.\"	$Id$
.\"
.\" Copyright (c) 2011, 2012 Kristaps Dzonsons <kristaps@bsd.lv>
.\" Copyright (c) 2011, 2012, 2014 Ingo Schwarze <schwarze@openbsd.org>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd $Mdocdate$
.Dt APROPOS 1
.Os
.Sh NAME
.Nm apropos ,
.Nm whatis
.Nd search manual page databases
.Sh SYNOPSIS
.Nm
.Op Fl C Ar file
.Op Fl M Ar path
.Op Fl m Ar path
.Op Fl O Ar outkey
.Op Fl S Ar arch
.Op Fl s Ar section
.Ar expression ...
.Sh DESCRIPTION
The
.Nm apropos
and
.Nm whatis
utilities query manual page databases generated by
.Xr mandocdb 8 ,
evaluating
.Ar expression
for each file in each database.
By default, it displays the names, section numbers, and description lines
of all matching manuals.
.Pp
By default,
.Nm
searches for
.Xr mandocdb 8
databases in the default paths stipulated by
.Xr man 1
and uses case-insensitive substring matching
.Pq the Cm = No operator
over manual names and descriptions
.Pq the Li \&Nm No and Li \&Nd No macro keys .
Multiple terms imply pairwise
.Fl o .
.Nm whatis
maps terms only to case-sensitive manual names.
.Pp
Its arguments are as follows:
.Bl -tag -width Ds
.It Fl C Ar file
Specify an alternative configuration
.Ar file
in
.Xr man.conf 5
format.
.It Fl M Ar path
Use the colon-separated path instead of the default list of paths
searched for
.Xr mandocdb 8
databases.
Invalid paths, or paths without manual databases, are ignored.
.It Fl m Ar path
Prepend the colon-separated paths to the list of paths searched
for
.Xr mandocdb 8
databases.
Invalid paths, or paths without manual databases, are ignored.
.It Fl O Ar outkey
Show the values associated with the key
.Ar outkey
instead of the manual descriptions.
.It Fl S Ar arch
Restrict the search to pages for the specified
.Xr machine 1
architecture.
.Ar arch
is case insensitive.
By default, pages for all architectures are shown.
.It Fl s Ar section
Restrict the search to the specified section of the manual.
By default, pages from all sections are shown.
See
.Xr man 1
for a listing of sections.
.El
.Pp
An
.Ar expression
consists of search terms joined by logical operators
.Fl a
.Pq and
and
.Fl o
.Pq or .
The
.Fl a
operator has precedence over
.Fl o
and both are evaluated left-to-right.
.Bl -tag -width Ds
.It \&( Ar expr No \&)
True if the subexpression
.Ar expr
is true.
.It Ar expr1 Fl a Ar expr2
True if both
.Ar expr1
and
.Ar expr2
are true (logical
.Sq and ) .
.It Ar expr1 Oo Fl o Oc Ar expr2
True if
.Ar expr1
and/or
.Ar expr2
evaluate to true (logical
.Sq or ) .
.It Ar term
True if
.Ar term
is satisfied.
This has syntax
.Sm off
.Oo
.Op Ar key Op , Ar key ...
.Pq Cm = | ~
.Oc
.Ar val
.Sm on ,
where
.Ar key
is an
.Xr mdoc 7
macro to query and
.Ar val
is its value.
See
.Sx Macro Keys
for a list of available keys.
Operator
.Cm =
evaluates a substring, while
.Cm ~
evaluates a regular expression.
.It Fl i Ar term
If
.Ar term
is a regular expression, it
is evaluated case-insensitively.
Has no effect on substring terms.
.El
.Pp
.Nm whatis
considers an
.Ar expression
to consist of an opaque keyword.
.Pp
Results are sorted by manual sections and names, with output formatted as
.Pp
.D1 name[, name...](sec) \- description
.Pp
Where
.Dq name
is the manual's name,
.Dq sec
is the manual section, and
.Dq description
is the manual's short description.
If an architecture is specified for the manual, it is displayed as
.Pp
.D1 name(sec/arch) \- description
.Pp
Resulting manuals may be accessed as
.Pp
.Dl $ man \-s sec name
.Pp
If an architecture is specified in the output, use
.Pp
.Dl $ man \-s sec \-S arch name
.Ss Macro Keys
Queries evaluate over a subset of
.Xr mdoc 7
macros indexed by
.Xr mandocdb 8 .
In addition to the macro keys listed below, the special key
.Cm any
may be used to match any available macro key.
