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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXIT STATUS | ENVIRONMENT | FILES | SEE ALSO | AUTHOR | BUGS | COLOPHON |
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APROPOS(1) Manual pager utils APROPOS(1)
apropos - search the manual page names and descriptions
apropos [-dalv?V] [-e|-w|-r] [-s list] [-m system[,...]] [-M path]
[-L locale] [-C file] keyword ...
Each manual page has a short description available within it.
apropos searches the descriptions for instances of keyword.
keyword is usually a regular expression, as if (-r) was used, or
may contain wildcards (-w), or match the exact keyword (-e).
Using these options, it may be necessary to quote the keyword or
escape (\) the special characters to stop the shell from
interpreting them.
The standard matching rules allow matches to be made against the
page name and word boundaries in the description.
The database searched by apropos is updated by the mandb program.
Depending on your installation, this may be run by a periodic cron
job, or may need to be run manually after new manual pages have
been installed.
-d, --debug
Print debugging information.
-v, --verbose
Print verbose warning messages.
-r, --regex
Interpret each keyword as a regular expression. This is
the default behaviour. Each keyword will be matched
against the page names and the descriptions independently.
It can match any part of either. The match is not limited
to word boundaries.
-w, --wildcard
Interpret each keyword as a pattern containing shell style
wildcards. Each keyword will be matched against the page
names and the descriptions independently. If --exact is
also used, a match will only be found if an expanded
keyword matches an entire description or page name.
Otherwise the keyword is also allowed to match on word
boundaries in the description.
-e, --exact
Each keyword will be exactly matched against the page names
and the descriptions.
-a, --and
Only display items that match all the supplied keywords.
The default is to display items that match any keyword.
-l, --long
Do not trim output to the terminal width. Normally, output
will be truncated to the terminal width to avoid ugly
results from poorly-written NAME sections.
-s list, --sections=list, --section=list
Search only the given manual sections. list is a colon- or
comma-separated list of sections. If an entry in list is a
simple section, for example "3", then the displayed list of
descriptions will include pages in sections "3", "3perl",
"3x", and so on; while if an entry in list has an
extension, for example "3perl", then the list will only
include pages in that exact part of the manual section.
-m system[,...], --systems=system[,...]
If this system has access to other operating systems'
manual page descriptions, they can be searched using this
option. To search NewOS's manual page descriptions, use
the option -m NewOS.
The system specified can be a combination of comma-
delimited operating system names. To include a search of
the native operating system's whatis descriptions, include
the system name man in the argument string. This option
will override the $SYSTEM environment variable.
-M path, --manpath=path
Specify an alternate set of colon-delimited manual page
hierarchies to search. By default, apropos uses the
$MANPATH environment variable, unless it is empty or unset,
in which case it will determine an appropriate manpath
based on your $PATH environment variable. This option
overrides the contents of $MANPATH.
-L locale, --locale=locale
apropos will normally determine your current locale by a
call to the C function setlocale(3) which interrogates
various environment variables, possibly including
$LC_MESSAGES and $LANG. To temporarily override the
determined value, use this option to supply a locale string
directly to apropos. Note that it will not take effect
until the search for pages actually begins. Output such as
the help message will always be displayed in the initially
determined locale.
-C file, --config-file=file
Use this user configuration file rather than the default of
~/.manpath.
-?, --help
Print a help message and exit.
--usage
Print a short usage message and exit.
-V, --version
Display version information.
0 Successful program execution.
1 Usage, syntax or configuration file error.
2 Operational error.
16 Nothing was found that matched the criteria specified.
SYSTEM If $SYSTEM is set, it will have the same effect as if it
had been specified as the argument to the -m option.
MANPATH
If $MANPATH is set, its value is interpreted as the colon-
delimited manual page hierarchy search path to use.
See the SEARCH PATH section of manpath(5) for the default
behaviour and details of how this environment variable is
handled.
MANWIDTH
If $MANWIDTH is set, its value is used as the terminal
width (see the --long option). If it is not set, the
terminal width will be calculated using the value of
$COLUMNS, and ioctl(2) if available, or falling back to 80
characters if all else fails.
POSIXLY_CORRECT
If $POSIXLY_CORRECT is set, even to a null value, the
default apropos search will be as an extended regex (-r).
Nowadays, this is the default behaviour anyway.
/usr/share/man/index.(bt|db|dir|pag)
A traditional global index database cache.
/var/cache/man/index.(bt|db|dir|pag)
An FHS compliant global index database cache.
/usr/share/man/.../whatis
A traditional whatis text database.
man(1), whatis(1), mandb(8)
Wilf. ([email protected]).
Fabrizio Polacco ([email protected]).
Colin Watson ([email protected]).
https://gitlab.com/man-db/man-db/-/issues
https://savannah.nongnu.org/bugs/?group=man-db
This page is part of the man-db (manual pager suite) project.
Information about the project can be found at
⟨http://www.nongnu.org/man-db/⟩. If you have a bug report for this
manual page, send it to [email protected]. This page was
obtained from the project's upstream Git repository
⟨https://gitlab.com/cjwatson/man-db⟩ on 2025-08-11. (At that
time, the date of the most recent commit that was found in the
repository was 2025-05-19.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
[email protected]
2.13.1 2025-05-02 APROPOS(1)
Pages that refer to this page: lexgrog(1), man(1), manpath(1), whatis(1)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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