NAME

       whatis - display one-line manual page descriptions

SYNOPSIS

       whatis  [-dlv?V]  [-r|-w] [-s list] [-m system[,...]] [-M path] [-L locale] [-C file] name
       ...

DESCRIPTION

       Each manual page has a short description available within it.  whatis searches the  manual
       page names and displays the manual page descriptions of any name matched.

       name  may contain wildcards (-w) or be a regular expression (-r).  Using these options, it
       may be necessary to quote the name or escape (\) the special characters to stop the  shell
       from interpreting them.

       index  databases  are  used  during  the  search,  and  are  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.  To produce an old style text
       whatis database from the relative index database, issue the command:

       whatis -M manpath -w '*' | sort > manpath/whatis

       where manpath is a manual page hierarchy such as /usr/man.

OPTIONS

       -d, --debug
              Print debugging information.

       -v, --verbose
              Print verbose warning messages.

       -r, --regex
              Interpret each name as a regular expression.  If a name matches any part of a  page
              name, a match will be made.  This option causes whatis to be somewhat slower due to
              the nature of database searches.

       -w, --wildcard
              Interpret each name as a pattern containing shell style wildcards.  For a match  to
              be  made,  an  expanded  name  must match the entire page name.  This option causes
              whatis to be somewhat slower due to the nature of database searches.

       -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 names, they can
              be accessed using this option.  To search NewOS's manual page names, 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  manual  page  names,
              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,  whatis  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
              whatis  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 whatis.  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.

              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.

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

       apropos(1), man(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/cjwatson/man-db/-/issues
       https://savannah.nongnu.org/bugs/?group=man-db