apropos

APROPOS(1)                     Manual pager utils                     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 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.

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 system's 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.

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 option.

       MANPATH
              If $MANPATH is set, its value is interpreted as the colon-
              delimited manual page hierarchy search path to use.

       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://savannah.nongnu.org/bugs/?group=man-db



2.9.4                              2021-02-08                         APROPOS(1)