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).