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.
Print debugging information.
Print verbose warning messages.
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.
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.
Each keyword will be exactly matched against the page names and the descriptions.
Only display items that match all the supplied keywords. The default is to display items that match any keyword.
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.
list,
--sections=list,
--section=listSearch 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.
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.
path,
--manpath=pathSpecify 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.
locale,
--locale=localeapropos 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.
file,
--config-file=fileUse this user configuration file rather than the default of
~/.manpath.
Print a help message and exit.
Print a short usage message and exit.
Display version information.
Successful program execution.
Usage, syntax or configuration file error.
Operational error.
Nothing was found that matched the criteria specified.
If $SYSTEM is set, it will have the same effect as if it had been specified as the argument to the -m option.
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.
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.
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/ . . . /whatisA traditional whatis text database.
Wilf. (G.Wilford@ee.surrey.ac.uk).
Fabrizio Polacco (fpolacco@debian.org).
Colin Watson (cjwatson@debian.org).