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man

format and display the on-line manual pages


  1. man.1.man
  2. man.7.man


1. man.1.man

Manpage of man

man

Section: User Commands (1)
Updated: September 19, 2005
Index Return to Main Contents
 

NAME

man - format and display the on-line manual pages  

SYNOPSIS

man [-acdfFhkKtwW] [--path] [-m system] [-p string] [-C config_file] [-M pathlist] [-P pager] [-B browser] [-H ] [-S section_list] [section] name ...

 

DESCRIPTION

man formats and displays the on-line manual pages. If you specify section, man only looks in that section of the manual. name is normally the name of the manual page, which is typically the name of a command, function, or file. However, if name contains a slash (/) then man interprets it as a file specification, so that you can do man ./foo.5 or even man /cd/foo/bar.1.gz.

See below for a description of where man looks for the manual page files.
   

OPTIONS

-C config_file
Specify the configuration file to use; the default is /etc/man.config. (See man.config(5).)
-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 -M at all. See SEARCH PATH FOR MANUAL PAGES.
-P pager
Specify which pager to use. This option overrides the MANPAGER environment variable, which in turn overrides the PAGER variable. By default, man uses /usr/bin/less -is.
-B
Specify which browser to use on HTML files. This option overrides the BROWSER environment variable. By default, man uses /usr/bin/less-is,
-H
Specify a command that renders HTML files as text. This option overrides the HTMLPAGER environment variable. By default, man uses /bin/cat,
-S section_list
List is a colon separated list of manual sections to search. This option overrides the MANSECT environment variable.
-a
By default, man will exit after displaying the first manual page it finds. Using this option forces man to display all the manual pages that match name, not just the first.
-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.
-d
Don't actually display the man pages, but do print gobs of debugging information.
-D
Both display and print debugging info.
-f
Equivalent to whatis.
-F or --preformat
Format only - do not display.
-h
Print a help message and exit.
-k
Equivalent to apropos.
-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.)
-m system
Specify an alternate set of man pages to search based on the system name given.
-p string
Specify the sequence of preprocessors to run before nroff or 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 MANROFFSEQ environment variable.
-t
Use /usr/bin/groff -Tps -mandoc to format the manual page, passing the output to stdout. The default output format of /usr/bin/groff -Tps -mandoc is Postscript, refer to the manual page of /usr/bin/groff -Tps -mandoc for ways to pick an alternate format.

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.

-w or --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 man for man pages. If manpath is a link to man, then "manpath" is equivalent to "man --path".
-W
Like -w, but print file names one per line, without additional information. This is useful in shell commands like man -aW man | xargs ls -l

 

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 /etc/man.config. 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.config contains the line NOCACHE.

It is possible to make 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 man is not made suid, then a cat directory should have mode 0777 if all users should be able to leave cat pages there.

The option -c forces reformatting a page, even if a recent cat page exists.

 

HTML PAGES

Man will find HTML pages if they live in directories named as expected to be "", thus a valid name for an HTML version of the ls(1) man page would be /usr/share/mman1/ls.

 

SEARCH PATH FOR MANUAL PAGES

man uses a sophisticated method of finding manual page files, based on the invocation options and environment variables, the /etc/man.config configuration file, and some built in conventions and heuristics.

First of all, when the name argument to man contains a slash (/), man assumes it is a file specification itself, and there is no searching involved.

But in the normal case where name doesn't contain a slash, man searches a variety of directories for a file that could be a manual page for the topic named.

If you specify the -M pathlist option, pathlist is a colon-separated list of the directories that man searches.

If you don't specify -M but set the MANPATH environment variable, the value of that variable is the list of the directories that man searches.

If you don't specify an explicit path list with -M or MANPATH, man develops its own path list based on the contents of the configuration file /etc/man.config. The MANPATH statements in the configuration file identify particular directories to include in the search path.

Furthermore, the MANPATH_MAP statements add to the search path depending on your command search path (i.e. your PATH environment variable). For each directory that may be in the command search path, a MANPATH_MAP statement specifies a directory that should be added to the search path for manual page files. man looks at the PATH variable and adds the corresponding directories to the manual page file search path. Thus, with the proper use of MANPATH_MAP, when you issue the command man xyz, you get a manual page for the program that would run if you issued the command xyz.

In addition, for each directory in the command search path (we'll call it a "command directory") for which you do not have a MANPATH_MAP statement, 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.

You can disable the automatic "nearby" searches by including a NOAUTOPATH statement in /etc/man.config.

In each directory in the search path as described above, man searches for a file named topic.section, 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 manN or catN where N is the manual section number. If the file is in a catN subdirectory, man assumes it is a formatted manual page file (cat page). Otherwise, man assumes it is unformatted. In either case, if the filename has a known compression suffix (like .gz), man assumes it is gzipped.

