Section: Linux Programmer's Manual (7)
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man - macros to format man pages
groff -Tascii -man
groff -Tps -man
This manual page explains the
macro package (often called the
macro package) and related conventions for creating manual (man) pages.
This macro package should be used by developers when
writing or porting man pages for Linux. It is fairly compatible with other
versions of this macro package, so porting man pages should not be a major
problem (exceptions include the NET-2 BSD release, which uses a totally
different macro package called mdoc; see
Note that NET-2 BSD mdoc man pages can be used with
simply by specifying the
option instead of the
option. Using the
option is, however, recommended, since this will automatically detect which
macro package is in use.
The first command in a man page (after comment lines) should be
title section date source manual,
The title of the man page (e.g.,
The section number the man page should be placed in (e.g.,
The date of the last revision---remember to change this every time a
change is made to the man page, since this is the most general way of doing
The source of the command.
For binaries, use something like:
GNU, NET-2, SLS Distribution, MCC Distribution.
For system calls, use the version of the kernel that you are currently
For library calls, use the source of the function:
GNU, 4.3BSD, Linux DLL 4.4.1.
The title of the manual (e.g.,
Linux Programmer's Manual).
Note that BSD mdoc-formatted pages begin with the
command, not the
The manual sections are traditionally defined as follows:
- 1 Commands
Those commands that can be executed by the user from within
- 2 System calls
Those functions which must be performed by the kernel.
- 3 Library calls
Most of the
functions, such as
- 4 Special files
Files found in
- 5 File formats and conventions
The format for
and other human-readable files.
- 6 Games
- 7 Conventions and miscellaneous
A description of the standard file system layout, network protocols,
ASCII and other character codes, this man page, and other things.
- 8 System management commands
many of which only root can execute.
- 9 Kernel routines
This is an obsolete manual section.
Once it was thought a good idea to document the Linux kernel here,
but in fact very little has been documented, and the documentation
that exists is outdated already. There are better sources of
information for kernel developers.
Sections are started with
followed by the heading name. If the name contains spaces and appears
on the same line as
then place the heading in double quotes. Traditional or suggested
NAME, SYNOPSIS, DESCRIPTION, RETURN VALUE,
EXIT STATUS, ERROR HANDLING, ERRORS,
OPTIONS, USAGE, EXAMPLES, FILES, ENVIRONMENT, DIAGNOSTICS, SECURITY,
CONFORMING TO, NOTES, BUGS, AUTHOR, and SEE ALSO.
Where a traditional heading would apply, please use it;
this kind of consistency can make the information easier to understand.
However, feel free to create your own headings if they make things easier
The only required heading is NAME, which should be the first section and
be followed on the next line by a one line description of the program:
It is extremely important that this format is followed, and that there is a
backslash before the single dash which follows the command name. This
syntax is used by the
program to create a database of short command descriptions for the
chess \- the game of chess
Some other traditional sections have the following contents:
briefly describes the command or function's interface.
For commands, this shows the syntax of the command and its arguments
boldface is used for as-is text and italics are used to indicate replaceable
arguments. Brackets () surround optional arguments, vertical bars (|)
separate choices, and ellipses (...) can be repeated.
For functions, it shows any required data declarations or
directives, followed by the function declaration.
gives an explanation of what the command, function, or format does.
Discuss how it interacts with files and standard input, and what it
produces on standard output or standard error.
Omit internals and implementation details unless they're critical for
understanding the interface.
Describe the usual case; for information on options use the
If there is some kind of input grammar or complex set of subcommands,
consider describing them in a separate
section (and just place an overview in the
- RETURN VALUE
list of the values the library routine will return to the caller
and the conditions that cause these values to be returned.
- EXIT STATUS
lists the possible exit status values or a program and
the conditions that cause these values to be returned.
describes the options accepted by the program and how they change
describes the grammar of any sublanguage this implements.
provides one or more examples describing how this function, file or
command is used.
lists the files the program or function uses, such as
configuration files, startup files,
and files the program directly operates on.
Give the full pathname of these files, and use the installation
process to modify the directory part to match user preferences.
For many programs, the default installation location is in
so your base manual page should use
as the base.
lists all environment variables that affect your program or function
and how they affect it.
gives an overview of the most common error messages and how to
cope with them. You don't need to explain system error messages
or fatal signals that can appear during execution of any program
unless they're special in some way to your program.
discusses security issues and implications.
