$CDROM of=$OF bs=$BLOCKSIZE # Raw device copy. echo; echo "Remove data CD." echo "Insert blank CDR." echo "Press ENTER when ready. " read ready # Wait for input, $ready not used. echo "Copying $OF to CDR." cdrecord -v -isosize speed=$SPEED dev=$DEVICE $OF # Uses Joerg Schilling's "cdrecord" package (see its docs). # http://www.fokus.gmd.de/nthp/employees/schilling/cdrecord.html echo; echo "Done copying $OF to CDR on device $CDROM." echo "Do you want to erase the image file (y/n)? " # Probably a huge file. read answer case "$answer" in [yY]) rm -f $OF echo "$OF erased." ;; *) echo "$OF not erased.";; esac echo # Exercise: # Change the above "case" statement to also accept "yes" and "Yes" as input. exit 0

Example A-6. Collatz series

#!/bin/bash # collatz.sh # The notorious "hailstone" or Collatz series. # ------------------------------------------- # 1) Get the integer "seed" from the command line. # 2) NUMBER <--- seed # 3) Print NUMBER. # 4) If NUMBER is even, divide by 2, or # 5)+ if odd, multiply by 3 and add 1. # 6) NUMBER <--- result # 7) Loop back to step 3 (for specified number of iterations). # # The theory is that every sequence, #+ no matter how large the initial value, #+ eventually settles down to repeating "4,2,1..." cycles, #+ even after fluctuating through a wide range of values. # # This is an instance of an "iterate," #+ an operation that feeds its output back into the input. # Sometimes the result is a "chaotic" series. MAX_ITERATIONS=200 # For large seed numbers (>32000), increase MAX_ITERATIONS. h=${1:-$$} # Seed # Use $PID as seed, #+ if not specified as command-line arg. echo echo "C($h) --- $MAX_ITERATIONS Iterations" echo for ((i=1; i<=MAX_ITERATIONS; i++)) do echo -n "$h " # ^^^^^ # tab let "remainder = h % 2" if [ "$remainder" -eq 0 ] # Even? then let "h /= 2" # Divide by 2. else let "h = h*3 + 1" # Multiply by 3 and add 1. fi COLUMNS=10 # Output 10 values per line. let "line_break = i % $COLUMNS" if [ "$line_break" -eq 0 ] then echo fi done echo # For more information on this mathematical function, #+ see _Computers, Pattern, Chaos, and Beauty_, by Pickover, p. 185 ff., #+ as listed in the bibliography. exit 0

Example A-7. days-between: Days between two dates

#!/bin/bash # days-between.sh: Number of days between two dates. # Usage: ./days-between.sh [M]M/[D]D/YYYY [M]M/[D]D/YYYY # # Note: Script modified to account for changes in Bash, v. 2.05b +, #+ that closed the loophole permitting large negative #+ integer return values. ARGS=2 # Two command line parameters expected. E_PARAM_ERR=65 # Param error. REFYR=1600 # Reference year. CENTURY=100 DIY=365 ADJ_DIY=367 # Adjusted for leap year + fraction. MIY=12 DIM=31 LEAPCYCLE=4 MAXRETVAL=255 # Largest permissible #+ positive return value from a function. diff= # Declare global variable for date difference. value= # Declare global variable for absolute value. day= # Declare globals for day, month, year. month= year= Param_Error () # Command line parameters wrong. { echo "Usage: `basename $0` [M]M/[D]D/YYYY [M]M/[D]D/YYYY" echo " (date must be after 1/3/1600)" exit $E_PARAM_ERR } Parse_Date () # Parse date from command line params. { month=${1%%/**} dm=${1%/**} # Day and month. day=${dm#*/} let "year = `basename $1`" # Not a filename, but works just the same. } check_date () # Checks for invalid date(s) passed. { [ "$day" -gt "$DIM" ] || [ "$month" -gt "$MIY" ] || [ "$year" -lt "$REFYR" ] && Param_Error # Exit script on bad value(s). # Uses or-list / and-list. # # Exercise: Implement more rigorous date checking. } strip_leading_zero () # Better to strip possible leading zero(s) { #+ from day and/or month return ${1#0} #+ since otherwise Bash will interpret them } #+ as octal values (POSIX.2, sect 2.9.2.1). day_index () # Gauss' Formula: { # Days from March 1, 1600 to date passed as param. # ^^^^^^^^^^^^^ day=$1 month=$2 year=$3 let "month = $month - 2" if [ "$month" -le 0 ] then let "month += 12" let "year -= 1" fi let "year -= $REFYR" let "indexyr = $year / $CENTURY" let "Days = $DIY*$year + $year/$LEAPCYCLE - $indexyr \ + $indexyr/$LEAPCYCLE + $ADJ_DIY*$month/$MIY + $day - $DIM" # For an in-depth explanation of this algorithm, see #+ http://weblogs.asp.net/pgreborio/archive/2005/01/06/347968.aspx echo $Days } calculate_difference () # Difference between two day indices. { let "diff = $1 - $2" # Global variable. } abs () # Absolute value { # Uses global "value" variable. if [ "$1" -lt 0 ] # If negative then #+ then let "value = 0 - $1" #+ change sign, else #+ else let "value = $1" #+ leave it alone. fi } if [ $# -ne "$ARGS" ] # Require two command line params. then Param_Error fi Parse_Date $1 check_date $day $month $year # See if valid date. strip_leading_zero $day # Remove any leading zeroes day=$? #+ on day and/or month. strip_leading_zero $month month=$? let "date1 = `day_index $day $month $year`" Parse_Date $2 check_date $day $month $year strip_leading_zero $day day=$? strip_leading_zero $month month=$? date2=$(day_index $day $month $year) # Command substitution. calculate_difference $date1 $date2 abs $diff # Make sure it's positive. diff=$value echo $diff exit 0 # Compare this script with #+ the implementation of Gauss' Formula in a C program at: #+ http://buschencrew.hypermart.net/software/datedif

Example A-8. Making a dictionary

#!/bin/bash # makedict.sh [make dictionary] # Modification of /usr/sbin/mkdict (/usr/sbin/cracklib-forman) script. # Original script copyright 1993, by Alec Muffett. # # This modified script included in this document in a manner #+ consistent with the "LICENSE" document of the "Crack" package #+ that the original script is a part of. # This script processes text files to produce a sorted list #+ of words found in the files. # This may be useful for compiling dictionaries #+ and for other lexicographic purposes. E_BADARGS=65 if [ ! -r "$1" ] # Need at least one then #+ valid file argument. echo "Usage: $0 files-to-process" exit $E_BADARGS fi # SORT="sort" # No longer necessary to define options #+ to sort. Changed from original script. cat $* | # Contents of specified files to stdout. tr A-Z a-z | # Convert to lowercase. tr ' ' '\012' | # New: change spaces to newlines. # tr -cd '\012[a-z][0-9]' | # Get rid of everything non-alphanumeric #+ (in original script). tr -c '\012a-z' '\012' | # Rather than deleting non-alpha chars, #+ change them to newlines. sort | # $SORT options unnecessary now. uniq | # Remove duplicates. grep -v '^#' | # Delete lines beginning with a hashmark. grep -v '^$' # Delete blank lines. exit 0

Example A-9. Soundex conversion

#!/bin/bash # soundex.sh: Calculate "soundex" code for names # ======================================================= # Soundex script # by # Mendel Cooper # thegrendel@theriver.com # 23 January, 2002 # # Placed in the Public Domain. # # A slightly different version of this script appeared in #+ Ed Schaefer's July, 2002 "Shell Corner" column #+ in "Unix Review" on-line, #+ http://www.unixreview.com/documents/uni1026336632258/ # ======================================================= ARGCOUNT=1 # Need name as argument. E_WRONGARGS=70 if [ $# -ne "$ARGCOUNT" ] then echo "Usage: `basename $0` name" exit $E_WRONGARGS fi assign_value () # Assigns numerical value { #+ to letters of name. val1=bfpv # 'b,f,p,v' = 1 val2=cgjkqsxz # 'c,g,j,k,q,s,x,z' = 2 val3=dt # etc. val4=l val5=mn val6=r # Exceptionally clever use of 'tr' follows. # Try to figure out what is going on here. value=$( echo "$1" \ | tr -d wh \ | tr $val1 1 | tr $val2 2 | tr $val3 3 \ | tr $val4 4 | tr $val5 5 | tr $val6 6 \ | tr -s 123456 \ | tr -d aeiouy ) # Assign letter values. # Remove duplicate numbers, except when separated by vowels. # Ignore vowels, except as separators, so delete them last. # Ignore 'w' and 'h', even as separators, so delete them first. # # The above command substitution lays more pipe than a plumber <g>. } input_name="$1" echo echo "Name = $input_name" # Change all characters of name input to lowercase. # ------------------------------------------------ name=$( echo $input_name | tr A-Z a-z ) # ------------------------------------------------ # Just in case argument to script is mixed case. # Prefix of soundex code: first letter of name. # -------------------------------------------- char_pos=0 # Initialize character position. prefix0=${name:$char_pos:1} prefix=`echo $prefix0 | tr a-z A-Z` # Uppercase 1st letter of soundex. let "char_pos += 1" # Bump character position to 2nd letter of name. name1=${name:$char_pos} # ++++++++++++++++++++++++++ Exception Patch +++++++++++++++++++++++++++++++++ # Now, we run both the input name and the name shifted one char to the right #+ through the value-assigning function. # If we get the same value out, that means that the first two characters #+ of the name have the same value assigned, and that one should cancel. # However, we also need to test whether the first letter of the name #+ is a vowel or 'w' or 'h', because otherwise this would bollix things up. char1=`echo $prefix | tr A-Z a-z` # First letter of name, lowercased. assign_value $name s1=$value assign_value $name1 s2=$value assign_value $char1 s3=$value s3=9$s3 # If first letter of name is a vowel #+ or 'w' or 'h', #+ then its "value" will be null (unset). #+ Therefore, set it to 9, an otherwise #+ unused value, which can be tested for. if [[ "$s1" -ne "$s2" || "$s3" -eq 9 ]] then suffix=$s2 else suffix=${s2:$char_pos} fi # ++++++++++++++++++++++ end Exception Patch +++++++++++++++++++++++++++++++++ padding=000 # Use at most 3 zeroes to pad. soun=$prefix$suffix$padding # Pad with zeroes. MAXLEN=4 # Truncate to maximum of 4 chars. soundex=${soun:0:$MAXLEN} echo "Soundex = $soundex" echo # The soundex code is a method of indexing and classifying names #+ by grouping together the ones that sound alike. # The soundex code for a given name is the first letter of the name, #+ followed by a calculated three-number code. # Similar sounding names should have almost the same soundex codes. # Examples: # Smith and Smythe both have a "S-530" soundex. # Harrison = H-625 # Hargison = H-622 # Harriman = H-655 # This works out fairly well in practice, but there are numerous anomalies. # # # The U.S. Census and certain other governmental agencies use soundex, # as do genealogical researchers. # # For more information, #+ see the "National Archives and Records Administration home page", #+ http://www.nara.gov/genealogy/soundex/soundex.html # Exercise: # -------- # Simplify the "Exception Patch" section of this script. exit 0

Example A-10. Game of Life

#!/bin/bash # life.sh: "Life in the Slow Lane" # Version 0.2: Patched by Daniel Albers #+ to allow non-square grids as input. # ##################################################################### # # This is the Bash script version of John Conway's "Game of Life". # # "Life" is a simple implementation of cellular automata. # # --------------------------------------------------------------------- # # On a rectangular grid, let each "cell" be either "living" or "dead." # # Designate a living cell with a dot, and a dead one with a blank space.# # Begin with an arbitrarily drawn dot-and-blank grid, # #+ and let this be the starting generation, "generation 0." # # Determine each successive generation by the following rules: # # 1) Each cell has 8 neighbors, the adjoining cells # #+ left, right, top, bottom, and the 4 diagonals. # # # # 123 # # 4*5 The aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html is the cell under consideration. # # 678 # # # # 2) A living cell with either 2 or 3 living neighbors remains alive. # SURVIVE=2 # # 3) A dead cell with 3 living neighbors comes alive (a "birth"). # BIRTH=3 # # 4) All other cases result in a dead cell for the next generation. # # ##################################################################### # startfile=gen0 # Read the starting generation from the file "gen0" ... # Default, if no other file specified when invoking script. # if [ -n "$1" ] # Specify another "generation 0" file. then startfile="$1" fi ############################################ # Abort script if "startfile" not specified #+ and #+ default file "gen0" not present. E_NOSTARTFILE=68 if [ ! -e "$startfile" ] then echo "Startfile \""$startfile"\" missing!" exit $E_NOSTARTFILE fi ############################################ ALIVE1=. DEAD1=_ # Represent living and dead cells in the start-up file. # ---------------------------------------------------------- # # This script uses a 10 x 10 grid (may be increased, #+ but a large grid will slow execution). ROWS=10 COLS=10 # Change above two variables to match grid size, as desired. # ---------------------------------------------------------- # GENERATIONS=10 # How many generations to cycle through. # Adjust this upwards, #+ if you have time on your hands. NONE_ALIVE=85 # Exit status on premature bailout, #+ if no cells left alive. TRUE=0 FALSE=1 ALIVE=0 DEAD=1 avar= # Global; holds current generation. generation=0 # Initialize generation count. # ================================================================= let "cells = $ROWS aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html $COLS" # How many cells. # Arrays containing "cells." declare -a initial declare -a current display () { alive=0 # How many cells alive at any given time. # Initially zero. declare -a arr arr=( `echo "$1"` ) # Convert passed arg to array. element_count=${#arr[*]} local i local rowcheck for ((i=0; i<$element_count; i++)) do # Insert newline at end of each row. let "rowcheck = $i % COLS" if [ "$rowcheck" -eq 0 ] then echo # Newline. echo -n " " # Indent. fi cell=${arr[i]} if [ "$cell" = . ] then let "alive += 1" fi echo -n "$cell" | sed -e 's/_/ /g' # Print out array and change underscores to spaces. done return } IsValid () # Test whether cell coordinate valid. { if [ -z "$1" -o -z "$2" ] # Mandatory arguments missing? then return $FALSE fi local row local lower_limit=0 # Disallow negative coordinate. local upper_limit local left local right let "upper_limit = $ROWS aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html $COLS - 1" # Total number of cells. if [ "$1" -lt "$lower_limit" -o "$1" -gt "$upper_limit" ] then return $FALSE # Out of array bounds. fi row=$2 let "left = $row aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html $COLS" # Left limit. let "right = $left + $COLS - 1" # Right limit. if [ "$1" -lt "$left" -o "$1" -gt "$right" ] then return $FALSE # Beyond row boundary. fi return $TRUE # Valid coordinate. } IsAlive () # Test whether cell is alive. # Takes array, cell number, { #+ state of cell as arguments. GetCount "$1" $2 # Get alive cell count in neighborhood. local nhbd=$? if [ "$nhbd" -eq "$BIRTH" ] # Alive in any case. then return $ALIVE fi if [ "$3" = "." -a "$nhbd" -eq "$SURVIVE" ] then # Alive only if previously alive. return $ALIVE fi return $DEAD # Dead by default. } GetCount () # Count live cells in passed cell's neighborhood. # Two arguments needed: # $1) variable holding array # $2) cell number { local cell_number=$2 local array local top local center local bottom local r local row local i local t_top local t_cen local t_bot local count=0 local ROW_NHBD=3 array=( `echo "$1"` ) let "top = $cell_number - $COLS - 1" # Set up cell neighborhood. let "center = $cell_number - 1" let "bottom = $cell_number + $COLS - 1" let "r = $cell_number / $COLS" for ((i=0; i<$ROW_NHBD; i++)) # Traverse from left to right. do let "t_top = $top + $i" let "t_cen = $center + $i" let "t_bot = $bottom + $i" let "row = $r" # Count center row. IsValid $t_cen $row # Valid cell position? if [ $? -eq "$TRUE" ] then if [ ${array[$t_cen]} = "$ALIVE1" ] # Is it alive? then # Yes? let "count += 1" # Increment count. fi fi let "row = $r - 1" # Count top row. IsValid $t_top $row if [ $? -eq "$TRUE" ] then if [ ${array[$t_top]} = "$ALIVE1" ] # Redundancy here. then # Can be optimized? let "count += 1" fi fi let "row = $r + 1" # Count bottom row. IsValid $t_bot $row if [ $? -eq "$TRUE" ] then if [ ${array[$t_bot]} = "$ALIVE1" ] then let "count += 1" fi fi done if [ ${array[$cell_number]} = "$ALIVE1" ] then let "count -= 1" # Make sure value of tested cell itself fi #+ is not counted. return $count } next_gen () # Update generation array. { local array local i=0 array=( `echo "$1"` ) # Convert passed arg to array. while [ "$i" -lt "$cells" ] do IsAlive "$1" $i ${array[$i]} # Is cell alive? if [ $? -eq "$ALIVE" ] then # If alive, then array[$i]=. #+ represent the cell as a period. else array[$i]="_" # Otherwise underscore fi #+ (will later be converted to space). let "i += 1" done # let "generation += 1" # Increment generation count. # Why was the above line commented out? # Set variable to pass as parameter to "display" function. avar=`echo ${array[@]}` # Convert array back to string variable. display "$avar" # Display it. echo; echo echo "Generation $generation - $alive alive" if [ "$alive" -eq 0 ] then echo echo "Unexpected exit: no more cells alive!" exit $NONE_ALIVE # No point in continuing fi #+ if no live cells. } # ========================================================= # main () # Load initial array with contents of startup file. initial=( `cat "$startfile" | sed -e '/#/d' | tr -d '\n' |\ sed -e 's/\./\. /g' -e 's/_/_ /g'` ) # Delete lines containing '#' comment character. # Remove linefeeds and insert space between elements. clear # Clear screen. echo # Title echo "=======================" echo " $GENERATIONS generations" echo " of" echo "\"Life in the Slow Lane\"" echo "=======================" # -------- Display first generation. -------- Gen0=`echo ${initial[@]}` display "$Gen0" # Display only. echo; echo echo "Generation $generation - $alive alive" # ------------------------------------------- let "generation += 1" # Bump generation count. echo # ------- Display second generation. ------- Cur=`echo ${initial[@]}` next_gen "$Cur" # Update & display. # ------------------------------------------ let "generation += 1" # Increment generation count. # ------ Main loop for displaying subsequent generations ------ while [ "$generation" -le "$GENERATIONS" ] do Cur="$avar" next_gen "$Cur" let "generation += 1" done # ============================================================== echo exit 0 # CEOF:EOF # The grid in this script has a "boundary problem." # The the top, bottom, and sides border on a void of dead cells. # Exercise: Change the script to have the grid wrap around, # + so that the left and right sides will "touch," # + as will the top and bottom. # # Exercise: Create a new "gen0" file to seed this script. # Use a 12 x 16 grid, instead of the original 10 x 10 one. # Make the necessary changes to the script, #+ so it will run with the altered file. # # Exercise: Modify this script so that it can determine the grid size #+ from the "gen0" file, and set any variables necessary #+ for the script to run. # This would make unnecessary any changes to variables #+ in the script for an altered grid size. # # Exercise: Optimize this script. # It has some redundant code.

Example A-11. Data file for Game of Life

# gen0 # # This is an example "generation 0" start-up file for "life.sh". # -------------------------------------------------------------- # The "gen0" file is a 10 x 10 grid using a period (.) for live cells, #+ and an underscore (_) for dead ones. We cannot simply use spaces #+ for dead cells in this file because of a peculiarity in Bash arrays. # [Exercise for the reader: explain this.] # # Lines beginning with a '#' are comments, and the script ignores them. __.__..___ ___._.____ ____.___.. _._______. ____._____ ..__...___ ____._____ ___...____ __.._..___ _..___..__

+++

The following two scripts are by Mark Moraes of the University of Toronto. See the file Moraes-COPYRIGHT for permissions and restrictions. This file is included in the combined HTML/source tarball of the ABS Guide.

Example A-12. behead: Removing mail and news message headers

#! /bin/sh # Strips off the header from a mail/News message i.e. till the first # empty line. # Author: Mark Moraes, University of Toronto # See the included file "Moraes-COPYRIGHT" for copyright info. # ==> These comments added by author of this document. if [ $# -eq 0 ]; then # ==> If no command line args present, then works on file redirected to stdin. sed -e '1,/^$/d' -e '/^[ ]*$/d' # --> Delete empty lines and all lines until # --> first one beginning with white space. else # ==> If command line args present, then work on files named. for i do sed -e '1,/^$/d' -e '/^[ ]*$/d' $i # --> Ditto, as above. done fi # ==> Exercise: Add error checking and other options. # ==> # ==> Note that the small sed script repeats, except for the arg passed. # ==> Does it make sense to embed it in a function? Why or why not?

Example A-13. ftpget: Downloading files via ftp

#! /bin/sh # $Id: ftpget,v 1.2 91/05/07 21:15:43 moraes Exp $ # Script to perform batch anonymous ftp. Essentially converts a list of # of command line arguments into input to ftp. # ==> This script is nothing but a shell wrapper around "ftp" . . . # Simple, and quick - written as a companion to ftplist # -h specifies the remote host (default prep.ai.mit.edu) # -d specifies the remote directory to cd to - you can provide a sequence # of -d options - they will be cd'ed to in turn. If the paths are relative, # make sure you get the sequence right. Be careful with relative paths - # there are far too many symlinks nowadays. # (default is the ftp login directory) # -v turns on the verbose option of ftp, and shows all responses from the # ftp server. # -f remotefile[:localfile] gets the remote file into localfile # -m pattern does an mget with the specified pattern. Remember to quote # shell characters. # -c does a local cd to the specified directory # For example, # ftpget -h expo.lcs.mit.edu -d contrib -f xplaces.shar:xplaces.sh \ # -d ../pub/R3/fixes -c ~/fixes -m 'fix*' # will get xplaces.shar from ~ftp/contrib on expo.lcs.mit.edu, and put it # in xplaces.sh in the current working directory, and get all fixes from # ~ftp/pub/R3/fixes and put them in the ~/fixes directory. # Obviously, the sequence of the options is important, since the equivalent # commands are executed by ftp in corresponding order # # Mark Moraes <moraes@csri.toronto.edu>, Feb 1, 1989 # # ==> These comments added by author of this document. # PATH=/local/bin:/usr/ucb:/usr/bin:/bin # export PATH # ==> Above 2 lines from original script probably superfluous. E_BADARGS=65 TMPFILE=/tmp/ftp.$$ # ==> Creates temp file, using process id of script ($$) # ==> to construct filename. SITE=`domainname`.toronto.edu # ==> 'domainname' similar to 'hostname' # ==> May rewrite this to parameterize this for general use. usage="Usage: $0 [-h remotehost] [-d remotedirectory]... \ [-f remfile:localfile]... [-c localdirectory] [-m filepattern] [-v]" ftpflags="-i -n" verbflag= set -f # So we can use globbing in -m set x `getopt vh:d:c:m:f: $*` if [ $? != 0 ]; then echo $usage exit $E_BADARGS fi shift trap 'rm -f ${TMPFILE} ; exit' 0 1 2 3 15 # ==> Signals: HUP INT (Ctl-C) QUIT TERM # ==> Delete tempfile in case of abnormal exit from script. echo "user anonymous ${USER-gnu}@${SITE} > ${TMPFILE}" # ==> Added quotes (recommended in complex echoes). echo binary >> ${TMPFILE} for i in $* # ==> Parse command line args. do case $i in -v) verbflag=-v; echo hash >> ${TMPFILE}; shift;; -h) remhost=$2; shift 2;; -d) echo cd $2 >> ${TMPFILE}; if [ x${verbflag} != x ]; then echo pwd >> ${TMPFILE}; fi; shift 2;; -c) echo lcd $2 >> ${TMPFILE}; shift 2;; -m) echo mget "$2" >> ${TMPFILE}; shift 2;; -f) f1=`expr "$2" : "\([^:]*\).*"`; f2=`expr "$2" : "[^:]*:\(.*\)"`; echo get ${f1} ${f2} >> ${TMPFILE}; shift 2;; --) shift; break;; esac # ==> 'lcd' and 'mget' are ftp commands. See "man ftp" . . . done if [ $# -ne 0 ]; then echo $usage exit $E_BADARGS # ==> Changed from "exit 2" to conform with style standard. fi if [ x${verbflag} != x ]; then ftpflags="${ftpflags} -v" fi if [ x${remhost} = x ]; then remhost=prep.ai.mit.edu # ==> Change to match appropriate ftp site. fi echo quit >> ${TMPFILE} # ==> All commands saved in tempfile. ftp ${ftpflags} ${remhost} < ${TMPFILE} # ==> Now, tempfile batch processed by ftp. rm -f ${TMPFILE} # ==> Finally, tempfile deleted (you may wish to copy it to a logfile). # ==> Exercises: # ==> --------- # ==> 1) Add error checking. # ==> 2) Add bells & whistles. # See the included file "Moraes-COPYRIGHT" for copyright info. #+ on this script.

+

Antek Sawicki contributed the following script, which makes very clever use of the parameter substitution operators discussed in Section 9.3.

Example A-14. password: Generating random 8-character passwords

#!/bin/bash # May need to be invoked with #!/bin/bash2 on older machines. # # Random password generator for Bash 2.x + #+ by Antek Sawicki <tenox@tenox.tc>, #+ who generously gave usage permission to the ABS Guide author. # # ==> Comments added by document author ==> MATRIX="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz" # ==> Password will consist of alphanumeric characters. LENGTH="8" # ==> May change 'LENGTH' for longer password. while [ "${n:=1}" -le "$LENGTH" ] # ==> Recall that := is "default substitution" operator. # ==> So, if 'n' has not been initialized, set it to 1. do PASS="$PASS${MATRIX:$(($RANDOM%${#MATRIX})):1}" # ==> Very clever, but tricky. # ==> Starting from the innermost nesting... # ==> ${#MATRIX} returns length of array MATRIX. # ==> $RANDOM%${#MATRIX} returns random number between 1 # ==> and [length of MATRIX] - 1. # ==> ${MATRIX:$(($RANDOM%${#MATRIX})):1} # ==> returns expansion of MATRIX at random position, by length 1. # ==> See {var:pos:len} parameter substitution in Chapter 9. # ==> and the associated examples. # ==> PASS=... simply pastes this result onto previous PASS (concatenation). # ==> To visualize this more clearly, uncomment the following line # echo "$PASS" # ==> to see PASS being built up, # ==> one character at a time, each iteration of the loop. let n+=1 # ==> Increment 'n' for next pass. done echo "$PASS" # ==> Or, redirect to a file, as desired. exit 0

+

James R. Van Zandt contributed this script which uses named pipes and, in his words, "really exercises quoting and escaping."

Example A-15. fifo: Making daily backups, using named pipes

#!/bin/bash # ==> Script by James R. Van Zandt, and used here with his permission. # ==> Comments added by author of this document. HERE=`uname -n` # ==> hostname THERE=bilbo echo "starting remote backup to $THERE at `date +%r`" # ==> `date +%r` returns time in 12-hour format, i.e. "08:08:34 PM". # make sure /pipe really is a pipe and not a plain file rm -rf /pipe mkfifo /pipe # ==> Create a "named pipe", named "/pipe" ... # ==> 'su xyz' runs commands as user "xyz". # ==> 'ssh' invokes secure shell (remote login client). su xyz -c "ssh $THERE \"cat > /home/xyz/backup/${HERE}-daily.tar.gz\" < /pipe"& cd / tar -czf - bin boot dev etc home info lib man root sbin share usr var > /pipe # ==> Uses named pipe, /pipe, to communicate between processes: # ==> 'tar/gzip' writes to /pipe and 'ssh' reads from /pipe. # ==> The end result is this backs up the main directories, from / on down. # ==> What are the advantages of a "named pipe" in this situation, # ==>+ as opposed to an "anonymous pipe", with |? # ==> Will an anonymous pipe even work here? # ==> Is it necessary to delete the pipe before exiting the script? # ==> How could that be done? exit 0

+

Stéphane Chazelas used the following script to demonstrate generating prime numbers without arrays.

Example A-16. Generating prime numbers using the modulo operator

#!/bin/bash # primes.sh: Generate prime numbers, without using arrays. # Script contributed by Stephane Chazelas. # This does authorsnote.html endnotes.html use the classic "Sieve of Eratosthenes" algorithm, #+ but instead the more intuitive method of testing each candidate number #+ for factors (divisors), using the "%" modulo operator. LIMIT=1000 # Primes, 2 ... 1000. Primes() { (( n = $1 + 1 )) # Bump to next integer. shift # Next parameter in list. # echo "_n=$n i=$i_" if (( n == LIMIT )) then echo $* return fi for i; do # "i" set to "@", previous values of $n. # echo "-n=$n i=$i-" (( i aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html i > n )) && break # Optimization. (( n % i )) && continue # Sift out non-primes using modulo operator. Primes $n $@ # Recursion inside loop. return done Primes $n $@ $n # Recursion outside loop. # Successively accumulate positional parameters. # "$@" is the accumulating list of primes. } Primes 1 exit $? # Pipe output of the script to 'fmt' for prettier printing. # Uncomment lines 16 and 24 to help figure out what is going on. # Compare the speed of this algorithm for generating primes #+ with the Sieve of Eratosthenes (ex68.sh). # Exercise: Rewrite this script without recursion, for faster execution.

+

Rick Boivie's revision of Jordi Sanfeliu's tree script.

Example A-17. tree: Displaying a directory tree

#!/bin/bash # tree.sh # Written by Rick Boivie. # Used with permission. # This is a revised and simplified version of a script #+ by Jordi Sanfeliu (and patched by Ian Kjos). # This script replaces the earlier version used in #+ previous releases of the Advanced Bash Scripting Guide. # ==> Comments added by the author of this document. search () { for dir in `echo *` # ==> `echo *` lists all the files in current working directory, #+ ==> without line breaks. # ==> Similar effect to for dir in aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html # ==> but "dir in `echo *`" will not handle filenames with blanks. do if [ -d "$dir" ] ; then # ==> If it is a directory (-d)... zz=0 # ==> Temp variable, keeping track of directory level. while [ $zz != $1 ] # Keep track of inner nested loop. do echo -n "| " # ==> Display vertical connector symbol, # ==> with 2 spaces & no line feed in order to indent. zz=`expr $zz + 1` # ==> Increment zz. done if [ -L "$dir" ] ; then # ==> If directory is a symbolic link... echo "+---$dir" `ls -l $dir | sed 's/^.*'$dir' //'` # ==> Display horiz. connector and list directory name, but... # ==> delete date/time part of long listing. else echo "+---$dir" # ==> Display horizontal connector symbol... # ==> and print directory name. numdirs=`expr $numdirs + 1` # ==> Increment directory count. if cd "$dir" ; then # ==> If can move to subdirectory... search `expr $1 + 1` # with recursion ;-) # ==> Function calls itself. cd .. fi fi fi done } if [ $# != 0 ] ; then cd $1 # move to indicated directory. #else # stay in current directory fi echo "Initial directory = `pwd`" numdirs=0 search 0 echo "Total directories = $numdirs" exit 0

Patsie's version of a directory tree script.

Example A-18. tree2: Alternate directory tree script

#!/bin/bash # tree2.sh # Lightly modified/reformatted by ABS Guide author. # Included in ABS Guide with permission of script author (thanks!). ## Recursive file/dirsize checking script, by Patsie ## ## This script builds a list of files/directories and their size (du -akx) ## and processes this list to a human readable tree shape ## The 'du -akx' is only as good as the permissions the owner has. ## So preferably run as root* to get the best results, or use only on ## directories for which you have read permissions. Anything you can't ## read is not in the list. #* ABS Guide author advises caution when running scripts as root! ########## THIS IS CONFIGURABLE ########## TOP=5 # Top 5 biggest (sub)directories. MAXRECURS=5 # Max 5 subdirectories/recursions deep. E_BL=80 # Blank line already returned. E_DIR=81 # Directory not specified. ########## DON'T CHANGE ANYTHING BELOW THIS LINE ########## PID=$$ # Our own process ID. SELF=`basename $0` # Our own program name. TMP="/tmp/${SELF}.${PID}.tmp" # Temporary 'du' result. # Convert number to dotted thousand. function dot { echo " $*" | sed -e :a -e 's/\(.*[0-9]\)\([0-9]\{3\}\)/\1,\2/;ta' | tail -c 12; } # Usage: tree <recursion> <indent prefix> <min size> <directory> function tree { recurs="$1" # How deep nested are we? prefix="$2" # What do we display before file/dirname? minsize="$3" # What is the minumum file/dirsize? dirname="$4" # Which directory are we checking? # Get ($TOP) biggest subdirs/subfiles from TMP file. LIST=`egrep "[[:space:]]${dirname}/[^/]*$" "$TMP" | awk '{if($1>'$minsize') print;}' | sort -nr | head -$TOP` [ -z "$LIST" ] && return # Empty list, then go back. cnt=0 num=`echo "$LIST" | wc -l` # How many entries in the list. ## Main loop echo "$LIST" | while read size name; do ((cnt+=1)) # Count entry number. bname=`basename "$name"` # We only need a basename of the entry. [ -d "$name" ] && bname="$bname/" # If it's a directory, append a slash. echo "`dot $size`$prefix +-$bname" # Display the result. # Call ourself recursively if it's a directory #+ and we're not nested too deep ($MAXRECURS). # The recursion goes up: $((recurs+1)) # The prefix gets a space if it's the last entry, #+ or a pipe if there are more entries. # The minimum file/dirsize becomes #+ a tenth of his parent: $((size/10)). # Last argument is the full directory name to check. if [ -d "$name" -a $recurs -lt $MAXRECURS ]; then [ $cnt -lt $num ] \ || (tree $((recurs+1)) "$prefix " $((size/10)) "$name") \ && (tree $((recurs+1)) "$prefix |" $((size/10)) "$name") fi done [ $? -eq 0 ] && echo " $prefix" # Every time we jump back add a 'blank' line. return $E_BL # We return 80 to tell we added a blank line already. } ### ### ### main program ### ### ### rootdir="$@" [ -d "$rootdir" ] || { echo "$SELF: Usage: $SELF <directory>" >&2; exit $E_DIR; } # We should be called with a directory name. echo "Building inventory list, please wait ..." # Show "please wait" message. du -akx "$rootdir" 1>"$TMP" 2>/dev/null # Build a temporary list of all files/dirs and their size. size=`tail -1 "$TMP" | awk '{print $1}'` # What is our rootdirectory's size? echo "`dot $size` $rootdir" # Display rootdirectory's entry. tree 0 "" 0 "$rootdir" # Display the tree below our rootdirectory. rm "$TMP" 2>/dev/null # Clean up TMP file. exit $?

Noah Friedman permitted use of his string function script. It essentially reproduces some of the C-library string manipulation functions.