If you want to see where (or if) man would find the manual page for a particular topic, use the --path (-w) option.

 

ENVIRONMENT

MANPATH
If MANPATH is set, 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 -M invocation option. See SEARCH PATH FOR MANUAL PAGES.
MANPL
If MANPL is set, its value is used as the display page length. Otherwise, the entire man page will occupy one (long) page.
MANROFFSEQ
If MANROFFSEQ is set, its value is used to determine the set of preprocessors run before running nroff or troff. By default, pages are passed through the tbl preprocessor before nroff.
MANSECT
If MANSECT is set, its value is used to determine which manual sections to search.
MANWIDTH
If 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.
MANPAGER
If MANPAGER is set, its value is used as the name of the program to use to display the man page. If not, then PAGER is used. If that has no value either, /usr/bin/less -is is used.
BROWSER
The name of a browser to use for displaying HTML manual pages. If it is not set, /usr/bin/less -is is used.
HTMLPAGER
The command to use for rendering HTML manual pages as text. If it is not set, /bin/cat is used.
LANG
If 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 .../../foo.1, and if it cannot find such a file, then in .../foo.1, where ... is a directory on the search path.
NLSPATH, LC_MESSAGES, LANG
The environment variables NLSPATH and LC_MESSAGES (or 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 col(1) called by man also use e.g. LC_CTYPE.
PATH
PATH helps determine the search path for manual page files. See SEARCH PATH FOR MANUAL PAGES.
SYSTEM
SYSTEM is used to get the default alternate system name (for use with the -m option).
 

BUGS

The -t option only works if a troff-like program is installed.
If you see blinking \255 or <AD> instead of hyphens, put `LESSCHARSET=latin1' in your environment.  

TIPS

If you add the line


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

to your .emacs file, then hitting F1 will give you the man page for the library call at the current cursor position.

To get a plain text version of a man page, without backspaces and underscores, try


  # man foo | col -b > foo.mantxt  

AUTHOR

John W. Eaton was the original author of 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.  

SEE ALSO

apropos(1), whatis(1), less(1), groff(1), man.config(5).


 

Index

NAME
SYNOPSIS
DESCRIPTION
OPTIONS
CAT PAGES
HTML PAGES
SEARCH PATH FOR MANUAL PAGES
ENVIRONMENT
BUGS
TIPS
AUTHOR
SEE ALSO

This document was created by man2html using the manual pages.
Time: 17:31:37 GMT, October 23, 2013

2. man.7.man

Manpage of MAN

MAN

Section: Linux Programmer's Manual (7)
Updated: 2007-05-30
Index Return to Main Contents
 

NAME

man - macros to format man pages  

SYNOPSIS

groff -Tascii -man file ...

groff -Tps -man file ...

man [section] title  

DESCRIPTION

This manual page explains the groff an.tmac macro package (often called the man macro package). This macro package should be used by developers when writing or porting man pages for Linux. It is fairly compatible with other versions of this macro package, so porting man pages should not be a major problem (exceptions include the NET-2 BSD release, which uses a totally different macro package called mdoc; see mdoc(7)).

Note that NET-2 BSD mdoc man pages can be used with groff simply by specifying the -mdoc option instead of the -man option. Using the -mandoc option is, however, recommended, since this will automatically detect which macro package is in use.

For conventions that should be employed when writing man pages for the Linux man-pages package, see man-pages(7).  

Title line

The first command in a man page (after comment lines, that is, lines that start with .\") should be

.TH title section date source manual

For details of the arguments that should be supplied to the TH command, see man-pages(7).

Note that BSD mdoc-formatted pages begin with the Dd command, not the TH command.  

Sections

Sections are started with .SH followed by the heading name.

The only mandatory heading is NAME, which should be the first section and be followed on the next line by a one line description of the program:

.SH NAME

It is extremely important that this format is followed, and that there is a backslash before the single dash which follows the command name. This syntax is used by the makewhatis(8) program to create a database of short command descriptions for the whatis(1) and apropos(1) commands.

For a list of other sections that might appear in a manual page, see man-pages(7).  

Fonts

The commands to select the type face are:
.B
Bold
.BI
Bold alternating with italics (especially useful for function specifications)
.BR
Bold alternating with Roman (especially useful for referring to other manual pages)
.I
Italics
.IB
Italics alternating with bold
.IR
Italics alternating with Roman
.RB
Roman alternating with bold
.RI
Roman alternating with italics
.SB
Small alternating with bold
.SM
Small (useful for acronyms)

Traditionally, each command can have up to six arguments, but the GNU implementation removes this limitation (you might still want to limit yourself to 6 arguments for portability's sake). Arguments are delimited by spaces. Double quotes can be used to specify an argument which contains spaces. All of the arguments will be printed next to each other without intervening spaces, so that the .BR command can be used to specify a word in bold followed by a mark of punctuation in Roman. If no arguments are given, the command is applied to the following line of text.  

