-d

Print debugging information.

-v

Print verbose warning messages.

-r

Interpret each keyword as a regular expression. This is the default behaviour. Each keyword will be matched against the pagenames and the descriptions independently. It can match any part of either. The match is not limited to word boundaries.

-w

Interpret each keyword as a pattern containing shell style wildcards. Each keyword will be matched against the page names andthe descriptions independently. If --exact is also used, a match will only be found if an expanded keyword matches an entiredescription or page name. Otherwise the keyword is also allowed to match on word boundaries in the description.

-e

Each keyword will be exactly matched against the page names and the descriptions.

-a

Only display items that match all the supplied keywords. The default is to display items that match any keyword.

-l

Do not trim output to the terminal width. Normally, output will be truncated to the terminal width to avoid ugly results frompoorly-written NAME sections.

-s

Search only the given manual sections. list is a colon- or comma-separated list of sections. If an entry in list is a simplesection, for example "3", then the displayed list of descriptions will include pages in sections "3", "3perl", "3x", and soon; while if an entry in list has an extension, for example "3perl", then the list will only include pages in that exact partof the manual section.

-m

If this system has access to other operating system's manual page descriptions, they can be searched using this option. Tosearch 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 oper‐ating system's whatis descriptions, include the system name man in the argument string. This option will override the $SYSTEMenvironment variable.

-M

Specify an alternate set of colon-delimited manual page hierarchies to search. By default, apropos uses the $MANPATH environ‐ment variable, unless it is empty or unset, in which case it will determine an appropriate manpath based on your $PATH envi‐ronment variable. This option overrides the contents of $MANPATH.

-L

apropos will normally determine your current locale by a call to the C function setlocale(3) which interrogates various envi‐ronment variables, possibly including $LC_MESSAGES and $LANG. To temporarily override the determined value, use this optionto 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

Use this user configuration file rather than the default of ~/.manpath.

-?

Print a help message and exit.

--usage

Print a short usage message and exit.

-V

Display version information.EXIT STATUS0 Successful program execution.1 Usage, syntax or configuration file error.2 Operational error.16 Nothing was found that matched the criteria specified.ENVIRONMENTSYSTEM If $SYSTEM is set, it will have the same effect as if it had been specified as the argument to the -m option.MANPATHIf $MANPATH is set, its value is interpreted as the colon-delimited manual page hierarchy search path to use.MANWIDTHIf $MANWIDTH is set, its value is used as the terminal width (see the --long option). If it is not set, the terminal widthwill be calculated using the value of $COLUMNS, an ioctl(2) if available, or falling back to 80 characters if all else fails.POSIXLY_CORRECTIf $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/.../whatisA traditional whatis text database.