Warn about configurations or environments that should be avoided,
commands that may have security implications, and so on, especially
if they aren't obvious.
Discussing security in a separate section isn't necessary;
if it's easier to understand, place security information in the
other sections (such as the
However, please include security information somewhere!
- CONFORMING TO
describes any standards or conventions this implements.
provides miscellaneous notes.
lists limitations, known defects or inconveniences,
and other questionable activities.
lists authors of the documentation or program so you can mail in bug
- SEE ALSO
lists related man pages in alphabetical order, possibly followed by
other related pages or documents.
Conventionally this is the last section.
Although there are many arbitrary conventions for man pages in the UNIX
world, the existence of several hundred Linux-specific man pages defines our
For functions, the arguments are always specified using italics,
even in the SYNOPSIS section,
where the rest of the function is specified in bold:
int myfunction(int argc, char **argv);
Filenames are always in italics (e.g.,
except in the SYNOPSIS section, where included files are in bold (e.g.,
Special macros, which are usually in upper case, are in bold (e.g.,
When enumerating a list of error codes, the codes are in bold (this list
usually uses the
Any reference to another man page (or to the subject of the current man
page) is in bold. If the manual section number is given, it is given in
Roman (normal) font, without any spaces (e.g.,
The commands to select the type face are:
Bold alternating with italics
(especially useful for function specifications)
Bold alternating with Roman
(especially useful for referring to other
Italics alternating with bold
Italics alternating with Roman
Roman alternating with bold
Roman alternating with italics
Small alternating with bold
Small (useful for acronyms)
Traditionally, each command can have up to six arguments, but the GNU
implementation removes this limitation (you might still want to limit
yourself to 6 arguments for portability's sake).
Arguments are delimited by
spaces. Double quotes can be used to specify an argument which contains
spaces. All of the arguments will be printed next to each other without
intervening spaces, so that the
command can be used to specify a word in bold followed by a mark of
punctuation in Roman.
If no arguments are given, the command is applied to the following line
OTHER MACROS AND STRINGS
Below are other relevant macros and predefined strings.
Unless noted otherwise, all macros
cause a break (end the current line of text).
Many of these macros set or use the "prevailing indent."
The "prevailing indent" value is set by any macro with the parameter
macros may omit
in which case the current prevailing indent will be used.
As a result, successive indented paragraphs can use the same indent without
re-specifying the indent value.
A normal (non-indented) paragraph resets the prevailing indent value
to its default value (0.5 inches).
By default a given indent is measured in ens;
try to use ens or ems as units for
indents, since these will automatically adjust to font size changes.
The other key macro definitions are:
(begin a new paragraph).
(begin a new paragraph).
Begin a new paragraph and reset prevailing indent.
Relative Margin Indent
- .RS i
Start relative margin indent: moves the left margin
to the right (if
is omitted, the prevailing indent value is used).
A new prevailing indent is set to 0.5 inches.
As a result, all following paragraph(s) will be
indented until the corresponding
End relative margin indent and
restores the previous value of the prevailing indent.
Indented Paragraph Macros
- .HP i
Begin paragraph with a hanging indent
(the first line of the paragraph is at the left margin of
normal paragraphs, and the rest of the paragraph's lines are indented).
- .IP x i
Indented paragraph with optional hanging tag.
If the tag
is omitted, the entire following paragraph is indented by
If the tag
is provided, it is hung at the left margin
before the following indented paragraph
(this is just like
except the tag is included with the command instead of being on the
If the tag is too long, the text after the tag will be moved down to the
next line (text will not be lost or garbled).
For bulleted lists, use this macro with \(bu (bullet) or \(em (em dash)
as the tag, and for numbered lists, use the number or letter followed by
a period as the tag;
this simplifies translation to other formats.
- .TP i
Begin paragraph with hanging tag. The tag is given on the next line, but
its results are like those of the
Hypertext Link Macros
(Feature supported with
In order to use hypertext link macros, it is necessary to load the
Use the request
to do this.
- .URL url link trailer
Inserts a hypertext link to the URI (URL)
as the text of the link.
will be printed immediately afterwards.
When generating HTML this should translate into the HTML command
This and other related macros are new, and
many tools won't do anything with them, but
since many tools (including troff) will simply ignore undefined macros
(or at worst insert their text) these are safe to insert.
