path: root/man/en/man.man

.\" Man page for man (and the former manpath)
.\"
.\" Copyright (c) 1990, 1991, John W. Eaton.
.\"
.\" You may distribute under the terms of the GNU General Public
.\" License as specified in the README file that comes with the man 1.0
.\" distribution.  
.\"
.\" John W. Eaton
.\" jwe@che.utexas.edu
.\" Department of Chemical Engineering
.\" The University of Texas at Austin
.\" Austin, Texas  78712
.\"
.\" Many changes - aeb
.\" More changes - flc
.\"
.TH man 1 "September 19, 2005"
.LO 1
.SH NAME
man \- format and display the on-line manual pages
.SH SYNOPSIS
.B man 
.RB [ \-acdfFhkKtwW ]
.RB [ --path ] 
.RB [ \-m 
.IR system ] 
.RB [ \-p 
.IR string ] 
.RB [ \-C 
.IR config_file ] 
.RB [ \-M 
.IR pathlist ]
.RB [ \-P
.IR pager ] 
.RB [ \-B
.IR browser ] 
.RB [ \-H
.IR htmlpager ] 
.RB [ \-S 
.IR section_list ] 
.RI [ section ] 
.I "name ..."

.SH DESCRIPTION
.B man
formats and displays the on-line manual pages.  If you specify
.IR section ,
.B man
only looks in that section of the manual.
.I name
is normally the name of the manual page, which is typically the name
of a command, function, or file.  
However, if
.I name
contains a slash
.RB ( / ) 
then 
.B man 
interprets it as a file specification, so that you can do
.B "man ./foo.5"
or even
.B "man /cd/foo/bar.1.gz\fR.\fP"
.PP
See below for a description of where 
.B man
looks for the manual page files.
 
.SH MANUAL SECTIONS
The standard sections of the manual include:
.TP
.B 1
User Commands
.TP
.B 2
System Calls
.TP
.B 3
C Library Functions
.TP
.B 4
Devices and Special Files
.TP
.B 5
File Formats and Conventions
.TP
.B 6
Games et. Al.
.TP
.B 7
Miscellanea
.TP
.B 8
System Administration tools and Deamons
.TP
Distributions customize the manual section to their specifics, which often include additional sections.  

.SH OPTIONS
.TP
.B \-\^C " config_file"
Specify the configuration file to use; the default is
.BR @man_config_file@ .
(See
.BR man.conf (5).)
.TP
.B \-\^M " path"
Specify the list of directories to search for man pages.
Separate the directories with colons.  An empty list is the same as
not specifying 
.B \-M
at all.  See
.BR "SEARCH PATH FOR MANUAL PAGES" .
.TP
.B \-\^P " pager"
Specify which pager to use. 
This option overrides the
.B MANPAGER
environment variable, which in turn overrides the
.B PAGER
variable.  By default,
.B man
uses
.BR "@pager@" .
.TP
.B \-\^B
Specify which browser to use on HTML files. 
This option overrides the
.B BROWSER
environment variable. By default,
.B man
uses
.BR @browser@ ,
.TP
.B \-\^H
Specify a command that renders HTML files as text. 
This option overrides the
.B HTMLPAGER
environment variable. By default,
.B man
uses
.BR @htmlpager@ ,
.TP
.B \-\^S " section_list"
List is a colon separated list of manual sections to search.
This option overrides the
.B MANSECT
environment variable.
.TP
.B \-\^a
By default,
.B man
will exit after displaying the first manual page it
finds.  Using this option forces
.B man
to display all the manual pages that match
.B name, 
not just the first.
.TP
.B \-\^c
Reformat the source man page, even when an up-to-date cat page exists.
This can be meaningful if the cat page was formatted for a screen
with a different number of columns, or if the preformatted page
is corrupted.
.TP
.B \-\^d
Don't actually display the man pages, but do print gobs of debugging
information.
.TP
.B \-\^D
Both display and print debugging info.
.TP
.B \-\^f
Equivalent to
.BR whatis .
.TP
.BR \-\^F " or " \-\-preformat
Format only - do not display.
.TP
.B \-\^h
Print a help message and exit.
.TP
.B \-\^k
Equivalent to
.BR apropos .
.TP
.B \-\^K
Search for the specified string in *all* man pages. Warning: this is
probably very slow! It helps to specify a section.
(Just to give a rough idea, on my machine this takes about a minute
per 500 man pages.)
.TP
.B \-\^m " system"
Specify an alternate set of man pages to search based on the system
name given.
.TP
.B \-\^p " string"
Specify the sequence of preprocessors to run before
.B nroff
or
.BR troff .
Not all installations will have a full set of preprocessors.
Some of the preprocessors and the letters used to designate them are: 
eqn (e), grap (g), pic (p), tbl (t), vgrind (v), refer (r).
This option overrides the
.B MANROFFSEQ
environment variable.
.TP
.B \-\^t
Use
.B @troff@
to format the manual page, passing the output to 
.B stdout.
The default output format of
.B @troff@ 
is Postscript, refer to the manual page of
.B @troff@
for ways to pick an alternate format.
.PP
Depending on the selected format and the availability of printing
devices, the output
may need to be passed through some filter or another before being
printed.
.TP
.B \-\^w \fRor\fP \-\-path
Don't actually display the man pages, but do print the location(s) of
the files that would be formatted or displayed. If no argument is given:
display (on stdout) the list of directories that is searched by
.B man
for man pages. If
.B manpath
is a link to man, then "manpath" is equivalent to "man --path".
.TP
.B \-\^W
Like \-\^w, but print file names one per line, without additional information.
This is useful in shell commands like
.ft CW
.B "man -aW man | xargs ls -l"
.ft