Example A-19. string functions: C-style string functions

#!/bin/bash # string.bash --- bash emulation of string(3) library routines # Author: Noah Friedman <friedman@prep.ai.mit.edu> # ==> Used with his kind permission in this document. # Created: 1992-07-01 # Last modified: 1993-09-29 # Public domain # Conversion to bash v2 syntax done by Chet Ramey # Commentary: # Code: #:docstring strcat: # Usage: strcat s1 s2 # # Strcat appends the value of variable s2 to variable s1. # # Example: # a="foo" # b="bar" # strcat a b # echo $a # => foobar # #:end docstring: ###;;;autoload ==> Autoloading of function commented out. function strcat () { local s1_val s2_val s1_val=${!1} # indirect variable expansion s2_val=${!2} eval "$1"=\'"${s1_val}${s2_val}"\' # ==> eval $1='${s1_val}${s2_val}' avoids problems, # ==> if one of the variables contains a single quote. } #:docstring strncat: # Usage: strncat s1 s2 $n # # Line strcat, but strncat appends a maximum of n characters from the value # of variable s2. It copies fewer if the value of variabl s2 is shorter # than n characters. Echoes result on stdout. # # Example: # a=foo # b=barbaz # strncat a b 3 # echo $a # => foobar # #:end docstring: ###;;;autoload function strncat () { local s1="$1" local s2="$2" local -i n="$3" local s1_val s2_val s1_val=${!s1} # ==> indirect variable expansion s2_val=${!s2} if [ ${#s2_val} -gt ${n} ]; then s2_val=${s2_val:0:$n} # ==> substring extraction fi eval "$s1"=\'"${s1_val}${s2_val}"\' # ==> eval $1='${s1_val}${s2_val}' avoids problems, # ==> if one of the variables contains a single quote. } #:docstring strcmp: # Usage: strcmp $s1 $s2 # # Strcmp compares its arguments and returns an integer less than, equal to, # or greater than zero, depending on whether string s1 is lexicographically # less than, equal to, or greater than string s2. #:end docstring: ###;;;autoload function strcmp () { [ "$1" = "$2" ] && return 0 [ "${1}" '<' "${2}" ] > /dev/null && return -1 return 1 } #:docstring strncmp: # Usage: strncmp $s1 $s2 $n # # Like strcmp, but makes the comparison by examining a maximum of n # characters (n less than or equal to zero yields equality). #:end docstring: ###;;;autoload function strncmp () { if [ -z "${3}" -o "${3}" -le "0" ]; then return 0 fi if [ ${3} -ge ${#1} -a ${3} -ge ${#2} ]; then strcmp "$1" "$2" return $? else s1=${1:0:$3} s2=${2:0:$3} strcmp $s1 $s2 return $? fi } #:docstring strlen: # Usage: strlen s # # Strlen returns the number of characters in string literal s. #:end docstring: ###;;;autoload function strlen () { eval echo "\${#${1}}" # ==> Returns the length of the value of the variable # ==> whose name is passed as an argument. } #:docstring strspn: # Usage: strspn $s1 $s2 # # Strspn returns the length of the maximum initial segment of string s1, # which consists entirely of characters from string s2. #:end docstring: ###;;;autoload function strspn () { # Unsetting IFS allows whitespace to be handled as normal chars. local IFS= local result="${1%%[!${2}]*}" echo ${#result} } #:docstring strcspn: # Usage: strcspn $s1 $s2 # # Strcspn returns the length of the maximum initial segment of string s1, # which consists entirely of characters not from string s2. #:end docstring: ###;;;autoload function strcspn () { # Unsetting IFS allows whitspace to be handled as normal chars. local IFS= local result="${1%%[${2}]*}" echo ${#result} } #:docstring strstr: # Usage: strstr s1 s2 # # Strstr echoes a substring starting at the first occurrence of string s2 in # string s1, or nothing if s2 does not occur in the string. If s2 points to # a string of zero length, strstr echoes s1. #:end docstring: ###;;;autoload function strstr () { # if s2 points to a string of zero length, strstr echoes s1 [ ${#2} -eq 0 ] && { echo "$1" ; return 0; } # strstr echoes nothing if s2 does not occur in s1 case "$1" in *$2*) ;; *) return 1;; esac # use the pattern matching code to strip off the match and everything # following it first=${1/$2*/} # then strip off the first unmatched portion of the string echo "${1##$first}" } #:docstring strtok: # Usage: strtok s1 s2 # # Strtok considers the string s1 to consist of a sequence of zero or more # text tokens separated by spans of one or more characters from the # separator string s2. The first call (with a non-empty string s1 # specified) echoes a string consisting of the first token on stdout. The # function keeps track of its position in the string s1 between separate # calls, so that subsequent calls made with the first argument an empty # string will work through the string immediately following that token. In # this way subsequent calls will work through the string s1 until no tokens # remain. The separator string s2 may be different from call to call. # When no token remains in s1, an empty value is echoed on stdout. #:end docstring: ###;;;autoload function strtok () { : } #:docstring strtrunc: # Usage: strtrunc $n $s1 {$s2} {$...} # # Used by many functions like strncmp to truncate arguments for comparison. # Echoes the first n characters of each string s1 s2 ... on stdout. #:end docstring: ###;;;autoload function strtrunc () { n=$1 ; shift for z; do echo "${z:0:$n}" done } # provide string # string.bash ends here # ========================================================================== # # ==> Everything below here added by the document author. # ==> Suggested use of this script is to delete everything below here, # ==> and "source" this file into your own scripts. # strcat string0=one string1=two echo echo "Testing \"strcat\" function:" echo "Original \"string0\" = $string0" echo "\"string1\" = $string1" strcat string0 string1 echo "New \"string0\" = $string0" echo # strlen echo echo "Testing \"strlen\" function:" str=123456789 echo "\"str\" = $str" echo -n "Length of \"str\" = " strlen str echo # Exercise: # -------- # Add code to test all the other string functions above. exit 0

Michael Zick's complex array example uses the md5sum check sum command to encode directory information.

Example A-20. Directory information

#! /bin/bash # directory-info.sh # Parses and lists directory information. # NOTE: Change lines 273 and 353 per "README" file. # Michael Zick is the author of this script. # Used here with his permission. # Controls # If overridden by command arguments, they must be in the order: # Arg1: "Descriptor Directory" # Arg2: "Exclude Paths" # Arg3: "Exclude Directories" # # Environment Settings override Defaults. # Command arguments override Environment Settings. # Default location for content addressed file descriptors. MD5UCFS=${1:-${MD5UCFS:-'/tmpfs/ucfs'}} # Directory paths never to list or enter declare -a \ EXCLUDE_PATHS=${2:-${EXCLUDE_PATHS:-'(/proc /dev /devfs /tmpfs)'}} # Directories never to list or enter declare -a \ EXCLUDE_DIRS=${3:-${EXCLUDE_DIRS:-'(ucfs lost+found tmp wtmp)'}} # Files never to list or enter declare -a \ EXCLUDE_FILES=${3:-${EXCLUDE_FILES:-'(core "Name with Spaces")'}} # Here document used as a comment block. : <<LSfieldsDoc # # # # # List Filesystem Directory Information # # # # # # # ListDirectory "FileGlob" "Field-Array-Name" # or # ListDirectory -of "FileGlob" "Field-Array-Filename" # '-of' meaning 'output to filename' # # # # # String format description based on: ls (GNU fileutils) version 4.0.36 Produces a line (or more) formatted: inode permissions hard-links owner group ... 32736 -rw------- 1 mszick mszick size day month date hh:mm:ss year path 2756608 Sun Apr 20 08:53:06 2003 /home/mszick/core Unless it is formatted: inode permissions hard-links owner group ... 266705 crw-rw---- 1 root uucp major minor day month date hh:mm:ss year path 4, 68 Sun Apr 20 09:27:33 2003 /dev/ttyS4 NOTE: that pesky comma after the major number NOTE: the 'path' may be multiple fields: /home/mszick/core /proc/982/fd/0 -> /dev/null /proc/982/fd/1 -> /home/mszick/.xsession-errors /proc/982/fd/13 -> /tmp/tmpfZVVOCs (deleted) /proc/982/fd/7 -> /tmp/kde-mszick/ksycoca /proc/982/fd/8 -> socket:[11586] /proc/982/fd/9 -> pipe:[11588] If that isn't enough to keep your parser guessing, either or both of the path components may be relative: ../Built-Shared -> Built-Static ../linux-2.4.20.tar.bz2 -> ../../../SRCS/linux-2.4.20.tar.bz2 The first character of the 11 (10?) character permissions field: 's' Socket 'd' Directory 'b' Block device 'c' Character device 'l' Symbolic link NOTE: Hard links not marked - test for identical inode numbers on identical filesystems. All information about hard linked files are shared, except for the names and the name's location in the directory system. NOTE: A "Hard link" is known as a "File Alias" on some systems. '-' An undistingushed file Followed by three groups of letters for: User, Group, Others Character 1: '-' Not readable; 'r' Readable Character 2: '-' Not writable; 'w' Writable Character 3, User and Group: Combined execute and special '-' Not Executable, Not Special 'x' Executable, Not Special 's' Executable, Special 'S' Not Executable, Special Character 3, Others: Combined execute and sticky (tacky?) '-' Not Executable, Not Tacky 'x' Executable, Not Tacky 't' Executable, Tacky 'T' Not Executable, Tacky Followed by an access indicator Haven't tested this one, it may be the eleventh character or it may generate another field ' ' No alternate access '+' Alternate access LSfieldsDoc ListDirectory() { local -a T local -i of=0 # Default return in variable # OLD_IFS=$IFS # Using BASH default ' \t\n' case "$#" in 3) case "$1" in -of) of=1 ; shift ;; aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html ) return 1 ;; esac ;; 2) : ;; # Poor man's "continue" *) return 1 ;; esac # NOTE: the (ls) command is NOT quoted (") T=( $(ls --inode --ignore-backups --almost-all --directory \ --full-time --color=none --time=status --sort=none \ --format=long $1) ) case $of in # Assign T back to the array whose name was passed as $2 0) eval $2=\( \"\$\{T\[@\]\}\" \) ;; # Write T into filename passed as $2 1) echo "${T[@]}" > "$2" ;; esac return 0 } # # # # # Is that string a legal number? # # # # # # # IsNumber "Var" # # # # # There has to be a better way, sigh... IsNumber() { local -i int if [ $# -eq 0 ] then return 1 else (let int=$1) 2>/dev/null return $? # Exit status of the let thread fi } # # # # # Index Filesystem Directory Information # # # # # # # IndexList "Field-Array-Name" "Index-Array-Name" # or # IndexList -if Field-Array-Filename Index-Array-Name # IndexList -of Field-Array-Name Index-Array-Filename # IndexList -if -of Field-Array-Filename Index-Array-Filename # # # # # : <<IndexListDoc Walk an array of directory fields produced by ListDirectory Having suppressed the line breaks in an otherwise line oriented report, build an index to the array element which starts each line. Each line gets two index entries, the first element of each line (inode) and the element that holds the pathname of the file. The first index entry pair (Line-Number==0) are informational: Index-Array-Name[0] : Number of "Lines" indexed Index-Array-Name[1] : "Current Line" pointer into Index-Array-Name The following index pairs (if any) hold element indexes into the Field-Array-Name per: Index-Array-Name[Line-Number aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html 2] : The "inode" field element. NOTE: This distance may be either +11 or +12 elements. Index-Array-Name[(Line-Number aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html 2) + 1] : The "pathname" element. NOTE: This distance may be a variable number of elements. Next line index pair for Line-Number+1. IndexListDoc IndexList() { local -a LIST # Local of listname passed local -a -i INDEX=( 0 0 ) # Local of index to return local -i Lidx Lcnt local -i if=0 of=0 # Default to variable names case "$#" in # Simplistic option testing 0) return 1 ;; 1) return 1 ;; 2) : ;; # Poor man's continue 3) case "$1" in -if) if=1 ;; -of) of=1 ;; aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html ) return 1 ;; esac ; shift ;; 4) if=1 ; of=1 ; shift ; shift ;; *) return 1 esac # Make local copy of list case "$if" in 0) eval LIST=\( \"\$\{$1\[@\]\}\" \) ;; 1) LIST=( $(cat $1) ) ;; esac # Grok (grope?) the array Lcnt=${#LIST[@]} Lidx=0 until (( Lidx >= Lcnt )) do if IsNumber ${LIST[$Lidx]} then local -i inode name local ft inode=Lidx local m=${LIST[$Lidx+2]} # Hard Links field ft=${LIST[$Lidx+1]:0:1} # Fast-Stat case $ft in b) ((Lidx+=12)) ;; # Block device c) ((Lidx+=12)) ;; # Character device *) ((Lidx+=11)) ;; # Anything else esac name=Lidx case $ft in -) ((Lidx+=1)) ;; # The easy one b) ((Lidx+=1)) ;; # Block device c) ((Lidx+=1)) ;; # Character device d) ((Lidx+=1)) ;; # The other easy one l) ((Lidx+=3)) ;; # At LEAST two more fields # A little more elegance here would handle pipes, #+ sockets, deleted files - later. *) until IsNumber ${LIST[$Lidx]} || ((Lidx >= Lcnt)) do ((Lidx+=1)) done ;; # Not required esac INDEX[${#INDEX[*]}]=$inode INDEX[${#INDEX[*]}]=$name INDEX[0]=${INDEX[0]}+1 # One more "line" found # echo "Line: ${INDEX[0]} Type: $ft Links: $m Inode: \ # ${LIST[$inode]} Name: ${LIST[$name]}" else ((Lidx+=1)) fi done case "$of" in 0) eval $2=\( \"\$\{INDEX\[@\]\}\" \) ;; 1) echo "${INDEX[@]}" > "$2" ;; esac return 0 # What could go wrong? } # # # # # Content Identify File # # # # # # # DigestFile Input-Array-Name Digest-Array-Name # or # DigestFile -if Input-FileName Digest-Array-Name # # # # # # Here document used as a comment block. : <<DigestFilesDoc The key (no pun intended) to a Unified Content File System (UCFS) is to distinguish the files in the system based on their content. Distinguishing files by their name is just, so, 20th Century. The content is distinguished by computing a checksum of that content. This version uses the md5sum program to generate a 128 bit checksum representative of the file's contents. There is a chance that two files having different content might generate the same checksum using md5sum (or any checksum). Should that become a problem, then the use of md5sum can be replace by a cyrptographic signature. But until then... The md5sum program is documented as outputting three fields (and it does), but when read it appears as two fields (array elements). This is caused by the lack of whitespace between the second and third field. So this function gropes the md5sum output and returns: [0] 32 character checksum in hexidecimal (UCFS filename) [1] Single character: ' ' text file, '*' binary file [2] Filesystem (20th Century Style) name Note: That name may be the character '-' indicating STDIN read. DigestFilesDoc DigestFile() { local if=0 # Default, variable name local -a T1 T2 case "$#" in 3) case "$1" in -if) if=1 ; shift ;; aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html ) return 1 ;; esac ;; 2) : ;; # Poor man's "continue" *) return 1 ;; esac case $if in 0) eval T1=\( \"\$\{$1\[@\]\}\" \) T2=( $(echo ${T1[@]} | md5sum -) ) ;; 1) T2=( $(md5sum $1) ) ;; esac case ${#T2[@]} in 0) return 1 ;; 1) return 1 ;; 2) case ${T2[1]:0:1} in # SanScrit-2.0.5 \*) T2[${#T2[@]}]=${T2[1]:1} T2[1]=\* ;; *) T2[${#T2[@]}]=${T2[1]} T2[1]=" " ;; esac ;; 3) : ;; # Assume it worked *) return 1 ;; esac local -i len=${#T2[0]} if [ $len -ne 32 ] ; then return 1 ; fi eval $2=\( \"\$\{T2\[@\]\}\" \) } # # # # # Locate File # # # # # # # LocateFile [-l] FileName Location-Array-Name # or # LocateFile [-l] -of FileName Location-Array-FileName # # # # # # A file location is Filesystem-id and inode-number # Here document used as a comment block. : <<StatFieldsDoc Based on stat, version 2.2 stat -t and stat -lt fields [0] name [1] Total size File - number of bytes Symbolic link - string length of pathname [2] Number of (512 byte) blocks allocated [3] File type and Access rights (hex) [4] User ID of owner [5] Group ID of owner [6] Device number [7] Inode number [8] Number of hard links [9] Device type (if inode device) Major [10] Device type (if inode device) Minor [11] Time of last access May be disabled in 'mount' with noatime atime of files changed by exec, read, pipe, utime, mknod (mmap?) atime of directories changed by addition/deletion of files [12] Time of last modification mtime of files changed by write, truncate, utime, mknod mtime of directories changed by addtition/deletion of files [13] Time of last change ctime reflects time of changed inode information (owner, group permissions, link count -*-*- Per: Return code: 0 Size of array: 14 Contents of array Element 0: /home/mszick Element 1: 4096 Element 2: 8 Element 3: 41e8 Element 4: 500 Element 5: 500 Element 6: 303 Element 7: 32385 Element 8: 22 Element 9: 0 Element 10: 0 Element 11: 1051221030 Element 12: 1051214068 Element 13: 1051214068 For a link in the form of linkname -> realname stat -t linkname returns the linkname (link) information stat -lt linkname returns the realname information stat -tf and stat -ltf fields [0] name [1] ID-0? # Maybe someday, but Linux stat structure [2] ID-0? # does not have either LABEL nor UUID # fields, currently information must come # from file-system specific utilities These will be munged into: [1] UUID if possible [2] Volume Label if possible Note: 'mount -l' does return the label and could return the UUID [3] Maximum length of filenames [4] Filesystem type [5] Total blocks in the filesystem [6] Free blocks [7] Free blocks for non-root user(s) [8] Block size of the filesystem [9] Total inodes [10] Free inodes -*-*- Per: Return code: 0 Size of array: 11 Contents of array Element 0: /home/mszick Element 1: 0 Element 2: 0 Element 3: 255 Element 4: ef53 Element 5: 2581445 Element 6: 2277180 Element 7: 2146050 Element 8: 4096 Element 9: 1311552 Element 10: 1276425 StatFieldsDoc # LocateFile [-l] FileName Location-Array-Name # LocateFile [-l] -of FileName Location-Array-FileName LocateFile() { local -a LOC LOC1 LOC2 local lk="" of=0 case "$#" in 0) return 1 ;; 1) return 1 ;; 2) : ;; *) while (( "$#" > 2 )) do case "$1" in -l) lk=-1 ;; -of) of=1 ;; *) return 1 ;; esac shift done ;; esac # More Sanscrit-2.0.5 # LOC1=( $(stat -t $lk $1) ) # LOC2=( $(stat -tf $lk $1) ) # Uncomment above two lines if system has "stat" command installed. LOC=( ${LOC1[@]:0:1} ${LOC1[@]:3:11} ${LOC2[@]:1:2} ${LOC2[@]:4:1} ) case "$of" in 0) eval $2=\( \"\$\{LOC\[@\]\}\" \) ;; 1) echo "${LOC[@]}" > "$2" ;; esac return 0 # Which yields (if you are lucky, and have "stat" installed) # -*-*- Location Discriptor -*-*- # Return code: 0 # Size of array: 15 # Contents of array # Element 0: /home/mszick 20th Century name # Element 1: 41e8 Type and Permissions # Element 2: 500 User # Element 3: 500 Group # Element 4: 303 Device # Element 5: 32385 inode # Element 6: 22 Link count # Element 7: 0 Device Major # Element 8: 0 Device Minor # Element 9: 1051224608 Last Access # Element 10: 1051214068 Last Modify # Element 11: 1051214068 Last Status # Element 12: 0 UUID (to be) # Element 13: 0 Volume Label (to be) # Element 14: ef53 Filesystem type } # And then there was some test code ListArray() # ListArray Name { local -a Ta eval Ta=\( \"\$\{$1\[@\]\}\" \) echo echo "-*-*- List of Array -*-*-" echo "Size of array $1: ${#Ta[*]}" echo "Contents of array $1:" for (( i=0 ; i<${#Ta[*]} ; i++ )) do echo -e "\tElement $i: ${Ta[$i]}" done return 0 } declare -a CUR_DIR # For small arrays ListDirectory "${PWD}" CUR_DIR ListArray CUR_DIR declare -a DIR_DIG DigestFile CUR_DIR DIR_DIG echo "The new \"name\" (checksum) for ${CUR_DIR[9]} is ${DIR_DIG[0]}" declare -a DIR_ENT # BIG_DIR # For really big arrays - use a temporary file in ramdisk # BIG-DIR # ListDirectory -of "${CUR_DIR[11]}/*" "/tmpfs/junk2" ListDirectory "${CUR_DIR[11]}/*" DIR_ENT declare -a DIR_IDX # BIG-DIR # IndexList -if "/tmpfs/junk2" DIR_IDX IndexList DIR_ENT DIR_IDX declare -a IDX_DIG # BIG-DIR # DIR_ENT=( $(cat /tmpfs/junk2) ) # BIG-DIR # DigestFile -if /tmpfs/junk2 IDX_DIG DigestFile DIR_ENT IDX_DIG # Small (should) be able to parallize IndexList & DigestFile # Large (should) be able to parallize IndexList & DigestFile & the assignment echo "The \"name\" (checksum) for the contents of ${PWD} is ${IDX_DIG[0]}" declare -a FILE_LOC LocateFile ${PWD} FILE_LOC ListArray FILE_LOC exit 0

Stéphane Chazelas demonstrates object-oriented programming in a Bash script.

Example A-21. Object-oriented database

#!/bin/bash # obj-oriented.sh: Object-oriented programming in a shell script. # Script by Stephane Chazelas. # Important Note: # --------- ---- # If running this script under version 3 or later of Bash, #+ replace all periods in function names with a "legal" character, #+ for example, an underscore. person.new() # Looks almost like a class declaration in C++. { local obj_name=$1 name=$2 firstname=$3 birthdate=$4 eval "$obj_name.set_name() { eval \"$obj_name.get_name() { echo \$1 }\" }" eval "$obj_name.set_firstname() { eval \"$obj_name.get_firstname() { echo \$1 }\" }" eval "$obj_name.set_birthdate() { eval \"$obj_name.get_birthdate() { echo \$1 }\" eval \"$obj_name.show_birthdate() { echo \$(date -d \"1/1/1970 0:0:\$1 GMT\") }\" eval \"$obj_name.get_age() { echo \$(( (\$(date +%s) - \$1) / 3600 / 24 / 365 )) }\" }" $obj_name.set_name $name $obj_name.set_firstname $firstname $obj_name.set_birthdate $birthdate } echo person.new self Bozeman Bozo 101272413 # Create an instance of "person.new" (actually passing args to the function). self.get_firstname # Bozo self.get_name # Bozeman self.get_age # 28 self.get_birthdate # 101272413 self.show_birthdate # Sat Mar 17 20:13:33 MST 1973 echo # typeset -f #+ to see the created functions (careful, it scrolls off the page). exit 0

Mariusz Gniazdowski contributed a hash library for use in scripts.

Example A-22. Library of hash functions

# Hash: # Hash function library # Author: Mariusz Gniazdowski <mgniazd-at-gmail.com> # Date: 2005-04-07 # Functions making emulating hashes in Bash a little less painful. # Limitations: # aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html Only global variables are supported. # aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html Each hash instance generates one global variable per value. # aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html Variable names collisions are possible #+ if you define variable like __hash__hashname_key # aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html Keys must use chars that can be part of a Bash variable name #+ (no dashes, periods, etc.). # aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html The hash is created as a variable: # ... hashname_keyname # So if somone will create hashes like: # myhash_ + mykey = myhash__mykey # myhash + _mykey = myhash__mykey # Then there will be a collision. # (This should not pose a major problem.) Hash_config_varname_prefix=__hash__ # Emulates: hash[key]=value # # Params: # 1 - hash # 2 - key # 3 - value function hash_set { eval "${Hash_config_varname_prefix}${1}_${2}=\"${3}\"" } # Emulates: value=hash[key] # # Params: # 1 - hash # 2 - key # 3 - value (name of global variable to set) function hash_get_into { eval "$3=\"\$${Hash_config_varname_prefix}${1}_${2}\"" } # Emulates: echo hash[key] # # Params: # 1 - hash # 2 - key # 3 - echo params (like -n, for example) function hash_echo { eval "echo $3 \"\$${Hash_config_varname_prefix}${1}_${2}\"" } # Emulates: hash1[key1]=hash2[key2] # # Params: # 1 - hash1 # 2 - key1 # 3 - hash2 # 4 - key2 function hash_copy { eval "${Hash_config_varname_prefix}${1}_${2}\ =\"\$${Hash_config_varname_prefix}${3}_${4}\"" } # Emulates: hash[keyN-1]=hash[key2]=...hash[key1] # # Copies first key to rest of keys. # # Params: # 1 - hash1 # 2 - key1 # 3 - key2 # . . . # N - keyN function hash_dup { local hashName="$1" keyName="$2" shift 2 until [ ${#} -le 0 ]; do eval "${Hash_config_varname_prefix}${hashName}_${1}\ =\"\$${Hash_config_varname_prefix}${hashName}_${keyName}\"" shift; done; } # Emulates: unset hash[key] # # Params: # 1 - hash # 2 - key function hash_unset { eval "unset ${Hash_config_varname_prefix}${1}_${2}" } # Emulates something similar to: ref=&hash[key] # # The reference is name of the variable in which value is held. # # Params: # 1 - hash # 2 - key # 3 - ref - Name of global variable to set. function hash_get_ref_into { eval "$3=\"${Hash_config_varname_prefix}${1}_${2}\"" } # Emulates something similar to: echo &hash[key] # # That reference is name of variable in which value is held. # # Params: # 1 - hash # 2 - key # 3 - echo params (like -n for example) function hash_echo_ref { eval "echo $3 \"${Hash_config_varname_prefix}${1}_${2}\"" } # Emulates something similar to: $$hash[key](param1, param2, ...) # # Params: # 1 - hash # 2 - key # 3,4, ... - Function parameters function hash_call { local hash key hash=$1 key=$2 shift 2 eval "eval \"\$${Hash_config_varname_prefix}${hash}_${key} \\\"\\\$@\\\"\"" } # Emulates something similar to: isset(hash[key]) or hash[key]==NULL # # Params: # 1 - hash # 2 - key # Returns: # 0 - there is such key # 1 - there is no such key function hash_is_set { eval "if [[ \"\${${Hash_config_varname_prefix}${1}_${2}-a}\" = \"a\" && \"\${${Hash_config_varname_prefix}${1}_${2}-b}\" = \"b\" ]] then return 1; else return 0; fi" } # Emulates something similar to: # foreach($hash as $key => $value) { fun($key,$value); } # # It is possible to write different variations of this function. # Here we use a function call to make it as "generic" as possible. # # Params: # 1 - hash # 2 - function name function hash_foreach { local keyname oldIFS="$IFS" IFS=' ' for i in $(eval "echo \${!${Hash_config_varname_prefix}${1}_*}"); do keyname=$(eval "echo \${i##${Hash_config_varname_prefix}${1}_}") eval "$2 $keyname \"\$$i\"" done IFS="$oldIFS" } # NOTE: In lines 103 and 116, ampersand changed. # But, it doesn't matter, because these are comment lines anyhow.

Here is an example script using the foregoing hash library.

Example A-23. Colorizing text using hash functions

#!/bin/bash # hash-example.sh: Colorizing text. # Author: Mariusz Gniazdowski <mgniazd-at-gmail.com> . Hash.lib # Load the library of functions. hash_set colors red "\033[0;31m" hash_set colors blue "\033[0;34m" hash_set colors light_blue "\033[1;34m" hash_set colors light_red "\033[1;31m" hash_set colors cyan "\033[0;36m" hash_set colors light_green "\033[1;32m" hash_set colors light_gray "\033[0;37m" hash_set colors green "\033[0;32m" hash_set colors yellow "\033[1;33m" hash_set colors light_purple "\033[1;35m" hash_set colors purple "\033[0;35m" hash_set colors reset_color "\033[0;00m" # $1 - keyname # $2 - value try_colors() { echo -en "$2" echo "This line is $1." } hash_foreach colors try_colors hash_echo colors reset_color -en echo -e '\nLet us overwrite some colors with yellow.\n' # It's hard to read yellow text on some terminals. hash_dup colors yellow red light_green blue green light_gray cyan hash_foreach colors try_colors hash_echo colors reset_color -en echo -e '\nLet us delete them and try colors once more . . .\n' for i in red light_green blue green light_gray cyan; do hash_unset colors $i done hash_foreach colors try_colors hash_echo colors reset_color -en hash_set other txt "Other examples . . ." hash_echo other txt hash_get_into other txt text echo $text hash_set other my_fun try_colors hash_call other my_fun purple "`hash_echo colors purple`" hash_echo colors reset_color -en echo; echo "Back to normal?"; echo exit $? # On some terminals, the "light" colors print in bold, # and end up looking darker than the normal ones. # Why is this?

An example illustrating the mechanics of hashing, but from a different point of view.

Example A-24. More on hash functions

#!/bin/bash # $Id: ha.sh,v 1.2 2005/04/21 23:24:26 oliver Exp $ # Copyright 2005 Oliver Beckstein # Released under the GNU Public License # Author of script granted permission for inclusion in ABS Guide. # (Thank you!) #---------------------------------------------------------------- # pseudo hash based on indirect parameter expansion # API: access through functions: # # create the hash: # # newhash Lovers # # add entries (note single quotes for spaces) # # addhash Lovers Tristan Isolde # addhash Lovers 'Romeo Montague' 'Juliet Capulet' # # access value by key # # gethash Lovers Tristan ----> Isolde # # show all keys # # keyshash Lovers ----> 'Tristan' 'Romeo Montague' # # # Convention: instead of perls' foo{bar} = boing' syntax, # use # '_foo_bar=boing' (two underscores, no spaces) # # 1) store key in _NAME_keys[] # 2) store value in _NAME_values[] using the same integer index # The integer index for the last entry is _NAME_ptr # # NOTE: No error or sanity checks, just bare bones. function _inihash () { # private function # call at the beginning of each procedure # defines: _keys _values _ptr # # Usage: _inihash NAME local name=$1 _keys=_${name}_keys _values=_${name}_values _ptr=_${name}_ptr } function newhash () { # Usage: newhash NAME # NAME should not contain spaces or dots. # Actually: it must be a legal name for a Bash variable. # We rely on Bash automatically recognising arrays. local name=$1 local _keys _values _ptr _inihash ${name} eval ${_ptr}=0 } function addhash () { # Usage: addhash NAME KEY 'VALUE with spaces' # arguments with spaces need to be quoted with single quotes '' local name=$1 k="$2" v="$3" local _keys _values _ptr _inihash ${name} #echo "DEBUG(addhash): ${_ptr}=${!_ptr}" eval let ${_ptr}=${_ptr}+1 eval "$_keys[${!_ptr}]=\"${k}\"" eval "$_values[${!_ptr}]=\"${v}\"" } function gethash () { # Usage: gethash NAME KEY # Returns boing # ERR=0 if entry found, 1 otherwise # That's not a proper hash -- #+ we simply linearly search through the keys. local name=$1 key="$2" local _keys _values _ptr local k v i found h _inihash ${name} # _ptr holds the highest index in the hash found=0 for i in $(seq 1 ${!_ptr}); do h="\${${_keys}[${i}]}" # Safer to do it in two steps, eval k=${h} #+ especially when quoting for spaces. if [ "${k}" = "${key}" ]; then found=1; break; fi done; [ ${found} = 0 ] && return 1; # else: i is the index that matches the key h="\${${_values}[${i}]}" eval echo "${h}" return 0; } function keyshash () { # Usage: keyshash NAME # Returns list of all keys defined for hash name. local name=$1 key="$2" local _keys _values _ptr local k i h _inihash ${name} # _ptr holds the highest index in the hash for i in $(seq 1 ${!_ptr}); do h="\${${_keys}[${i}]}" # Safer to do it in two steps, eval k=${h} #+ especially when quoting for spaces. echo -n "'${k}' " done; } # ----------------------------------------------------------------------- # Now, let's test it. # (Per comments at the beginning of the script.) newhash Lovers addhash Lovers Tristan Isolde addhash Lovers 'Romeo Montague' 'Juliet Capulet' # Output results. echo gethash Lovers Tristan # Isolde echo keyshash Lovers # 'Tristan' 'Romeo Montague' echo; echo exit 0 # Exercise: # -------- # Add error checks to the functions.

Now for a script that installs and mounts those cute USB keychain solid-state "hard drives."

Example A-25. Mounting USB keychain storage devices

#!/bin/bash # ==> usb.sh # ==> Script for mounting and installing pen/keychain USB storage devices. # ==> Runs as root at system startup (see below). # ==> # ==> Newer Linux distros (2004 or later) autodetect # ==> and install USB pen drives, and therefore don't need this script. # ==> But, it's still instructive. # This code is free software covered by GNU GPL license version 2 or above. # Please refer to http://www.gnu.org/ for the full license text. # # Some code lifted from usb-mount by Michael Hamilton's usb-mount (LGPL) #+ see http://users.actrix.co.nz/michael/usbmount.html # # INSTALL # ------- # Put this in /etc/hotplug/usb/diskonkey. # Then look in /etc/hotplug/usb.distmap, and copy all usb-storage entries #+ into /etc/hotplug/usb.usermap, substituting "usb-storage" for "diskonkey". # Otherwise this code is only run during the kernel module invocation/removal #+ (at least in my tests), which defeats the purpose. # # TODO # ---- # Handle more than one diskonkey device at one time (e.g. /dev/diskonkey1 #+ and /mnt/diskonkey1), etc. The biggest problem here is the handling in #+ devlabel, which I haven't yet tried. # # AUTHOR and SUPPORT # ------------------ # Konstantin Riabitsev, <icon linux duke edu>. # Send any problem reports to my email address at the moment. # # ==> Comments added by ABS Guide author. SYMLINKDEV=/dev/diskonkey MOUNTPOINT=/mnt/diskonkey DEVLABEL=/sbin/devlabel DEVLABELCONFIG=/etc/sysconfig/devlabel IAM=$0 ## # Functions lifted near-verbatim from usb-mount code. # function allAttachedScsiUsb { find /proc/scsi/ -path '/proc/scsi/usb-storage*' -type f | xargs grep -l 'Attached: Yes' } function scsiDevFromScsiUsb { echo $1 | awk -F"[-/]" '{ n=$(NF-1); print "/dev/sd" substr("abcdefghijklmnopqrstuvwxyz", n+1, 1) }' } if [ "${ACTION}" = "add" ] && [ -f "${DEVICE}" ]; then ## # lifted from usbcam code. # if [ -f /var/run/console.lock ]; then CONSOLEOWNER=`cat /var/run/console.lock` elif [ -f /var/lock/console.lock ]; then CONSOLEOWNER=`cat /var/lock/console.lock` else CONSOLEOWNER= fi for procEntry in $(allAttachedScsiUsb); do scsiDev=$(scsiDevFromScsiUsb $procEntry) # Some bug with usb-storage? # Partitions are not in /proc/partitions until they are accessed #+ somehow. /sbin/fdisk -l $scsiDev >/dev/null ## # Most devices have partitioning info, so the data would be on #+ /dev/sd?1. However, some stupider ones don't have any partitioning #+ and use the entire device for data storage. This tries to #+ guess semi-intelligently if we have a /dev/sda1 /dev/sdb1 and if not, then #+ it uses the entire device and hopes for the better. # if grep -q `basename $scsiDev`1 /proc/partitions; then part="$scsiDev""1" else part=$scsiDev fi ## # Change ownership of the partition to the console user so they can #+ mount it. # if [ ! -z "$CONSOLEOWNER" ]; then chown $CONSOLEOWNER:disk $part fi ## # This checks if we already have this UUID defined with devlabel. # If not, it then adds the device to the list. # prodid=`$DEVLABEL printid -d $part` if ! grep -q $prodid $DEVLABELCONFIG; then # cross our fingers and hope it works $DEVLABEL add -d $part -s $SYMLINKDEV 2>/dev/null fi ## # Check if the mount point exists and create if it doesn't. # if [ ! -e $MOUNTPOINT ]; then mkdir -p $MOUNTPOINT fi ## # Take care of /etc/fstab so mounting is easy. # if ! grep -q "^$SYMLINKDEV" /etc/fstab; then # Add an fstab entry echo -e \ "$SYMLINKDEV\t\t$MOUNTPOINT\t\tauto\tnoauto,owner,kudzu 0 0" \ >> /etc/fstab fi done if [ ! -z "$REMOVER" ]; then ## # Make sure this script is triggered on device removal. # mkdir -p `dirname $REMOVER` ln -s $IAM $REMOVER fi elif [ "${ACTION}" = "remove" ]; then ## # If the device is mounted, unmount it cleanly. # if grep -q "$MOUNTPOINT" /etc/mtab; then # unmount cleanly umount -l $MOUNTPOINT fi ## # Remove it from /etc/fstab if it's there. # if grep -q "^$SYMLINKDEV" /etc/fstab; then grep -v "^$SYMLINKDEV" /etc/fstab > /etc/.fstab.new mv -f /etc/.fstab.new /etc/fstab fi fi exit 0

Converting a text file to HTML format.

