WHATIS - display one-line manual page descriptions - man(1) - [phpMan]

Che Dong

⚡ TLDR: WHATIS (tldr-pages)

Display one-line descriptions from manual pages.

Display a description from a man page
whatis {{command}}
Don't cut the description off at the end of the line
whatis {{-l|--long}} {{command}}
Display descriptions for all commands matching a `glob`
whatis {{-w|--wildcard}} {{net*}}
Search man page descriptions with a `regex`
whatis {{-r|--regex}} '{{wish[0-9]\.[0-9}}'
Display descriptions in a specific language
whatis {{-L|--locale}} {{en}} {{command}}

WHATIS(1) Manual pager utils WHATIS(1)

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 dis‐
played 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 envi‐
ronment variable.

-M path, --manpath=path
Specify an alternate set of colon-delimited manual page hierarchies to search. By de‐
fault, 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 setlo‐
cale(3) which interrogates various environment variables, possibly including $LC_MES‐
SAGES 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 ar‐
gument to the -m option.

MANPATH
If $MANPATH is set, its value is interpreted as the colon-delimited manual page hier‐
archy 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.

man > WHATIS(1)