It can be useful to define your own
macro in manual pages for the benefit of those viewing it with a roff
viewer other than
That way, the URL, link text, and trailer text (if any) are still visible.
Here's an example:
\\$2 \(laURL: \\$1 \(ra\\$3
.if \n[.g] .mso www.tmac
(later in the page)
This software comes from the
.URL "http://www.gnu.org/" "GNU Project" " of the"
.URL "http://www.fsf.org/" "Free Software Foundation" .
In the above, if
is being used, the
macro package's definition of the URL macro will supersede the locally
A number of other link macros are available. See
for more details.
Reset tabs to default tab values (every 0.5 inches);
does not cause a break.
- .PD d
Set inter-paragraph vertical distance to d
(if omitted, d=0.4v);
does not cause a break.
- .SS t
but used for a subsection inside a section).
package has the following predefined strings:
Registration Symbol: ®
Change to default font size
Left angled doublequote: ``
Right angled doublequote: ''
is a troff macro package, in reality a large number of other tools
process man page files that don't implement all of troff's abilities.
Thus, it's best to avoid some of troff's more exotic abilities where possible
to permit these other tools to work correctly.
Avoid using the various troff preprocessors
(if you must, go ahead and use
but try to use the
commands instead for two-column tables).
Avoid using computations; most other tools can't process them.
Use simple commands that are easy to translate to other formats.
The following troff macros are believed to be safe (though in many cases
they will be ignored by translators):
You may also use many troff escape sequences (those sequences beginning
When you need to include the backslash character as normal text,
Other sequences you may use, where x or xx are any characters and N
is any digit, include:
Avoid using the escape sequences for drawing graphics.
Do not use the optional parameter for
Use only positive values for
Don't define a macro
with the same name as a macro in this or the
mdoc macro package with a different meaning; it's likely that
such redefinitions will be ignored.
Every positive indent
should be paired with a matching negative indent
(although you should be using the
The condition test
should only have 't' or 'n' as the condition.
that can be ignored should be used.
and the \f escape sequence)
should only have the values 1, 2, 3, 4, R, I, B, P, or CW
(the ft command may also have no parameters).
If you use capabilities beyond these, check the
results carefully on several tools.
Once you've confirmed that the additional capability is safe,
let the maintainer of this
document know about the safe command or sequence
that should be added to this list.
By all means include full URLs (or URIs) in the text itself;
some tools such as
can automatically turn them into hypertext links.
You can also use the new
macro to identify links to related information.
If you include URLs, use the full URL
(e.g., <http://www.kernelnotes.org>) to ensure that tools
can automatically find the URLs.
Tools processing these files should open the file and examine the first
non-whitespace character. A period (.) or single quote (')
at the beginning of a line indicates a troff-based file (such as man or mdoc).
A left angle bracket (<) indicates an SGML/XML-based
file (such as HTML or Docbook). Anything else suggests simple ASCII
text (e.g., a "catman" result).
Many man pages begin with '\" followed by a space and a list of characters,
indicating how the page is to be preprocessed.
For portability's sake to non-troff translators we recommend that you avoid
using anything other than
and Linux can detect that automatically.
However, you might want to include this information so your man page
can be handled by other (less capable) systems.
Here are the definitions of the preprocessors invoked by these characters:
Most of the macros describe formatting (e.g., font type and spacing) instead
of marking semantic content (e.g., this text is a reference to another page),
compared to formats like mdoc and DocBook (even HTML has more semantic
This situation makes it harder to vary the
format for different media,
to make the formatting consistent for a given media, and to automatically
By sticking to the safe subset described above, it should be easier to
automate transitioning to a different reference page format in the future.
The Sun macro
is not implemented.
James Clark (email@example.com) wrote the implementation of the macro package.
Rickard E. Faith (firstname.lastname@example.org) wrote the initial version of
this manual page.
Jens Schweikhardt (email@example.com) wrote the Linux Man-Page Mini-HOWTO
(which influenced this manual page).
David A. Wheeler (firstname.lastname@example.org) heavily modified this
manual page, such as adding detailed information on sections and macros.
- OTHER MACROS AND STRINGS
- Normal Paragraphs
- Relative Margin Indent
- Indented Paragraph Macros
- Hypertext Link Macros
- Miscellaneous Macros
- Predefined Strings
- SAFE SUBSET
- SEE ALSO
linux.jgfs.net manual pages