Example A-26. Converting to HTML

#!/bin/bash # tohtml.sh [v. 0.2, reldate: 06/26/80, still buggy] # Convert a text file to HTML format. # Author: Mendel Cooper # License: GPL3 # Usage: sh tohtml.sh < textfile > htmlfile # Script can easily be modified to accept source and target filenames. # Assumptions: # 1) Paragraphs in (target) text file are separated by a blank line. # 2) Jpeg images (*.jpg) are located in "images" subdirectory. # In the target file, the image names are enclosed in square brackets, # for example, [image01.jpg]. # 3) Emphasized (italic) phrases begin with a space+underscore #+ or the first character on the line is an underscore, #+ and end with an underscore+space or underscore+end-of-line. # Settings FNTSIZE=2 # Small-medium font size IMGDIR="images" # Image directory # Headers HDR01='<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">' HDR02='<!-- Converted to HTML by ***tohtml.sh*** script -->' HDR03='<!-- script author: M. Leo Cooper <thegrendel@theriver.com> -->' HDR10='<html>' HDR11='<head>' HDR11a='</head>' HDR12a='<title>' HDR12b='</title>' HDR121='<META NAME="GENERATOR" CONTENT="tohtml.sh script">' HDR13='<body bgcolor="#dddddd">' # Change background color to suit. HDR14a='<font size=' HDR14b='>' # Footers FTR10='</body>' FTR11='</html>' # Tags BOLD="<b>" CENTER="<center>" END_CENTER="</center>" LF="<br>" write_headers () { echo "$HDR01" echo echo "$HDR02" echo "$HDR03" echo echo echo "$HDR10" echo "$HDR11" echo "$HDR121" echo "$HDR11a" echo "$HDR13" echo echo -n "$HDR14a" echo -n "$FNTSIZE" echo "$HDR14b" echo echo "$BOLD" # Everything in bold (more easily readable). } process_text () { while read line # Read one line at a time. do { if [ ! "$line" ] # Blank line? then # Then new paragraph must follow. echo echo "$LF" # Insert two <br> tags. echo "$LF" echo continue # Skip the underscore test. else # Otherwise . . . if [[ "$line" =~ "\[*jpg\]" ]] # Is a graphic? then # Strip away brackets. temp=$( echo "$line" | sed -e 's/\[//' -e 's/\]//' ) line=""$CENTER" <img src="\"$IMGDIR"/$temp\"> "$END_CENTER" " # Add image tag. # And, center it. fi fi echo "$line" | grep -q _ if [ "$?" -eq 0 ] # If line contains underscore ... then # =================================================== # Convert underscored phrase to italics. temp=$( echo "$line" | sed -e 's/ _/ <i>/' -e 's/_/<\/i> /' | sed -e 's/^_/<i>/' -e 's/_/<\/i>/' ) # Process only underscores prefixed by space, #+ or at beginning or end of line. # Do not convert underscores embedded within a word! line="$temp" # Slows script execution. Can be optimized? # =================================================== fi echo echo "$line" echo } # End while done } # End process_text () write_footers () # Termination tags. { echo "$FTR10" echo "$FTR11" } # main () { # ========= write_headers process_text write_footers # ========= # } exit $? # Exercises: # --------- # 1) Fixup: Check for closing underscore before a comma or period. # 2) Add a test for the presence of a closing underscore #+ in phrases to be italicized.

Here is something to warm the hearts of webmasters and mistresses: a script that saves weblogs.

Example A-27. Preserving weblogs

#!/bin/bash # archiveweblogs.sh v1.0 # Troy Engel <tengel@fluid.com> # Slightly modified by document author. # Used with permission. # # This script will preserve the normally rotated and #+ thrown away weblogs from a default RedHat/Apache installation. # It will save the files with a date/time stamp in the filename, #+ bzipped, to a given directory. # # Run this from crontab nightly at an off hour, #+ as bzip2 can suck up some serious CPU on huge logs: # 0 2 aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html /opt/sbin/archiveweblogs.sh PROBLEM=66 # Set this to your backup dir. BKP_DIR=/opt/backups/weblogs # Default Apache/RedHat stuff LOG_DAYS="4 3 2 1" LOG_DIR=/var/log/httpd LOG_FILES="access_log error_log" # Default RedHat program locations LS=/bin/ls MV=/bin/mv ID=/usr/bin/id CUT=/bin/cut COL=/usr/bin/column BZ2=/usr/bin/bzip2 # Are we root? USER=`$ID -u` if [ "X$USER" != "X0" ]; then echo "PANIC: Only root can run this script!" exit $PROBLEM fi # Backup dir exists/writable? if [ ! -x $BKP_DIR ]; then echo "PANIC: $BKP_DIR doesn't exist or isn't writable!" exit $PROBLEM fi # Move, rename and bzip2 the logs for logday in $LOG_DAYS; do for logfile in $LOG_FILES; do MYFILE="$LOG_DIR/$logfile.$logday" if [ -w $MYFILE ]; then DTS=`$LS -lgo --time-style=+%Y%m%d $MYFILE | $COL -t | $CUT -d ' ' -f7` $MV $MYFILE $BKP_DIR/$logfile.$DTS $BZ2 $BKP_DIR/$logfile.$DTS else # Only spew an error if the file exits (ergo non-writable). if [ -f $MYFILE ]; then echo "ERROR: $MYFILE not writable. Skipping." fi fi done done exit 0

How to keep the shell from expanding and reinterpreting text strings.

Example A-28. Protecting literal strings

#! /bin/bash # protect_literal.sh # set -vx :<<-'_Protect_Literal_String_Doc' Copyright (c) Michael S. Zick, 2003; All Rights Reserved License: Unrestricted reuse in any form, for any purpose. Warranty: None Revision: $ID$ Documentation redirected to the Bash no-operation. Bash will '/dev/null' this block when the script is first read. (Uncomment the above set command to see this action.) Remove the first (Sha-Bang) line when sourcing this as a library procedure. Also comment out the example use code in the two places where shown. Usage: _protect_literal_str 'Whatever string meets your ${fancy}' Just echos the argument to standard out, hard quotes restored. $(_protect_literal_str 'Whatever string meets your ${fancy}') as the right-hand-side of an assignment statement. Does: As the right-hand-side of an assignment, preserves the hard quotes protecting the contents of the literal during assignment. Notes: The strange names (_*) are used to avoid trampling on the user's chosen names when this is sourced as a library. _Protect_Literal_String_Doc # The 'for illustration' function form _protect_literal_str() { # Pick an un-used, non-printing character as local IFS. # Not required, but shows that we are ignoring it. local IFS=$'\x1B' # \ESC character # Enclose the All-Elements-Of in hard quotes during assignment. local tmp=$'\x27'$@$'\x27' # local tmp=$'\''$@$'\'' # Even uglier. local len=${#tmp} # Info only. echo $tmp is $len long. # Output AND information. } # This is the short-named version. _pls() { local IFS=$'x1B' # \ESC character (not required) echo $'\x27'$@$'\x27' # Hard quoted parameter glob } # :<<-'_Protect_Literal_String_Test' # # # Remove the above "# " to disable this code. # # # # See how that looks when printed. echo echo "- - Test One - -" _protect_literal_str 'Hello $user' _protect_literal_str 'Hello "${username}"' echo # Which yields: # - - Test One - - # 'Hello $user' is 13 long. # 'Hello "${username}"' is 21 long. # Looks as expected, but why all of the trouble? # The difference is hidden inside the Bash internal order #+ of operations. # Which shows when you use it on the RHS of an assignment. # Declare an array for test values. declare -a arrayZ # Assign elements with various types of quotes and escapes. arrayZ=( zero "$(_pls 'Hello ${Me}')" 'Hello ${You}' "\'Pass: ${pw}\'" ) # Now list that array and see what is there. echo "- - Test Two - -" for (( i=0 ; i<${#arrayZ[*]} ; i++ )) do echo Element $i: ${arrayZ[$i]} is: ${#arrayZ[$i]} long. done echo # Which yields: # - - Test Two - - # Element 0: zero is: 4 long. # Our marker element # Element 1: 'Hello ${Me}' is: 13 long. # Our "$(_pls '...' )" # Element 2: Hello ${You} is: 12 long. # Quotes are missing # Element 3: \'Pass: \' is: 10 long. # ${pw} expanded to nothing # Now make an assignment with that result. declare -a array2=( ${arrayZ[@]} ) # And print what happened. echo "- - Test Three - -" for (( i=0 ; i<${#array2[*]} ; i++ )) do echo Element $i: ${array2[$i]} is: ${#array2[$i]} long. done echo # Which yields: # - - Test Three - - # Element 0: zero is: 4 long. # Our marker element. # Element 1: Hello ${Me} is: 11 long. # Intended result. # Element 2: Hello is: 5 long. # ${You} expanded to nothing. # Element 3: 'Pass: is: 6 long. # Split on the whitespace. # Element 4: ' is: 1 long. # The end quote is here now. # Our Element 1 has had its leading and trailing hard quotes stripped. # Although not shown, leading and trailing whitespace is also stripped. # Now that the string contents are set, Bash will always, internally, #+ hard quote the contents as required during its operations. # Why? # Considering our "$(_pls 'Hello ${Me}')" construction: # " ... " -> Expansion required, strip the quotes. # $( ... ) -> Replace with the result of..., strip this. # _pls ' ... ' -> called with literal arguments, strip the quotes. # The result returned includes hard quotes; BUT the above processing #+ has already been done, so they become part of the value assigned. # # Similarly, during further usage of the string variable, the ${Me} #+ is part of the contents (result) and survives any operations # (Until explicitly told to evaluate the string). # Hint: See what happens when the hard quotes ($'\x27') are replaced #+ with soft quotes ($'\x22') in the above procedures. # Interesting also is to remove the addition of any quoting. # _Protect_Literal_String_Test # # # Remove the above "# " to disable this code. # # # exit 0

But, what if you want the shell to expand and reinterpret strings?

Example A-29. Unprotecting literal strings

#! /bin/bash # unprotect_literal.sh # set -vx :<<-'_UnProtect_Literal_String_Doc' Copyright (c) Michael S. Zick, 2003; All Rights Reserved License: Unrestricted reuse in any form, for any purpose. Warranty: None Revision: $ID$ Documentation redirected to the Bash no-operation. Bash will '/dev/null' this block when the script is first read. (Uncomment the above set command to see this action.) Remove the first (Sha-Bang) line when sourcing this as a library procedure. Also comment out the example use code in the two places where shown. Usage: Complement of the "$(_pls 'Literal String')" function. (See the protect_literal.sh example.) StringVar=$(_upls ProtectedSringVariable) Does: When used on the right-hand-side of an assignment statement; makes the substitions embedded in the protected string. Notes: The strange names (_*) are used to avoid trampling on the user's chosen names when this is sourced as a library. _UnProtect_Literal_String_Doc _upls() { local IFS=$'x1B' # \ESC character (not required) eval echo $@ # Substitution on the glob. } # :<<-'_UnProtect_Literal_String_Test' # # # Remove the above "# " to disable this code. # # # _pls() { local IFS=$'x1B' # \ESC character (not required) echo $'\x27'$@$'\x27' # Hard quoted parameter glob } # Declare an array for test values. declare -a arrayZ # Assign elements with various types of quotes and escapes. arrayZ=( zero "$(_pls 'Hello ${Me}')" 'Hello ${You}' "\'Pass: ${pw}\'" ) # Now make an assignment with that result. declare -a array2=( ${arrayZ[@]} ) # Which yielded: # - - Test Three - - # Element 0: zero is: 4 long # Our marker element. # Element 1: Hello ${Me} is: 11 long # Intended result. # Element 2: Hello is: 5 long # ${You} expanded to nothing. # Element 3: 'Pass: is: 6 long # Split on the whitespace. # Element 4: ' is: 1 long # The end quote is here now. # set -vx # Initialize 'Me' to something for the embedded ${Me} substitution. # This needs to be done ONLY just prior to evaluating the #+ protected string. # (This is why it was protected to begin with.) Me="to the array guy." # Set a string variable destination to the result. newVar=$(_upls ${array2[1]}) # Show what the contents are. echo $newVar # Do we really need a function to do this? newerVar=$(eval echo ${array2[1]}) echo $newerVar # I guess not, but the _upls function gives us a place to hang #+ the documentation on. # This helps when we forget what a # construction like: #+ $(eval echo ... ) means. # What if Me isn't set when the protected string is evaluated? unset Me newestVar=$(_upls ${array2[1]}) echo $newestVar # Just gone, no hints, no runs, no errors. # Why in the world? # Setting the contents of a string variable containing character #+ sequences that have a meaning in Bash is a general problem in #+ script programming. # # This problem is now solved in eight lines of code #+ (and four pages of description). # Where is all this going? # Dynamic content Web pages as an array of Bash strings. # Content set per request by a Bash 'eval' command #+ on the stored page template. # Not intended to replace PHP, just an interesting thing to do. ### # Don't have a webserver application? # No problem, check the example directory of the Bash source; #+ there is a Bash script for that also. # _UnProtect_Literal_String_Test # # # Remove the above "# " to disable this code. # # # exit 0

This interesting script helps hunt down spammers.

