whatis - display one-line manual page descriptions
whatis [-dlv?V] [-r|-w] [-s
list] [-m system[,...]] [-M path]
[-L locale] [-C file] name ...
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.
- -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.
- 0
- Successful program execution.
- 1
- Usage, syntax or configuration file error.
- 2
- Operational error.
- 16
- Nothing was found that matched the criteria specified.
- 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.
- /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.
Wilf. (G.Wilford@ee.surrey.ac.uk).
Fabrizio Polacco (fpolacco@debian.org).
Colin Watson (cjwatson@debian.org).
https://gitlab.com/man-db/man-db/-/issues
https://savannah.nongnu.org/bugs/?group=man-db