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.  De-
       pending 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 in-
       stalled.

OPTIONS
       -d, --debug
              Print debugging information.

       -v, --verbose
              Print verbose warning messages.

       -r, --regex
              Interpret each keyword as a regular expression.  This is the de-
              fault  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 wild-
              cards.  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  en-
              tire  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 sim-
              ple section, for example "3", then the  displayed  list  of  de-
              scriptions  will  include  pages in sections "3", "3perl", "3x",
              and so on; while if an entry in list has an extension, for exam-
              ple "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 op-
              erating system names.  To include a search of the native operat-
              ing system's whatis descriptions, include the system name man in
              the argument string.  This option will override the $SYSTEM  en-
              vironment variable.

       -M path, --manpath=path
              Specify  an alternate set of colon-delimited manual page hierar-
              chies to search.  By default, apropos uses the $MANPATH environ-
              ment  variable,  unless  it  is empty or unset, in which case it
              will determine an appropriate manpath based on your $PATH  envi-
              ronment  variable.   This option overrides the contents of $MAN-
              PATH.

       -L locale, --locale=locale
              apropos will normally determine your current locale by a call to
              the  C function setlocale(3) which interrogates various environ-
              ment 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-delim-
              ited 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).

2.9.1                             2020-02-25                        APROPOS(1)