Example A-30. Spammer Identification

#!/bin/bash # $Id: is_spammer.bash,v 1.12.2.11 2004/10/01 21:42:33 mszick Exp $ # Above line is RCS info. # The latest version of this script is available from http://www.morethan.org. # # Spammer-identification # by Michael S. Zick # Used in the ABS Guide with permission. ####################################################### # Documentation # See also "Quickstart" at end of script. ####################################################### :<<-'__is_spammer_Doc_' Copyright (c) Michael S. Zick, 2004 License: Unrestricted reuse in any form, for any purpose. Warranty: None -{Its a script; the user is on their own.}- Impatient? Application code: goto "# # # Hunt the Spammer' program code # # #" Example output: ":<<-'_is_spammer_outputs_'" How to use: Enter script name without arguments. Or goto "Quickstart" at end of script. Provides Given a domain name or IP(v4) address as input: Does an exhaustive set of queries to find the associated network resources (short of recursing into TLDs). Checks the IP(v4) addresses found against Blacklist nameservers. If found to be a blacklisted IP(v4) address, reports the blacklist text records. (Usually hyper-links to the specific report.) Requires A working Internet connection. (Exercise: Add check and/or abort if not on-line when running script.) Bash with arrays (2.05b+). The external program 'dig' -- a utility program provided with the 'bind' set of programs. Specifically, the version which is part of Bind series 9.x See: http://www.isc.org All usages of 'dig' are limited to wrapper functions, which may be rewritten as required. See: dig_wrappers.bash for details. ("Additional documentation" -- below) Usage Script requires a single argument, which may be: 1) A domain name; 2) An IP(v4) address; 3) A filename, with one name or address per line. Script accepts an optional second argument, which may be: 1) A Blacklist server name; 2) A filename, with one Blacklist server name per line. If the second argument is not provided, the script uses a built-in set of (free) Blacklist servers. See also, the Quickstart at the end of this script (after 'exit'). Return Codes 0 - All OK 1 - Script failure 2 - Something is Blacklisted Optional environment variables SPAMMER_TRACE If set to a writable file, script will log an execution flow trace. SPAMMER_DATA If set to a writable file, script will dump its discovered data in the form of GraphViz file. See: http://www.research.att.com/sw/tools/graphviz SPAMMER_LIMIT Limits the depth of resource tracing. Default is 2 levels. A setting of 0 (zero) means 'unlimited' . . . Caution: script might recurse the whole Internet! A limit of 1 or 2 is most useful when processing a file of domain names and addresses. A higher limit can be useful when hunting spam gangs. Additional documentation Download the archived set of scripts explaining and illustrating the function contained within this script. http://personal.riverusers.com/mszick_clf.tar.bz2 Study notes This script uses a large number of functions. Nearly all general functions have their own example script. Each of the example scripts have tutorial level comments. Scripting project Add support for IP(v6) addresses. IP(v6) addresses are recognized but not processed. Advanced project Add the reverse lookup detail to the discovered information. Report the delegation chain and abuse contacts. Modify the GraphViz file output to include the newly discovered information. __is_spammer_Doc_ ####################################################### #### Special IFS settings used for string parsing. #### # Whitespace == :Space:Tab:Line Feed:Carriage Return: WSP_IFS=$'\x20'$'\x09'$'\x0A'$'\x0D' # No Whitespace == Line Feed:Carriage Return NO_WSP=$'\x0A'$'\x0D' # Field separator for dotted decimal IP addresses ADR_IFS=${NO_WSP}'.' # Array to dotted string conversions DOT_IFS='.'${WSP_IFS} # # # Pending operations stack machine # # # # This set of functions described in func_stack.bash. # (See "Additional documentation" above.) # # # # Global stack of pending operations. declare -f -a _pending_ # Global sentinel for stack runners declare -i _p_ctrl_ # Global holder for currently executing function declare -f _pend_current_ # # # Debug version only - remove for regular use # # # # # The function stored in _pend_hook_ is called # immediately before each pending function is # evaluated. Stack clean, _pend_current_ set. # # This thingy demonstrated in pend_hook.bash. declare -f _pend_hook_ # # # # The do nothing function pend_dummy() { : ; } # Clear and initialize the function stack. pend_init() { unset _pending_[@] pend_func pend_stop_mark _pend_hook_='pend_dummy' # Debug only. } # Discard the top function on the stack. pend_pop() { if [ ${#_pending_[@]} -gt 0 ] then local -i _top_ _top_=${#_pending_[@]}-1 unset _pending_[$_top_] fi } # pend_func function_name [$(printf '%q\n' arguments)] pend_func() { local IFS=${NO_WSP} set -f _pending_[${#_pending_[@]}]=$@ set +f } # The function which stops the release: pend_stop_mark() { _p_ctrl_=0 } pend_mark() { pend_func pend_stop_mark } # Execute functions until 'pend_stop_mark' . . . pend_release() { local -i _top_ # Declare _top_ as integer. _p_ctrl_=${#_pending_[@]} while [ ${_p_ctrl_} -gt 0 ] do _top_=${#_pending_[@]}-1 _pend_current_=${_pending_[$_top_]} unset _pending_[$_top_] $_pend_hook_ # Debug only. eval $_pend_current_ done } # Drop functions until 'pend_stop_mark' . . . pend_drop() { local -i _top_ local _pd_ctrl_=${#_pending_[@]} while [ ${_pd_ctrl_} -gt 0 ] do _top_=$_pd_ctrl_-1 if [ "${_pending_[$_top_]}" == 'pend_stop_mark' ] then unset _pending_[$_top_] break else unset _pending_[$_top_] _pd_ctrl_=$_top_ fi done if [ ${#_pending_[@]} -eq 0 ] then pend_func pend_stop_mark fi } #### Array editors #### # This function described in edit_exact.bash. # (See "Additional documentation," above.) # edit_exact <excludes_array_name> <target_array_name> edit_exact() { [ $# -eq 2 ] || [ $# -eq 3 ] || return 1 local -a _ee_Excludes local -a _ee_Target local _ee_x local _ee_t local IFS=${NO_WSP} set -f eval _ee_Excludes=\( \$\{$1\[@\]\} \) eval _ee_Target=\( \$\{$2\[@\]\} \) local _ee_len=${#_ee_Target[@]} # Original length. local _ee_cnt=${#_ee_Excludes[@]} # Exclude list length. [ ${_ee_len} -ne 0 ] || return 0 # Can't edit zero length. [ ${_ee_cnt} -ne 0 ] || return 0 # Can't edit zero length. for (( x = 0; x < ${_ee_cnt} ; x++ )) do _ee_x=${_ee_Excludes[$x]} for (( n = 0 ; n < ${_ee_len} ; n++ )) do _ee_t=${_ee_Target[$n]} if [ x"${_ee_t}" == x"${_ee_x}" ] then unset _ee_Target[$n] # Discard match. [ $# -eq 2 ] && break # If 2 arguments, then done. fi done done eval $2=\( \$\{_ee_Target\[@\]\} \) set +f return 0 } # This function described in edit_by_glob.bash. # edit_by_glob <excludes_array_name> <target_array_name> edit_by_glob() { [ $# -eq 2 ] || [ $# -eq 3 ] || return 1 local -a _ebg_Excludes local -a _ebg_Target local _ebg_x local _ebg_t local IFS=${NO_WSP} set -f eval _ebg_Excludes=\( \$\{$1\[@\]\} \) eval _ebg_Target=\( \$\{$2\[@\]\} \) local _ebg_len=${#_ebg_Target[@]} local _ebg_cnt=${#_ebg_Excludes[@]} [ ${_ebg_len} -ne 0 ] || return 0 [ ${_ebg_cnt} -ne 0 ] || return 0 for (( x = 0; x < ${_ebg_cnt} ; x++ )) do _ebg_x=${_ebg_Excludes[$x]} for (( n = 0 ; n < ${_ebg_len} ; n++ )) do [ $# -eq 3 ] && _ebg_x=${_ebg_x}'*' # Do prefix edit if [ ${_ebg_Target[$n]:=} ] #+ if defined & set. then _ebg_t=${_ebg_Target[$n]/#${_ebg_x}/} [ ${#_ebg_t} -eq 0 ] && unset _ebg_Target[$n] fi done done eval $2=\( \$\{_ebg_Target\[@\]\} \) set +f return 0 } # This function described in unique_lines.bash. # unique_lines <in_name> <out_name> unique_lines() { [ $# -eq 2 ] || return 1 local -a _ul_in local -a _ul_out local -i _ul_cnt local -i _ul_pos local _ul_tmp local IFS=${NO_WSP} set -f eval _ul_in=\( \$\{$1\[@\]\} \) _ul_cnt=${#_ul_in[@]} for (( _ul_pos = 0 ; _ul_pos < ${_ul_cnt} ; _ul_pos++ )) do if [ ${_ul_in[${_ul_pos}]:=} ] # If defined & not empty then _ul_tmp=${_ul_in[${_ul_pos}]} _ul_out[${#_ul_out[@]}]=${_ul_tmp} for (( zap = _ul_pos ; zap < ${_ul_cnt} ; zap++ )) do [ ${_ul_in[${zap}]:=} ] && [ 'x'${_ul_in[${zap}]} == 'x'${_ul_tmp} ] && unset _ul_in[${zap}] done fi done eval $2=\( \$\{_ul_out\[@\]\} \) set +f return 0 } # This function described in char_convert.bash. # to_lower <string> to_lower() { [ $# -eq 1 ] || return 1 local _tl_out _tl_out=${1//A/a} _tl_out=${_tl_out//B/b} _tl_out=${_tl_out//C/c} _tl_out=${_tl_out//D/d} _tl_out=${_tl_out//E/e} _tl_out=${_tl_out//F/f} _tl_out=${_tl_out//G/g} _tl_out=${_tl_out//H/h} _tl_out=${_tl_out//I/i} _tl_out=${_tl_out//J/j} _tl_out=${_tl_out//K/k} _tl_out=${_tl_out//L/l} _tl_out=${_tl_out//M/m} _tl_out=${_tl_out//N/n} _tl_out=${_tl_out//O/o} _tl_out=${_tl_out//P/p} _tl_out=${_tl_out//Q/q} _tl_out=${_tl_out//R/r} _tl_out=${_tl_out//S/s} _tl_out=${_tl_out//T/t} _tl_out=${_tl_out//U/u} _tl_out=${_tl_out//V/v} _tl_out=${_tl_out//W/w} _tl_out=${_tl_out//X/x} _tl_out=${_tl_out//Y/y} _tl_out=${_tl_out//Z/z} echo ${_tl_out} return 0 } #### Application helper functions #### # Not everybody uses dots as separators (APNIC, for example). # This function described in to_dot.bash # to_dot <string> to_dot() { [ $# -eq 1 ] || return 1 echo ${1//[#|@|%]/.} return 0 } # This function described in is_number.bash. # is_number <input> is_number() { [ "$#" -eq 1 ] || return 1 # is blank? [ x"$1" == 'x0' ] && return 0 # is zero? local -i tst let tst=$1 2>/dev/null # else is numeric! return $? } # This function described in is_address.bash. # is_address <input> is_address() { [ $# -eq 1 ] || return 1 # Blank ==> false local -a _ia_input local IFS=${ADR_IFS} _ia_input=( $1 ) if [ ${#_ia_input[@]} -eq 4 ] && is_number ${_ia_input[0]} && is_number ${_ia_input[1]} && is_number ${_ia_input[2]} && is_number ${_ia_input[3]} && [ ${_ia_input[0]} -lt 256 ] && [ ${_ia_input[1]} -lt 256 ] && [ ${_ia_input[2]} -lt 256 ] && [ ${_ia_input[3]} -lt 256 ] then return 0 else return 1 fi } # This function described in split_ip.bash. # split_ip <IP_address> #+ <array_name_norm> [<array_name_rev>] split_ip() { [ $# -eq 3 ] || # Either three [ $# -eq 2 ] || return 1 #+ or two arguments local -a _si_input local IFS=${ADR_IFS} _si_input=( $1 ) IFS=${WSP_IFS} eval $2=\(\ \$\{_si_input\[@\]\}\ \) if [ $# -eq 3 ] then # Build query order array. local -a _dns_ip _dns_ip[0]=${_si_input[3]} _dns_ip[1]=${_si_input[2]} _dns_ip[2]=${_si_input[1]} _dns_ip[3]=${_si_input[0]} eval $3=\(\ \$\{_dns_ip\[@\]\}\ \) fi return 0 } # This function described in dot_array.bash. # dot_array <array_name> dot_array() { [ $# -eq 1 ] || return 1 # Single argument required. local -a _da_input eval _da_input=\(\ \$\{$1\[@\]\}\ \) local IFS=${DOT_IFS} local _da_output=${_da_input[@]} IFS=${WSP_IFS} echo ${_da_output} return 0 } # This function described in file_to_array.bash # file_to_array <file_name> <line_array_name> file_to_array() { [ $# -eq 2 ] || return 1 # Two arguments required. local IFS=${NO_WSP} local -a _fta_tmp_ _fta_tmp_=( $(cat $1) ) eval $2=\( \$\{_fta_tmp_\[@\]\} \) return 0 } # Columnized print of an array of multi-field strings. # col_print <array_name> <min_space> < #+ tab_stop [tab_stops]> col_print() { [ $# -gt 2 ] || return 0 local -a _cp_inp local -a _cp_spc local -a _cp_line local _cp_min local _cp_mcnt local _cp_pos local _cp_cnt local _cp_tab local -i _cp local -i _cpf local _cp_fld # WARNING: FOLLOWING LINE NOT BLANK -- IT IS QUOTED SPACES. local _cp_max=' ' set -f local IFS=${NO_WSP} eval _cp_inp=\(\ \$\{$1\[@\]\}\ \) [ ${#_cp_inp[@]} -gt 0 ] || return 0 # Empty is easy. _cp_mcnt=$2 _cp_min=${_cp_max:1:${_cp_mcnt}} shift shift _cp_cnt=$# for (( _cp = 0 ; _cp < _cp_cnt ; _cp++ )) do _cp_spc[${#_cp_spc[@]}]="${_cp_max:2:$1}" #" shift done _cp_cnt=${#_cp_inp[@]} for (( _cp = 0 ; _cp < _cp_cnt ; _cp++ )) do _cp_pos=1 IFS=${NO_WSP}$'\x20' _cp_line=( ${_cp_inp[${_cp}]} ) IFS=${NO_WSP} for (( _cpf = 0 ; _cpf < ${#_cp_line[@]} ; _cpf++ )) do _cp_tab=${_cp_spc[${_cpf}]:${_cp_pos}} if [ ${#_cp_tab} -lt ${_cp_mcnt} ] then _cp_tab="${_cp_min}" fi echo -n "${_cp_tab}" (( _cp_pos = ${_cp_pos} + ${#_cp_tab} )) _cp_fld="${_cp_line[${_cpf}]}" echo -n ${_cp_fld} (( _cp_pos = ${_cp_pos} + ${#_cp_fld} )) done echo done set +f return 0 } # # # # 'Hunt the Spammer' data flow # # # # # Application return code declare -i _hs_RC # Original input, from which IP addresses are removed # After which, domain names to check declare -a uc_name # Original input IP addresses are moved here # After which, IP addresses to check declare -a uc_address # Names against which address expansion run # Ready for name detail lookup declare -a chk_name # Addresses against which name expansion run # Ready for address detail lookup declare -a chk_address # Recursion is depth-first-by-name. # The expand_input_address maintains this list #+ to prohibit looking up addresses twice during #+ domain name recursion. declare -a been_there_addr been_there_addr=( '127.0.0.1' ) # Whitelist localhost # Names which we have checked (or given up on) declare -a known_name # Addresses which we have checked (or given up on) declare -a known_address # List of zero or more Blacklist servers to check. # Each 'known_address' will be checked against each server, #+ with negative replies and failures suppressed. declare -a list_server # Indirection limit - set to zero == no limit indirect=${SPAMMER_LIMIT:=2} # # # # 'Hunt the Spammer' information output data # # # # # Any domain name may have multiple IP addresses. # Any IP address may have multiple domain names. # Therefore, track unique address-name pairs. declare -a known_pair declare -a reverse_pair # In addition to the data flow variables; known_address #+ known_name and list_server, the following are output to the #+ external graphics interface file. # Authority chain, parent -> SOA fields. declare -a auth_chain # Reference chain, parent name -> child name declare -a ref_chain # DNS chain - domain name -> address declare -a name_address # Name and service pairs - domain name -> service declare -a name_srvc # Name and resource pairs - domain name -> Resource Record declare -a name_resource # Parent and Child pairs - parent name -> child name # This MAY NOT be the same as the ref_chain followed! declare -a parent_child # Address and Blacklist hit pairs - address->server declare -a address_hits # Dump interface file data declare -f _dot_dump _dot_dump=pend_dummy # Initially a no-op # Data dump is enabled by setting the environment variable SPAMMER_DATA #+ to the name of a writable file. declare _dot_file # Helper function for the dump-to-dot-file function # dump_to_dot <array_name> <prefix> dump_to_dot() { local -a _dda_tmp local -i _dda_cnt local _dda_form=' '${2}'%04u %s\n' local IFS=${NO_WSP} eval _dda_tmp=\(\ \$\{$1\[@\]\}\ \) _dda_cnt=${#_dda_tmp[@]} if [ ${_dda_cnt} -gt 0 ] then for (( _dda = 0 ; _dda < _dda_cnt ; _dda++ )) do printf "${_dda_form}" \ "${_dda}" "${_dda_tmp[${_dda}]}" >>${_dot_file} done fi } # Which will also set _dot_dump to this function . . . dump_dot() { local -i _dd_cnt echo '# Data vintage: '$(date -R) >${_dot_file} echo '# ABS Guide: is_spammer.bash; v2, 2004-msz' >>${_dot_file} echo >>${_dot_file} echo 'digraph G {' >>${_dot_file} if [ ${#known_name[@]} -gt 0 ] then echo >>${_dot_file} echo '# Known domain name nodes' >>${_dot_file} _dd_cnt=${#known_name[@]} for (( _dd = 0 ; _dd < _dd_cnt ; _dd++ )) do printf ' N%04u [label="%s"] ;\n' \ "${_dd}" "${known_name[${_dd}]}" >>${_dot_file} done fi if [ ${#known_address[@]} -gt 0 ] then echo >>${_dot_file} echo '# Known address nodes' >>${_dot_file} _dd_cnt=${#known_address[@]} for (( _dd = 0 ; _dd < _dd_cnt ; _dd++ )) do printf ' A%04u [label="%s"] ;\n' \ "${_dd}" "${known_address[${_dd}]}" >>${_dot_file} done fi echo >>${_dot_file} echo '/*' >>${_dot_file} echo ' aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html Known relationships :: User conversion to' >>${_dot_file} echo ' aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html graphic form by hand or program required.' >>${_dot_file} echo ' *' >>${_dot_file} if [ ${#auth_chain[@]} -gt 0 ] then echo >>${_dot_file} echo '# Authority ref. edges followed & field source.' >>${_dot_file} dump_to_dot auth_chain AC fi if [ ${#ref_chain[@]} -gt 0 ] then echo >>${_dot_file} echo '# Name ref. edges followed and field source.' >>${_dot_file} dump_to_dot ref_chain RC fi if [ ${#name_address[@]} -gt 0 ] then echo >>${_dot_file} echo '# Known name->address edges' >>${_dot_file} dump_to_dot name_address NA fi if [ ${#name_srvc[@]} -gt 0 ] then echo >>${_dot_file} echo '# Known name->service edges' >>${_dot_file} dump_to_dot name_srvc NS fi if [ ${#name_resource[@]} -gt 0 ] then echo >>${_dot_file} echo '# Known name->resource edges' >>${_dot_file} dump_to_dot name_resource NR fi if [ ${#parent_child[@]} -gt 0 ] then echo >>${_dot_file} echo '# Known parent->child edges' >>${_dot_file} dump_to_dot parent_child PC fi if [ ${#list_server[@]} -gt 0 ] then echo >>${_dot_file} echo '# Known Blacklist nodes' >>${_dot_file} _dd_cnt=${#list_server[@]} for (( _dd = 0 ; _dd < _dd_cnt ; _dd++ )) do printf ' LS%04u [label="%s"] ;\n' \ "${_dd}" "${list_server[${_dd}]}" >>${_dot_file} done fi unique_lines address_hits address_hits if [ ${#address_hits[@]} -gt 0 ] then echo >>${_dot_file} echo '# Known address->Blacklist_hit edges' >>${_dot_file} echo '# CAUTION: dig warnings can trigger false hits.' >>${_dot_file} dump_to_dot address_hits AH fi echo >>${_dot_file} echo ' *' >>${_dot_file} echo ' aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html That is a lot of relationships. Happy graphing.' >>${_dot_file} echo ' */' >>${_dot_file} echo '}' >>${_dot_file} return 0 } # # # # 'Hunt the Spammer' execution flow # # # # # Execution trace is enabled by setting the #+ environment variable SPAMMER_TRACE to the name of a writable file. declare -a _trace_log declare _log_file # Function to fill the trace log trace_logger() { _trace_log[${#_trace_log[@]}]=${_pend_current_} } # Dump trace log to file function variable. declare -f _log_dump _log_dump=pend_dummy # Initially a no-op. # Dump the trace log to a file. dump_log() { local -i _dl_cnt _dl_cnt=${#_trace_log[@]} for (( _dl = 0 ; _dl < _dl_cnt ; _dl++ )) do echo ${_trace_log[${_dl}]} >> ${_log_file} done _dl_cnt=${#_pending_[@]} if [ ${_dl_cnt} -gt 0 ] then _dl_cnt=${_dl_cnt}-1 echo '# # # Operations stack not empty # # #' >> ${_log_file} for (( _dl = ${_dl_cnt} ; _dl >= 0 ; _dl-- )) do echo ${_pending_[${_dl}]} >> ${_log_file} done fi } # # # Utility program 'dig' wrappers # # # # # These wrappers are derived from the #+ examples shown in dig_wrappers.bash. # # The major difference is these return #+ their results as a list in an array. # # See dig_wrappers.bash for details and #+ use that script to develop any changes. # # # # # Short form answer: 'dig' parses answer. # Forward lookup :: Name -> Address # short_fwd <domain_name> <array_name> short_fwd() { local -a _sf_reply local -i _sf_rc local -i _sf_cnt IFS=${NO_WSP} echo -n '.' # echo 'sfwd: '${1} _sf_reply=( $(dig +short ${1} -c in -t a 2>/dev/null) ) _sf_rc=$? if [ ${_sf_rc} -ne 0 ] then _trace_log[${#_trace_log[@]}]='## Lookup error '${_sf_rc}' on '${1}' ##' # [ ${_sf_rc} -ne 9 ] && pend_drop return ${_sf_rc} else # Some versions of 'dig' return warnings on stdout. _sf_cnt=${#_sf_reply[@]} for (( _sf = 0 ; _sf < ${_sf_cnt} ; _sf++ )) do [ 'x'${_sf_reply[${_sf}]:0:2} == 'x;;' ] && unset _sf_reply[${_sf}] done eval $2=\( \$\{_sf_reply\[@\]\} \) fi return 0 } # Reverse lookup :: Address -> Name # short_rev <ip_address> <array_name> short_rev() { local -a _sr_reply local -i _sr_rc local -i _sr_cnt IFS=${NO_WSP} echo -n '.' # echo 'srev: '${1} _sr_reply=( $(dig +short -x ${1} 2>/dev/null) ) _sr_rc=$? if [ ${_sr_rc} -ne 0 ] then _trace_log[${#_trace_log[@]}]='## Lookup error '${_sr_rc}' on '${1}' ##' # [ ${_sr_rc} -ne 9 ] && pend_drop return ${_sr_rc} else # Some versions of 'dig' return warnings on stdout. _sr_cnt=${#_sr_reply[@]} for (( _sr = 0 ; _sr < ${_sr_cnt} ; _sr++ )) do [ 'x'${_sr_reply[${_sr}]:0:2} == 'x;;' ] && unset _sr_reply[${_sr}] done eval $2=\( \$\{_sr_reply\[@\]\} \) fi return 0 } # Special format lookup used to query blacklist servers. # short_text <ip_address> <array_name> short_text() { local -a _st_reply local -i _st_rc local -i _st_cnt IFS=${NO_WSP} # echo 'stxt: '${1} _st_reply=( $(dig +short ${1} -c in -t txt 2>/dev/null) ) _st_rc=$? if [ ${_st_rc} -ne 0 ] then _trace_log[${#_trace_log[@]}]='##Text lookup error '${_st_rc}' on '${1}'##' # [ ${_st_rc} -ne 9 ] && pend_drop return ${_st_rc} else # Some versions of 'dig' return warnings on stdout. _st_cnt=${#_st_reply[@]} for (( _st = 0 ; _st < ${#_st_cnt} ; _st++ )) do [ 'x'${_st_reply[${_st}]:0:2} == 'x;;' ] && unset _st_reply[${_st}] done eval $2=\( \$\{_st_reply\[@\]\} \) fi return 0 } # The long forms, a.k.a., the parse it yourself versions # RFC 2782 Service lookups # dig +noall +nofail +answer _ldap._tcp.openldap.org -t srv # _<service>._<protocol>.<domain_name> # _ldap._tcp.openldap.org. 3600 IN SRV 0 0 389 ldap.openldap.org. # domain TTL Class SRV Priority Weight Port Target # Forward lookup :: Name -> poor man's zone transfer # long_fwd <domain_name> <array_name> long_fwd() { local -a _lf_reply local -i _lf_rc local -i _lf_cnt IFS=${NO_WSP} echo -n ':' # echo 'lfwd: '${1} _lf_reply=( $( dig +noall +nofail +answer +authority +additional \ ${1} -t soa ${1} -t mx ${1} -t any 2>/dev/null) ) _lf_rc=$? if [ ${_lf_rc} -ne 0 ] then _trace_log[${#_trace_log[@]}]='# Zone lookup err '${_lf_rc}' on '${1}' #' # [ ${_lf_rc} -ne 9 ] && pend_drop return ${_lf_rc} else # Some versions of 'dig' return warnings on stdout. _lf_cnt=${#_lf_reply[@]} for (( _lf = 0 ; _lf < ${_lf_cnt} ; _lf++ )) do [ 'x'${_lf_reply[${_lf}]:0:2} == 'x;;' ] && unset _lf_reply[${_lf}] done eval $2=\( \$\{_lf_reply\[@\]\} \) fi return 0 } # The reverse lookup domain name corresponding to the IPv6 address: # 4321:0:1:2:3:4:567:89ab # would be (nibble, I.E: Hexdigit) reversed: # b.a.9.8.7.6.5.0.4.0.0.0.3.0.0.0.2.0.0.0.1.0.0.0.0.0.0.0.1.2.3.4.IP6.ARPA. # Reverse lookup :: Address -> poor man's delegation chain # long_rev <rev_ip_address> <array_name> long_rev() { local -a _lr_reply local -i _lr_rc local -i _lr_cnt local _lr_dns _lr_dns=${1}'.in-addr.arpa.' IFS=${NO_WSP} echo -n ':' # echo 'lrev: '${1} _lr_reply=( $( dig +noall +nofail +answer +authority +additional \ ${_lr_dns} -t soa ${_lr_dns} -t any 2>/dev/null) ) _lr_rc=$? if [ ${_lr_rc} -ne 0 ] then _trace_log[${#_trace_log[@]}]='# Deleg lkp error '${_lr_rc}' on '${1}' #' # [ ${_lr_rc} -ne 9 ] && pend_drop return ${_lr_rc} else # Some versions of 'dig' return warnings on stdout. _lr_cnt=${#_lr_reply[@]} for (( _lr = 0 ; _lr < ${_lr_cnt} ; _lr++ )) do [ 'x'${_lr_reply[${_lr}]:0:2} == 'x;;' ] && unset _lr_reply[${_lr}] done eval $2=\( \$\{_lr_reply\[@\]\} \) fi return 0 } # # # Application specific functions # # # # Mung a possible name; suppresses root and TLDs. # name_fixup <string> name_fixup(){ local -a _nf_tmp local -i _nf_end local _nf_str local IFS _nf_str=$(to_lower ${1}) _nf_str=$(to_dot ${_nf_str}) _nf_end=${#_nf_str}-1 [ ${_nf_str:${_nf_end}} != '.' ] && _nf_str=${_nf_str}'.' IFS=${ADR_IFS} _nf_tmp=( ${_nf_str} ) IFS=${WSP_IFS} _nf_end=${#_nf_tmp[@]} case ${_nf_end} in 0) # No dots, only dots. echo return 1 ;; 1) # Only a TLD. echo return 1 ;; 2) # Maybe okay. echo ${_nf_str} return 0 # Needs a lookup table? if [ ${#_nf_tmp[1]} -eq 2 ] then # Country coded TLD. echo return 1 else echo ${_nf_str} return 0 fi ;; esac echo ${_nf_str} return 0 } # Grope and mung original input(s). split_input() { [ ${#uc_name[@]} -gt 0 ] || return 0 local -i _si_cnt local -i _si_len local _si_str unique_lines uc_name uc_name _si_cnt=${#uc_name[@]} for (( _si = 0 ; _si < _si_cnt ; _si++ )) do _si_str=${uc_name[$_si]} if is_address ${_si_str} then uc_address[${#uc_address[@]}]=${_si_str} unset uc_name[$_si] else if ! uc_name[$_si]=$(name_fixup ${_si_str}) then unset ucname[$_si] fi fi done uc_name=( ${uc_name[@]} ) _si_cnt=${#uc_name[@]} _trace_log[${#_trace_log[@]}]='#Input '${_si_cnt}' unchkd name input(s).#' _si_cnt=${#uc_address[@]} _trace_log[${#_trace_log[@]}]='#Input '${_si_cnt}' unchkd addr input(s).#' return 0 } # # # Discovery functions -- recursively interlocked by external data # # # # # # The leading 'if list is empty; return 0' in each is required. # # # # Recursion limiter # limit_chk() <next_level> limit_chk() { local -i _lc_lmt # Check indirection limit. if [ ${indirect} -eq 0 ] || [ $# -eq 0 ] then # The 'do-forever' choice echo 1 # Any value will do. return 0 # OK to continue. else # Limiting is in effect. if [ ${indirect} -lt ${1} ] then echo ${1} # Whatever. return 1 # Stop here. else _lc_lmt=${1}+1 # Bump the given limit. echo ${_lc_lmt} # Echo it. return 0 # OK to continue. fi fi } # For each name in uc_name: # Move name to chk_name. # Add addresses to uc_address. # Pend expand_input_address. # Repeat until nothing new found. # expand_input_name <indirection_limit> expand_input_name() { [ ${#uc_name[@]} -gt 0 ] || return 0 local -a _ein_addr local -a _ein_new local -i _ucn_cnt local -i _ein_cnt local _ein_tst _ucn_cnt=${#uc_name[@]} if ! _ein_cnt=$(limit_chk ${1}) then return 0 fi for (( _ein = 0 ; _ein < _ucn_cnt ; _ein++ )) do if short_fwd ${uc_name[${_ein}]} _ein_new then for (( _ein_cnt = 0 ; _ein_cnt < ${#_ein_new[@]}; _ein_cnt++ )) do _ein_tst=${_ein_new[${_ein_cnt}]} if is_address ${_ein_tst} then _ein_addr[${#_ein_addr[@]}]=${_ein_tst} fi done fi done unique_lines _ein_addr _ein_addr # Scrub duplicates. edit_exact chk_address _ein_addr # Scrub pending detail. edit_exact known_address _ein_addr # Scrub already detailed. if [ ${#_ein_addr[@]} -gt 0 ] # Anything new? then uc_address=( ${uc_address[@]} ${_ein_addr[@]} ) pend_func expand_input_address ${1} _trace_log[${#_trace_log[@]}]='#Add '${#_ein_addr[@]}' unchkd addr inp.#' fi edit_exact chk_name uc_name # Scrub pending detail. edit_exact known_name uc_name # Scrub already detailed. if [ ${#uc_name[@]} -gt 0 ] then chk_name=( ${chk_name[@]} ${uc_name[@]} ) pend_func detail_each_name ${1} fi unset uc_name[@] return 0 } # For each address in uc_address: # Move address to chk_address. # Add names to uc_name. # Pend expand_input_name. # Repeat until nothing new found. # expand_input_address <indirection_limit> expand_input_address() { [ ${#uc_address[@]} -gt 0 ] || return 0 local -a _eia_addr local -a _eia_name local -a _eia_new local -i _uca_cnt local -i _eia_cnt local _eia_tst unique_lines uc_address _eia_addr unset uc_address[@] edit_exact been_there_addr _eia_addr _uca_cnt=${#_eia_addr[@]} [ ${_uca_cnt} -gt 0 ] && been_there_addr=( ${been_there_addr[@]} ${_eia_addr[@]} ) for (( _eia = 0 ; _eia < _uca_cnt ; _eia++ )) do if short_rev ${_eia_addr[${_eia}]} _eia_new then for (( _eia_cnt = 0 ; _eia_cnt < ${#_eia_new[@]} ; _eia_cnt++ )) do _eia_tst=${_eia_new[${_eia_cnt}]} if _eia_tst=$(name_fixup ${_eia_tst}) then _eia_name[${#_eia_name[@]}]=${_eia_tst} fi done fi done unique_lines _eia_name _eia_name # Scrub duplicates. edit_exact chk_name _eia_name # Scrub pending detail. edit_exact known_name _eia_name # Scrub already detailed. if [ ${#_eia_name[@]} -gt 0 ] # Anything new? then uc_name=( ${uc_name[@]} ${_eia_name[@]} ) pend_func expand_input_name ${1} _trace_log[${#_trace_log[@]}]='#Add '${#_eia_name[@]}' unchkd name inp.#' fi edit_exact chk_address _eia_addr # Scrub pending detail. edit_exact known_address _eia_addr # Scrub already detailed. if [ ${#_eia_addr[@]} -gt 0 ] # Anything new? then chk_address=( ${chk_address[@]} ${_eia_addr[@]} ) pend_func detail_each_address ${1} fi return 0 } # The parse-it-yourself zone reply. # The input is the chk_name list. # detail_each_name <indirection_limit> detail_each_name() { [ ${#chk_name[@]} -gt 0 ] || return 0 local -a _den_chk # Names to check local -a _den_name # Names found here local -a _den_address # Addresses found here local -a _den_pair # Pairs found here local -a _den_rev # Reverse pairs found here local -a _den_tmp # Line being parsed local -a _den_auth # SOA contact being parsed local -a _den_new # The zone reply local -a _den_pc # Parent-Child gets big fast local -a _den_ref # So does reference chain local -a _den_nr # Name-Resource can be big local -a _den_na # Name-Address local -a _den_ns # Name-Service local -a _den_achn # Chain of Authority local -i _den_cnt # Count of names to detail local -i _den_lmt # Indirection limit local _den_who # Named being processed local _den_rec # Record type being processed local _den_cont # Contact domain local _den_str # Fixed up name string local _den_str2 # Fixed up reverse local IFS=${WSP_IFS} # Local, unique copy of names to check unique_lines chk_name _den_chk unset chk_name[@] # Done with globals. # Less any names already known edit_exact known_name _den_chk _den_cnt=${#_den_chk[@]} # If anything left, add to known_name. [ ${_den_cnt} -gt 0 ] && known_name=( ${known_name[@]} ${_den_chk[@]} ) # for the list of (previously) unknown names . . . for (( _den = 0 ; _den < _den_cnt ; _den++ )) do _den_who=${_den_chk[${_den}]} if long_fwd ${_den_who} _den_new then unique_lines _den_new _den_new if [ ${#_den_new[@]} -eq 0 ] then _den_pair[${#_den_pair[@]}]='0.0.0.0 '${_den_who} fi # Parse each line in the reply. for (( _line = 0 ; _line < ${#_den_new[@]} ; _line++ )) do IFS=${NO_WSP}$'\x09'$'\x20' _den_tmp=( ${_den_new[${_line}]} ) IFS=${WSP_IFS} # If usable record and not a warning message . . . if [ ${#_den_tmp[@]} -gt 4 ] && [ 'x'${_den_tmp[0]} != 'x;;' ] then _den_rec=${_den_tmp[3]} _den_nr[${#_den_nr[@]}]=${_den_who}' '${_den_rec} # Begin at RFC1033 (+++) case ${_den_rec} in #<name> [<ttl>] [<class>] SOA <origin> <person> SOA) # Start Of Authority if _den_str=$(name_fixup ${_den_tmp[0]}) then _den_name[${#_den_name[@]}]=${_den_str} _den_achn[${#_den_achn[@]}]=${_den_who}' '${_den_str}' SOA' # SOA origin -- domain name of master zone record if _den_str2=$(name_fixup ${_den_tmp[4]}) then _den_name[${#_den_name[@]}]=${_den_str2} _den_achn[${#_den_achn[@]}]=${_den_who}' '${_den_str2}' SOA.O' fi # Responsible party e-mail address (possibly bogus). # Possibility of first.last@domain.name ignored. set -f if _den_str2=$(name_fixup ${_den_tmp[5]}) then IFS=${ADR_IFS} _den_auth=( ${_den_str2} ) IFS=${WSP_IFS} if [ ${#_den_auth[@]} -gt 2 ] then _den_cont=${_den_auth[1]} for (( _auth = 2 ; _auth < ${#_den_auth[@]} ; _auth++ )) do _den_cont=${_den_cont}'.'${_den_auth[${_auth}]} done _den_name[${#_den_name[@]}]=${_den_cont}'.' _den_achn[${#_den_achn[@]}]=${_den_who}' '${_den_cont}'. SOA.C' fi fi set +f fi ;; A) # IP(v4) Address Record if _den_str=$(name_fixup ${_den_tmp[0]}) then _den_name[${#_den_name[@]}]=${_den_str} _den_pair[${#_den_pair[@]}]=${_den_tmp[4]}' '${_den_str} _den_na[${#_den_na[@]}]=${_den_str}' '${_den_tmp[4]} _den_ref[${#_den_ref[@]}]=${_den_who}' '${_den_str}' A' else _den_pair[${#_den_pair[@]}]=${_den_tmp[4]}' unknown.domain' _den_na[${#_den_na[@]}]='unknown.domain '${_den_tmp[4]} _den_ref[${#_den_ref[@]}]=${_den_who}' unknown.domain A' fi _den_address[${#_den_address[@]}]=${_den_tmp[4]} _den_pc[${#_den_pc[@]}]=${_den_who}' '${_den_tmp[4]} ;; NS) # Name Server Record # Domain name being serviced (may be other than current) if _den_str=$(name_fixup ${_den_tmp[0]}) then _den_name[${#_den_name[@]}]=${_den_str} _den_ref[${#_den_ref[@]}]=${_den_who}' '${_den_str}' NS' # Domain name of service provider if _den_str2=$(name_fixup ${_den_tmp[4]}) then _den_name[${#_den_name[@]}]=${_den_str2} _den_ref[${#_den_ref[@]}]=${_den_who}' '${_den_str2}' NSH' _den_ns[${#_den_ns[@]}]=${_den_str2}' NS' _den_pc[${#_den_pc[@]}]=${_den_str}' '${_den_str2} fi fi ;; MX) # Mail Server Record # Domain name being serviced (wildcards not handled here) if _den_str=$(name_fixup ${_den_tmp[0]}) then _den_name[${#_den_name[@]}]=${_den_str} _den_ref[${#_den_ref[@]}]=${_den_who}' '${_den_str}' MX' fi # Domain name of service provider if _den_str=$(name_fixup ${_den_tmp[5]}) then _den_name[${#_den_name[@]}]=${_den_str} _den_ref[${#_den_ref[@]}]=${_den_who}' '${_den_str}' MXH' _den_ns[${#_den_ns[@]}]=${_den_str}' MX' _den_pc[${#_den_pc[@]}]=${_den_who}' '${_den_str} fi ;; PTR) # Reverse address record # Special name if _den_str=$(name_fixup ${_den_tmp[0]}) then _den_ref[${#_den_ref[@]}]=${_den_who}' '${_den_str}' PTR' # Host name (not a CNAME) if _den_str2=$(name_fixup ${_den_tmp[4]}) then _den_rev[${#_den_rev[@]}]=${_den_str}' '${_den_str2} _den_ref[${#_den_ref[@]}]=${_den_who}' '${_den_str2}' PTRH' _den_pc[${#_den_pc[@]}]=${_den_who}' '${_den_str} fi fi ;; AAAA) # IP(v6) Address Record if _den_str=$(name_fixup ${_den_tmp[0]}) then _den_name[${#_den_name[@]}]=${_den_str} _den_pair[${#_den_pair[@]}]=${_den_tmp[4]}' '${_den_str} _den_na[${#_den_na[@]}]=${_den_str}' '${_den_tmp[4]} _den_ref[${#_den_ref[@]}]=${_den_who}' '${_den_str}' AAAA' else _den_pair[${#_den_pair[@]}]=${_den_tmp[4]}' unknown.domain' _den_na[${#_den_na[@]}]='unknown.domain '${_den_tmp[4]} _den_ref[${#_den_ref[@]}]=${_den_who}' unknown.domain' fi # No processing for IPv6 addresses _den_pc[${#_den_pc[@]}]=${_den_who}' '${_den_tmp[4]} ;; CNAME) # Alias name record # Nickname if _den_str=$(name_fixup ${_den_tmp[0]}) then _den_name[${#_den_name[@]}]=${_den_str} _den_ref[${#_den_ref[@]}]=${_den_who}' '${_den_str}' CNAME' _den_pc[${#_den_pc[@]}]=${_den_who}' '${_den_str} fi # Hostname if _den_str=$(name_fixup ${_den_tmp[4]}) then _den_name[${#_den_name[@]}]=${_den_str} _den_ref[${#_den_ref[@]}]=${_den_who}' '${_den_str}' CHOST' _den_pc[${#_den_pc[@]}]=${_den_who}' '${_den_str} fi ;; # TXT) # ;; esac fi done else # Lookup error == 'A' record 'unknown address' _den_pair[${#_den_pair[@]}]='0.0.0.0 '${_den_who} fi done # Control dot array growth. unique_lines _den_achn _den_achn # Works best, all the same. edit_exact auth_chain _den_achn # Works best, unique items. if [ ${#_den_achn[@]} -gt 0 ] then IFS=${NO_WSP} auth_chain=( ${auth_chain[@]} ${_den_achn[@]} ) IFS=${WSP_IFS} fi unique_lines _den_ref _den_ref # Works best, all the same. edit_exact ref_chain _den_ref # Works best, unique items. if [ ${#_den_ref[@]} -gt 0 ] then IFS=${NO_WSP} ref_chain=( ${ref_chain[@]} ${_den_ref[@]} ) IFS=${WSP_IFS} fi unique_lines _den_na _den_na edit_exact name_address _den_na if [ ${#_den_na[@]} -gt 0 ] then IFS=${NO_WSP} name_address=( ${name_address[@]} ${_den_na[@]} ) IFS=${WSP_IFS} fi unique_lines _den_ns _den_ns edit_exact name_srvc _den_ns if [ ${#_den_ns[@]} -gt 0 ] then IFS=${NO_WSP} name_srvc=( ${name_srvc[@]} ${_den_ns[@]} ) IFS=${WSP_IFS} fi unique_lines _den_nr _den_nr edit_exact name_resource _den_nr if [ ${#_den_nr[@]} -gt 0 ] then IFS=${NO_WSP} name_resource=( ${name_resource[@]} ${_den_nr[@]} ) IFS=${WSP_IFS} fi unique_lines _den_pc _den_pc edit_exact parent_child _den_pc if [ ${#_den_pc[@]} -gt 0 ] then IFS=${NO_WSP} parent_child=( ${parent_child[@]} ${_den_pc[@]} ) IFS=${WSP_IFS} fi # Update list known_pair (Address and Name). unique_lines _den_pair _den_pair edit_exact known_pair _den_pair if [ ${#_den_pair[@]} -gt 0 ] # Anything new? then IFS=${NO_WSP} known_pair=( ${known_pair[@]} ${_den_pair[@]} ) IFS=${WSP_IFS} fi # Update list of reverse pairs. unique_lines _den_rev _den_rev edit_exact reverse_pair _den_rev if [ ${#_den_rev[@]} -gt 0 ] # Anything new? then IFS=${NO_WSP} reverse_pair=( ${reverse_pair[@]} ${_den_rev[@]} ) IFS=${WSP_IFS} fi # Check indirection limit -- give up if reached. if ! _den_lmt=$(limit_chk ${1}) then return 0 fi # Execution engine is LIFO. Order of pend operations is important. # Did we define any new addresses? unique_lines _den_address _den_address # Scrub duplicates. edit_exact known_address _den_address # Scrub already processed. edit_exact un_address _den_address # Scrub already waiting. if [ ${#_den_address[@]} -gt 0 ] # Anything new? then uc_address=( ${uc_address[@]} ${_den_address[@]} ) pend_func expand_input_address ${_den_lmt} _trace_log[${#_trace_log[@]}]='# Add '${#_den_address[@]}' unchkd addr. #' fi # Did we find any new names? unique_lines _den_name _den_name # Scrub duplicates. edit_exact known_name _den_name # Scrub already processed. edit_exact uc_name _den_name # Scrub already waiting. if [ ${#_den_name[@]} -gt 0 ] # Anything new? then uc_name=( ${uc_name[@]} ${_den_name[@]} ) pend_func expand_input_name ${_den_lmt} _trace_log[${#_trace_log[@]}]='#Added '${#_den_name[@]}' unchkd name#' fi return 0 } # The parse-it-yourself delegation reply # Input is the chk_address list. # detail_each_address <indirection_limit> detail_each_address() { [ ${#chk_address[@]} -gt 0 ] || return 0 unique_lines chk_address chk_address edit_exact known_address chk_address if [ ${#chk_address[@]} -gt 0 ] then known_address=( ${known_address[@]} ${chk_address[@]} ) unset chk_address[@] fi return 0 } # # # Application specific output functions # # # # Pretty print the known pairs. report_pairs() { echo echo 'Known network pairs.' col_print known_pair 2 5 30 if [ ${#auth_chain[@]} -gt 0 ] then echo echo 'Known chain of authority.' col_print auth_chain 2 5 30 55 fi if [ ${#reverse_pair[@]} -gt 0 ] then echo echo 'Known reverse pairs.' col_print reverse_pair 2 5 55 fi return 0 } # Check an address against the list of blacklist servers. # A good place to capture for GraphViz: address->status(server(reports)) # check_lists <ip_address> check_lists() { [ $# -eq 1 ] || return 1 local -a _cl_fwd_addr local -a _cl_rev_addr local -a _cl_reply local -i _cl_rc local -i _ls_cnt local _cl_dns_addr local _cl_lkup split_ip ${1} _cl_fwd_addr _cl_rev_addr _cl_dns_addr=$(dot_array _cl_rev_addr)'.' _ls_cnt=${#list_server[@]} echo ' Checking address '${1} for (( _cl = 0 ; _cl < _ls_cnt ; _cl++ )) do _cl_lkup=${_cl_dns_addr}${list_server[${_cl}]} if short_text ${_cl_lkup} _cl_reply then if [ ${#_cl_reply[@]} -gt 0 ] then echo ' Records from '${list_server[${_cl}]} address_hits[${#address_hits[@]}]=${1}' '${list_server[${_cl}]} _hs_RC=2 for (( _clr = 0 ; _clr < ${#_cl_reply[@]} ; _clr++ )) do echo ' '${_cl_reply[${_clr}]} done fi fi done return 0 } # # # The usual application glue # # # # Who did it? credits() { echo echo 'Advanced Bash Scripting Guide: is_spammer.bash, v2, 2004-msz' } # How to use it? # (See also, "Quickstart" at end of script.) usage() { cat <<-'_usage_statement_' The script is_spammer.bash requires either one or two arguments. arg 1) May be one of: a) A domain name b) An IPv4 address c) The name of a file with any mix of names and addresses, one per line. arg 2) May be one of: a) A Blacklist server domain name b) The name of a file with Blacklist server domain names, one per line. c) If not present, a default list of (free) Blacklist servers is used. d) If a filename of an empty, readable, file is given, Blacklist server lookup is disabled. All script output is written to stdout. Return codes: 0 -> All OK, 1 -> Script failure, 2 -> Something is Blacklisted. Requires the external program 'dig' from the 'bind-9' set of DNS programs. See: http://www.isc.org The domain name lookup depth limit defaults to 2 levels. Set the environment variable SPAMMER_LIMIT to change. SPAMMER_LIMIT=0 means 'unlimited' Limit may also be set on the command line. If arg#1 is an integer, the limit is set to that value and then the above argument rules are applied. Setting the environment variable 'SPAMMER_DATA' to a filename will cause the script to write a GraphViz graphic file. For the development version; Setting the environment variable 'SPAMMER_TRACE' to a filename will cause the execution engine to log a function call trace. _usage_statement_ } # The default list of Blacklist servers: # Many choices, see: http://www.spews.org/lists.html declare -a default_servers # See: http://www.spamhaus.org (Conservative, well maintained) default_servers[0]='sbl-xbl.spamhaus.org' # See: http://ordb.org (Open mail relays) default_servers[1]='relays.ordb.org' # See: http://www.spamcop.net/ (You can report spammers here) default_servers[2]='bl.spamcop.net' # See: http://www.spews.org (An 'early detect' system) default_servers[3]='l2.spews.dnsbl.sorbs.net' # See: http://www.dnsbl.us.sorbs.net/using.shtml default_servers[4]='dnsbl.sorbs.net' # See: http://dsbl.org/usage (Various mail relay lists) default_servers[5]='list.dsbl.org' default_servers[6]='multihop.dsbl.org' default_servers[7]='unconfirmed.dsbl.org' # User input argument #1 setup_input() { if [ -e ${1} ] && [ -r ${1} ] # Name of readable file then file_to_array ${1} uc_name echo 'Using filename >'${1}'< as input.' else if is_address ${1} # IP address? then uc_address=( ${1} ) echo 'Starting with address >'${1}'<' else # Must be a name. uc_name=( ${1} ) echo 'Starting with domain name >'${1}'<' fi fi return 0 } # User input argument #2 setup_servers() { if [ -e ${1} ] && [ -r ${1} ] # Name of a readable file then file_to_array ${1} list_server echo 'Using filename >'${1}'< as blacklist server list.' else list_server=( ${1} ) echo 'Using blacklist server >'${1}'<' fi return 0 } # User environment variable SPAMMER_TRACE live_log_die() { if [ ${SPAMMER_TRACE:=} ] # Wants trace log? then if [ ! -e ${SPAMMER_TRACE} ] then if ! touch ${SPAMMER_TRACE} 2>/dev/null then pend_func echo $(printf '%q\n' \ 'Unable to create log file >'${SPAMMER_TRACE}'<') pend_release exit 1 fi _log_file=${SPAMMER_TRACE} _pend_hook_=trace_logger _log_dump=dump_log else if [ ! -w ${SPAMMER_TRACE} ] then pend_func echo $(printf '%q\n' \ 'Unable to write log file >'${SPAMMER_TRACE}'<') pend_release exit 1 fi _log_file=${SPAMMER_TRACE} echo '' > ${_log_file} _pend_hook_=trace_logger _log_dump=dump_log fi fi return 0 } # User environment variable SPAMMER_DATA data_capture() { if [ ${SPAMMER_DATA:=} ] # Wants a data dump? then if [ ! -e ${SPAMMER_DATA} ] then if ! touch ${SPAMMER_DATA} 2>/dev/null then pend_func echo $(printf '%q]n' \ 'Unable to create data output file >'${SPAMMER_DATA}'<') pend_release exit 1 fi _dot_file=${SPAMMER_DATA} _dot_dump=dump_dot else if [ ! -w ${SPAMMER_DATA} ] then pend_func echo $(printf '%q\n' \ 'Unable to write data output file >'${SPAMMER_DATA}'<') pend_release exit 1 fi _dot_file=${SPAMMER_DATA} _dot_dump=dump_dot fi fi return 0 } # Grope user specified arguments. do_user_args() { if [ $# -gt 0 ] && is_number $1 then indirect=$1 shift fi case $# in # Did user treat us well? 1) if ! setup_input $1 # Needs error checking. then pend_release $_log_dump exit 1 fi list_server=( ${default_servers[@]} ) _list_cnt=${#list_server[@]} echo 'Using default blacklist server list.' echo 'Search depth limit: '${indirect} ;; 2) if ! setup_input $1 # Needs error checking. then pend_release $_log_dump exit 1 fi if ! setup_servers $2 # Needs error checking. then pend_release $_log_dump exit 1 fi echo 'Search depth limit: '${indirect} ;; *) pend_func usage pend_release $_log_dump exit 1 ;; esac return 0 } # A general purpose debug tool. # list_array <array_name> list_array() { [ $# -eq 1 ] || return 1 # One argument required. local -a _la_lines set -f local IFS=${NO_WSP} eval _la_lines=\(\ \$\{$1\[@\]\}\ \) echo echo "Element count "${#_la_lines[@]}" array "${1} local _ln_cnt=${#_la_lines[@]} for (( _i = 0; _i < ${_ln_cnt}; _i++ )) do echo 'Element '$_i' >'${_la_lines[$_i]}'<' done set +f return 0 } # # # 'Hunt the Spammer' program code # # # pend_init # Ready stack engine. pend_func credits # Last thing to print. # # # Deal with user # # # live_log_die # Setup debug trace log. data_capture # Setup data capture file. echo do_user_args $@ # # # Haven't exited yet - There is some hope # # # # Discovery group - Execution engine is LIFO - pend # in reverse order of execution. _hs_RC=0 # Hunt the Spammer return code pend_mark pend_func report_pairs # Report name-address pairs. # The two detail_* are mutually recursive functions. # They also pend expand_* functions as required. # These two (the last of ???) exit the recursion. pend_func detail_each_address # Get all resources of addresses. pend_func detail_each_name # Get all resources of names. # The two expand_* are mutually recursive functions, #+ which pend additional detail_* functions as required. pend_func expand_input_address 1 # Expand input names by address. pend_func expand_input_name 1 # #xpand input addresses by name. # Start with a unique set of names and addresses. pend_func unique_lines uc_address uc_address pend_func unique_lines uc_name uc_name # Separate mixed input of names and addresses. pend_func split_input pend_release # # # Pairs reported -- Unique list of IP addresses found echo _ip_cnt=${#known_address[@]} if [ ${#list_server[@]} -eq 0 ] then echo 'Blacklist server list empty, none checked.' else if [ ${_ip_cnt} -eq 0 ] then echo 'Known address list empty, none checked.' else _ip_cnt=${_ip_cnt}-1 # Start at top. echo 'Checking Blacklist servers.' for (( _ip = _ip_cnt ; _ip >= 0 ; _ip-- )) do pend_func check_lists $( printf '%q\n' ${known_address[$_ip]} ) done fi fi pend_release $_dot_dump # Graphics file dump $_log_dump # Execution trace echo ############################## # Example output from script # ############################## :<<-'_is_spammer_outputs_' ./is_spammer.bash 0 web4.alojamentos7.com Starting with domain name >web4.alojamentos7.com< Using default blacklist server list. Search depth limit: 0 .:....::::...:::...:::.......::..::...:::.......:: Known network pairs. 66.98.208.97 web4.alojamentos7.com. 66.98.208.97 ns1.alojamentos7.com. 69.56.202.147 ns2.alojamentos.ws. 66.98.208.97 alojamentos7.com. 66.98.208.97 web.alojamentos7.com. 69.56.202.146 ns1.alojamentos.ws. 69.56.202.146 alojamentos.ws. 66.235.180.113 ns1.alojamentos.org. 66.235.181.192 ns2.alojamentos.org. 66.235.180.113 alojamentos.org. 66.235.180.113 web6.alojamentos.org. 216.234.234.30 ns1.theplanet.com. 12.96.160.115 ns2.theplanet.com. 216.185.111.52 mail1.theplanet.com. 69.56.141.4 spooling.theplanet.com. 216.185.111.40 theplanet.com. 216.185.111.40 www.theplanet.com. 216.185.111.52 mail.theplanet.com. Checking Blacklist servers. Checking address 66.98.208.97 Records from dnsbl.sorbs.net "Spam Received See: http://www.dnsbl.sorbs.net/lookup.shtml?66.98.208.97" Checking address 69.56.202.147 Checking address 69.56.202.146 Checking address 66.235.180.113 Checking address 66.235.181.192 Checking address 216.185.111.40 Checking address 216.234.234.30 Checking address 12.96.160.115 Checking address 216.185.111.52 Checking address 69.56.141.4 Advanced Bash Scripting Guide: is_spammer.bash, v2, 2004-msz _is_spammer_outputs_ exit ${_hs_RC} #################################################### # The script ignores everything from here on down # #+ because of the 'exit' command, just above. # #################################################### Quickstart ========== Prerequisites Bash version 2.05b or 3.00 (bash --version) A version of Bash which supports arrays. Array support is included by default Bash configurations. 'dig,' version 9.x.x (dig $HOSTNAME, see first line of output) A version of dig which supports the +short options. See: dig_wrappers.bash for details. Optional Prerequisites 'named,' a local DNS caching program. Any flavor will do. Do twice: dig $HOSTNAME Check near bottom of output for: SERVER: 127.0.0.1#53 That means you have one running. Optional Graphics Support 'date,' a standard *nix thing. (date -R) dot Program to convert graphic description file to a diagram. (dot -V) A part of the Graph-Viz set of programs. See: [http://www.research.att.com/sw/tools/graphviz||GraphViz] 'dotty,' a visual editor for graphic description files. Also a part of the Graph-Viz set of programs. Quick Start In the same directory as the is_spammer.bash script; Do: ./is_spammer.bash Usage Details 1. Blacklist server choices. (a) To use default, built-in list: Do nothing. (b) To use your own list: i. Create a file with a single Blacklist server domain name per line. ii. Provide that filename as the last argument to the script. (c) To use a single Blacklist server: Last argument to the script. (d) To disable Blacklist lookups: i. Create an empty file (touch spammer.nul) Your choice of filename. ii. Provide the filename of that empty file as the last argument to the script. 2. Search depth limit. (a) To use the default value of 2: Do nothing. (b) To set a different limit: A limit of 0 means: no limit. i. export SPAMMER_LIMIT=1 or whatever limit you want. ii. OR provide the desired limit as the first argument to the script. 3. Optional execution trace log. (a) To use the default setting of no log output: Do nothing. (b) To write an execution trace log: export SPAMMER_TRACE=spammer.log or whatever filename you want. 4. Optional graphic description file. (a) To use the default setting of no graphic file: Do nothing. (b) To write a Graph-Viz graphic description file: export SPAMMER_DATA=spammer.dot or whatever filename you want. 5. Where to start the search. (a) Starting with a single domain name: i. Without a command line search limit: First argument to script. ii. With a command line search limit: Second argument to script. (b) Starting with a single IP address: i. Without a command line search limit: First argument to script. ii. With a command line search limit: Second argument to script. (c) Starting with (mixed) multiple name(s) and/or address(es): Create a file with one name or address per line. Your choice of filename. i. Without a command line search limit: Filename as first argument to script. ii. With a command line search limit: Filename as second argument to script. 6. What to do with the display output. (a) To view display output on screen: Do nothing. (b) To save display output to a file: Redirect stdout to a filename. (c) To discard display output: Redirect stdout to /dev/null. 7. Temporary end of decision making. press RETURN wait (optionally, watch the dots and colons). 8. Optionally check the return code. (a) Return code 0: All OK (b) Return code 1: Script setup failure (c) Return code 2: Something was blacklisted. 9. Where is my graph (diagram)? The script does not directly produce a graph (diagram). It only produces a graphic description file. You can process the graphic descriptor file that was output with the 'dot' program. Until you edit that descriptor file, to describe the relationships you want shown, all that you will get is a bunch of labeled name and address nodes. All of the script's discovered relationships are within a comment block in the graphic descriptor file, each with a descriptive heading. The editing required to draw a line between a pair of nodes from the information in the descriptor file may be done with a text editor. Given these lines somewhere in the descriptor file: # Known domain name nodes N0000 [label="guardproof.info."] ; N0002 [label="third.guardproof.info."] ; # Known address nodes A0000 [label="61.141.32.197"] ; /apps /backup /bin /boot /data /dev /etc /home /lib /lost+found /media /misc /mnt /net /opt /proc /root /sbin /selinux /srv /sys /tftpboot /tmp /usr /var # Known name->address edges NA0000 third.guardproof.info. 61.141.32.197 # Known parent->child edges PC0000 guardproof.info. third.guardproof.info. */ Turn that into the following lines by substituting node identifiers into the relationships: # Known domain name nodes N0000 [label="guardproof.info."] ; N0002 [label="third.guardproof.info."] ; # Known address nodes A0000 [label="61.141.32.197"] ; # PC0000 guardproof.info. third.guardproof.info. N0000->N0002 ; # NA0000 third.guardproof.info. 61.141.32.197 N0002->A0000 ; /apps /backup /bin /boot /data /dev /etc /home /lib /lost+found /media /misc /mnt /net /opt /proc /root /sbin /selinux /srv /sys /tftpboot /tmp /usr /var # Known name->address edges NA0000 third.guardproof.info. 61.141.32.197 # Known parent->child edges PC0000 guardproof.info. third.guardproof.info. */ Process that with the 'dot' program, and you have your first network diagram. In addition to the conventional graphic edges, the descriptor file includes similar format pair-data that describes services, zone records (sub-graphs?), blacklisted addresses, and other things which might be interesting to include in your graph. This additional information could be displayed as different node shapes, colors, line sizes, etc. The descriptor file can also be read and edited by a Bash script (of course). You should be able to find most of the functions required within the "is_spammer.bash" script. # End Quickstart. Additional Note ========== ==== Michael Zick points out that there is a "makeviz.bash" interactive Web site at rediris.es. Can't give the full URL, since this is not a publically accessible site.

