EXPR
Section: User Commands (1)
Updated: March 2007
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NAME
expr  evaluate expressions
SYNOPSIS
expr
EXPRESSION
expr
OPTION
DESCRIPTION
 help

display this help and exit
 version

output version information and exit
Print the value of EXPRESSION to standard output. A blank line below
separates increasing precedence groups. EXPRESSION may be:
 ARG1  ARG2

ARG1 if it is neither null nor 0, otherwise ARG2
 ARG1 & ARG2

ARG1 if neither argument is null or 0, otherwise 0
 ARG1 < ARG2

ARG1 is less than ARG2
 ARG1 <= ARG2

ARG1 is less than or equal to ARG2
 ARG1 = ARG2

ARG1 is equal to ARG2
 ARG1 != ARG2

ARG1 is unequal to ARG2
 ARG1 >= ARG2

ARG1 is greater than or equal to ARG2
 ARG1 > ARG2

ARG1 is greater than ARG2
 ARG1 + ARG2

arithmetic sum of ARG1 and ARG2
 ARG1  ARG2

arithmetic difference of ARG1 and ARG2
 ARG1 * ARG2

arithmetic product of ARG1 and ARG2
 ARG1 / ARG2

arithmetic quotient of ARG1 divided by ARG2
 ARG1 % ARG2

arithmetic remainder of ARG1 divided by ARG2
 STRING : REGEXP

anchored pattern match of REGEXP in STRING
 match STRING REGEXP

same as STRING : REGEXP
 substr STRING POS LENGTH

substring of STRING, POS counted from 1
 index STRING CHARS

index in STRING where any CHARS is found, or 0
 length STRING

length of STRING
 + TOKEN

interpret TOKEN as a string, even if it is a

keyword like `match' or an operator like `/'
 ( EXPRESSION )

value of EXPRESSION
Beware that many operators need to be escaped or quoted for shells.
Comparisons are arithmetic if both ARGs are numbers, else lexicographical.
Pattern matches return the string matched between \( and \) or null; if
\( and \) are not used, they return the number of characters matched or 0.
Exit status is 0 if EXPRESSION is neither null nor 0, 1 if EXPRESSION is null
or 0, 2 if EXPRESSION is syntactically invalid, and 3 if an error occurred.
AUTHOR
Written by Mike Parker.
REPORTING BUGS
Report bugs to <bugcoreutils@gnu.org>.
COPYRIGHT
Copyright © 2006 Free Software Foundation, Inc.
This is free software. You may redistribute copies of it under the terms of
the GNU General Public License <http://www.gnu.org/licenses/gpl.html>.
There is NO WARRANTY, to the extent permitted by law.
SEE ALSO
The full documentation for
expr
is maintained as a Texinfo manual. If the
info
and
expr
programs are properly installed at your site, the command

info expr
should give you access to the complete manual.
Index
 NAME

 SYNOPSIS

 DESCRIPTION

 AUTHOR

 REPORTING BUGS

 COPYRIGHT

 SEE ALSO

linux.jgfs.net manual pages