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NAME
apropos - search the manual page names and descriptions
SYNOPSIS
apropos [-dalv?V] [-e|-w|-r] [-s list] [-m system[,...]] [-M path] [-L locale] [-C file] keyword ...
DESCRIPTION
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 descrip‐
tion.
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.
OPTIONS
-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 appro‐
priate 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 inter‐
rogates 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.
EXIT STATUS
0 Successful program execution.
1 Usage, syntax or configuration file error.
2 Operational error.
16 Nothing was found that matched the criteria specified.
ENVIRONMENT
SYSTEM If $SYSTEM is set, it will have the same effect as if it had been specified as the argument to the -m op‐
tion.
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.
FILES
/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.
SEE ALSO
man(1), whatis(1), mandb(8)
AUTHOR
Wilf. (G.Wilford@ee.surrey.ac.uk).
Fabrizio Polacco (fpolacco@debian.org).
Colin Watson (cjwatson@debian.org).
BUGS
https://gitlab.com/man-db/man-db/-/issues
https://savannah.nongnu.org/bugs/?group=man-db
2.12.0 2023-09-23 APROPOS(1)
NAME
apropos - search the manual page names and descriptions
SYNOPSIS
apropos [-dalv?V] [-e|-w|-r] [-s list] [-m system[,...]] [-M path] [-L locale] [-C file] keyword ...
DESCRIPTION
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 descrip‐
tion.
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.
OPTIONS
-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 appro‐
priate 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 inter‐
rogates 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.
EXIT STATUS
0 Successful program execution.
1 Usage, syntax or configuration file error.
2 Operational error.
16 Nothing was found that matched the criteria specified.
ENVIRONMENT
SYSTEM If $SYSTEM is set, it will have the same effect as if it had been specified as the argument to the -m op‐
tion.
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.
FILES
/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.
SEE ALSO
man(1), whatis(1), mandb(8)
AUTHOR
Wilf. (G.Wilford@ee.surrey.ac.uk).
Fabrizio Polacco (fpolacco@debian.org).
Colin Watson (cjwatson@debian.org).
BUGS
https://gitlab.com/man-db/man-db/-/issues
https://savannah.nongnu.org/bugs/?group=man-db
2.12.0 2023-09-23 APROPOS(1)