Another anti-spam script.

Example A-31. Spammer Hunt

#!/bin/bash # whx.sh: "whois" spammer lookup # Author: Walter Dnes # Slight revisions (first section) by ABS Guide author. # Used in ABS Guide with permission. # Needs version 3.x or greater of Bash to run (because of =~ operator). # Commented by script author and ABS Guide author. E_BADARGS=65 # Missing command-line arg. E_NOHOST=66 # Host not found. E_TIMEOUT=67 # Host lookup timed out. E_UNDEF=68 # Some other (undefined) error. HOSTWAIT=10 # Specify up to 10 seconds for host query reply. # The actual wait may be a bit longer. OUTFILE=whois.txt # Output file. PORT=4321 if [ -z "$1" ] # Check for (required) command-line arg. then echo "Usage: $0 domain name or IP address" exit $E_BADARGS fi if [[ "$1" =~ "[a-zA-Z][a-zA-Z]$" ]] # Ends in two alpha chars? then # It's a domain name && must do host lookup. IPADDR=$(host -W $HOSTWAIT $1 | awk '{print $4}') # Doing host lookup to get IP address. # Extract final field. else IPADDR="$1" # Command-line arg was IP address. fi echo; echo "IP Address is: "$IPADDR""; echo if [ -e "$OUTFILE" ] then rm -f "$OUTFILE" echo "Stale output file \"$OUTFILE\" removed."; echo fi # Sanity checks. # (This section needs more work.) # =============================== if [ -z "$IPADDR" ] # No response. then echo "Host not found!" exit $E_NOHOST # Bail out. fi if [[ "$IPADDR" =~ "^[;;]" ]] # ;; connection timed out; no servers could be reached then echo "Host lookup timed out!" exit $E_TIMEOUT # Bail out. fi if [[ "$IPADDR" =~ "[(NXDOMAIN)]$" ]] # Host xxxxxxxxx.xxx not found: 3(NXDOMAIN) then echo "Host not found!" exit $E_NOHOST # Bail out. fi if [[ "$IPADDR" =~ "[(SERVFAIL)]$" ]] # Host xxxxxxxxx.xxx not found: 2(SERVFAIL) then echo "Host not found!" exit $E_NOHOST # Bail out. fi # ======================== Main body of script ======================== AFRINICquery() { # Define the function that queries AFRINIC. Echo a notification to the #+ screen, and then run the actual query, redirecting output to $OUTFILE. echo "Searching for $IPADDR in whois.afrinic.net" whois -h whois.afrinic.net "$IPADDR" > $OUTFILE # Check for presence of reference to an rwhois. # Warn about non-functional rwhois.infosat.net server #+ and attempt rwhois query. if grep -e "^remarks: .*rwhois\.[^ ]\+" "$OUTFILE" then echo " " >> $OUTFILE echo "***" >> $OUTFILE echo "***" >> $OUTFILE echo "Warning: rwhois.infosat.net was not working as of 2005/02/02" >> $OUTFILE echo " when this script was written." >> $OUTFILE echo "***" >> $OUTFILE echo "***" >> $OUTFILE echo " " >> $OUTFILE RWHOIS=`grep "^remarks: .*rwhois\.[^ ]\+" "$OUTFILE" | tail -n 1 |\ sed "s/\(^.*\)\(rwhois\..*\)\(:4.*\)/\2/"` whois -h ${RWHOIS}:${PORT} "$IPADDR" >> $OUTFILE fi } APNICquery() { echo "Searching for $IPADDR in whois.apnic.net" whois -h whois.apnic.net "$IPADDR" > $OUTFILE # Just about every country has its own internet registrar. # I don't normally bother consulting them, because the regional registry #+ usually supplies sufficient information. # There are a few exceptions, where the regional registry simply #+ refers to the national registry for direct data. # These are Japan and South Korea in APNIC, and Brasil in LACNIC. # The following if statement checks $OUTFILE (whois.txt) for the presence #+ of "KR" (South Korea) or "JP" (Japan) in the country field. # If either is found, the query is re-run against the appropriate #+ national registry. if grep -E "^country:[ ]+KR$" "$OUTFILE" then echo "Searching for $IPADDR in whois.krnic.net" whois -h whois.krnic.net "$IPADDR" >> $OUTFILE elif grep -E "^country:[ ]+JP$" "$OUTFILE" then echo "Searching for $IPADDR in whois.nic.ad.jp" whois -h whois.nic.ad.jp "$IPADDR"/e >> $OUTFILE fi } ARINquery() { echo "Searching for $IPADDR in whois.arin.net" whois -h whois.arin.net "$IPADDR" > $OUTFILE # Several large internet providers listed by ARIN have their own #+ internal whois service, referred to as "rwhois". # A large block of IP addresses is listed with the provider #+ under the ARIN registry. # To get the IP addresses of 2nd-level ISPs or other large customers, #+ one has to refer to the rwhois server on port 4321. # I originally started with a bunch of "if" statements checking for #+ the larger providers. # This approach is unwieldy, and there's always another rwhois server #+ that I didn't know about. # A more elegant approach is to check $OUTFILE for a reference #+ to a whois server, parse that server name out of the comment section, #+ and re-run the query against the appropriate rwhois server. # The parsing looks a bit ugly, with a long continued line inside #+ backticks. # But it only has to be done once, and will work as new servers are added. #@ ABS Guide author comment: it isn't all that ugly, and is, in fact, #@+ an instructive use of Regular Expressions. if grep -E "^Comment: .*rwhois.[^ ]+" "$OUTFILE" then RWHOIS=`grep -e "^Comment:.*rwhois\.[^ ]\+" "$OUTFILE" | tail -n 1 |\ sed "s/^\(.*\)\(rwhois\.[^ ]\+\)\(.*$\)/\2/"` echo "Searching for $IPADDR in ${RWHOIS}" whois -h ${RWHOIS}:${PORT} "$IPADDR" >> $OUTFILE fi } LACNICquery() { echo "Searching for $IPADDR in whois.lacnic.net" whois -h whois.lacnic.net "$IPADDR" > $OUTFILE # The following if statement checks $OUTFILE (whois.txt) for the presence of #+ "BR" (Brasil) in the country field. # If it is found, the query is re-run against whois.registro.br. if grep -E "^country:[ ]+BR$" "$OUTFILE" then echo "Searching for $IPADDR in whois.registro.br" whois -h whois.registro.br "$IPADDR" >> $OUTFILE fi } RIPEquery() { echo "Searching for $IPADDR in whois.ripe.net" whois -h whois.ripe.net "$IPADDR" > $OUTFILE } # Initialize a few variables. # aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html slash8 is the most significant octet # aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html slash16 consists of the two most significant octets # aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html octet2 is the second most significant octet slash8=`echo $IPADDR | cut -d. -f 1` if [ -z "$slash8" ] # Yet another sanity check. then echo "Undefined error!" exit $E_UNDEF fi slash16=`echo $IPADDR | cut -d. -f 1-2` # ^ Period specified as 'cut" delimiter. if [ -z "$slash16" ] then echo "Undefined error!" exit $E_UNDEF fi octet2=`echo $slash16 | cut -d. -f 2` if [ -z "$octet2" ] then echo "Undefined error!" exit $E_UNDEF fi # Check for various odds and ends of reserved space. # There is no point in querying for those addresses. if [ $slash8 == 0 ]; then echo $IPADDR is '"This Network"' space\; Not querying elif [ $slash8 == 10 ]; then echo $IPADDR is RFC1918 space\; Not querying elif [ $slash8 == 14 ]; then echo $IPADDR is '"Public Data Network"' space\; Not querying elif [ $slash8 == 127 ]; then echo $IPADDR is loopback space\; Not querying elif [ $slash16 == 169.254 ]; then echo $IPADDR is link-local space\; Not querying elif [ $slash8 == 172 ] && [ $octet2 -ge 16 ] && [ $octet2 -le 31 ];then echo $IPADDR is RFC1918 space\; Not querying elif [ $slash16 == 192.168 ]; then echo $IPADDR is RFC1918 space\; Not querying elif [ $slash8 -ge 224 ]; then echo $IPADDR is either Multicast or reserved space\; Not querying elif [ $slash8 -ge 200 ] && [ $slash8 -le 201 ]; then LACNICquery "$IPADDR" elif [ $slash8 -ge 202 ] && [ $slash8 -le 203 ]; then APNICquery "$IPADDR" elif [ $slash8 -ge 210 ] && [ $slash8 -le 211 ]; then APNICquery "$IPADDR" elif [ $slash8 -ge 218 ] && [ $slash8 -le 223 ]; then APNICquery "$IPADDR" # If we got this far without making a decision, query ARIN. # If a reference is found in $OUTFILE to APNIC, AFRINIC, LACNIC, or RIPE, #+ query the appropriate whois server. else ARINquery "$IPADDR" if grep "whois.afrinic.net" "$OUTFILE"; then AFRINICquery "$IPADDR" elif grep -E "^OrgID:[ ]+RIPE$" "$OUTFILE"; then RIPEquery "$IPADDR" elif grep -E "^OrgID:[ ]+APNIC$" "$OUTFILE"; then APNICquery "$IPADDR" elif grep -E "^OrgID:[ ]+LACNIC$" "$OUTFILE"; then LACNICquery "$IPADDR" fi fi #@ --------------------------------------------------------------- # Try also: # wget http://logi.cc/nw/whois.php3?ACTION=doQuery&DOMAIN=$IPADDR #@ --------------------------------------------------------------- # We've now finished the querying. # Echo a copy of the final result to the screen. cat $OUTFILE # Or "less $OUTFILE" . . . exit 0 #@ ABS Guide author comments: #@ Nothing fancy here, but still a very useful tool for hunting spammers. #@ Sure, the script can be cleaned up some, and it's still a bit buggy, #@+ (exercise for reader), but all the same, it's a nice piece of coding #@+ by Walter Dnes. #@ Thank you!

"Little Monster's" front end to wget.

Example A-32. Making wget easier to use

#!/bin/bash # wgetter2.bash # Author: Little Monster [monster@monstruum.co.uk] # ==> Used in ABS Guide with permission of script author. # ==> This script still needs debugging and fixups (exercise for reader). # ==> It could also use some additional editing in the comments. # This is wgetter2 -- #+ a Bash script to make wget a bit more friendly, and save typing. # Carefully crafted by Little Monster. # More or less complete on 02/02/2005. # If you think this script can be improved, #+ email me at: monster@monstruum.co.uk # ==> and cc: to the author of the ABS Guide, please. # This script is licenced under the GPL. # You are free to copy, alter and re-use it, #+ but please don't try to claim you wrote it. # Log your changes here instead. # ======================================================================= # changelog: # 07/02/2005. Fixups by Little Monster. # 02/02/2005. Minor additions by Little Monster. # (See after # +++++++++++ ) # 29/01/2005. Minor stylistic edits and cleanups by author of ABS Guide. # Added exit error codes. # 22/11/2004. Finished initial version of second version of wgetter: # wgetter2 is born. # 01/12/2004. Changed 'runn' function so it can be run 2 ways -- # either ask for a file name or have one input on the CL. # 01/12/2004. Made sensible handling of no URL's given. # 01/12/2004. Made loop of main options, so you don't # have to keep calling wgetter 2 all the time. # Runs as a session instead. # 01/12/2004. Added looping to 'runn' function. # Simplified and improved. # 01/12/2004. Added state to recursion setting. # Enables re-use of previous value. # 05/12/2004. Modified the file detection routine in the 'runn' function # so it's not fooled by empty values, and is cleaner. # 01/02/2004. Added cookie finding routine from later version (which # isn't ready yet), so as not to have hard-coded paths. # ======================================================================= # Error codes for abnormal exit. E_USAGE=67 # Usage message, then quit. E_NO_OPTS=68 # No command-line args entered. E_NO_URLS=69 # No URLs passed to script. E_NO_SAVEFILE=70 # No save filename passed to script. E_USER_EXIT=71 # User decides to quit. # Basic default wget command we want to use. # This is the place to change it, if required. # NB: if using a proxy, set http_proxy = yourproxy in .wgetrc. # Otherwise delete --proxy=on, below. # ==================================================================== CommandA="wget -nc -c -t 5 --progress=bar --random-wait --proxy=on -r" # ==================================================================== # -------------------------------------------------------------------- # Set some other variables and explain them. pattern=" -A .jpg,.JPG,.jpeg,.JPEG,.gif,.GIF,.htm,.html,.shtml,.php" # wget's option to only get certain types of file. # comment out if not using today=`date +%F` # Used for a filename. home=$HOME # Set HOME to an internal variable. # In case some other path is used, change it here. depthDefault=3 # Set a sensible default recursion. Depth=$depthDefault # Otherwise user feedback doesn't tie in properly. RefA="" # Set blank referring page. Flag="" # Default to not saving anything, #+ or whatever else might be wanted in future. lister="" # Used for passing a list of urls directly to wget. Woptions="" # Used for passing wget some options for itself. inFile="" # Used for the run function. newFile="" # Used for the run function. savePath="$home/w-save" Config="$home/.wgetter2rc" # This is where some variables can be stored, #+ if permanently changed from within the script. Cookie_List="$home/.cookielist" # So we know where the cookies are kept . . . cFlag="" # Part of the cookie file selection routine. # Define the options available. Easy to change letters here if needed. # These are the optional options; you don't just wait to be asked. save=s # Save command instead of executing it. cook=c # Change cookie file for this session. help=h # Usage guide. list=l # Pass wget the -i option and URL list. runn=r # Run saved commands as an argument to the option. inpu=i # Run saved commands interactively. wopt=w # Allow to enter options to pass directly to wget. # -------------------------------------------------------------------- if [ -z "$1" ]; then # Make sure we get something for wget to eat. echo "You must at least enter a URL or option!" echo "-$help for usage." exit $E_NO_OPTS fi # +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ # added added added added added added added added added added added added if [ ! -e "$Config" ]; then # See if configuration file exists. echo "Creating configuration file, $Config" echo "# This is the configuration file for wgetter2" > "$Config" echo "# Your customised settings will be saved in this file" >> "$Config" else source $Config # Import variables we set outside the script. fi if [ ! -e "$Cookie_List" ]; then # Set up a list of cookie files, if there isn't one. echo "Hunting for cookies . . ." find -name cookies.txt >> $Cookie_List # Create the list of cookie files. fi # Isolate this in its own 'if' statement, #+ in case we got interrupted while searching. if [ -z "$cFlag" ]; then # If we haven't already done this . . . echo # Make a nice space after the command prompt. echo "Looks like you haven't set up your source of cookies yet." n=0 # Make sure the counter #+ doesn't contain random values. while read; do Cookies[$n]=$REPLY # Put the cookie files we found into an array. echo "$n) ${Cookies[$n]}" # Create a menu. n=$(( n + 1 )) # Increment the counter. done < $Cookie_List # Feed the read statement. echo "Enter the number of the cookie file you want to use." echo "If you won't be using cookies, just press RETURN." echo echo "I won't be asking this again. Edit $Config" echo "If you decide to change at a later date" echo "or use the -${cook} option for per session changes." read if [ ! -z $REPLY ]; then # User didn't just press return. Cookie=" --load-cookies ${Cookies[$REPLY]}" # Set the variable here as well as in the config file. echo "Cookie=\" --load-cookies ${Cookies[$REPLY]}\"" >> $Config fi echo "cFlag=1" >> $Config # So we know not to ask again. fi # end added section end added section end added section end added section # +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ # Another variable. # This one may or may not be subject to variation. # A bit like the small print. CookiesON=$Cookie # echo "cookie file is $CookiesON" # For debugging. # echo "home is ${home}" # For debugging. # Got caught with this one! wopts() { echo "Enter options to pass to wget." echo "It is assumed you know what you're doing." echo echo "You can pass their arguments here too." # That is to say, everything passed here is passed to wget. read Wopts # Read in the options to be passed to wget. Woptions=" $Wopts" # ^ Why the leading space? # Assign to another variable. # Just for fun, or something . . . echo "passing options ${Wopts} to wget" # Mainly for debugging. # Is cute. return } save_func() { echo "Settings will be saved." if [ ! -d $savePath ]; then # See if directory exists. mkdir $savePath # Create the directory to save things in #+ if it isn't already there. fi Flag=S # Tell the final bit of code what to do. # Set a flag since stuff is done in main. return } usage() # Tell them how it works. { echo "Welcome to wgetter. This is a front end to wget." echo "It will always run wget with these options:" echo "$CommandA" echo "and the pattern to match: $pattern \ (which you can change at the top of this script)." echo "It will also ask you for recursion depth, \ and if you want to use a referring page." echo "Wgetter accepts the following options:" echo "" echo "-$help : Display this help." echo "-$save : Save the command to a file $savePath/wget-($today) \ instead of running it." echo "-$runn : Run saved wget commands instead of starting a new one -" echo "Enter filename as argument to this option." echo "-$inpu : Run saved wget commands interactively --" echo "The script will ask you for the filename." echo "-$cook : Change the cookies file for this session." echo "-$list : Tell wget to use URL's from a list instead of \ from the command line." echo "-$wopt : Pass any other options direct to wget." echo "" echo "See the wget man page for additional options \ you can pass to wget." echo "" exit $E_USAGE # End here. Don't process anything else. } list_func() # Gives the user the option to use the -i option to wget, #+ and a list of URLs. { while [ 1 ]; do echo "Enter the name of the file containing URL's (press q to change your mind)." read urlfile if [ ! -e "$urlfile" ] && [ "$urlfile" != q ]; then # Look for a file, or the quit option. echo "That file does not exist!" elif [ "$urlfile" = q ]; then # Check quit option. echo "Not using a url list." return else echo "using $urlfile." echo "If you gave url's on the command line, I'll use those first." # Report wget standard behaviour to the user. lister=" -i $urlfile" # This is what we want to pass to wget. return fi done } cookie_func() # Give the user the option to use a different cookie file. { while [ 1 ]; do echo "Change the cookies file. Press return if you don't want to change it." read Cookies # NB: this is not the same as Cookie, earlier. # There is an 's' on the end. # Bit like chocolate chips. if [ -z "$Cookies" ]; then # Escape clause for wusses. return elif [ ! -e "$Cookies" ]; then echo "File does not exist. Try again." # Keep em going . . . else CookiesON=" --load-cookies $Cookies" # File is good -- use it! return fi done } run_func() { if [ -z "$OPTARG" ]; then # Test to see if we used the in-line option or the query one. if [ ! -d "$savePath" ]; then # If directory doesn't exist . . . echo "$savePath does not appear to exist." echo "Please supply path and filename of saved wget commands:" read newFile until [ -f "$newFile" ]; do # Keep going till we get something. echo "Sorry, that file does not exist. Please try again." # Try really hard to get something. read newFile done # ----------------------------------------------------------------------- # if [ -z ( grep wget ${newfile} ) ]; then # Assume they haven't got the right file and bail out. # echo "Sorry, that file does not contain wget commands. Aborting." # exit # fi # # This is bogus code. # It doesn't actually work. # If anyone wants to fix it, feel free! # ----------------------------------------------------------------------- filePath="${newFile}" else echo "Save path is $savePath" echo "Please enter name of the file which you want to use." echo "You have a choice of:" ls $savePath # Give them a choice. read inFile until [ -f "$savePath/$inFile" ]; do # Keep going till #+ we get something. if [ ! -f "${savePath}/${inFile}" ]; then # If file doesn't exist. echo "Sorry, that file does not exist. Please choose from:" ls $savePath # If a mistake is made. read inFile fi done filePath="${savePath}/${inFile}" # Make one variable . . . fi else filePath="${savePath}/${OPTARG}" # Which can be many things . . . fi if [ ! -f "$filePath" ]; then # If a bogus file got through. echo "You did not specify a suitable file." echo "Run this script with the -${save} option first." echo "Aborting." exit $E_NO_SAVEFILE fi echo "Using: $filePath" while read; do eval $REPLY echo "Completed: $REPLY" done < $filePath # Feed the actual file we are using into a 'while' loop. exit } # Fish out any options we are using for the script. # This is based on the demo in "Learning The Bash Shell" (O'Reilly). while getopts ":$save$cook$help$list$runn:$inpu$wopt" opt do case $opt in $save) save_func;; # Save some wgetter sessions for later. $cook) cookie_func;; # Change cookie file. $help) usage;; # Get help. $list) list_func;; # Allow wget to use a list of URLs. $runn) run_func;; # Useful if you are calling wgetter from, #+ for example, a cron script. $inpu) run_func;; # When you don't know what your files are named. $wopt) wopts;; # Pass options directly to wget. \?) echo "Not a valid option." echo "Use -${wopt} to pass options directly to wget," echo "or -${help} for help";; # Catch anything else. esac done shift $((OPTIND - 1)) # Do funky magic stuff with $#. if [ -z "$1" ] && [ -z "$lister" ]; then # We should be left with at least one URL #+ on the command line, unless a list is #+ being used -- catch empty CL's. echo "No URL's given! You must enter them on the same line as wgetter2." echo "E.g., wgetter2 http://somesite http://anothersite." echo "Use $help option for more information." exit $E_NO_URLS # Bail out, with appropriate error code. fi URLS=" $@" # Use this so that URL list can be changed if we stay in the option loop. while [ 1 ]; do # This is where we ask for the most used options. # (Mostly unchanged from version 1 of wgetter) if [ -z $curDepth ]; then Current="" else Current=" Current value is $curDepth" fi echo "How deep should I go? \ (integer: Default is $depthDefault.$Current)" read Depth # Recursion -- how far should we go? inputB="" # Reset this to blank on each pass of the loop. echo "Enter the name of the referring page (default is none)." read inputB # Need this for some sites. echo "Do you want to have the output logged to the terminal" echo "(y/n, default is yes)?" read noHide # Otherwise wget will just log it to a file. case $noHide in # Now you see me, now you don't. y|Y ) hide="";; n|N ) hide=" -b";; aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html ) hide="";; esac if [ -z ${Depth} ]; then # User accepted either default or current depth, #+ in which case Depth is now empty. if [ -z ${curDepth} ]; then # See if a depth was set on a previous iteration. Depth="$depthDefault" # Set the default recursion depth if nothing #+ else to use. else Depth="$curDepth" # Otherwise, set the one we used before. fi fi Recurse=" -l $Depth" # Set how deep we want to go. curDepth=$Depth # Remember setting for next time. if [ ! -z $inputB ]; then RefA=" --referer=$inputB" # Option to use referring page. fi WGETTER="${CommandA}${pattern}${hide}${RefA}${Recurse}\ ${CookiesON}${lister}${Woptions}${URLS}" # Just string the whole lot together . . . # NB: no embedded spaces. # They are in the individual elements so that if any are empty, #+ we don't get an extra space. if [ -z "${CookiesON}" ] && [ "$cFlag" = "1" ] ; then echo "Warning -- can't find cookie file" # This should be changed, #+ in case the user has opted to not use cookies. fi if [ "$Flag" = "S" ]; then echo "$WGETTER" >> $savePath/wget-${today} # Create a unique filename for today, or append to it if it exists. echo "$inputB" >> $savePath/site-list-${today} # Make a list, so it's easy to refer back to, #+ since the whole command is a bit confusing to look at. echo "Command saved to the file $savePath/wget-${today}" # Tell the user. echo "Referring page URL saved to the file$ \ savePath/site-list-${today}" # Tell the user. Saver=" with save option" # Stick this somewhere, so it appears in the loop if set. else echo "*****************" echo "*****Getting*****" echo "*****************" echo "" echo "$WGETTER" echo "" echo "*****************" eval "$WGETTER" fi echo "" echo "Starting over$Saver." echo "If you want to stop, press q." echo "Otherwise, enter some URL's:" # Let them go again. Tell about save option being set. read case $REPLY in # Need to change this to a 'trap' clause. q|Q ) exit $E_USER_EXIT;; # Exercise for the reader? aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html ) URLS=" $REPLY";; esac echo "" done exit 0

Example A-33. A podcasting script

#!/bin/bash # bashpodder.sh: # By Linc 10/1/2004 # Find the latest script at #+ http://linc.homeunix.org:8080/scripts/bashpodder # Last revision 12/14/2004 - Many Contributors! # If you use this and have made improvements or have comments #+ drop me an email at linc dot fessenden at gmail dot com # I'd appreciate it! # ==> ABS Guide extra comments. # ==> Author of this script has kindly granted permission # ==>+ for inclusion in ABS Guide. # ==> ################################################################ # # ==> What is "podcasting"? # ==> It's broadcasting "radio shows" over the Internet. # ==> These shows can be played on iPods and other music file players. # ==> This script makes it possible. # ==> See documentation at the script author's site, above. # ==> ################################################################ # Make script crontab friendly: cd $(dirname $0) # ==> Change to directory where this script lives. # datadir is the directory you want podcasts saved to: datadir=$(date +%Y-%m-%d) # ==> Will create a directory with the name: YYYY-MM-DD # Check for and create datadir if necessary: if test ! -d $datadir then mkdir $datadir fi # Delete any temp file: rm -f temp.log # Read the bp.conf file and wget any url not already in the podcast.log file: while read podcast do # ==> Main action follows. file=$(wget -q $podcast -O - | tr '\r' '\n' | tr \' \" | \ sed -n 's/.*url="\([^"]*\)".*/\1/p') for url in $file do echo $url >> temp.log if ! grep "$url" podcast.log > /dev/null then wget -q -P $datadir "$url" fi done done < bp.conf # Move dynamically created log file to permanent log file: cat podcast.log >> temp.log sort temp.log | uniq > podcast.log rm temp.log # Create an m3u playlist: ls $datadir | grep -v m3u > $datadir/podcast.m3u exit 0 ################################################# For a different scripting approach to Podcasting, see Phil Salkie's article, "Internet Radio to Podcast with Shell Tools" in the September, 2005 issue of LINUX JOURNAL, http://www.linuxjournal.com/article/8171 #################################################

