`help2man' Reference Manual
help2man produces simple manual pages from the ‘--help’ and ‘--version’ output of other commands.
Overview of help2man
help2man is a tool for automatically generating simple manual pages from program output.
Although manual pages are optional for GNU programs other projects, such as Debian require them (see Man Pages)
This program is intended to provide an easy way for software authors to include a manual page in their distribution without having to maintain that document.
Given a program which produces reasonably standard ‘--help’ and ‘--version’ outputs, help2man can re-arrange that output into something which resembles a manual page.
How to Run help2man
The format for running the help2man program is:
help2man [option]... executable
help2man supports the following options:
- ‘-n string’
- Use string as the description for the ‘NAME’ paragraph of the manual page.
By default (for want of anything better) this paragraph contains ‘manual page for program version’.
This option overrides an include file ‘[name]’ section (see Including text).
- ‘-s section’
- Use section as the section for the man page. The default section is 1.
- ‘-m manual’
- Set the name of the manual section to section, used as a centred heading for the manual page. By default ‘User Commands’ is used for pages in section 1, ‘Games’ for section 6 and ‘System Administration Utilities’ for sections 8 and 1M.
- ‘-S source’
- The program source is used as a page footer, and often contains the name of the organisation or a suite of which the program is part. By default the value is the package name and version.
- ‘-L locale’
- Select output locale (default ‘C’). Both the program and help2man must support the given locale (see Localised man pages).
- ‘-i file’
- Include material from file (see Including text).
- ‘-I file’
- A variant of ‘--include’ for use in Makefile pattern rules which does not require file to exist.
- ‘-o file’
- Send output to file rather than
- Name of Texinfo manual.
- Suppress inclusion of a ‘SEE ALSO’ paragraph directing the reader to the Texinfo documentation.
- Drop lt- prefix from instances of the program name in the synopsis (libtool creates wrapper scripts in the build directory which invoke foo as .libs/lt-foo).
- Show help or version information.
By default help2man passes the standard ‘--help’ and ‘--version’ options to the executable although alternatives may be specified using:
- ‘-h option’
- Help option string.
- ‘-v option’
- Version option string.
- Version string.
- Include stderr when parsing option output.
Here are some recommendations for what to include in your --help output. Including these gives help2man the best chance at generating a respectable man page, as well as benefitting users directly.
- A synopsis of how to invoke the program. If different usages of the
program have different invocations, then list them all. For example
(edited for brevity):
Usage: cp [OPTION]... SOURCE DEST or: cp [OPTION]... SOURCE... DIRECTORY ...
argvfor the program name in these synopses, just as it is, with no directory stripping. This is in contrast to the canonical (constant) name of the program which is used in --version.
- A very brief explanation of what the program does, including default and/or
typical behaviour. For example, here is cp's:
Copy SOURCE to DEST, or multiple SOURCE(s) to DIRECTORY.
- A list of options, indented to column 2. If the program supports
one-character options, put those first, then the equivalent long option
(if any). If the option takes an argument, include that too, giving it
a meaningful name. Align the descriptions in a convenient column, if
desired. Note that to be correctly recognised by help2man
the description must be separated from the options by at least two
spaces and descriptions continued on subsequent lines must start at
the same column.
Here again is an (edited) excerpt from cp, showing a short option with an equivalent long option, a long option only, and a short option only:
-a, --archive same as -dpR --backup[=CONTROL] make a backup of each ... -b like --backup but ...
For programs that take many options, it may be desirable to split the option list into sections such as `Global', `Output control', or whatever makes sense in the particular case. It is usually best to alphabetise (by short option name first, then long) within each section, or the entire list if there are no sections.
- Any useful additional information about program behaviour, such as influential environment variables, further explanation of options, etc. For example, cp discusses VERSION_CONTROL and sparse files.
- A few examples of typical usage, at your discretion. One good example is usually worth a thousand words of description, so this is highly recommended.
- In closing, a line stating how to email bug reports. Typically, mailing-address will be ‘email@example.com’; please use this form for GNU programs whenever possible. It's also good to mention the home page of the program, other mailing lists, etc.
popt programming interfaces let you
specify option descriptions for --help
in the same structure as the rest of the option definition; you may wish to
consider using these routines for option parsing instead of
Including Additional Text in the Output
Additional static text may be included in the generated manual page by using
the ‘--include’ and
‘--opt-include’ options (see
Invoking help2man). While these files can be
named anything, for consistency we suggest to use the extension
.h2m for help2man include files.
The format for files included with these option is simple:
[section] text /pattern/ text
Blocks of verbatim *roff text are inserted into the output either at the start of the given ‘[section]’ (case insensitive), or after a paragraph matching ‘/pattern/’.