.Pp
Names and description:
.Bl -column "xLix" description -offset indent -compact
.It Li \&Nm Ta manual name
.It Li \&Nd Ta one-line manual description
.It Li arch Ta machine architecture (case-insensitive)
.It Li sec  Ta manual section number
.El
.Pp
Sections and cross references:
.Bl -column "xLix" description -offset indent -compact
.It Li \&Sh Ta section header (excluding standard sections)
.It Li \&Ss Ta subsection header
.It Li \&Xr Ta cross reference to another manual page
.It Li \&Rs Ta bibliographic reference
.El
.Pp
Semantic markup for command line utilities:
.Bl -column "xLix" description -offset indent -compact
.It Li \&Fl Ta command line options (flags)
.It Li \&Cm Ta command modifier
.It Li \&Ar Ta command argument
.It Li \&Ic Ta internal or interactive command
.It Li \&Ev Ta environmental variable
.It Li \&Pa Ta file system path
.El
.Pp
Semantic markup for function libraries:
.Bl -column "xLix" description -offset indent -compact
.It Li \&Lb Ta function library name
.It Li \&In Ta include file
.It Li \&Ft Ta function return type
.It Li \&Fn Ta function name
.It Li \&Fa Ta function argument type and name
.It Li \&Vt Ta variable type
.It Li \&Va Ta variable name
.It Li \&Dv Ta defined variable or preprocessor constant
.It Li \&Er Ta error constant
.It Li \&Ev Ta environmental variable
.El
.Pp
Various semantic markup:
.Bl -column "xLix" description -offset indent -compact
.It Li \&An Ta author name
.It Li \&Lk Ta hyperlink
.It Li \&Mt Ta Do mailto Dc hyperlink
.It Li \&Cd Ta kernel configuration declaration
.It Li \&Ms Ta mathematical symbol
.It Li \&Tn Ta tradename
.El
.Pp
Physical markup:
.Bl -column "xLix" description -offset indent -compact
.It Li \&Em Ta italic font or underline
.It Li \&Sy Ta boldface font
.It Li \&Li Ta typewriter font
.El
.Pp
Text production:
.Bl -column "xLix" description -offset indent -compact
.It Li \&St Ta reference to a standards document
.It Li \&At Ta At No version reference
.It Li \&Bx Ta Bx No version reference
.It Li \&Bsx Ta Bsx No version reference
.It Li \&Nx Ta Nx No version reference
.It Li \&Fx Ta Fx No version reference
.It Li \&Ox Ta Ox No version reference
.It Li \&Dx Ta Dx No version reference
.El
.Sh ENVIRONMENT
.Bl -tag -width MANPATH
.It Ev MANPATH
The standard search path used by
.Xr man 1
may be changed by specifying a path in the
.Ev MANPATH
environment variable.
Invalid paths, or paths without manual databases, are ignored.
Overridden by
.Fl M .
If
.Ev MANPATH
begins with a colon, it is appended to the default list;
if it ends with a colon, it is prepended to the default list;
or if it contains two adjacent colons,
the standard search path is inserted between the colons.
If none of these conditions are met, it overrides the
standard search path.
.El
.Sh FILES
.Bl -tag -width "/etc/man.conf" -compact
.It Pa mandoc.db
name of the
.Xr mandocdb 8
keyword database
.It Pa /etc/man.conf
default
.Xr man 1
configuration file
.El
.Sh EXIT STATUS
.Ex -std
.Sh EXAMPLES
Search for
.Qq .cf
as a substring of manual names and descriptions:
.Pp
.Dl $ apropos .cf
.Pp
Include matches for
.Qq .cnf
and
.Qq .conf
as well:
.Pp
.Dl $ apropos .cf .cnf .conf
.Pp
Search in names and descriptions using a regular expression:
.Pp
.Dl $ apropos '~set.?[ug]id'
.Pp
Search for manuals in the library section mentioning both the
.Qq optind
and the
.Qq optarg
variables:
.Pp
.Dl $ apropos \-s 3 Va=optind \-a Va=optarg
.Pp
Do exactly the same as calling
.Xr whatis 1
with the argument
.Qq ssh :
.Pp
.Dl $ apropos \-\- \-i 'Nm~[[:<:]]ssh[[:>:]]'
.Pp
The following two invocations are equivalent:
.Pp
.D1 Li $ apropos -S Ar arch Li -s Ar section expression
.Bd -ragged -offset indent
.Li $ apropos \e( Ar expression Li \e)
.Li -a arch~^( Ns Ar arch Ns Li |any)$
.Li -a sec~^ Ns Ar section Ns Li $
.Ed
.Sh SEE ALSO
.Xr man 1 ,
.Xr re_format 7 ,
.Xr mandocdb 8
.Sh HISTORY
An
.Nm
utility first appeared in
.Bx 2 .
It was rewritten from scratch for
.Ox 5.6 .
.Pp
The
.Fl M
option and the
.Ev MANPATH
variable first appeared in
.Bx 4.3 ;
.Fl m
in
.Bx 4.3 Reno ;
.Fl C
in
.Bx 4.4 Lite1 ;
and
.Fl S
and
.Fl s
in
.Ox 4.5 .
.Sh AUTHORS
.An -nosplit
.An Bill Joy
wrote the original
.Bx
.Nm
in February 1979.
The current version was written by
.An Kristaps Dzonsons Aq Mt kristaps@bsd.lv
and
.An Ingo Schwarze Aq Mt schwarze@openbsd.org .