Example A-34. Nightly backup to a firewire HD

#!/bin/bash # nightly-backup.sh # http://www.richardneill.org/source.php#nightly-backup-rsync # Copyright (c) 2005 Richard Neill <backup@richardneill.org>. # This is Free Software licensed under the GNU GPL. # ==> Included in ABS Guide with script author's kind permission. # ==> (Thanks!) # This does a backup from the host computer to a locally connected #+ firewire HDD using rsync and ssh. # It then rotates the backups. # Run it via cron every night at 5am. # This only backs up the home directory. # If ownerships (other than the user's) should be preserved, #+ then run the rsync process as root (and re-instate the -o). # We save every day for 7 days, then every week for 4 weeks, #+ then every month for 3 months. # See: http://www.mikerubel.org/computers/rsync_snapshots/ #+ for more explanation of the theory. # Save as: $HOME/bin/nightly-backup_firewire-hdd.sh # Known bugs: # ---------- # i) Ideally, we want to exclude ~/.tmp and the browser caches. # ii) If the user is sitting at the computer at 5am, #+ and files are modified while the rsync is occurring, #+ then the BACKUP_JUSTINCASE branch gets triggered. # To some extent, this is a #+ feature, but it also causes a "disk-space leak". ##### BEGIN CONFIGURATION SECTION ############################################ LOCAL_USER=rjn # User whose home directory should be backed up. MOUNT_POINT=/backup # Mountpoint of backup drive. # NO trailing slash! # This must be unique (eg using a udev symlink) SOURCE_DIR=/home/$LOCAL_USER # NO trailing slash - it DOES matter to rsync. BACKUP_DEST_DIR=$MOUNT_POINT/backup/`hostname -s`.${LOCAL_USER}.nightly_backup DRY_RUN=false #If true, invoke rsync with -n, to do a dry run. # Comment out or set to false for normal use. VERBOSE=false # If true, make rsync verbose. # Comment out or set to false otherwise. COMPRESS=false # If true, compress. # Good for internet, bad on LAN. # Comment out or set to false otherwise. ### Exit Codes ### E_VARS_NOT_SET=64 E_COMMANDLINE=65 E_MOUNT_FAIL=70 E_NOSOURCEDIR=71 E_UNMOUNTED=72 E_BACKUP=73 ##### END CONFIGURATION SECTION ############################################## # Check that all the important variables have been set: if [ -z "$LOCAL_USER" ] || [ -z "$SOURCE_DIR" ] || [ -z "$MOUNT_POINT" ] || [ -z "$BACKUP_DEST_DIR" ] then echo 'One of the variables is not set! Edit the file: $0. BACKUP FAILED.' exit $E_VARS_NOT_SET fi if [ "$#" != 0 ] # If command-line param(s) . . . then # Here document(ation). cat <<-ENDOFTEXT Automatic Nightly backup run from cron. Read the source for more details: $0 The backup directory is $BACKUP_DEST_DIR . It will be created if necessary; initialisation is no longer required. WARNING: Contents of $BACKUP_DEST_DIR are rotated. Directories named 'backup.\$i' will eventually be DELETED. We keep backups from every day for 7 days (1-8), then every week for 4 weeks (9-12), then every month for 3 months (13-15). You may wish to add this to your crontab using 'crontab -e' # Back up files: $SOURCE_DIR to $BACKUP_DEST_DIR #+ every night at 3:15 am 15 03 aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html /home/$LOCAL_USER/bin/nightly-backup_firewire-hdd.sh Don't forget to verify the backups are working, especially if you don't read cron's mail!" ENDOFTEXT exit $E_COMMANDLINE fi # Parse the options. # ================== if [ "$DRY_RUN" == "true" ]; then DRY_RUN="-n" echo "WARNING:" echo "THIS IS A 'DRY RUN'!" echo "No data will actually be transferred!" else DRY_RUN="" fi if [ "$VERBOSE" == "true" ]; then VERBOSE="-v" else VERBOSE="" fi if [ "$COMPRESS" == "true" ]; then COMPRESS="-z" else COMPRESS="" fi # Every week (actually of 8 days) and every month, #+ extra backups are preserved. DAY_OF_MONTH=`date +%d` # Day of month (01..31). if [ $DAY_OF_MONTH = 01 ]; then # First of month. MONTHSTART=true elif [ $DAY_OF_MONTH = 08 \ -o $DAY_OF_MONTH = 16 \ -o $DAY_OF_MONTH = 24 ]; then # Day 8,16,24 (use 8, not 7 to better handle 31-day months) WEEKSTART=true fi # Check that the HDD is mounted. # At least, check that *something* is mounted here! # We can use something unique to the device, rather than just guessing #+ the scsi-id by having an appropriate udev rule in #+ /etc/udev/rules.d/10-rules.local #+ and by putting a relevant entry in /etc/fstab. # Eg: this udev rule: # BUS="scsi", KERNEL="sd*", SYSFS{vendor}="WDC WD16", # SYSFS{model}="00JB-00GVA0 ", NAME="%k", SYMLINK="lacie_1394d%n" if mount | grep $MOUNT_POINT >/dev/null; then echo "Mount point $MOUNT_POINT is indeed mounted. OK" else echo -n "Attempting to mount $MOUNT_POINT..." # If it isn't mounted, try to mount it. sudo mount $MOUNT_POINT 2>/dev/null if mount | grep $MOUNT_POINT >/dev/null; then UNMOUNT_LATER=TRUE echo "OK" # Note: Ensure that this is also unmounted #+ if we exit prematurely with failure. else echo "FAILED" echo -e "Nothing is mounted at $MOUNT_POINT. BACKUP FAILED!" exit $E_MOUNT_FAIL fi fi # Check that source dir exists and is readable. if [ ! -r $SOURCE_DIR ] ; then echo "$SOURCE_DIR does not exist, or cannot be read. BACKUP FAILED." exit $E_NOSOURCEDIR fi # Check that the backup directory structure is as it should be. # If not, create it. # Create the subdirectories. # Note that backup.0 will be created as needed by rsync. for ((i=1;i<=15;i++)); do if [ ! -d $BACKUP_DEST_DIR/backup.$i ]; then if /bin/mkdir -p $BACKUP_DEST_DIR/backup.$i ; then # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ No [ ] test brackets. Why? echo "Warning: directory $BACKUP_DEST_DIR/backup.$i is missing," echo "or was not initialised. (Re-)creating it." else echo "ERROR: directory $BACKUP_DEST_DIR/backup.$i" echo "is missing and could not be created." if [ "$UNMOUNT_LATER" == "TRUE" ]; then # Before we exit, unmount the mount point if necessary. cd sudo umount $MOUNT_POINT && echo "Unmounted $MOUNT_POINT again. Giving up." fi exit $E_UNMOUNTED fi fi done # Set the permission to 700 for security #+ on an otherwise permissive multi-user system. if ! /bin/chmod 700 $BACKUP_DEST_DIR ; then echo "ERROR: Could not set permissions on $BACKUP_DEST_DIR to 700." if [ "$UNMOUNT_LATER" == "TRUE" ]; then # Before we exit, unmount the mount point if necessary. cd ; sudo umount $MOUNT_POINT \ && echo "Unmounted $MOUNT_POINT again. Giving up." fi exit $E_UNMOUNTED fi # Create the symlink: current -> backup.1 if required. # A failure here is not critical. cd $BACKUP_DEST_DIR if [ ! -h current ] ; then if ! /bin/ln -s backup.1 current ; then echo "WARNING: could not create symlink current -> backup.1" fi fi # Now, do the rsync. echo "Now doing backup with rsync..." echo "Source dir: $SOURCE_DIR" echo -e "Backup destination dir: $BACKUP_DEST_DIR\n" /usr/bin/rsync $DRY_RUN $VERBOSE -a -S --delete --modify-window=60 \ --link-dest=../backup.1 $SOURCE_DIR $BACKUP_DEST_DIR/backup.0/ # Only warn, rather than exit if the rsync failed, #+ since it may only be a minor problem. # E.g., if one file is not readable, rsync will fail. # This shouldn't prevent the rotation. # Not using, e.g., `date +%a` since these directories #+ are just full of links and don't consume *that much* space. if [ $? != 0 ]; then BACKUP_JUSTINCASE=backup.`date +%F_%T`.justincase echo "WARNING: the rsync process did not entirely succeed." echo "Something might be wrong." echo "Saving an extra copy at: $BACKUP_JUSTINCASE" echo "WARNING: if this occurs regularly, a LOT of space will be consumed," echo "even though these are just hard-links!" fi # Save a readme in the backup parent directory. # Save another one in the recent subdirectory. echo "Backup of $SOURCE_DIR on `hostname` was last run on \ `date`" > $BACKUP_DEST_DIR/README.txt echo "This backup of $SOURCE_DIR on `hostname` was created on \ `date`" > $BACKUP_DEST_DIR/backup.0/README.txt # If we are not in a dry run, rotate the backups. [ -z "$DRY_RUN" ] && # Check how full the backup disk is. # Warn if 90%. if 98% or more, we'll probably fail, so give up. # (Note: df can output to more than one line.) # We test this here, rather than before #+ so that rsync may possibly have a chance. DISK_FULL_PERCENT=`/bin/df $BACKUP_DEST_DIR | tr "\n" ' ' | awk '{print $12}' | grep -oE [0-9]+ ` echo "Disk space check on backup partition \ $MOUNT_POINT $DISK_FULL_PERCENT% full." if [ $DISK_FULL_PERCENT -gt 90 ]; then echo "Warning: Disk is greater than 90% full." fi if [ $DISK_FULL_PERCENT -gt 98 ]; then echo "Error: Disk is full! Giving up." if [ "$UNMOUNT_LATER" == "TRUE" ]; then # Before we exit, unmount the mount point if necessary. cd; sudo umount $MOUNT_POINT && echo "Unmounted $MOUNT_POINT again. Giving up." fi exit $E_UNMOUNTED fi # Create an extra backup. # If this copy fails, give up. if [ -n "$BACKUP_JUSTINCASE" ]; then if ! /bin/cp -al $BACKUP_DEST_DIR/backup.0 \ $BACKUP_DEST_DIR/$BACKUP_JUSTINCASE then echo "ERROR: Failed to create extra copy \ $BACKUP_DEST_DIR/$BACKUP_JUSTINCASE" if [ "$UNMOUNT_LATER" == "TRUE" ]; then # Before we exit, unmount the mount point if necessary. cd ;sudo umount $MOUNT_POINT && echo "Unmounted $MOUNT_POINT again. Giving up." fi exit $E_UNMOUNTED fi fi # At start of month, rotate the oldest 8. if [ "$MONTHSTART" == "true" ]; then echo -e "\nStart of month. \ Removing oldest backup: $BACKUP_DEST_DIR/backup.15" && /bin/rm -rf $BACKUP_DEST_DIR/backup.15 && echo "Rotating monthly,weekly backups: \ $BACKUP_DEST_DIR/backup.[8-14] -> $BACKUP_DEST_DIR/backup.[9-15]" && /bin/mv $BACKUP_DEST_DIR/backup.14 $BACKUP_DEST_DIR/backup.15 && /bin/mv $BACKUP_DEST_DIR/backup.13 $BACKUP_DEST_DIR/backup.14 && /bin/mv $BACKUP_DEST_DIR/backup.12 $BACKUP_DEST_DIR/backup.13 && /bin/mv $BACKUP_DEST_DIR/backup.11 $BACKUP_DEST_DIR/backup.12 && /bin/mv $BACKUP_DEST_DIR/backup.10 $BACKUP_DEST_DIR/backup.11 && /bin/mv $BACKUP_DEST_DIR/backup.9 $BACKUP_DEST_DIR/backup.10 && /bin/mv $BACKUP_DEST_DIR/backup.8 $BACKUP_DEST_DIR/backup.9 # At start of week, rotate the second-oldest 4. elif [ "$WEEKSTART" == "true" ]; then echo -e "\nStart of week. \ Removing oldest weekly backup: $BACKUP_DEST_DIR/backup.12" && /bin/rm -rf $BACKUP_DEST_DIR/backup.12 && echo "Rotating weekly backups: \ $BACKUP_DEST_DIR/backup.[8-11] -> $BACKUP_DEST_DIR/backup.[9-12]" && /bin/mv $BACKUP_DEST_DIR/backup.11 $BACKUP_DEST_DIR/backup.12 && /bin/mv $BACKUP_DEST_DIR/backup.10 $BACKUP_DEST_DIR/backup.11 && /bin/mv $BACKUP_DEST_DIR/backup.9 $BACKUP_DEST_DIR/backup.10 && /bin/mv $BACKUP_DEST_DIR/backup.8 $BACKUP_DEST_DIR/backup.9 else echo -e "\nRemoving oldest daily backup: $BACKUP_DEST_DIR/backup.8" && /bin/rm -rf $BACKUP_DEST_DIR/backup.8 fi && # Every day, rotate the newest 8. echo "Rotating daily backups: \ $BACKUP_DEST_DIR/backup.[1-7] -> $BACKUP_DEST_DIR/backup.[2-8]" && /bin/mv $BACKUP_DEST_DIR/backup.7 $BACKUP_DEST_DIR/backup.8 && /bin/mv $BACKUP_DEST_DIR/backup.6 $BACKUP_DEST_DIR/backup.7 && /bin/mv $BACKUP_DEST_DIR/backup.5 $BACKUP_DEST_DIR/backup.6 && /bin/mv $BACKUP_DEST_DIR/backup.4 $BACKUP_DEST_DIR/backup.5 && /bin/mv $BACKUP_DEST_DIR/backup.3 $BACKUP_DEST_DIR/backup.4 && /bin/mv $BACKUP_DEST_DIR/backup.2 $BACKUP_DEST_DIR/backup.3 && /bin/mv $BACKUP_DEST_DIR/backup.1 $BACKUP_DEST_DIR/backup.2 && /bin/mv $BACKUP_DEST_DIR/backup.0 $BACKUP_DEST_DIR/backup.1 && SUCCESS=true if [ "$UNMOUNT_LATER" == "TRUE" ]; then # Unmount the mount point if it wasn't mounted to begin with. cd ; sudo umount $MOUNT_POINT && echo "Unmounted $MOUNT_POINT again." fi if [ "$SUCCESS" == "true" ]; then echo 'SUCCESS!' exit 0 fi # Should have already exited if backup worked. echo 'BACKUP FAILED! Is this just a dry run? Is the disk full?) ' exit $E_BACKUP

Example A-35. An expanded cd command

########################################################################### # # cdll # by Phil Braham # # ############################################ # Latest version of this script available from # http://freshmeat.net/projects/cd/ # ############################################ # # .cd_new # # An enhancement of the Unix cd command # # There are unlimited stack entries and special entries. The stack # entries keep the last cd_maxhistory # directories that have been used. The special entries can be # assigned to commonly used directories. # # The special entries may be pre-assigned by setting the environment # variables CDSn or by using the -u or -U command. # # The following is a suggestion for the .profile file: # # . cdll # Set up the cd command # alias cd='cd_new' # Replace the cd command # cd -U # Upload pre-assigned entries for # #+ the stack and special entries # cd -D # Set non-default mode # alias @="cd_new @" # Allow @ to be used to get history # # For help type: # # cd -h or # cd -H # # ########################################################################### # # Version 1.2.1 # # Written by Phil Braham - Realtime Software Pty Ltd # (realtime@mpx.com.au) # Please send any suggestions or enhancements to the author (also at # phil@braham.net) # ############################################################################ cd_hm () { ${PRINTF} "%s" "cd [dir] [0-9] [@[s|h] [-g [<dir>]] [-d] \ [-D] [-r<n>] [dir|0-9] [-R<n>] [<dir>|0-9] [-s<n>] [-S<n>] [-u] [-U] [-f] [-F] [-h] [-H] [-v] <dir> Go to directory 0-n Go to previous directory (0 is previous, 1 is last but 1 etc) n is up to max history (default is 50) @ List history and special entries @h List history entries @s List special entries -g [<dir>] Go to literal name (bypass special names) This is to allow access to dirs called '0','1','-h' etc -d Change default action - verbose. (See note) -D Change default action - silent. (See note) -s<n> Go to the special entry <n>* -S<n> Go to the special entry <n> and replace it with the current dir* -r<n> [<dir>] Go to directory <dir> and then put it on special entry <n>* -R<n> [<dir>] Go to directory <dir> and put current dir on special entry <n>* -a<n> Alternative suggested directory. See note below. -f [<file>] File entries to <file>. -u [<file>] Update entries from <file>. If no filename supplied then default file (${CDPath}${2:-"$CDFile"}) is used -F and -U are silent versions -v Print version number -h Help -H Detailed help *The special entries (0 - 9) are held until log off, replaced by another entry or updated with the -u command Alternative suggested directories: If a directory is not found then CD will suggest any possibilities. These are directories starting with the same letters and if any are found they are listed prefixed with -a<n> where <n> is a number. It's possible to go to the directory by entering cd -a<n> on the command line. The directory for -r<n> or -R<n> may be a number. For example: $ cd -r3 4 Go to history entry 4 and put it on special entry 3 $ cd -R3 4 Put current dir on the special entry 3 and go to history entry 4 $ cd -s3 Go to special entry 3 Note that commands R,r,S and s may be used without a number and refer to 0: $ cd -s Go to special entry 0 $ cd -S Go to special entry 0 and make special entry 0 current dir $ cd -r 1 Go to history entry 1 and put it on special entry 0 $ cd -r Go to history entry 0 and put it on special entry 0 " if ${TEST} "$CD_MODE" = "PREV" then ${PRINTF} "$cd_mnset" else ${PRINTF} "$cd_mset" fi } cd_Hm () { cd_hm ${PRINTF} "%s" " The previous directories (0-$cd_maxhistory) are stored in the environment variables CD[0] - CD[$cd_maxhistory] Similarly the special directories S0 - $cd_maxspecial are in the environment variable CDS[0] - CDS[$cd_maxspecial] and may be accessed from the command line The default pathname for the -f and -u commands is $CDPath The default filename for the -f and -u commands is $CDFile Set the following environment variables: CDL_PROMPTLEN - Set to the length of prompt you require. Prompt string is set to the right characters of the current directory. If not set then prompt is left unchanged CDL_PROMPT_PRE - Set to the string to prefix the prompt. Default is: non-root: \"\\[\\e[01;34m\\]\" (sets colour to blue). root: \"\\[\\e[01;31m\\]\" (sets colour to red). CDL_PROMPT_POST - Set to the string to suffix the prompt. Default is: non-root: \"\\[\\e[00m\\]$\" (resets colour and displays $). root: \"\\[\\e[00m\\]#\" (resets colour and displays #). CDPath - Set the default path for the -f & -u options. Default is home directory CDFile - Set the default filename for the -f & -u options. Default is cdfile " cd_version } cd_version () { printf "Version: ${VERSION_MAJOR}.${VERSION_MINOR} Date: ${VERSION_DATE}\n" } # # Truncate right. # # params: # p1 - string # p2 - length to truncate to # # returns string in tcd # cd_right_trunc () { local tlen=${2} local plen=${#1} local str="${1}" local diff local filler="<--" if ${TEST} ${plen} -le ${tlen} then tcd="${str}" else let diff=${plen}-${tlen} elen=3 if ${TEST} ${diff} -le 2 then let elen=${diff} fi tlen=-${tlen} let tlen=${tlen}+${elen} tcd=${filler:0:elen}${str:tlen} fi } # # Three versions of do history: # cd_dohistory - packs history and specials side by side # cd_dohistoryH - Shows only hstory # cd_dohistoryS - Shows only specials # cd_dohistory () { cd_getrc ${PRINTF} "History:\n" local -i count=${cd_histcount} while ${TEST} ${count} -ge 0 do cd_right_trunc "${CD[count]}" ${cd_lchar} ${PRINTF} "%2d %-${cd_lchar}.${cd_lchar}s " ${count} "${tcd}" cd_right_trunc "${CDS[count]}" ${cd_rchar} ${PRINTF} "S%d %-${cd_rchar}.${cd_rchar}s\n" ${count} "${tcd}" count=${count}-1 done } cd_dohistoryH () { cd_getrc ${PRINTF} "History:\n" local -i count=${cd_maxhistory} while ${TEST} ${count} -ge 0 do ${PRINTF} "${count} %-${cd_flchar}.${cd_flchar}s\n" ${CD[$count]} count=${count}-1 done } cd_dohistoryS () { cd_getrc ${PRINTF} "Specials:\n" local -i count=${cd_maxspecial} while ${TEST} ${count} -ge 0 do ${PRINTF} "S${count} %-${cd_flchar}.${cd_flchar}s\n" ${CDS[$count]} count=${count}-1 done } cd_getrc () { cd_flchar=$(stty -a | awk -F \; '/rows/ { print $2 $3 }' | awk -F \ '{ print $4 }') if ${TEST} ${cd_flchar} -ne 0 then cd_lchar=${cd_flchar}/2-5 cd_rchar=${cd_flchar}/2-5 cd_flchar=${cd_flchar}-5 else cd_flchar=${FLCHAR:=75} # cd_flchar is used for for the @s & @h history cd_lchar=${LCHAR:=35} cd_rchar=${RCHAR:=35} fi } cd_doselection () { local -i nm=0 cd_doflag="TRUE" if ${TEST} "${CD_MODE}" = "PREV" then if ${TEST} -z "$cd_npwd" then cd_npwd=0 fi fi tm=$(echo "${cd_npwd}" | cut -b 1) if ${TEST} "${tm}" = "-" then pm=$(echo "${cd_npwd}" | cut -b 2) nm=$(echo "${cd_npwd}" | cut -d $pm -f2) case "${pm}" in a) cd_npwd=${cd_sugg[$nm]} ;; s) cd_npwd="${CDS[$nm]}" ;; S) cd_npwd="${CDS[$nm]}" ; CDS[$nm]=`pwd` ;; r) cd_npwd="$2" ; cd_specDir=$nm ; cd_doselection "$1" "$2";; R) cd_npwd="$2" ; CDS[$nm]=`pwd` ; cd_doselection "$1" "$2";; esac fi if ${TEST} "${cd_npwd}" != "." -a "${cd_npwd}" \ != ".." -a "${cd_npwd}" -le ${cd_maxhistory} >>/dev/null 2>&1 then cd_npwd=${CD[$cd_npwd]} else case "$cd_npwd" in @) cd_dohistory ; cd_doflag="FALSE" ;; @h) cd_dohistoryH ; cd_doflag="FALSE" ;; @s) cd_dohistoryS ; cd_doflag="FALSE" ;; -h) cd_hm ; cd_doflag="FALSE" ;; -H) cd_Hm ; cd_doflag="FALSE" ;; -f) cd_fsave "SHOW" $2 ; cd_doflag="FALSE" ;; -u) cd_upload "SHOW" $2 ; cd_doflag="FALSE" ;; -F) cd_fsave "NOSHOW" $2 ; cd_doflag="FALSE" ;; -U) cd_upload "NOSHOW" $2 ; cd_doflag="FALSE" ;; -g) cd_npwd="$2" ;; -d) cd_chdefm 1; cd_doflag="FALSE" ;; -D) cd_chdefm 0; cd_doflag="FALSE" ;; -r) cd_npwd="$2" ; cd_specDir=0 ; cd_doselection "$1" "$2";; -R) cd_npwd="$2" ; CDS[0]=`pwd` ; cd_doselection "$1" "$2";; -s) cd_npwd="${CDS[0]}" ;; -S) cd_npwd="${CDS[0]}" ; CDS[0]=`pwd` ;; -v) cd_version ; cd_doflag="FALSE";; esac fi } cd_chdefm () { if ${TEST} "${CD_MODE}" = "PREV" then CD_MODE="" if ${TEST} $1 -eq 1 then ${PRINTF} "${cd_mset}" fi else CD_MODE="PREV" if ${TEST} $1 -eq 1 then ${PRINTF} "${cd_mnset}" fi fi } cd_fsave () { local sfile=${CDPath}${2:-"$CDFile"} if ${TEST} "$1" = "SHOW" then ${PRINTF} "Saved to %s\n" $sfile fi ${RM} -f ${sfile} local -i count=0 while ${TEST} ${count} -le ${cd_maxhistory} do echo "CD[$count]=\"${CD[$count]}\"" >> ${sfile} count=${count}+1 done count=0 while ${TEST} ${count} -le ${cd_maxspecial} do echo "CDS[$count]=\"${CDS[$count]}\"" >> ${sfile} count=${count}+1 done } cd_upload () { local sfile=${CDPath}${2:-"$CDFile"} if ${TEST} "${1}" = "SHOW" then ${PRINTF} "Loading from %s\n" ${sfile} fi . ${sfile} } cd_new () { local -i count local -i choose=0 cd_npwd="${1}" cd_specDir=-1 cd_doselection "${1}" "${2}" if ${TEST} ${cd_doflag} = "TRUE" then if ${TEST} "${CD[0]}" != "`pwd`" then count=$cd_maxhistory while ${TEST} $count -gt 0 do CD[$count]=${CD[$count-1]} count=${count}-1 done CD[0]=`pwd` fi command cd "${cd_npwd}" 2>/dev/null if ${TEST} $? -eq 1 then ${PRINTF} "Unknown dir: %s\n" "${cd_npwd}" local -i ftflag=0 for i in "${cd_npwd}"* do if ${TEST} -d "${i}" then if ${TEST} ${ftflag} -eq 0 then ${PRINTF} "Suggest:\n" ftflag=1 fi ${PRINTF} "\t-a${choose} %s\n" "$i" cd_sugg[$choose]="${i}" choose=${choose}+1 fi done fi fi if ${TEST} ${cd_specDir} -ne -1 then CDS[${cd_specDir}]=`pwd` fi if ${TEST} ! -z "${CDL_PROMPTLEN}" then cd_right_trunc "${PWD}" ${CDL_PROMPTLEN} cd_rp=${CDL_PROMPT_PRE}${tcd}${CDL_PROMPT_POST} export PS1="$(echo -ne ${cd_rp})" fi } ######################################################################### # # # Initialisation here # # # ######################################################################### # VERSION_MAJOR="1" VERSION_MINOR="2.1" VERSION_DATE="24-MAY-2003" # alias cd=cd_new # # Set up commands RM=/bin/rm TEST=test PRINTF=printf # Use builtin printf ######################################################################### # # # Change this to modify the default pre- and post prompt strings. # # These only come into effect if CDL_PROMPTLEN is set. # # # ######################################################################### if ${TEST} ${EUID} -eq 0 then # CDL_PROMPT_PRE=${CDL_PROMPT_PRE:="$HOSTNAME@"} CDL_PROMPT_PRE=${CDL_PROMPT_PRE:="\\[\\e[01;31m\\]"} # Root is in red CDL_PROMPT_POST=${CDL_PROMPT_POST:="\\[\\e[00m\\]#"} else CDL_PROMPT_PRE=${CDL_PROMPT_PRE:="\\[\\e[01;34m\\]"} # Users in blue CDL_PROMPT_POST=${CDL_PROMPT_POST:="\\[\\e[00m\\]$"} fi ######################################################################### # # cd_maxhistory defines the max number of history entries allowed. typeset -i cd_maxhistory=50 ######################################################################### # # cd_maxspecial defines the number of special entries. typeset -i cd_maxspecial=9 # # ######################################################################### # # cd_histcount defines the number of entries displayed in #+ the history command. typeset -i cd_histcount=9 # ######################################################################### export CDPath=${HOME}/ # Change these to use a different # #+ default path and filename # export CDFile=${CDFILE:=cdfile} # for the -u and -f commands # # ######################################################################### # typeset -i cd_lchar cd_rchar cd_flchar # This is the number of chars to allow for the # cd_flchar=${FLCHAR:=75} #+ cd_flchar is used for for the @s & @h history# typeset -ax CD CDS # cd_mset="\n\tDefault mode is now set - entering cd with no parameters \ has the default action\n\tUse cd -d or -D for cd to go to \ previous directory with no parameters\n" cd_mnset="\n\tNon-default mode is now set - entering cd with no \ parameters is the same as entering cd 0\n\tUse cd -d or \ -D to change default cd action\n" # ==================================================================== # : <<DOCUMENTATION Written by Phil Braham. Realtime Software Pty Ltd. Released under GNU license. Free to use. Please pass any modifications or comments to the author Phil Braham: realtime@mpx.com.au ======================================================================= cdll is a replacement for cd and incorporates similar functionality to the bash pushd and popd commands but is independent of them. This version of cdll has been tested on Linux using Bash. It will work on most Linux versions but will probably not work on other shells without modification. Introduction ============ cdll allows easy moving about between directories. When changing to a new directory the current one is automatically put onto a stack. By default 50 entries are kept, but this is configurable. Special directories can be kept for easy access - by default up to 10, but this is configurable. The most recent stack entries and the special entries can be easily viewed. The directory stack and special entries can be saved to, and loaded from, a file. This allows them to be set up on login, saved before logging out or changed when moving project to project. In addition, cdll provides a flexible command prompt facility that allows, for example, a directory name in colour that is truncated from the left if it gets too long. Setting up cdll =============== Copy cdll to either your local home directory or a central directory such as /usr/bin (this will require root access). Copy the file cdfile to your home directory. It will require read and write access. This a default file that contains a directory stack and special entries. To replace the cd command you must add commands to your login script. The login script is one or more of: /etc/profile ~/.bash_profile ~/.bash_login ~/.profile ~/.bashrc /etc/bash.bashrc.local To setup your login, ~/.bashrc is recommended, for global (and root) setup add the commands to /etc/bash.bashrc.local To set up on login, add the command: . <dir>/cdll For example if cdll is in your local home directory: . ~/cdll If in /usr/bin then: . /usr/bin/cdll If you want to use this instead of the buitin cd command then add: alias cd='cd_new' We would also recommend the following commands: alias @='cd_new @' cd -U cd -D If you want to use cdll's prompt facilty then add the following: CDL_PROMPTLEN=nn Where nn is a number described below. Initially 99 would be suitable number. Thus the script looks something like this: ###################################################################### # CD Setup ###################################################################### CDL_PROMPTLEN=21 # Allow a prompt length of up to 21 characters . /usr/bin/cdll # Initialise cdll alias cd='cd_new' # Replace the built in cd command alias @='cd_new @' # Allow @ at the prompt to display history cd -U # Upload directories cd -D # Set default action to non-posix ###################################################################### The full meaning of these commands will become clear later. There are a couple of caveats. If another program changes the directory without calling cdll, then the directory won't be put on the stack and also if the prompt facility is used then this will not be updated. Two programs that can do this are pushd and popd. To update the prompt and stack simply enter: cd . Note that if the previous entry on the stack is the current directory then the stack is not updated. Usage ===== cd [dir] [0-9] [@[s|h] [-g <dir>] [-d] [-D] [-r<n>] [dir|0-9] [-R<n>] [<dir>|0-9] [-s<n>] [-S<n>] [-u] [-U] [-f] [-F] [-h] [-H] [-v] <dir> Go to directory 0-n Goto previous directory (0 is previous, 1 is last but 1, etc.) n is up to max history (default is 50) @ List history and special entries (Usually available as $ @) @h List history entries @s List special entries -g [<dir>] Go to literal name (bypass special names) This is to allow access to dirs called '0','1','-h' etc -d Change default action - verbose. (See note) -D Change default action - silent. (See note) -s<n> Go to the special entry <n> -S<n> Go to the special entry <n> and replace it with the current dir -r<n> [<dir>] Go to directory <dir> and then put it on special entry <n> -R<n> [<dir>] Go to directory <dir> and put current dir on special entry <n> -a<n> Alternative suggested directory. See note below. -f [<file>] File entries to <file>. -u [<file>] Update entries from <file>. If no filename supplied then default file (~/cdfile) is used -F and -U are silent versions -v Print version number -h Help -H Detailed help Examples ======== These examples assume non-default mode is set (that is, cd with no parameters will go to the most recent stack directory), that aliases have been set up for cd and @ as described above and that cd's prompt facility is active and the prompt length is 21 characters. /home/phil$ @ # List the entries with the @ History: # Output of the @ command ..... # Skipped these entries for brevity 1 /home/phil/ummdev S1 /home/phil/perl # Most recent two history entries 0 /home/phil/perl/eg S0 /home/phil/umm/ummdev # and two special entries are shown /home/phil$ cd /home/phil/utils/Cdll # Now change directories /home/phil/utils/Cdll$ @ # Prompt reflects the directory. History: # New history ..... 1 /home/phil/perl/eg S1 /home/phil/perl # History entry 0 has moved to 1 0 /home/phil S0 /home/phil/umm/ummdev # and the most recent has entered To go to a history entry: /home/phil/utils/Cdll$ cd 1 # Go to history entry 1. /home/phil/perl/eg$ # Current directory is now what was 1 To go to a special entry: /home/phil/perl/eg$ cd -s1 # Go to special entry 1 /home/phil/umm/ummdev$ # Current directory is S1 To go to a directory called, for example, 1: /home/phil$ cd -g 1 # -g ignores the special meaning of 1 /home/phil/1$ To put current directory on the special list as S1: cd -r1 . # OR cd -R1 . # These have the same effect if the directory is #+ . (the current directory) To go to a directory and add it as a special The directory for -r<n> or -R<n> may be a number. For example: $ cd -r3 4 Go to history entry 4 and put it on special entry 3 $ cd -R3 4 Put current dir on the special entry 3 and go to history entry 4 $ cd -s3 Go to special entry 3 Note that commands R,r,S and s may be used without a number and refer to 0: $ cd -s Go to special entry 0 $ cd -S Go to special entry 0 and make special entry 0 current dir $ cd -r 1 Go to history entry 1 and put it on special entry 0 $ cd -r Go to history entry 0 and put it on special entry 0 Alternative suggested directories: If a directory is not found, then CD will suggest any possibilities. These are directories starting with the same letters and if any are found they are listed prefixed with -a<n> where <n> is a number. It's possible to go to the directory by entering cd -a<n> on the command line. Use cd -d or -D to change default cd action. cd -H will show current action. The history entries (0-n) are stored in the environment variables CD[0] - CD[n] Similarly the special directories S0 - 9 are in the environment variable CDS[0] - CDS[9] and may be accessed from the command line, for example: ls -l ${CDS[3]} cat ${CD[8]}/file.txt The default pathname for the -f and -u commands is ~ The default filename for the -f and -u commands is cdfile Configuration ============= The following environment variables can be set: CDL_PROMPTLEN - Set to the length of prompt you require. Prompt string is set to the right characters of the current directory. If not set, then prompt is left unchanged. Note that this is the number of characters that the directory is shortened to, not the total characters in the prompt. CDL_PROMPT_PRE - Set to the string to prefix the prompt. Default is: non-root: "\\[\\e[01;34m\\]" (sets colour to blue). root: "\\[\\e[01;31m\\]" (sets colour to red). CDL_PROMPT_POST - Set to the string to suffix the prompt. Default is: non-root: "\\[\\e[00m\\]$" (resets colour and displays $). root: "\\[\\e[00m\\]#" (resets colour and displays #). Note: CDL_PROMPT_PRE & _POST only t CDPath - Set the default path for the -f & -u options. Default is home directory CDFile - Set the default filename for the -f & -u options. Default is cdfile There are three variables defined in the file cdll which control the number of entries stored or displayed. They are in the section labeled 'Initialisation here' towards the end of the file. cd_maxhistory - The number of history entries stored. Default is 50. cd_maxspecial - The number of special entries allowed. Default is 9. cd_histcount - The number of history and special entries displayed. Default is 9. Note that cd_maxspecial should be >= cd_histcount to avoid displaying special entries that can't be set. Version: 1.2.1 Date: 24-MAY-2003 DOCUMENTATION

Example A-36. A soundcard setup script

#!/bin/bash # soundcard-on.sh # Script author: Mkarcher # http://www.thinkwiki.org/wiki ... # /Script_for_configuring_the_CS4239_sound_chip_in_PnP_mode # ABS Guide author made minor changes and added comments. # Couldn't contact script author to ask for permission to use, but ... #+ the script was released under the FDL, #+ so its use here should be both legal and ethical. # Sound-via-pnp-script for Thinkpad 600E #+ and possibly other computers with onboard CS4239/CS4610 #+ that do not work with the PCI driver #+ and are not recognized by the PnP code of snd-cs4236. # Also for some 770-series Thinkpads, such as the 770x. # Run as root user, of course. # # These are old and very obsolete laptop computers, #+ but this particular script is very instructive, #+ as it shows how to set up and hack device files. # Search for sound card pnp device: for dev in /sys/bus/pnp/devices/00:00 /sys/bus/pnp/devices/00:01 /sys/bus/pnp/devices/00:02 /sys/bus/pnp/devices/00:03 /sys/bus/pnp/devices/00:04 /sys/bus/pnp/devices/00:05 /sys/bus/pnp/devices/00:06 /sys/bus/pnp/devices/00:07 /sys/bus/pnp/devices/00:08 /sys/bus/pnp/devices/00:09 /sys/bus/pnp/devices/00:0a /sys/bus/pnp/devices/00:0b /sys/bus/pnp/devices/00:0c do grep CSC0100 $dev/id > /dev/null && WSSDEV=$dev grep CSC0110 $dev/id > /dev/null && CTLDEV=$dev done # On 770x: # WSSDEV = /sys/bus/pnp/devices/00:07 # CTLDEV = /sys/bus/pnp/devices/00:06 # These are symbolic links to /sys/devices/pnp0/ ... # Activate devices: # Thinkpad boots with devices disabled unless "fast boot" is turned off #+ (in BIOS). echo activate > $WSSDEV/resources echo activate > $CTLDEV/resources # Parse resource settings. { read # Discard "state = active" (see below). read bla port1 read bla port2 read bla port3 read bla irq read bla dma1 read bla dma2 # The "bla's" are labels in the first field: "io," "state," etc. # These are discarded. # Hack: with PnPBIOS: ports are: port1: WSS, port2: #+ OPL, port3: sb (unneeded) # with ACPI-PnP:ports are: port1: OPL, port2: sb, port3: WSS # (ACPI bios seems to be wrong here, the PnP-card-code in snd-cs4236.c #+ uses the PnPBIOS port order) # Detect port order using the fixed OPL port as reference. if [ ${port2%%-*} = 0x388 ] # ^^^^ Strip out everything following hyphen in port address. # So, if port1 is 0x530-0x537 #+ we're left with 0x530 -- the start address of the port. then # PnPBIOS: usual order port=${port1%%-*} oplport=${port2%%-*} else # ACPI: mixed-up order port=${port3%%-*} oplport=${port1%%-*} fi } < $WSSDEV/resources # To see what's going on here: # --------------------------- # cat /sys/devices/pnp0/00:07/resources # # state = active # io 0x530-0x537 # io 0x388-0x38b # io 0x220-0x233 # irq 5 # dma 1 # dma 0 # ^^^ "bla" labels in first field (discarded). { read # Discard first line, as above. read bla port1 cport=${port1%%-*} # ^^^^ # Just want _start_ address of port. } < $CTLDEV/resources # Load the module: modprobe --ignore-install snd-cs4236 port=$port cport=$cport\ fm_port=$oplport irq=$irq dma1=$dma1 dma2=$dma2 isapnp=0 index=0 # See the modprobe manpage. exit $?

Example A-37. Locating split paragraphs in a text file

#!/bin/bash # find-splitpara.sh # Finds split paragraphs in a text file, #+ and tags the line numbers. ARGCOUNT=1 # Expect one arg. E_WRONGARGS=65 file="$1" # Target filename. lineno=1 # Line number. Start at 1. Flag=0 # Blank line flag. if [ $# -ne "$ARGCOUNT" ] then echo "Usage: `basename $0` FILENAME" exit $E_WRONGARGS fi file_read () # Scan file for pattern, then print line. { while read line do if [[ "$line" =~ ^[a-z] && $Flag -eq 1 ]] then # Line begins with lc character, following blank line. echo -n "$lineno:: " echo "$line" fi if [[ "$line" =~ "^$" ]] then # If blank line, Flag=1 #+ set flag. else Flag=0 fi ((lineno++)) done } < $file # Redirect file into function's stdin. file_read exit $? # ---------------------------------------------------------------- This is line one of an example paragraph, bla, bla, bla. This is line two, and line three should follow on next line, but there is a blank line separating the two parts of the paragraph. # ---------------------------------------------------------------- Running this script on a file containing the above paragraph yields: 4:: there is a blank line separating the two parts of the paragraph. There will be additional output for all the other split paragraphs in the target file.

Example A-38. Insertion sort

#!/bin/bash # insertion-sort.bash: Insertion sort implementation in Bash # Heavy use of Bash array features: #+ (string) slicing, merging, etc # URL: http://www.lugmen.org.ar/~jjo/jjotip/insertion-sort.bash.d #+ /insertion-sort.bash.sh # # Author: JuanJo Ciarlante <jjo@irrigacion.gov.ar> # Lightly reformatted by ABS Guide author. # License: GPLv2 # Used in ABS Guide with author's permission (thanks!). # # Test with: ./insertion-sort.bash -t # Or: bash insertion-sort.bash -t # The following *doesn't* work: # sh insertion-sort.bash -t # Why not? Hint: which Bash-specific features are disabled #+ when running a script by 'sh script.sh'? # : ${DEBUG:=0} # Debug, override with: DEBUG=1 ./scriptname . . . # Parameter substitution -- set DEBUG to 0 if not previously set. # Global array: "list" typeset -a list # Load whitespace-separated numbers from stdin. if [ "$1" = "-t" ]; then DEBUG=1 read -a list < <( od -Ad -w24 -t u2 /dev/urandom ) # Random list. # ^ ^ process substition else read -a list fi numelem=${#list[*]} # Shows the list, marking the element whose index is $1 #+ by surrounding it with the two chars passed as $2. # Whole line prefixed with $3. showlist() { echo "$3"${list[@]:0:$1} ${2:0:1}${list[$1]}${2:1:1} ${list[@]:$1+1}; } # Loop _pivot_ -- from second element to end of list. for(( i=1; i<numelem; i++ )) do ((DEBUG))&&showlist i "[]" " " # From current _pivot_, back to first element. for(( j=i; j; j-- )) do # Search for the 1st elem. less than current "pivot" . . . [[ "${list[j-1]}" -le "${list[i]}" ]] && break done (( i==j )) && continue ## No insertion was needed for this element. # . . . Move list[i] (pivot) to the left of list[j]: list=(${list[@]:0:j} ${list[i]} ${list[j]}\ # {0,j-1} {i} {j} ${list[@]:j+1:i-(j+1)} ${list[@]:i+1}) # {j+1,i-1} {i+1,last} ((DEBUG))&&showlist j "<>" "*" done echo echo "------" echo $'Result:\n'${list[@]} exit $?