Patterns use the Perl regular expression syntax and may be followed by the ‘i’, ‘s’ or ‘m’ modifiers (see perlre(1))
Lines before the first section or pattern which begin with ‘-’ are processed as options. Anything else is silently ignored and may be used for comments, RCS keywords and the like.
The section output order (for those included) is:
NAME SYNOPSIS DESCRIPTION OPTIONS ENVIRONMENT FILES EXAMPLES other AUTHOR REPORTING BUGS COPYRIGHT SEE ALSO
Any ‘[name]’ or ‘[synopsis]’ sections appearing in the include file will replace what would have automatically been produced (although you can still override the former with ‘--name’ if required).
Other sections are prepended to the automatically produced output for the standard sections given above, or included at other (above) in the order they were encountered in the include file.
Using help2man With make
A suggested use of help2man in Makefiles is to have the manual page depend not on the binary, but on the source file(s) in which the ‘--help’ and ‘--version’ output are defined.
This usage allows a manual page to be generated by the maintainer and included in the distribution without requiring the end-user to have help2man installed.
An example rule for the program
prog could be:
prog.1: $(srcdir)/main.c -$(HELP2MAN) --output=$@ --name='an example program' ./prog
The value of
HELP2MAN may be set in
using either of:
AM_MISSING_PROG(HELP2MAN, help2man, $missing_dir)
for automake, or something like:
AC_PATH_PROG(HELP2MAN, help2man, false // No help2man //)
for autoconf alone.
Producing Native Language Manual Pages
Manual pages may be produced for any locale supported by both the program and help2man with the ‘--locale’ (‘-L’) option.
help2man -L fr_FR@euro -o cp.fr.1 cp
See http://translationproject.org/domain/help2man.html for the languages currently supported by help2man, and see Reports for how to submit other translations.
Changing the Location of Message Catalogs
When creating localised manual pages from a program's build directory it is probable that the translations installed in the standard location will not be (if installed at all) correct for the version of the program being built.
A preloadable library is provided with help2man which will intercept
bindtextdomain calls configuring the location of message catalogs
for the domain given by $TEXTDOMAIN and
override the location to the path given by $LOCALEDIR.
So for example:
mkdir -p tmp/fr/LC_MESSAGES cp po/fr.gmo tmp/fr/LC_MESSAGES/prog.mo LD_PRELOAD="/usr/lib/help2man/bindtextdomain.so" \ LOCALEDIR=tmp \ TEXTDOMAIN=prog \ help2man -L fr_FR@euro -i prog.fr.h2m -o prog.fr.1 prog rm -rf tmp
will cause prog to load the message catalog from ‘tmp’ rather than ‘/usr/share/locale’.
- The generalisation of ‘fr_FR@euro’ to ‘fr’ in the example above is done by
gettext, if a more specific match were available it would also have been re-mapped.
- This preload has only been tested against eglibc 2.11.2 and gettext 0.18.1.1 on a GNU/Linux system; let me know if it does (or doesn't) work for you (see Reports).
Example help2man Output
Given a hypothetical program foo which produces the following output:
$ foo --version GNU foo 1.1 Copyright (C) 2011 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. Written by A. Programmer. $ foo --help GNU `foo' does nothing interesting except serve as an example for `help2man'. Usage: foo [OPTION]... Options: -a, --option an option -b, --another-option[=VALUE] another option --help display this help and exit --version output version information and exit Examples: foo do nothing foo --option the same thing, giving `--option' Report bugs to <firstname.lastname@example.org>.
help2man will produce nroff input for a manual page which will be formatted something like this:
FOO(1) User Commands FOO(1) NAME foo - manual page for foo 1.1 SYNOPSIS foo [OPTION]... DESCRIPTION GNU `foo' does nothing interesting except serve as an example for `help2man'. OPTIONS -a, --option an option -b, --another-option[=VALUE] another option --help display this help and exit --version output version information and exit EXAMPLES foo do nothing foo --option the same thing, giving `--option' AUTHOR Written by A. Programmer. REPORTING BUGS Report bugs to <email@example.com>. COPYRIGHT Copyright © 2011 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. SEE ALSO The full documentation for foo is maintained as a Texinfo manual. If the info and foo programs are properly installed at your site, the command info foo should give you access to the complete manual. foo 1.1 May 2011 FOO(1)
Reporting Bugs or Suggestions
If you find problems or have suggestions about this program or manual, please report them to firstname.lastname@example.org.
Note to translators: Translations are handled though the Translation Project see http://translationproject.org/html/translators.html for details.
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