.SH "CAT PAGES"
Man will try to save the formatted man pages, in order to save
formatting time the next time these pages are needed.
Traditionally, formatted versions of pages in DIR/manX are
saved in DIR/catX, but other mappings from man dir to cat dir
can be specified in
.BR @man_config_file@ .
No cat pages are saved when the required cat directory does not exist.
No cat pages are saved when they are formatted for a line length
different from 80.
No cat pages are saved when man.conf contains the line NOCACHE.
.PP
It is possible to make
.B man
suid to a user man. Then, if a cat directory
has owner man and mode 0755 (only writable by man), and the cat files
have owner man and mode 0644 or 0444 (only writable by man, or not
writable at all), no ordinary user can change the cat pages or put
other files in the cat directory. If
.B man
is not made suid, then a cat directory should have mode 0777
if all users should be able to leave cat pages there.
.PP
The option
.B \-c
forces reformatting a page, even if a recent cat page exists.

.SH "HTML PAGES"
Man will find HTML pages if they live in directories named as
'html' followed by a section extension.  The last file extension is
expected to be ".html", thus a valid name for an HTML version of the
.BR ls (1)
man page would be
.IR /usr/share/man/htmlman1/ls.1.html .

.SH "SEARCH PATH FOR MANUAL PAGES"
.B man
uses a sophisticated method of finding manual page files, based on the
invocation options and environment variables, the 
.B @man_config_file@ 
configuration file, and some built in conventions and heuristics.
.PP
First of all, when the 
.I name
argument to 
.B man
contains a slash 
.RB ( / ),
.B man
assumes it is a file specification itself,
and there is no searching involved.
.PP
But in the normal case where 
.I name
doesn't contain a slash,
.B man
searches a variety of directories for a file that could be a manual page
for the topic named.
.PP
If you specify the 
.BI "-M " pathlist
option,
.I pathlist 
is a colon-separated list of the directories that 
.B man 
searches.
.PP
If you don't specify
.B -M
but set the
.B MANPATH
environment variable, the value of that variable is the list of the 
directories that 
.B man
searches.
.PP
If you don't specify an explicit path list with 
.B -M
or 
.BR MANPATH ,
.B man
develops its own path list based on the contents of the configuration 
file
.BR @man_config_file@ .
The
.B MANPATH
statements in the configuration file identify particular directories to 
include in the search path.
.PP
Furthermore, the 
.B MANPATH_MAP 
statements add to the search path depending on your command search path
(i.e. your
.B PATH 
environment variable).  For each directory that may be in the command
search path, a
.B MANPATH_MAP
statement specifies a directory that should be added to the search
path for manual page files.
.B man
looks at the 
.B PATH
variable and adds the corresponding directories to the manual page
file search path.  Thus, with the proper use of
.BR MANPATH_MAP ,
when you issue the command
.BR "man xyz" ,
you get a manual page for the program that would run if you issued the
command 
.BR xyz .
.PP
In addition, for each directory in the command search path (we'll call
it a "command directory") for which you do
.I not
have a 
.B MANPATH_MAP 
statement,
.B man
automatically looks for a manual page directory "nearby"
namely as a subdirectory in the command directory itself or
in the parent directory of the command directory.
.PP
You can disable the automatic "nearby" searches by including a
.B NOAUTOPATH
statement in 
.BR @man_config_file@ .
.PP
In each directory in the search path as described above, 
.B man
searches for a file named
.IB topic . section\fR,
with an optional suffix on the section number and 
possibly a compression suffix.
If it doesn't find such a file, it then looks in any subdirectories
named
.BI man N
or 
.BI cat N
where
.I N
is the manual section number.
If the file is in a 
.BI cat N
subdirectory, 
.B man
assumes it is a formatted manual page file (cat page).  Otherwise,
.B man
assumes it is unformatted.  In either case, if the filename has a
known compression suffix (like
.BR .gz ),
.B man
assumes it is gzipped.
.PP
If you want to see where (or if)
.B man
would find the manual page for a particular topic, use the 
.BR "--path " ( -w )
option.