Example A-39. Standard Deviation

#!/bin/bash # sd.sh: Standard Deviation # The Standard Deviation indicates how consistent a set of data is. # It shows to what extent the individual data points deviate from the #+ arithmetic mean, i.e., how much they "bounce around" (or cluster). # It is essentially the average deviation-distance of the #+ data points from the mean. # =========================================================== # # To calculate the Standard Deviation: # # 1 Find the arithmetic mean (average) of all the data points. # 2 Subtract each data point from the arithmetic mean, # and square that difference. # 3 Add all of the individual difference-squares in # 2. # 4 Divide the sum in # 3 by the number of data points. # This is known as the "variance." # 5 The square root of # 4 gives the Standard Deviation. # =========================================================== # count=0 # Number of data points; global. SC=9 # Scale to be used by bc. Nine decimal places. E_DATAFILE=90 # Data file error. # ----------------- Set data file --------------------- if [ ! -z $1 ] # Specify filename as cmd-line arg? then datafile="$1" # ASCII text file, else #+ one (numerical) data point per line! datafile=sample.dat fi # See example data file, below. if [ ! -e "$datafile" ] then echo "\""$datafile"\" does not exist!" exit $E_DATAFILE fi # ----------------------------------------------------- arith_mean () { local rt=0 # Running total. local am=0 # Arithmetic mean. local ct=0 # Number of data points. while read value # Read one data point at a time. do rt=$(echo "scale=$SC; $rt + $value" | bc) (( ct++ )) done am=$(echo "scale=$SC; $rt / $ct" | bc) echo $am; return $ct # This function "returns" TWO values! # Caution: This little trick will not work if $ct > 255! # To handle a larger number of data points, #+ simply comment out the "return $ct" above. } <"$datafile" # Feed in data file. sd () { mean1=$1 # Arithmetic mean (passed to function). n=$2 # How many data points. sum2=0 # Sum of squared differences ("variance"). avg2=0 # Average of $sum2. sdev=0 # Standard Deviation. while read value # Read one line at a time. do diff=$(echo "scale=$SC; $mean1 - $value" | bc) # Difference between arith. mean and data point. dif2=$(echo "scale=$SC; $diff aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html $diff" | bc) # Squared. sum2=$(echo "scale=$SC; $sum2 + $dif2" | bc) # Sum of squares. done avg2=$(echo "scale=$SC; $sum2 / $n" | bc) # Avg. of sum of squares. sdev=$(echo "scale=$SC; sqrt($avg2)" | bc) # Square root = echo $sdev # Standard Deviation. } <"$datafile" # Rewinds data file. # ======================================================= # mean=$(arith_mean); count=$? # Two returns from function! std_dev=$(sd $mean $count) echo echo "Number of data points in \""$datafile"\" = $count" echo "Arithmetic mean (average) = $mean" echo "Standard Deviation = $std_dev" echo # ======================================================= # exit # This script could stand some drastic streamlining, # but not at the cost of reduced legibility, please. # ++++++++++++++++++++++++++++++++++++++++ # # A sample data file (sample1.dat): # 18.35 # 19.0 # 18.88 # 18.91 # 18.64 # $ sh sd.sh sample1.dat # Number of data points in "sample1.dat" = 5 # Arithmetic mean (average) = 18.756000000 # Standard Deviation = .235338054 # ++++++++++++++++++++++++++++++++++++++++ #

Example A-40. A pad file generator for shareware authors

#!/bin/bash # pad.sh ###################################################### # PAD (xml) file creator #+ Written by Mendel Cooper <thegrendel@theriver.com>. #+ Released to the Public Domain. # # Generates a "PAD" descriptor file for shareware #+ packages, according to the specifications #+ of the ASP. # http://www.asp-shareware.org/pad ###################################################### # Accepts (optional) save filename as a command-line argument. if [ -n "$1" ] then savefile=$1 else savefile=save_file.xml # Default save_file name. fi # ===== PAD file headers ===== HDR1="<?xml version=\"1.0\" encoding=\"Windows-1252\" ?>" HDR2="<XML_DIZ_INFO>" HDR3="<MASTER_PAD_VERSION_INFO>" HDR4="\t<MASTER_PAD_VERSION>1.15</MASTER_PAD_VERSION>" HDR5="\t<MASTER_PAD_INFO>Portable Application Description, or PAD for short, is a data set that is used by shareware authors to disseminate information to anyone interested in their software products. To find out more go to http://www.asp-shareware.org/pad</MASTER_PAD_INFO>" HDR6="</MASTER_PAD_VERSION_INFO>" # ============================ fill_in () { if [ -z "$2" ] then echo -n "$1? " # Get user input. else echo -n "$1 $2? " # Additional query? fi read var # May paste to fill in field. # This shows how flexible "read" can be. if [ -z "$var" ] then echo -e "\t\t<$1 />" >>$savefile # Indent with 2 tabs. return else echo -e "\t\t<$1>$var</$1>" >>$savefile return ${#var} # Return length of input string. fi } check_field_length () # Check length of program description fields. { # $1 = maximum field length # $2 = actual field length if [ "$2" -gt "$1" ] then echo "Warning: Maximum field length of $1 characters exceeded!" fi } clear # Clear screen. echo "PAD File Creator" echo "--- ---- -------" echo # Write File Headers to file. echo $HDR1 >$savefile echo $HDR2 >>$savefile echo $HDR3 >>$savefile echo -e $HDR4 >>$savefile echo -e $HDR5 >>$savefile echo $HDR6 >>$savefile # Company_Info echo "COMPANY INFO" CO_HDR="Company_Info" echo "<$CO_HDR>" >>$savefile fill_in Company_Name fill_in Address_1 fill_in Address_2 fill_in City_Town fill_in State_Province fill_in Zip_Postal_Code fill_in Country # If applicable: # fill_in ASP_Member "[Y/N]" # fill_in ASP_Member_Number # fill_in ESC_Member "[Y/N]" fill_in Company_WebSite_URL clear # Clear screen between sections. # Contact_Info echo "CONTACT INFO" CONTACT_HDR="Contact_Info" echo "<$CONTACT_HDR>" >>$savefile fill_in Author_First_Name fill_in Author_Last_Name fill_in Author_Email fill_in Contact_First_Name fill_in Contact_Last_Name fill_in Contact_Email echo -e "\t</$CONTACT_HDR>" >>$savefile # END Contact_Info clear # Support_Info echo "SUPPORT INFO" SUPPORT_HDR="Support_Info" echo "<$SUPPORT_HDR>" >>$savefile fill_in Sales_Email fill_in Support_Email fill_in General_Email fill_in Sales_Phone fill_in Support_Phone fill_in General_Phone fill_in Fax_Phone echo -e "\t</$SUPPORT_HDR>" >>$savefile # END Support_Info echo "</$CO_HDR>" >>$savefile # END Company_Info clear # Program_Info echo "PROGRAM INFO" PROGRAM_HDR="Program_Info" echo "<$PROGRAM_HDR>" >>$savefile fill_in Program_Name fill_in Program_Version fill_in Program_Release_Month fill_in Program_Release_Day fill_in Program_Release_Year fill_in Program_Cost_Dollars fill_in Program_Cost_Other fill_in Program_Type "[Shareware/Freeware/GPL]" fill_in Program_Release_Status "[Beta, Major Upgrade, etc.]" fill_in Program_Install_Support fill_in Program_OS_Support "[Win9x/Win2k/Linux/etc.]" fill_in Program_Language "[English/Spanish/etc.]" echo; echo # File_Info echo "FILE INFO" FILEINFO_HDR="File_Info" echo "<$FILEINFO_HDR>" >>$savefile fill_in Filename_Versioned fill_in Filename_Previous fill_in Filename_Generic fill_in Filename_Long fill_in File_Size_Bytes fill_in File_Size_K fill_in File_Size_MB echo -e "\t</$FILEINFO_HDR>" >>$savefile # END File_Info clear # Expire_Info echo "EXPIRE INFO" EXPIRE_HDR="Expire_Info" echo "<$EXPIRE_HDR>" >>$savefile fill_in Has_Expire_Info "Y/N" fill_in Expire_Count fill_in Expire_Based_On fill_in Expire_Other_Info fill_in Expire_Month fill_in Expire_Day fill_in Expire_Year echo -e "\t</$EXPIRE_HDR>" >>$savefile # END Expire_Info clear # More Program_Info echo "ADDITIONAL PROGRAM INFO" fill_in Program_Change_Info fill_in Program_Specific_Category fill_in Program_Categories fill_in Includes_JAVA_VM "[Y/N]" fill_in Includes_VB_Runtime "[Y/N]" fill_in Includes_DirectX "[Y/N]" # END More Program_Info echo "</$PROGRAM_HDR>" >>$savefile # END Program_Info clear # Program Description echo "PROGRAM DESCRIPTIONS" PROGDESC_HDR="Program_Descriptions" echo "<$PROGDESC_HDR>" >>$savefile LANG="English" echo "<$LANG>" >>$savefile fill_in Keywords "[comma + space separated]" echo echo "45, 80, 250, 450, 2000 word program descriptions" echo "(may cut and paste into field)" # It would be highly appropriate to compose the following #+ "Char_Desc" fields with a text editor, #+ then cut-and-paste the text into the answer fields. echo echo " |---------------45 characters---------------|" fill_in Char_Desc_45 check_field_length 45 "$?" echo fill_in Char_Desc_80 check_field_length 80 "$?" fill_in Char_Desc_250 check_field_length 250 "$?" fill_in Char_Desc_450 fill_in Char_Desc_2000 echo "</$LANG>" >>$savefile echo "</$PROGDESC_HDR>" >>$savefile # END Program Description clear echo "Done."; echo; echo echo "Save file is: \""$savefile"\"" exit 0

Example A-41. A man page editor

#!/bin/bash # maned.sh # A rudimentary man page editor # Version: 0.1 (Alpha, probably buggy) # Author: Mendel Cooper <thegrendel@theriver.com> # Reldate: 16 June 2008 # License: GPL3 savefile= # Global, used in multiple functions. E_NOINPUT=90 # User input missing (error). May or may not be critical. # =========== Markup Tags ============ # TopHeader=".TH" NameHeader=".SH NAME" SyntaxHeader=".SH SYNTAX" SynopsisHeader=".SH SYNOPSIS" InstallationHeader=".SH INSTALLATION" DescHeader=".SH DESCRIPTION" OptHeader=".SH OPTIONS" FilesHeader=".SH FILES" EnvHeader=".SH ENVIRONMENT" AuthHeader=".SH AUTHOR" BugsHeader=".SH BUGS" SeeAlsoHeader=".SH SEE ALSO" BOLD=".B" # Add more tags, as needed. # See groff docs for markup meanings. # ==================================== # start () { clear # Clear screen. echo "ManEd" echo "-----" echo echo "Simple man page creator" echo "Author: Mendel Cooper" echo; echo; echo } progname () { echo -n "Program name? " read name echo -n "Manpage section? [Hit RETURN for default (\"1\") ] " read section if [ -z "$section" ] then section=1 # Most man pages are in section 1. fi if [ -n "$name" ] then savefile=""$name"."$section"" # Filename suffix = section. echo -n "$1 " >>$savefile name1=$(echo "$name" | tr a-z A-Z) # Change to uppercase, #+ per man page convention. echo -n "$name1" >>$savefile else echo "Error! No input." # Mandatory input. exit $E_NOINPUT # Critical! fi echo -n " \"$section\"">>$savefile # Append, always append. echo -n "Version? " read ver echo -n " \"Version $ver \"">>$savefile echo >>$savefile echo -n "Short description [0 - 5 words]? " read sdesc echo "$NameHeader">>$savefile echo ""$BOLD" "$name"">>$savefile echo "\- "$sdesc"">>$savefile } fill_in () { # This function more or less copied from "pad.sh" script. echo -n "$2? " # Get user input. read var # May paste (a single line only!) to fill in field. if [ -n "$var" ] then echo "$1 " >>$savefile echo -n "$var" >>$savefile else # Don't append empty field to file. return $E_NOINPUT # Not critical here. fi echo >>$savefile } end () { clear echo -n "Would you like to view the saved man page (y/n)? " read ans if [ "$ans" = "n" -o "$ans" = "N" ]; then exit; fi exec less "$savefile" # Exit script and hand off control to "less" ... #+ ... which formats for viewing man page source. } # ---------------------------------------- # start progname "$TopHeader" fill_in "$SynopsisHeader" "Synopsis" fill_in "$DescHeader" "Long description" # May paste in *single line* of text. fill_in "$OptHeader" "Options" fill_in "$FilesHeader" "Files" fill_in "$AuthHeader" "Author" fill_in "$BugsHeader" "Bugs" fill_in "$SeeAlsoHeader" "See also" # fill_in "$OtherHeader" ... as necessary. end # ... exit not needed. # ---------------------------------------- # # Note that the generated man page will usually #+ require manual fine-tuning with a text editor. # However, it's a distinct improvement upon #+ writing man source from scratch #+ or even editing a blank man page template. # The main deficiency of the script is that it permits #+ pasting only a single text line into the input fields. # This may be a long, cobbled-together line, which groff # will automatically wrap and hyphenate. # However, if you want multiple (newline-separated) paragraphs, #+ these must be inserted by manual text editing on the #+ script-generated man page. # Exercise (difficult): Fix this! # This script is not nearly as elaborate as the #+ full-featured "manedit" package (http://wolfpack.twu.net), #+ but it's much easier to use.

Example A-42. Petals Around the Rose

#!/bin/bash -i # petals.sh ######################################################################### # Petals Around the Rose # # # # Version 0.1 Created by Serghey Rodin # # Version 0.2 Modded by ABS Guide Author # # # # License: GPL3 # # Used in ABS Guide with permission. # # ##################################################################### # hits=0 # Correct guesses. WIN=6 # Mastered the game. ALMOST=5 # One short of mastery. EXIT=exit # Give up early? RANDOM=$$ # Seeds the random number generator from PID of script. # Bones (ASCII graphics for dice) bone1[1]="| |" bone1[2]="| o |" bone1[3]="| o |" bone1[4]="| o o |" bone1[5]="| o o |" bone1[6]="| o o |" bone2[1]="| o |" bone2[2]="| |" bone2[3]="| o |" bone2[4]="| |" bone2[5]="| o |" bone2[6]="| o o |" bone3[1]="| |" bone3[2]="| o |" bone3[3]="| o |" bone3[4]="| o o |" bone3[5]="| o o |" bone3[6]="| o o |" bone="+---------+" # Functions instructions () { clear echo -n "Do you need instructions? (y/n) "; read ans if [ "$ans" = "y" -o "$ans" = "Y" ]; then clear echo -e '\E[34;47m' # Blue type. # "cat document" cat <<INSTRUCTIONSZZZ The name of the game is Petals Around the Rose, and that name is significant. Five dice will roll and you must guess the "answer" for each roll. It will be zero or an even number. After your guess, you will be told the answer for the roll, but . . . that's ALL the information you will get. Six consecutive correct guesses admits you to the Fellowship of the Rose. INSTRUCTIONSZZZ echo -e "\033[0m" # Turn off blue. else clear fi } fortune () { RANGE=7 FLOOR=0 number=0 while [ "$number" -le $FLOOR ] do number=$RANDOM let "number %= $RANGE" # 1 - 6. done return $number } throw () { # Calculate each individual die. fortune; B1=$? fortune; B2=$? fortune; B3=$? fortune; B4=$? fortune; B5=$? calc () { # Function embedded within a function! case "$1" in 3 ) rose=2;; 5 ) rose=4;; aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html ) rose=0;; esac # Simplified algorithm. # Doesn't really get to the heart of the matter. return $rose } answer=0 calc "$B1"; answer=$(expr $answer + $(echo $?)) calc "$B2"; answer=$(expr $answer + $(echo $?)) calc "$B3"; answer=$(expr $answer + $(echo $?)) calc "$B4"; answer=$(expr $answer + $(echo $?)) calc "$B5"; answer=$(expr $answer + $(echo $?)) } game () { # Generate graphic display of dice throw. throw echo -e "\033[1m" # Bold. echo -e "\n" echo -e "$bone\t$bone\t$bone\t$bone\t$bone" echo -e \ "${bone1[$B1]}\t${bone1[$B2]}\t${bone1[$B3]}\t${bone1[$B4]}\t${bone1[$B5]}" echo -e \ "${bone2[$B1]}\t${bone2[$B2]}\t${bone2[$B3]}\t${bone2[$B4]}\t${bone2[$B5]}" echo -e \ "${bone3[$B1]}\t${bone3[$B2]}\t${bone3[$B3]}\t${bone3[$B4]}\t${bone3[$B5]}" echo -e "$bone\t$bone\t$bone\t$bone\t$bone" echo -e "\n\n\t\t" echo -e "\033[0m" # Turn off bold. echo -n "There are how many petals around the rose? " } # ============================================================== # instructions while [ "$petal" != "$EXIT" ] # Main loop. do game read petal echo "$petal" | grep [0-9] >/dev/null # Filter response for digit. # Otherwise just roll dice again. if [ "$?" -eq 0 ] # If-loop #1. then if [ "$petal" == "$answer" ]; then # If-loop #2. echo -e "\nCorrect. There are $petal petals around the rose.\n" (( hits++ )) if [ "$hits" -eq "$WIN" ]; then # If-loop #3. echo -e '\E[31;47m' # Red type. echo -e "\033[1m" # Bold. echo "You have unraveled the mystery of the Rose Petals!" echo "Welcome to the Fellowship of the Rose!!!" echo "(You are herewith sworn to secrecy.)"; echo echo -e "\033[0m" # Turn off red & bold. break # Exit! else echo "You have $hits correct so far."; echo if [ "$hits" -eq "$ALMOST" ]; then echo "Just one more gets you to the heart of the mystery!"; echo fi fi # Close if-loop #3. else echo -e "\nWrong. There are $answer petals around the rose.\n" hits=0 # Reset number of correct guesses. fi # Close if-loop #2. echo -n "Hit ENTER for the next roll, or type \"exit\" to end. " read if [ "$REPLY" = "$EXIT" ]; then exit fi fi # Close if-loop #1. clear done # End of main (while) loop. ### exit $? # Resources: # --------- # 1) http://en.wikipedia.org/wiki/Petals_Around_the_Rose # (Wikipedia entry.) # 2) http://www.borrett.id.au/computing/petals-bg.htm # (How Bill Gates coped with the Petals Around the Rose challenge.)

Example A-43. Quacky: a Perquackey-type word game

#!/bin/bash # qky.sh ############################################################## # QUACKEY: a somewhat simplified version of Perquackey [TM]. # # # # Author: Mendel Cooper <thegrendel@theriver.com> # # version 0.1.02 03 May, 2008 # # License: GPL3 # ############################################################## WLIST=/usr/share/dict/word.lst # ^^^^^^^^ Word list file found here. # ASCII word list, one word per line, UNIX format. # A suggested list is the script author's "yawl" word list package. # http://ibiblio.org/pub/Linux/libs/yawl-0.3.2.tar.gz # or # http://personal.riverusers.com/~thegrendel/yawl-0.3.2.tar.gz NONCONS=0 # Word not constructable from letter set. CONS=1 # Constructable. SUCCESS=0 NG=1 FAILURE='' NULL=0 # Zero out value of letter (if found). MINWLEN=3 # Minimum word length. MAXCAT=5 # Maximum number of words in a given category. PENALTY=200 # General-purpose penalty for unacceptable words. total= E_DUP=70 # Duplicate word error. TIMEOUT=10 # Time for word input. NVLET=10 # 10 letters for non-vulnerable. VULET=13 # 13 letters for vulnerable (not yet implemented). declare -a Words declare -a Status declare -a Score=( 0 0 0 0 0 0 0 0 0 0 0 ) letters=( a n s r t m l k p r b c i d s i d z e w u e t f e y e r e f e g t g h h i t r s c i t i d i j a t a o l a m n a n o v n w o s e l n o s p a q e e r a b r s a o d s t g t i t l u e u v n e o x y m r k ) # Letter distribution table shamelessly borrowed from "Wordy" game, #+ ca. 1992, written by a certain fine fellow named Mendel Cooper. declare -a LS numelements=${#letters[@]} randseed="$1" instructions () { clear echo "Welcome to QUACKEY, the anagramming word construction game."; echo echo -n "Do you need instructions? (y/n) "; read ans if [ "$ans" = "y" -o "$ans" = "Y" ]; then clear echo -e '\E[31;47m' # Red foreground. '\E[34;47m' for blue. cat <<INSTRUCTION1 QUACKEY is a variant of Perquackey [TM]. The rules are the same, but the scoring is simplified and plurals of previously played words are allowed. "Vulnerable" play is not yet implemented, but it is otherwise feature-complete. As the game begins, the player gets 10 letters. The object is to construct valid dictionary words of at least 3-letter-length from the letterset. Each word-length category -- 3-letter, 4-letter, 5-letter, ... -- fills up with the fifth word entered, and no further words in that category are accepted. The penalty for too-short (two-letter), duplicate, unconstructable, and invalid (not in dictionary) words is -200. The same penalty applies to attempts to enter a word in a filled-up category. INSTRUCTION1 echo -n "Hit ENTER for next page of instructions. "; read az1 cat <<INSTRUCTION2 The scoring mostly corresponds to classic Perquackey: The first 3-letter word scores 60, plus 10 for each additional one. The first 4-letter word scores 120, plus 20 for each additional one. The first 5-letter word scores 200, plus 50 for each additional one. The first 6-letter word scores 300, plus 100 for each additional one. The first 7-letter word scores 500, plus 150 for each additional one. The first 8-letter word scores 750, plus 250 for each additional one. The first 9-letter word scores 1000, plus 500 for each additional one. The first 10-letter word scores 2000, plus 2000 for each additional one. Category completion bonuses are: 3-letter words 100 4-letter words 200 5-letter words 400 6-letter words 800 7-letter words 2000 8-letter words 10000 This is a simplification of the absurdly complicated Perquackey bonus scoring system. INSTRUCTION2 echo -n "Hit ENTER for final page of instructions. "; read az1 cat <<INSTRUCTION3 Hitting just ENTER for a word entry ends the game. Individual word entry is timed to a maximum of 10 seconds. aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html Timing out on an entry ends the game. aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html Other than that, the game is untimed. -------------------------------------------------- Game statistics are automatically saved to a file. -------------------------------------------------- For competitive ("duplicate") play, a previous letterset may be duplicated by repeating the script's random seed, command-line parameter \$1. For example, "qky 7633" specifies the letterset c a d i f r h u s k ... INSTRUCTION3 echo; echo -n "Hit ENTER to begin game. "; read az1 echo -e "\033[0m" # Turn off red. else clear fi clear } seed_random () { # Seed random number generator. if [ -n "$randseed" ] # Can specify random seed. then #+ for play in competitive mode. # RANDOM="$randseed" echo "RANDOM seed set to "$randseed"" else randseed="$$" # Or get random seed from process ID. echo "RANDOM seed not specified, set to Process ID of script ($$)." fi RANDOM="$randseed" echo } get_letset () { element=0 echo -n "Letterset:" for lset in $(seq $NVLET) do # Pick random letters to fill out letterset. LS[element]="${letters[$((RANDOM%numelements))]}" ((element++)) done echo echo "${LS[@]}" } add_word () { wrd="$1" local idx=0 Status[0]="" Status[3]="" Status[4]="" while [ "${Words[idx]}" != '' ] do if [ "${Words[idx]}" = "$wrd" ] then Status[3]="Duplicate-word-PENALTY" let "Score[0]= 0 - $PENALTY" let "Score[1]-=$PENALTY" return $E_DUP fi ((idx++)) done Words[idx]="$wrd" get_score } get_score() { local wlen=0 local score=0 local bonus=0 local first_word=0 local add_word=0 local numwords=0 wlen=${#wrd} numwords=${Score[wlen]} Score[2]=0 Status[4]="" # Initialize "bonus" to 0. case "$wlen" in 3) first_word=60 add_word=10;; 4) first_word=120 add_word=20;; 5) first_word=200 add_word=50;; 6) first_word=300 add_word=100;; 7) first_word=500 add_word=150;; 8) first_word=750 add_word=250;; 9) first_word=1000 add_word=500;; 10) first_word=2000 add_word=2000;; # This category modified from original rules! esac ((Score[wlen]++)) if [ ${Score[wlen]} -eq $MAXCAT ] then # Category completion bonus scoring simplified! case $wlen in 3 ) bonus=100;; 4 ) bonus=200;; 5 ) bonus=400;; 6 ) bonus=800;; 7 ) bonus=2000;; 8 ) bonus=10000;; esac # Needn't worry about 9's and 10's. Status[4]="Category-$wlen-completion***BONUS***" Score[2]=$bonus else Status[4]="" # Erase it. fi let "score = $first_word + $add_word aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html $numwords" if [ "$numwords" -eq 0 ] then Score[0]=$score else Score[0]=$add_word fi # All this to distinguish last-word score #+ from total running score. let "Score[1] += ${Score[0]}" let "Score[1] += ${Score[2]}" } get_word () { local wrd='' read -t $TIMEOUT wrd # Timed read. echo $wrd } is_constructable () { # This was the most complex and difficult-to-write function. local -a local_LS=( "${LS[@]}" ) # Local copy of letter set. local is_found=0 local idx=0 local pos local strlen local local_word=( "$1" ) strlen=${#local_word} while [ "$idx" -lt "$strlen" ] do is_found=$(expr index "${local_LS[*]}" "${local_word:idx:1}") if [ "$is_found" -eq "$NONCONS" ] # Not constructable! then echo "$FAILURE"; return else ((pos = ($is_found - 1) / 2)) # Compensate for spaces betw. letters! local_LS[pos]=$NULL # Zero out used letters. ((idx++)) # Bump index. fi done echo "$SUCCESS" return } is_valid () { # Surprisingly easy to check if word in dictionary ... fgrep -qw "$1" "$WLIST" # ... thanks to 'grep' ... echo $? } check_word () { if [ -z "$1" ] then return fi Status[1]="" Status[2]="" Status[3]="" Status[4]="" iscons=$(is_constructable "$1") if [ "$iscons" ] then Status[1]="constructable" v=$(is_valid "$1") if [ "$v" -eq "$SUCCESS" ] then Status[2]="valid" strlen=${#1} if [ ${Score[strlen]} -eq "$MAXCAT" ] # Category full! then Status[3]="Category-$strlen-overflow-PENALTY" return $NG fi case "$strlen" in 1 | 2 ) Status[3]="Two-letter-word-PENALTY" return $NG;; aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html ) Status[3]="" return $SUCCESS;; esac else Status[3]="Not-valid-PENALTY" return $NG fi else Status[3]="Not-constructable-PENALTY" return $NG fi ### FIXME: Streamline the above code. } display_words () { local idx=0 local wlen0 clear echo "Letterset: ${LS[@]}" echo "Threes: Fours: Fives: Sixes: Sevens: Eights:" echo "------------------------------------------------------------" while [ "${Words[idx]}" != '' ] do wlen0=${#Words[idx]} case "$wlen0" in 3) ;; 4) echo -n " " ;; 5) echo -n " " ;; 6) echo -n " " ;; 7) echo -n " " ;; 8) echo -n " " ;; esac echo "${Words[idx]}" ((idx++)) done ### FIXME: The word display is pretty crude. } play () { word="Start game" # Dummy word, to start ... while [ "$word" ] # If player just hits return (blank word), do #+ then game ends. echo "$word: "${Status[@]}"" echo -n "Last score: [${Score[0]}] TOTAL score: [${Score[1]}]: Next word: " total=${Score[1]} word=$(get_word) check_word "$word" if [ "$?" -eq "$SUCCESS" ] then add_word "$word" else let "Score[0]= 0 - $PENALTY" let "Score[1]-=$PENALTY" fi display_words done # Exit game. ### FIXME: The play () function calls too many other functions. ### This is perilously close to "spaghetti code" ... } end_of_game () { # Save and display stats. #######################Autosave########################## savefile=qky.save.$$ # ^^ PID of script echo `date` >> $savefile echo "Letterset # $randseed (random seed) ">> $savefile echo -n "Letterset: " >> $savefile echo "${LS[@]}" >> $savefile echo "---------" >> $savefile echo "Words constructed:" >> $savefile echo "${Words[@]}" >> $savefile echo >> $savefile echo "Score: $total" >> $savefile echo "Statistics for this round saved in \""$savefile"\"" ######################################################### echo "Score for this round: $total" echo "Words: ${Words[@]}" } # ---------# instructions seed_random get_letset play end_of_game # ---------# exit $? # TODO: # # 1) Clean up code! # 2) Prettify the display_words () function (maybe with widgets?). # 3) Improve the time-out ... maybe change to untimed entry, #+ but with a time limit for the overall round. # 4) An on-screen countdown timer would be nice. # 5) Implement "vulnerable" mode of play. # 6) Improve save-to-file capability (and maybe make it optional). # 7) Fix bugs!!! # Reference for more info: # http://personal.riverusers.com/~thegrendel/qky.README.html

Example A-44. Nim

#!/bin/bash # nim.sh: Game of Nim # Author: Mendel Cooper # Reldate: 15 July 2008 # License: GPL3 ROWS=5 # Five rows of pegs. WON=91 # Exit codes to keep track of wins/losses. LOST=92 # Possibly useful if running in batch mode. QUIT=99 peg_msg= # Peg/Pegs? Rows=( 0 5 4 3 2 1 ) # Array holding play info. # ${Rows[0]} holds total number of pegs, updated after each turn. # Other array elements hold number of pegs in corresponding row. instructions () { clear tput bold echo "Welcome to the game of Nim."; echo echo -n "Do you need instructions? (y/n) "; read ans if [ "$ans" = "y" -o "$ans" = "Y" ]; then clear echo -e '\E[33;41m' # Yellow fg., over red bg.; bold. cat <<INSTRUCTIONS Nim is a game with roots in the distant past. This particular variant starts with five rows of pegs. 1: | | | | | 2: | | | | 3: | | | 4: | | 5: | The number at the left identifies the row. The human player moves first, and alternates turns with the bot. A turn consists of removing at least one peg from a single row. It is permissable to remove ALL the pegs from a row. For example, in row 2, above, the player can remove 1, 2, 3, or 4 pegs. The player who removes the last peg loses. The strategy consists of trying to be the one who removes the next-to-last peg(s), leaving the loser with the final peg. To exit the game early, hit ENTER during your turn. INSTRUCTIONS echo; echo -n "Hit ENTER to begin game. "; read azx echo -e "\033[0m" # Restore display. else tput sgr0; clear fi clear } tally_up () { let "Rows[0] = ${Rows[1]} + ${Rows[2]} + ${Rows[3]} + ${Rows[4]} + \ ${Rows[5]}" # Add up how many pegs remaining. } display () { index=1 # Start with top row. echo while [ "$index" -le "$ROWS" ] do p=${Rows[index]} echo -n "$index: " # Show row number. # ------------------------------------------------ # Two concurrent inner loops. indent=$index while [ "$indent" -gt 0 ] do echo -n " " # Staggered rows. ((indent--)) # Spacing between pegs. done while [ "$p" -gt 0 ] do echo -n "| " ((p--)) done # ----------------------------------------------- echo ((index++)) done tally_up rp=${Rows[0]} if [ "$rp" -eq 1 ] then peg_msg=peg final_msg="Game over." else # Game not yet over . . . peg_msg=pegs final_msg="" # . . . So "final message" is blank. fi echo " $rp $peg_msg remaining." echo " "$final_msg"" echo } player_move () { echo "Your move:" echo -n "Which row? " while read idx do # Validity check, etc. if [ -z "$idx" ] # Hitting return quits. then echo "Premature exit."; echo tput sgr0 # Restore display. exit $QUIT fi if [ "$idx" -gt "$ROWS" -o "$idx" -lt 1 ] # Bounds check. then echo "Invalid row number!" echo -n "Which row? " else break fi # TODO: # Add check for non-numeric input. # Also, script crashes on input outside of range of long double. # Fix this. done echo -n "Remove how many? " while read num do # Validity check. if [ -z "$num" ] then echo "Premature exit."; echo tput sgr0 # Restore display. exit $QUIT fi if [ "$num" -gt ${Rows[idx]} -o "$num" -lt 1 ] then echo "Cannot remove $num!" echo -n "Remove how many? " else break fi done # TODO: # Add check for non-numeric input. # Also, script crashes on input outside of range of long double. # Fix this. let "Rows[idx] -= $num" display tally_up if [ ${Rows[0]} -eq 1 ] then echo " Human wins!" echo " Congratulations!" tput sgr0 # Restore display. echo exit $WON fi if [ ${Rows[0]} -eq 0 ] then # Snatching defeat from the jaws of victory . . . echo " Fool!" echo " You just removed the last peg!" echo " Bot wins!" tput sgr0 # Restore display. echo exit $LOST fi } bot_move () { row_b=0 while [[ $row_b -eq 0 || ${Rows[row_b]} -eq 0 ]] do row_b=$RANDOM # Choose random row. let "row_b %= $ROWS" done num_b=0 r0=${Rows[row_b]} if [ "$r0" -eq 1 ] then num_b=1 else let "num_b = $r0 - 1" # Leave only a single peg in the row. fi # Not a very strong strategy, #+ but probably a bit better than totally random. let "Rows[row_b] -= $num_b" echo -n "Bot: " echo "Removing from row $row_b ... " if [ "$num_b" -eq 1 ] then peg_msg=peg else peg_msg=pegs fi echo " $num_b $peg_msg." display tally_up if [ ${Rows[0]} -eq 1 ] then echo " Bot wins!" tput sgr0 # Restore display. exit $WON fi } # ================================================== # instructions # If human player needs them . . . tput bold # Bold characters for easier viewing. display # Show game board. while [ true ] # Main loop. do # Alternate human and bot turns. player_move bot_move done # ================================================== # # Exercise: # -------- # Improve the bot's strategy. # There is, in fact, a Nim strategy that can force a win. # See the Wikipedia article on Nim: http://en.wikipedia.org/wiki/Nim # Recode the bot to use this strategy (rather difficult). # Curiosities: # ----------- # Nim played a prominent role in Alain Resnais' 1961 New Wave film, #+ Last Year at Marienbad. # # In 1978, Leo Christopherson wrote an animated version of Nim, #+ Android Nim, for the TRS-80 Model I.

Example A-45. An all-purpose shell scripting homework assignment solution

#!/bin/bash # homework.sh: All-purpose homework assignment solution. # Author: M. Leo Cooper # If you substitute your own name as author, then it is plagiarism, #+ possibly a lesser sin than cheating on your homework! # License: Public Domain # This script may be turned in to your instructor #+ in fulfillment of ALL shell scripting homework assignments. # It's sparsely commented, but you, the student, can easily remedy that. # The script author repudiates all responsibility! DLA=1 P1=2 P2=4 P3=7 PP1=0 PP2=8 MAXL=9 E_LZY=99 declare -a L L[0]="3 4 0 17 29 8 13 18 19 17 20 2 19 14 17 28" L[1]="8 29 12 14 18 19 29 4 12 15 7 0 19 8 2 0 11 11 24 29 17 4 6 17 4 19" L[2]="29 19 7 0 19 29 8 29 7 0 21 4 29 13 4 6 11 4 2 19 4 3" L[3]="19 14 29 2 14 12 15 11 4 19 4 29 19 7 8 18 29" L[4]="18 2 7 14 14 11 22 14 17 10 29 0 18 18 8 6 13 12 4 13 19 26" L[5]="15 11 4 0 18 4 29 0 2 2 4 15 19 29 12 24 29 7 20 12 1 11 4 29" L[6]="4 23 2 20 18 4 29 14 5 29 4 6 17 4 6 8 14 20 18 29" L[7]="11 0 25 8 13 4 18 18 27" L[8]="0 13 3 29 6 17 0 3 4 29 12 4 29 0 2 2 14 17 3 8 13 6 11 24 26" L[9]="19 7 0 13 10 29 24 14 20 26" declare -a \ alph=( A B C D E F G H I J K L M N O P Q R S T U V W X Y Z . , : ' ' ) pt_lt () { echo -n "${alph[$1]}" echo -n -e "\a" sleep $DLA } b_r () { echo -e '\E[31;48m\033[1m' } cr () { echo -e "\a" sleep $DLA } restore () { echo -e '\033[0m' # Bold off. tput sgr0 # Normal. } p_l () { for ltr in $1 do pt_lt "$ltr" done } # ---------------------- b_r for i in $(seq 0 $MAXL) do p_l "${L[i]}" if [[ "$i" -eq "$P1" || "$i" -eq "$P2" || "$i" -eq "$P3" ]] then cr elif [[ "$i" -eq "$PP1" || "$i" -eq "$PP2" ]] then cr; cr fi done restore # ---------------------- echo exit $E_LZY # A typical example of an obfuscated script that is difficult #+ to understand, and frustrating to maintain. # In your career as a sysadmin, you'll run into these critters #+ all too often.

