Provided by: mandoc_1.14.6-4_amd64 
NAME
apropos, whatis — search manual page databases
SYNOPSIS
apropos [-afk] [-C file] [-M path] [-m path] [-O outkey] [-S arch] [-s section] expression ...
DESCRIPTION
The apropos and whatis utilities query manual page databases generated by makewhatis(8), evaluating
expression for each file in each database. By default, they display the names, section numbers, and
description lines of all matching manuals.
By default, apropos searches for makewhatis(8) databases in the default paths stipulated by man(1) and
uses case-insensitive extended regular expression matching over manual names and descriptions (the Nm and
Nd macro keys). Multiple terms imply pairwise -o.
whatis is a synonym for apropos -f.
The options are as follows:
-a Instead of showing only the title lines, show the complete manual pages, just like man(1) -a
would. If the standard output is a terminal device and -c is not specified, use less(1) to
paginate them. In -a mode, the options -IKOTW described in the mandoc(1) manual are also
available.
-C file
Specify an alternative configuration file in man.conf(5) format.
-f Search for all words in expression in manual page names only. The search is case-insensitive and
matches whole words only. In this mode, macro keys, comparison operators, and logical operators
are not available.
-k Support the full expression syntax. It is the default for apropos.
-M path
Use the colon-separated path instead of the default list of paths searched for makewhatis(8)
databases. Invalid paths, or paths without manual databases, are ignored.
-m path
Prepend the colon-separated paths to the list of paths searched for makewhatis(8) databases.
Invalid paths, or paths without manual databases, are ignored.
-O outkey
Show the values associated with the key outkey instead of the manual descriptions.
-S arch
Restrict the search to pages for the specified machine(1) architecture. arch is case-
insensitive. By default, pages for all architectures are shown.
-s section
Restrict the search to the specified section of the manual. By default, pages from all sections
are shown. See man(1) for a listing of sections.
The options -chlw are also supported and are documented in man(1). The options -fkl are mutually
exclusive and override each other.
An expression consists of search terms joined by logical operators -a (and) and -o (or). The -a operator
has precedence over -o and both are evaluated left-to-right.
( expr )
True if the subexpression expr is true.
expr1 -a expr2
True if both expr1 and expr2 are true (logical ‘and’).
expr1 [-o] expr2
True if expr1 and/or expr2 evaluate to true (logical ‘or’).
term True if term is satisfied. This has syntax [[key[,key...]](=|~)]val, where key is an mdoc(7)
macro to query and val is its value. See “Macro Keys” for a list of available keys. Operator =
evaluates a substring, while ~ evaluates a case-sensitive extended regular expression.
-i term
If term is a regular expression, it is evaluated case-insensitively. Has no effect on substring
terms.
Results are sorted first according to the section number in ascending numerical order, then by the page
name in ascending ascii(7) alphabetical order, case-insensitive.
Each output line is formatted as
name[, name...](sec) - description
Where “name” is the manual's name, “sec” is the manual section, and “description” is the manual's short
description. If an architecture is specified for the manual, it is displayed as
name(sec/arch) - description
Resulting manuals may be accessed as
$ man -s sec name
If an architecture is specified in the output, use
$ man -s sec -S arch name
Macro Keys
Queries evaluate over a subset of mdoc(7) macros indexed by makewhatis(8). In addition to the macro keys
listed below, the special key any may be used to match any available macro key.
Names and description:
Nm manual name
Nd one-line manual description
arch machine architecture (case-insensitive)
sec manual section number
Sections and cross references:
Sh section header (excluding standard sections)
Ss subsection header
Xr cross reference to another manual page
Rs bibliographic reference
Semantic markup for command line utilities:
Fl command line options (flags)
Cm command modifier
Ar command argument
Ic internal or interactive command
Ev environmental variable
Pa file system path
Semantic markup for function libraries:
Lb function library name
In include file
Ft function return type
Fn function name
Fa function argument type and name
Vt variable type
Va variable name
Dv defined variable or preprocessor constant
Er error constant
Ev environmental variable
Various semantic markup:
An author name
Lk hyperlink
Mt “mailto” hyperlink
Cd kernel configuration declaration
Ms mathematical symbol
Tn tradename
Physical markup:
Em italic font or underline
Sy boldface font
Li typewriter font
Text production:
St reference to a standards document
At AT&T UNIX version reference
Bx BSD version reference
Bsx BSD/OS version reference
Nx NetBSD version reference
Fx FreeBSD version reference
Ox OpenBSD version reference
Dx DragonFly version reference
In general, macro keys are supposed to yield complete results without expecting the user to consider
actual macro usage. For example, results include:
Fa function arguments appearing on Fn lines
Fn function names marked up with Fo macros
In include file names marked up with Fd macros
Vt types appearing as function return types and
types appearing in function arguments in the SYNOPSIS
ENVIRONMENT
MANPAGER Any non-empty value of the environment variable MANPAGER is used instead of the standard
pagination program, less(1); see man(1) for details. Only used if -a or -l is specified.
MANPATH A colon-separated list of directories to search for manual pages; see man(1) for details.
Overridden by -M, ignored if -l is specified.
PAGER Specifies the pagination program to use when MANPAGER is not defined. If neither PAGER nor
MANPAGER is defined, less(1) is used. Only used if -a or -l is specified.
FILES
mandoc.db name of the makewhatis(8) keyword database
/etc/man.conf default man(1) configuration file
EXIT STATUS
The apropos utility exits 0 on success, and >0 if an error occurs.
EXAMPLES
Search for ".cf" as a substring of manual names and descriptions:
$ apropos =.cf
Include matches for ".cnf" and ".conf" as well:
$ apropos =.cf =.cnf =.conf
Search in names and descriptions using a case-sensitive regular expression:
$ apropos '~set.?[ug]id'
Search for all manual pages in a given section:
$ apropos -s 9 .
Search for manuals in the library section mentioning both the "optind" and the "optarg" variables:
$ apropos -s 3 Va=optind -a Va=optarg
Do exactly the same as calling whatis with the argument "ssh":
$ apropos -- -i 'Nm~[[:<:]]ssh[[:>:]]'
The following two invocations are equivalent:
$ apropos -S arch -s section expression
$ apropos \( expression \) -a arch~^(arch|any)$ -a sec~^section$
SEE ALSO
man(1), re_format(7), makewhatis(8)
STANDARDS
The apropos utility is compliant with the IEEE Std 1003.1-2008 (“POSIX.1”) specification of man(1) -k.
All options, the whatis command, support for logical operators, macro keys, substring matching, sorting
of results, the environment variables MANPAGER and MANPATH, the database format, and the configuration
file are extensions to that specification.
HISTORY
Part of the functionality of whatis was already provided by the former manwhere utility in 1BSD. The
apropos and whatis utilities first appeared in 2BSD. They were rewritten from scratch for OpenBSD 5.6.
The -M option and the MANPATH variable first appeared in 4.3BSD; -m in 4.3BSD-Reno; -C in 4.4BSD Lite1;
and -S and -s in OpenBSD 4.5 for apropos and in OpenBSD 5.6 for whatis. The options -acfhIKklOTWw
appeared in OpenBSD 5.7.
AUTHORS
Bill Joy wrote manwhere in 1977 and the original BSD apropos and whatis in February 1979. The current
version was written by Kristaps Dzonsons <kristaps@bsd.lv> and Ingo Schwarze <schwarze@openbsd.org>.
Debian October 1, 2020 APROPOS(1)