.SH ENVIRONMENT
.TP
.B MANPATH
If
.B MANPATH
is set, 
.B man
uses it as the path to search for manual page files.  It overrides the
configuration file and the automatic search path, but is overridden by
the
.B -M
invocation option.  See 
.BR "SEARCH PATH FOR MANUAL PAGES" .
.TP
.B MANPL
If
.B MANPL
is set, its value is used as the display page length.
Otherwise, the entire man page will occupy one (long) page.
.TP
.B MANROFFSEQ
If
.B MANROFFSEQ
is set, its value is used to determine the set of preprocessors run
before running
.B nroff
or
.BR troff .
By default, pages are passed through
the tbl preprocessor before
.BR nroff .
.TP
.B MANSECT
If
.B MANSECT
is set, its value is used to determine which manual sections to search.
.TP
.B MANWIDTH
If
.B MANWIDTH
is set, its value is used as the width manpages should be displayed.
Otherwise the pages may be displayed over the whole width of your
screen.
.TP
.B MANPAGER
If
.B MANPAGER
is set, its value is used as the name of the program to use to display
the man page.  If not, then
.B PAGER
is used. If that has no value either,
.B @pager@
is used.
.TP
.B BROWSER
The name of a browser to use for displaying HTML manual pages.  If
it is not set, @browser@ is used.
.TP
.B HTMLPAGER
The command to use for rendering HTML manual pages as text.  If
it is not set, @htmlpager@ is used.
.TP
.B LANG
If
.B LANG
is set, its value defines the name of the subdirectory where man
first looks for man pages. Thus, the command `LANG=dk man 1 foo'
will cause man to look for the foo man page in .../dk/man1/foo.1,
and if it cannot find such a file, then in .../man1/foo.1,
where ... is a directory on the search path.
.TP
.B "NLSPATH, LC_MESSAGES, LANG"
The environment variables
.B NLSPATH
and
.B LC_MESSAGES
(or
.B LANG
when the latter does not exist)
play a role in locating the message catalog.
(But the English messages are compiled in, and for English no catalog
is required.)
Note that programs like
.BR col(1)
called by man also use e.g. LC_CTYPE.
.TP
.B PATH
.B PATH
helps determine the search path for manual page files.  See
.BR "SEARCH PATH FOR MANUAL PAGES" .
.TP
.B SYSTEM
.B SYSTEM
is used to get the default alternate system name (for use
with the
.B \-m
option). 
.SH BUGS
The
.B \-t
option only works if a troff-like program is installed.
.br
If you see blinking \e255 or <AD> instead of hyphens,
put `LESSCHARSET=latin1' in your environment.
.SH TIPS
If you add the line

 (global-set-key [(f1)] (lambda () (interactive) (manual-entry (current-word))))

to your
.IR .emacs 
file, then hitting F1 will give you the man page for the library call
at the current cursor position.
.LP
To get a plain text version of a man page, without backspaces
and underscores, try

  # man foo | col -b > foo.mantxt
.SH AUTHOR
John W. Eaton was the original author of
.BR "man" .
Zeyd M. Ben-Halim released man 1.2, and Andries Brouwer followed up with 
versions 1.3 thru 1.5p.
Federico Lucifredi <flucifredi@acm.org> is the current maintainer.
.SH "SEE ALSO"
apropos(1), whatis(1), less(1), groff(1), man.conf(5).