Example A-46. An alternate version of the getopt-simple.sh script

#!/bin/bash # UseGetOpt.sh # Author: Peggy Russell <prusselltechgroup@gmail.com> UseGetOpt () { declare inputOptions declare -r E_OPTERR=85 declare -r ScriptName=${0##*/} declare -r ShortOpts="adf:hlt" declare -r LongOpts="aoption,debug,file:,help,log,test" DoSomething () { echo "The function name is '${FUNCNAME}'" # Recall that $FUNCNAME is an internal variable #+ holding the name of the function it is in. } inputOptions=$(getopt -o "${ShortOpts}" --long \ "${LongOpts}" --name "${ScriptName}" -- "${@}") if [[ ($? -ne 0) || ($# -eq 0) ]]; then echo "Usage: ${ScriptName} [-dhlt] {OPTION...}" exit $E_OPTERR fi eval set -- "${inputOptions}" # Only for educational purposes. Can be removed. #----------------------------------------------- echo "++ Test: Number of arguments: [$#]" echo '++ Test: Looping through "$@"' for a in "$@"; do echo " ++ [$a]" done #----------------------------------------------- while true; do case "${1}" in --aoption | -a) # Argument found. echo "Option [$1]" ;; --debug | -d) # Enable informational messages. echo "Option [$1] Debugging enabled" ;; --file | -f) # Check for optional argument. case "$2" in #+ Double colon is optional argument. "") # Not there. echo "Option [$1] Use default" shift ;; *) # Got it echo "Option [$1] Using input [$2]" shift ;; esac DoSomething ;; --log | -l) # Enable Logging. echo "Option [$1] Logging enabled" ;; --test | -t) # Enable testing. echo "Option [$1] Testing enabled" ;; --help | -h) echo "Option [$1] Display help" break ;; --) # Done! $# is argument number for "--", $@ is "--" echo "Option [$1] Dash Dash" break ;; *) echo "Major internal error!" exit 8 ;; esac echo "Number of arguments: [$#]" shift done shift # Only for educational purposes. Can be removed. #---------------------------------------------------------------------- echo "++ Test: Number of arguments after \"--\" is [$#] They are: [$@]" echo '++ Test: Looping through "$@"' for a in "$@"; do echo " ++ [$a]" done #---------------------------------------------------------------------- } ################################### M A I N ######################## # If you remove "function UseGetOpt () {" and corresponding "}", #+ you can uncomment the "exit 0" line below, and invoke this script #+ with the various options from the command line. #------------------------------------------------------------------- # exit 0 echo "Test 1" UseGetOpt -f myfile one "two three" four echo;echo "Test 2" UseGetOpt -h echo;echo "Test 3 - Short Options" UseGetOpt -adltf myfile anotherfile echo;echo "Test 4 - Long Options" UseGetOpt --aoption --debug --log --test --file myfile anotherfile exit

To end this section, a review of the basics . . . and more.

Example A-47. Basics Reviewed

#!/bin/bash # basics-reviewed.bash # File extension == *.bash == specific to Bash # Copyright (c) Michael S. Zick, 2003; All rights reserved. # License: Use in any form, for any purpose. # Revision: $ID$ # # Edited for layout by M.C. # (author of the "Advanced Bash Scripting Guide") # Fixes and updates (04/08) by Cliff Bamford. # This script tested under Bash versions 2.04, 2.05a and 2.05b. # It may not work with earlier versions. # This demonstration script generates one --intentional-- #+ "command not found" error message. See line 436. # The current Bash maintainer, Chet Ramey, has fixed the items noted #+ for later versions of Bash. ###-------------------------------------------### ### Pipe the output of this script to 'more' ### ###+ else it will scroll off the page. ### ### ### ### You may also redirect its output ### ###+ to a file for examination. ### ###-------------------------------------------### # Most of the following points are described at length in #+ the text of the foregoing "Advanced Bash Scripting Guide." # This demonstration script is mostly just a reorganized presentation. # -- msz # Variables are not typed unless otherwise specified. # Variables are named. Names must contain a non-digit. # File descriptor names (as in, for example: 2>&1) #+ contain ONLY digits. # Parameters and Bash array elements are numbered. # (Parameters are very similar to Bash arrays.) # A variable name may be undefined (null reference). unset VarNull # A variable name may be defined but empty (null contents). VarEmpty='' # Two, adjacent, single quotes. # A variable name may be defined and non-empty. VarSomething='Literal' # A variable may contain: # aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html A whole number as a signed 32-bit (or larger) integer # aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html A string # A variable may also be an array. # A string may contain embedded blanks and may be treated #+ as if it where a function name with optional arguments. # The names of variables and the names of functions #+ are in different namespaces. # A variable may be defined as a Bash array either explicitly or #+ implicitly by the syntax of the assignment statement. # Explicit: declare -a ArrayVar # The echo command is a built-in. echo $VarSomething # The printf command is a built-in. # Translate %s as: String-Format printf %s $VarSomething # No linebreak specified, none output. echo # Default, only linebreak output. # The Bash parser word breaks on whitespace. # Whitespace, or the lack of it is significant. # (This holds true in general; there are, of course, exceptions.) # Translate the DOLLAR_SIGN character as: Content-Of. # Extended-Syntax way of writing Content-Of: echo ${VarSomething} # The ${ ... } Extended-Syntax allows more than just the variable #+ name to be specified. # In general, $VarSomething can always be written as: ${VarSomething}. # Call this script with arguments to see the following in action. # Outside of double-quotes, the special characters @ and aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html #+ specify identical behavior. # May be pronounced as: All-Elements-Of. # Without specification of a name, they refer to the #+ pre-defined parameter Bash-Array. # Glob-Pattern references echo $* # All parameters to script or function echo ${*} # Same # Bash disables filename expansion for Glob-Patterns. # Only character matching is active. # All-Elements-Of references echo $@ # Same as above echo ${@} # Same as above # Within double-quotes, the behavior of Glob-Pattern references #+ depends on the setting of IFS (Input Field Separator). # Within double-quotes, All-Elements-Of references behave the same. # Specifying only the name of a variable holding a string refers #+ to all elements (characters) of a string. # To specify an element (character) of a string, #+ the Extended-Syntax reference notation (see below) MAY be used. # Specifying only the name of a Bash array references #+ the subscript zero element, #+ NOT the FIRST DEFINED nor the FIRST WITH CONTENTS element. # Additional qualification is needed to reference other elements, #+ which means that the reference MUST be written in Extended-Syntax. # The general form is: ${name[subscript]}. # The string forms may also be used: ${name:subscript} #+ for Bash-Arrays when referencing the subscript zero element. # Bash-Arrays are implemented internally as linked lists, #+ not as a fixed area of storage as in some programming languages. # Characteristics of Bash arrays (Bash-Arrays): # -------------------------------------------- # If not otherwise specified, Bash-Array subscripts begin with #+ subscript number zero. Literally: [0] # This is called zero-based indexing. ### # If not otherwise specified, Bash-Arrays are subscript packed #+ (sequential subscripts without subscript gaps). ### # Negative subscripts are not allowed. ### # Elements of a Bash-Array need not all be of the same type. ### # Elements of a Bash-Array may be undefined (null reference). # That is, a Bash-Array may be "subscript sparse." ### # Elements of a Bash-Array may be defined and empty (null contents). ### # Elements of a Bash-Array may contain: # aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html A whole number as a signed 32-bit (or larger) integer # aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html A string # aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html A string formated so that it appears to be a function name # + with optional arguments ### # Defined elements of a Bash-Array may be undefined (unset). # That is, a subscript packed Bash-Array may be changed # + into a subscript sparse Bash-Array. ### # Elements may be added to a Bash-Array by defining an element #+ not previously defined. ### # For these reasons, I have been calling them "Bash-Arrays". # I'll return to the generic term "array" from now on. # -- msz echo "=========================================================" # Lines 202 - 334 supplied by Cliff Bamford. (Thanks!) # Demo --- Interaction with Arrays, quoting, IFS, echo, aboutauthor.html aliases.html arithexp.html arrays.html asciitable.html assortedtips.html authorsnote.html awk.html bash2.html bash-options.html bashver2.html bashver3.html basic.html biblio.html colorizing.html command-line-options.html commandsub.html communications.html comparison-ops.html complexfunct.html contributed-scripts.html copyright.html credits.html dblparens.html debugging.html declareref.html devproc.html devref1.html disclaimer.html dosbatch.html endnotes.html escapingsection.html exercises.html exitcodes.html exit-status.html external.html extmisc.html filearchiv.html files.html fto.html functions.html globbingref.html gotchas.html here-docs.html histcommands.html index.html intandnonint.html internal.html internalvariables.html invoking.html io-redirection.html ioredirintro.html ivr.html list-cons.html localization.html localvar.html loopcontrol.html loops1.html loops.html mathc.html mirrorsites.html miscellany.html moreadv.html nestedifthen.html nestedloops.html numerical-constants.html operations.html opprecedence.html ops.html optimizations.html options.html othertypesv.html parameter-substitution.html part1.html part2.html part3.html part4.html part5.html portabilityissues.html prelimexer.html process-sub.html procref1.html quoting.html quotingvar.html randomvar.html recess-time.html recurnolocvar.html recursionsct.html redirapps.html redircb.html refcards.html regexp.html restricted-sh.html revisionhistory.html sample-bashrc.html scriptanalysis.html scrstyle.html securityissues.html sedawk.html sha-bang.html special-chars.html standard-options.html string-manipulation.html subshells.html sysscripts.html systemdirs.html system.html terminalccmds.html testbranch.html testconstructs.html testsandcomparisons.html tests.html testtest.html textproc.html timedate.html todolist.html toolsused.html unofficialst.html untyped.html varassignment.html variables2.html variables.html varsubn.html wherehelp.html why-shell.html winscript.html wrapper.html writingscripts.html x16044.html x16712.html x16834.html x21467.html x8885.html xrefindex.html zeros.html and @ --- #+ all affect how things work ArrayVar[0]='zero' # 0 normal ArrayVar[1]=one # 1 unquoted literal ArrayVar[2]='two' # 2 normal ArrayVar[3]='three' # 3 normal ArrayVar[4]='I am four' # 4 normal with spaces ArrayVar[5]='five' # 5 normal unset ArrayVar[6] # 6 undefined ArrayValue[7]='seven' # 7 normal ArrayValue[8]='' # 8 defined but empty ArrayValue[9]='nine' # 9 normal echo '--- Here is the array we are using for this test' echo echo "ArrayVar[0]='zero' # 0 normal" echo "ArrayVar[1]=one # 1 unquoted literal" echo "ArrayVar[2]='two' # 2 normal" echo "ArrayVar[3]='three' # 3 normal" echo "ArrayVar[4]='I am four' # 4 normal with spaces" echo "ArrayVar[5]='five' # 5 normal" echo "unset ArrayVar[6] # 6 undefined" echo "ArrayValue[7]='seven' # 7 normal" echo "ArrayValue[8]='' # 8 defined but empty" echo "ArrayValue[9]='nine' # 9 normal" echo echo echo '---Case0: No double-quotes, Default IFS of space,tab,newline ---' IFS=$'\x20'$'\x09'$'\x0A' # In exactly this order. echo 'Here is: printf %q {${ArrayVar[*]}' printf %q ${ArrayVar[*]} echo echo 'Here is: printf %q {${ArrayVar[@]}' printf %q ${ArrayVar[@]} echo echo 'Here is: echo ${ArrayVar[*]}' echo ${ArrayVar[@]} echo 'Here is: echo {${ArrayVar[@]}' echo ${ArrayVar[@]} echo echo '---Case1: Within double-quotes - Default IFS of space-tab- newline ---' IFS=$'\x20'$'\x09'$'\x0A' # These three bytes, echo 'Here is: printf %q "{${ArrayVar[*]}"' printf %q "${ArrayVar[*]}" echo echo 'Here is: printf %q "{${ArrayVar[@]}"' printf %q "${ArrayVar[@]}" echo echo 'Here is: echo "${ArrayVar[*]}"' echo "${ArrayVar[@]}" echo 'Here is: echo "{${ArrayVar[@]}"' echo "${ArrayVar[@]}" echo echo '---Case2: Within double-quotes - IFS is q' IFS='q' echo 'Here is: printf %q "{${ArrayVar[*]}"' printf %q "${ArrayVar[*]}" echo echo 'Here is: printf %q "{${ArrayVar[@]}"' printf %q "${ArrayVar[@]}" echo echo 'Here is: echo "${ArrayVar[*]}"' echo "${ArrayVar[@]}" echo 'Here is: echo "{${ArrayVar[@]}"' echo "${ArrayVar[@]}" echo echo '---Case3: Within double-quotes - IFS is ^' IFS='^' echo 'Here is: printf %q "{${ArrayVar[*]}"' printf %q "${ArrayVar[*]}" echo echo 'Here is: printf %q "{${ArrayVar[@]}"' printf %q "${ArrayVar[@]}" echo echo 'Here is: echo "${ArrayVar[*]}"' echo "${ArrayVar[@]}" echo 'Here is: echo "{${ArrayVar[@]}"' echo "${ArrayVar[@]}" echo echo '---Case4: Within double-quotes - IFS is ^ followed by space,tab,newline' IFS=$'^'$'\x20'$'\x09'$'\x0A' # ^ + space tab newline echo 'Here is: printf %q "{${ArrayVar[*]}"' printf %q "${ArrayVar[*]}" echo echo 'Here is: printf %q "{${ArrayVar[@]}"' printf %q "${ArrayVar[@]}" echo echo 'Here is: echo "${ArrayVar[*]}"' echo "${ArrayVar[@]}" echo 'Here is: echo "{${ArrayVar[@]}"' echo "${ArrayVar[@]}" echo echo '---Case6: Within double-quotes - IFS set and empty ' IFS='' echo 'Here is: printf %q "{${ArrayVar[*]}"' printf %q "${ArrayVar[*]}" echo echo 'Here is: printf %q "{${ArrayVar[@]}"' printf %q "${ArrayVar[@]}" echo echo 'Here is: echo "${ArrayVar[*]}"' echo "${ArrayVar[@]}" echo 'Here is: echo "{${ArrayVar[@]}"' echo "${ArrayVar[@]}" echo echo '---Case7: Within double-quotes - IFS is unset' unset IFS echo 'Here is: printf %q "{${ArrayVar[*]}"' printf %q "${ArrayVar[*]}" echo echo 'Here is: printf %q "{${ArrayVar[@]}"' printf %q "${ArrayVar[@]}" echo echo 'Here is: echo "${ArrayVar[*]}"' echo "${ArrayVar[@]}" echo 'Here is: echo "{${ArrayVar[@]}"' echo "${ArrayVar[@]}" echo echo '---End of Cases---' echo "========================================================="; echo # Put IFS back to the default. # Default is exactly these three bytes. IFS=$'\x20'$'\x09'$'\x0A' # In exactly this order. # Interpretation of the above outputs: # A Glob-Pattern is I/O; the setting of IFS matters. ### # An All-Elements-Of does not consider IFS settings. ### # Note the different output using the echo command and the #+ quoted format operator of the printf command. # Recall: # Parameters are similar to arrays and have the similar behaviors. ### # The above examples demonstrate the possible variations. # To retain the shape of a sparse array, additional script #+ programming is required. ### # The source code of Bash has a routine to output the #+ [subscript]=value array assignment format. # As of version 2.05b, that routine is not used, #+ but that might change in future releases. # The length of a string, measured in non-null elements (characters): echo echo '- - Non-quoted references - -' echo 'Non-Null character count: '${#VarSomething}' characters.' # test='Lit'$'\x00''eral' # $'\x00' is a null character. # echo ${#test} # See that? # The length of an array, measured in defined elements, #+ including null content elements. echo echo 'Defined content count: '${#ArrayVar[@]}' elements.' # That is NOT the maximum subscript (4). # That is NOT the range of the subscripts (1 . . 4 inclusive). # It IS the length of the linked list. ### # Both the maximum subscript and the range of the subscripts may #+ be found with additional script programming. # The length of a string, measured in non-null elements (characters): echo echo '- - Quoted, Glob-Pattern references - -' echo 'Non-Null character count: '"${#VarSomething}"' characters.' # The length of an array, measured in defined elements, #+ including null-content elements. echo echo 'Defined element count: '"${#ArrayVar[*]}"' elements.' # Interpretation: Substitution does not effect the ${# ... } operation. # Suggestion: # Always use the All-Elements-Of character #+ if that is what is intended (independence from IFS). # Define a simple function. # I include an underscore in the name #+ to make it distinctive in the examples below. ### # Bash separates variable names and function names #+ in different namespaces. # The Mark-One eyeball isn't that advanced. ### _simple() { echo -n 'SimpleFunc'$@ # Newlines are swallowed in } #+ result returned in any case. # The ( ... ) notation invokes a command or function. # The $( ... ) notation is pronounced: Result-Of. # Invoke the function _simple echo echo '- - Output of function _simple - -' _simple # Try passing arguments. echo # or (_simple) # Try passing arguments. echo echo '- Is there a variable of that name? -' echo $_simple not defined # No variable by that name. # Invoke the result of function _simple (Error msg intended) ### $(_simple) # Gives an error message: # line 436: SimpleFunc: command not found # --------------------------------------- echo ### # The first word of the result of function _simple #+ is neither a valid Bash command nor the name of a defined function. ### # This demonstrates that the output of _simple is subject to evaluation. ### # Interpretation: # A function can be used to generate in-line Bash commands. # A simple function where the first word of result IS a bash command: ### _print() { echo -n 'printf %q '$@ } echo '- - Outputs of function _print - -' _print parm1 parm2 # An Output NOT A Command. echo $(_print parm1 parm2) # Executes: printf %q parm1 parm2 # See above IFS examples for the #+ various possibilities. echo $(_print $VarSomething) # The predictable result. echo # Function variables # ------------------ echo echo '- - Function variables - -' # A variable may represent a signed integer, a string or an array. # A string may be used like a function name with optional arguments. # set -vx # Enable if desired declare -f funcVar #+ in namespace of functions funcVar=_print # Contains name of function. $funcVar parm1 # Same as _print at this point. echo funcVar=$(_print ) # Contains result of function. $funcVar # No input, No output. $funcVar $VarSomething # The predictable result. echo funcVar=$(_print $VarSomething) # $VarSomething replaced HERE. $funcVar # The expansion is part of the echo #+ variable contents. funcVar="$(_print $VarSomething)" # $VarSomething replaced HERE. $funcVar # The expansion is part of the echo #+ variable contents. # The difference between the unquoted and the double-quoted versions #+ above can be seen in the "protect_literal.sh" example. # The first case above is processed as two, unquoted, Bash-Words. # The second case above is processed as one, quoted, Bash-Word. # Delayed replacement # ------------------- echo echo '- - Delayed replacement - -' funcVar="$(_print '$VarSomething')" # No replacement, single Bash-Word. eval $funcVar # $VarSomething replaced HERE. echo VarSomething='NewThing' eval $funcVar # $VarSomething replaced HERE. echo # Restore the original setting trashed above. VarSomething=Literal # There are a pair of functions demonstrated in the #+ "protect_literal.sh" and "unprotect_literal.sh" examples. # These are general purpose functions for delayed replacement literals #+ containing variables. # REVIEW: # ------ # A string can be considered a Classic-Array of elements (characters). # A string operation applies to all elements (characters) of the string #+ (in concept, anyway). ### # The notation: ${array_name[@]} represents all elements of the #+ Bash-Array: array_name. ### # The Extended-Syntax string operations can be applied to all #+ elements of an array. ### # This may be thought of as a For-Each operation on a vector of strings. ### # Parameters are similar to an array. # The initialization of a parameter array for a script #+ and a parameter array for a function only differ #+ in the initialization of ${0}, which never changes its setting. ### # Subscript zero of the script's parameter array contains #+ the name of the script. ### # Subscript zero of a function's parameter array DOES NOT contain #+ the name of the function. # The name of the current function is accessed by the $FUNCNAME variable. ### # A quick, review list follows (quick, not short). echo echo '- - Test (but not change) - -' echo '- null reference -' echo -n ${VarNull-'NotSet'}' ' # NotSet echo ${VarNull} # NewLine only echo -n ${VarNull:-'NotSet'}' ' # NotSet echo ${VarNull} # Newline only echo '- null contents -' echo -n ${VarEmpty-'Empty'}' ' # Only the space echo ${VarEmpty} # Newline only echo -n ${VarEmpty:-'Empty'}' ' # Empty echo ${VarEmpty} # Newline only echo '- contents -' echo ${VarSomething-'Content'} # Literal echo ${VarSomething:-'Content'} # Literal echo '- Sparse Array -' echo ${ArrayVar[@]-'not set'} # ASCII-Art time # State Y==yes, N==no # - :- # Unset Y Y ${# ... } == 0 # Empty N Y ${# ... } == 0 # Contents N N ${# ... } > 0 # Either the first and/or the second part of the tests #+ may be a command or a function invocation string. echo echo '- - Test 1 for undefined - -' declare -i t _decT() { t=$t-1 } # Null reference, set: t == -1 t=${#VarNull} # Results in zero. ${VarNull- _decT } # Function executes, t now -1. echo $t # Null contents, set: t == 0 t=${#VarEmpty} # Results in zero. ${VarEmpty- _decT } # _decT function NOT executed. echo $t # Contents, set: t == number of non-null characters VarSomething='_simple' # Set to valid function name. t=${#VarSomething} # non-zero length ${VarSomething- _decT } # Function _simple executed. echo $t # Note the Append-To action. # Exercise: clean up that example. unset t unset _decT VarSomething=Literal echo echo '- - Test and Change - -' echo '- Assignment if null reference -' echo -n ${VarNull='NotSet'}' ' # NotSet NotSet echo ${VarNull} unset VarNull echo '- Assignment if null reference -' echo -n ${VarNull:='NotSet'}' ' # NotSet NotSet echo ${VarNull} unset VarNull echo '- No assignment if null contents -' echo -n ${VarEmpty='Empty'}' ' # Space only echo ${VarEmpty} VarEmpty='' echo '- Assignment if null contents -' echo -n ${VarEmpty:='Empty'}' ' # Empty Empty echo ${VarEmpty} VarEmpty='' echo '- No change if already has contents -' echo ${VarSomething='Content'} # Literal echo ${VarSomething:='Content'} # Literal # "Subscript sparse" Bash-Arrays ### # Bash-Arrays are subscript packed, beginning with #+ subscript zero unless otherwise specified. ### # The initialization of ArrayVar was one way #+ to "otherwise specify". Here is the other way: ### echo declare -a ArraySparse ArraySparse=( [1]=one [2]='' [4]='four' ) # [0]=null reference, [2]=null content, [3]=null reference echo '- - Array-Sparse List - -' # Within double-quotes, default IFS, Glob-Pattern IFS=$'\x20'$'\x09'$'\x0A' printf %q "${ArraySparse[*]}" echo # Note that the output does not distinguish between "null content" #+ and "null reference". # Both print as escaped whitespace. ### # Note also that the output does NOT contain escaped whitespace #+ for the "null reference(s)" prior to the first defined element. ### # This behavior of 2.04, 2.05a and 2.05b has been reported #+ and may change in a future version of Bash. # To output a sparse array and maintain the [subscript]=value #+ relationship without change requires a bit of programming. # One possible code fragment: ### # local l=${#ArraySparse[@]} # Count of defined elements # local f=0 # Count of found subscripts # local i=0 # Subscript to test ( # Anonymous in-line function for (( l=${#ArraySparse[@]}, f = 0, i = 0 ; f < l ; i++ )) do # 'if defined then...' ${ArraySparse[$i]+ eval echo '\ ['$i']='${ArraySparse[$i]} ; (( f++ )) } done ) # The reader coming upon the above code fragment cold #+ might want to review "command lists" and "multiple commands on a line" #+ in the text of the foregoing "Advanced Bash Scripting Guide." ### # Note: # The "read -a array_name" version of the "read" command #+ begins filling array_name at subscript zero. # ArraySparse does not define a value at subscript zero. ### # The user needing to read/write a sparse array to either #+ external storage or a communications socket must invent #+ a read/write code pair suitable for their purpose. ### # Exercise: clean it up. unset ArraySparse echo echo '- - Conditional alternate (But not change)- -' echo '- No alternate if null reference -' echo -n ${VarNull+'NotSet'}' ' echo ${VarNull} unset VarNull echo '- No alternate if null reference -' echo -n ${VarNull:+'NotSet'}' ' echo ${VarNull} unset VarNull echo '- Alternate if null contents -' echo -n ${VarEmpty+'Empty'}' ' # Empty echo ${VarEmpty} VarEmpty='' echo '- No alternate if null contents -' echo -n ${VarEmpty:+'Empty'}' ' # Space only echo ${VarEmpty} VarEmpty='' echo '- Alternate if already has contents -' # Alternate literal echo -n ${VarSomething+'Content'}' ' # Content Literal echo ${VarSomething} # Invoke function echo -n ${VarSomething:+ $(_simple) }' ' # SimpleFunc Literal echo ${VarSomething} echo echo '- - Sparse Array - -' echo ${ArrayVar[@]+'Empty'} # An array of 'Empty'(ies) echo echo '- - Test 2 for undefined - -' declare -i t _incT() { t=$t+1 } # Note: # This is the same test used in the sparse array #+ listing code fragment. # Null reference, set: t == -1 t=${#VarNull}-1 # Results in minus-one. ${VarNull+ _incT } # Does not execute. echo $t' Null reference' # Null contents, set: t == 0 t=${#VarEmpty}-1 # Results in minus-one. ${VarEmpty+ _incT } # Executes. echo $t' Null content' # Contents, set: t == (number of non-null characters) t=${#VarSomething}-1 # non-null length minus-one ${VarSomething+ _incT } # Executes. echo $t' Contents' # Exercise: clean up that example. unset t unset _incT # ${name?err_msg} ${name:?err_msg} # These follow the same rules but always exit afterwards #+ if an action is specified following the question mark. # The action following the question mark may be a literal #+ or a function result. ### # ${name?} ${name:?} are test-only, the return can be tested. # Element operations # ------------------ echo echo '- - Trailing sub-element selection - -' # Strings, Arrays and Positional parameters # Call this script with multiple arguments #+ to see the parameter selections. echo '- All -' echo ${VarSomething:0} # all non-null characters echo ${ArrayVar[@]:0} # all elements with content echo ${@:0} # all parameters with content; # ignoring parameter[0] echo echo '- All after -' echo ${VarSomething:1} # all non-null after character[0] echo ${ArrayVar[@]:1} # all after element[0] with content echo ${@:2} # all after param[1] with content echo echo '- Range after -' echo ${VarSomething:4:3} # ral # Three characters after # character[3] echo '- Sparse array gotch -' echo ${ArrayVar[@]:1:2} # four - The only element with content. # Two elements after (if that many exist). # the FIRST WITH CONTENTS #+ (the FIRST WITH CONTENTS is being #+ considered as if it #+ were subscript zero). # Executed as if Bash considers ONLY array elements with CONTENT # printf %q "${ArrayVar[@]:0:3}" # Try this one # In versions 2.04, 2.05a and 2.05b, #+ Bash does not handle sparse arrays as expected using this notation. # # The current Bash maintainer, Chet Ramey, has corrected this. echo '- Non-sparse array -' echo ${@:2:2} # Two parameters following parameter[1] # New victims for string vector examples: stringZ=abcABC123ABCabc arrayZ=( abcabc ABCABC 123123 ABCABC abcabc ) sparseZ=( [1]='abcabc' [3]='ABCABC' [4]='' [5]='123123' ) echo echo ' - - Victim string - -'$stringZ'- - ' echo ' - - Victim array - -'${arrayZ[@]}'- - ' echo ' - - Sparse array - -'${sparseZ[@]}'- - ' echo ' - [0]==null ref, [2]==null ref, [4]==null content - ' echo ' - [1]=abcabc [3]=ABCABC [5]=123123 - ' echo ' - non-null-reference count: '${#sparseZ[@]}' elements' echo echo '- - Prefix sub-element removal - -' echo '- - Glob-Pattern match must include the first character. - -' echo '- - Glob-Pattern may be a literal or a function result. - -' echo # Function returning a simple, Literal, Glob-Pattern _abc() { echo -n 'abc' } echo '- Shortest prefix -' echo ${stringZ#123} # Unchanged (not a prefix). echo ${stringZ#$(_abc)} # ABC123ABCabc echo ${arrayZ[@]#abc} # Applied to each element. # echo ${sparseZ[@]#abc} # Version-2.05b core dumps. # Has since been fixed by Chet Ramey. # The -it would be nice- First-Subscript-Of # echo ${#sparseZ[@]#*} # This is NOT valid Bash. echo echo '- Longest prefix -' echo ${stringZ##1*3} # Unchanged (not a prefix) echo ${stringZ##a*C} # abc echo ${arrayZ[@]##a*c} # ABCABC 123123 ABCABC # echo ${sparseZ[@]##a*c} # Version-2.05b core dumps. # Has since been fixed by Chet Ramey. echo echo '- - Suffix sub-element removal - -' echo '- - Glob-Pattern match must include the last character. - -' echo '- - Glob-Pattern may be a literal or a function result. - -' echo echo '- Shortest suffix -' echo ${stringZ%1*3} # Unchanged (not a suffix). echo ${stringZ%$(_abc)} # abcABC123ABC echo ${arrayZ[@]%abc} # Applied to each element. # echo ${sparseZ[@]%abc} # Version-2.05b core dumps. # Has since been fixed by Chet Ramey. # The -it would be nice- Last-Subscript-Of # echo ${#sparseZ[@]%*} # This is NOT valid Bash. echo echo '- Longest suffix -' echo ${stringZ%%1*3} # Unchanged (not a suffix) echo ${stringZ%%b*c} # a echo ${arrayZ[@]%%b*c} # a ABCABC 123123 ABCABC a # echo ${sparseZ[@]%%b*c} # Version-2.05b core dumps. # Has since been fixed by Chet Ramey. echo echo '- - Sub-element replacement - -' echo '- - Sub-element at any location in string. - -' echo '- - First specification is a Glob-Pattern - -' echo '- - Glob-Pattern may be a literal or Glob-Pattern function result. - -' echo '- - Second specification may be a literal or function result. - -' echo '- - Second specification may be unspecified. Pronounce that' echo ' as: Replace-With-Nothing (Delete) - -' echo # Function returning a simple, Literal, Glob-Pattern _123() { echo -n '123' } echo '- Replace first occurrence -' echo ${stringZ/$(_123)/999} # Changed (123 is a component). echo ${stringZ/ABC/xyz} # xyzABC123ABCabc echo ${arrayZ[@]/ABC/xyz} # Applied to each element. echo ${sparseZ[@]/ABC/xyz} # Works as expected. echo echo '- Delete first occurrence -' echo ${stringZ/$(_123)/} echo ${stringZ/ABC/} echo ${arrayZ[@]/ABC/} echo ${sparseZ[@]/ABC/} # The replacement need not be a literal, #+ since the result of a function invocation is allowed. # This is general to all forms of replacement. echo echo '- Replace first occurrence with Result-Of -' echo ${stringZ/$(_123)/$(_simple)} # Works as expected. echo ${arrayZ[@]/ca/$(_simple)} # Applied to each element. echo ${sparseZ[@]/ca/$(_simple)} # Works as expected. echo echo '- Replace all occurrences -' echo ${stringZ//[b2]/X} # X-out b's and 2's echo ${stringZ//abc/xyz} # xyzABC123ABCxyz echo ${arrayZ[@]//abc/xyz} # Applied to each element. echo ${sparseZ[@]//abc/xyz} # Works as expected. echo echo '- Delete all occurrences -' echo ${stringZ//[b2]/} echo ${stringZ//abc/} echo ${arrayZ[@]//abc/} echo ${sparseZ[@]//abc/} echo echo '- - Prefix sub-element replacement - -' echo '- - Match must include the first character. - -' echo echo '- Replace prefix occurrences -' echo ${stringZ/#[b2]/X} # Unchanged (neither is a prefix). echo ${stringZ/#$(_abc)/XYZ} # XYZABC123ABCabc echo ${arrayZ[@]/#abc/XYZ} # Applied to each element. echo ${sparseZ[@]/#abc/XYZ} # Works as expected. echo echo '- Delete prefix occurrences -' echo ${stringZ/#[b2]/} echo ${stringZ/#$(_abc)/} echo ${arrayZ[@]/#abc/} echo ${sparseZ[@]/#abc/} echo echo '- - Suffix sub-element replacement - -' echo '- - Match must include the last character. - -' echo echo '- Replace suffix occurrences -' echo ${stringZ/%[b2]/X} # Unchanged (neither is a suffix). echo ${stringZ/%$(_abc)/XYZ} # abcABC123ABCXYZ echo ${arrayZ[@]/%abc/XYZ} # Applied to each element. echo ${sparseZ[@]/%abc/XYZ} # Works as expected. echo echo '- Delete suffix occurrences -' echo ${stringZ/%[b2]/} echo ${stringZ/%$(_abc)/} echo ${arrayZ[@]/%abc/} echo ${sparseZ[@]/%abc/} echo echo '- - Special cases of null Glob-Pattern - -' echo echo '- Prefix all -' # null substring pattern means 'prefix' echo ${stringZ/#/NEW} # NEWabcABC123ABCabc echo ${arrayZ[@]/#/NEW} # Applied to each element. echo ${sparseZ[@]/#/NEW} # Applied to null-content also. # That seems reasonable. echo echo '- Suffix all -' # null substring pattern means 'suffix' echo ${stringZ/%/NEW} # abcABC123ABCabcNEW echo ${arrayZ[@]/%/NEW} # Applied to each element. echo ${sparseZ[@]/%/NEW} # Applied to null-content also. # That seems reasonable. echo echo '- - Special case For-Each Glob-Pattern - -' echo '- - - - This is a nice-to-have dream - - - -' echo _GenFunc() { echo -n ${0} # Illustration only. # Actually, that would be an arbitrary computation. } # All occurrences, matching the AnyThing pattern. # Currently //apps/ //backup/ //bin/ //boot/ //data/ //dev/ //etc/ //home/ //lib/ //lost+found/ //media/ //misc/ //mnt/ //net/ //opt/ //proc/ //root/ //sbin/ //selinux/ //srv/ //sys/ //tftpboot/ //tmp/ //usr/ //var/ does not match null-content nor null-reference. # /#/ and /%/ does match null-content but not null-reference. echo ${sparseZ[@]//*/$(_GenFunc)} # A possible syntax would be to make #+ the parameter notation used within this construct mean: # ${1} - The full element # ${2} - The prefix, if any, to the matched sub-element # ${3} - The matched sub-element # ${4} - The suffix, if any, to the matched sub-element # # echo ${sparseZ[@]//*/$(_GenFunc ${3})} # Same as ${1} here. # Perhaps it will be implemented in a future version of Bash. exit 0