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