Other Macros and Strings

Below are other relevant macros and predefined strings. Unless noted otherwise, all macros cause a break (end the current line of text). Many of these macros set or use the "prevailing indent." The "prevailing indent" value is set by any macro with the parameter i below; macros may omit i in which case the current prevailing indent will be used. As a result, successive indented paragraphs can use the same indent without respecifying the indent value. A normal (nonindented) paragraph resets the prevailing indent value to its default value (0.5 inches). By default a given indent is measured in ens; try to use ens or ems as units for indents, since these will automatically adjust to font size changes. The other key macro definitions are:  

Normal Paragraphs

.LP
Same as .PP (begin a new paragraph).
.P
Same as .PP (begin a new paragraph).
.PP
Begin a new paragraph and reset prevailing indent.
 

Relative Margin Indent

.RS i
Start relative margin indent: moves the left margin i to the right (if i is omitted, the prevailing indent value is used). A new prevailing indent is set to 0.5 inches. As a result, all following paragraph(s) will be indented until the corresponding .RE.
.RE
End relative margin indent and restores the previous value of the prevailing indent.
 

Indented Paragraph Macros

.HP i
Begin paragraph with a hanging indent (the first line of the paragraph is at the left margin of normal paragraphs, and the rest of the paragraph's lines are indented).
.IP x i
Indented paragraph with optional hanging tag. If the tag x is omitted, the entire following paragraph is indented by i. If the tag x is provided, it is hung at the left margin before the following indented paragraph (this is just like .TP except the tag is included with the command instead of being on the following line). If the tag is too long, the text after the tag will be moved down to the next line (text will not be lost or garbled). For bulleted lists, use this macro with \(bu (bullet) or \(em (em dash) as the tag, and for numbered lists, use the number or letter followed by a period as the tag; this simplifies translation to other formats.
.TP i
Begin paragraph with hanging tag. The tag is given on the next line, but its results are like those of the .IP command.
 

Hypertext Link Macros

(Feature supported with groff only.) In order to use hypertext link macros, it is necessary to load the www.tmac macro package. Use the request .mso www.tmac to do this.
.URL url link trailer
Inserts a hypertext link to the URI (URL) url, with link as the text of the link. The trailer will be printed immediately afterward. When generating HTML this should translate into the HTML command <A HREF="url">link</A>trailer.
This and other related macros are new, and many tools won't do anything with them, but since many tools (including troff) will simply ignore undefined macros (or at worst insert their text) these are safe to insert.
It can be useful to define your own URL macro in manual pages for the benefit of those viewing it with a roff viewer other than groff. That way, the URL, link text, and trailer text (if any) are still visible.
Here's an example:
.de URL
\\$2 \(laURL: \\$1 \(ra\\$3
..
.if
[.g] .mso www.tmac
.TH ...
(later in the page)
This software comes from the
.URL "http://www.gnu.org/" "GNU Project" " of the"
.URL "http://www.fsf.org/" "Free Software Foundation" .
In the above, if groff is being used, the www.tmac macro package's definition of the URL macro will supersede the locally defined one.

A number of other link macros are available. See groff_www(7) for more details.  

Miscellaneous Macros

.DT
Reset tabs to default tab values (every 0.5 inches); does not cause a break.
.PD d
Set inter-paragraph vertical distance to d (if omitted, d=0.4v); does not cause a break.
.SS t
Subheading t (like .SH, but used for a subsection inside a section).
 

Predefined Strings

The man package has the following predefined strings:
\*R
Registration Symbol: ®
\*S
Change to default font size
\*(Tm
Trademark Symbol:
\*(lq
Left angled double quote: ``
\*(rq
Right angled double quote: ''
 

Safe Subset

Although technically man is a troff macro package, in reality a large number of other tools process man page files that don't implement all of troff's abilities. Thus, it's best to avoid some of troff's more exotic abilities where possible to permit these other tools to work correctly. Avoid using the various troff preprocessors (if you must, go ahead and use tbl(1), but try to use the IP and TP commands instead for two-column tables). Avoid using computations; most other tools can't process them. Use simple commands that are easy to translate to other formats. The following troff macros are believed to be safe (though in many cases they will be ignored by translators): \ , ., ad, bp, br, ce, de, ds, el, ie, if, fi, ft, hy, ig, in, na, ne, nf, nh, ps, so, sp, ti, tr.

You may also use many troff escape sequences (those sequences beginning with \). When you need to include the backslash character as normal text, use \e. Other sequences you may use, where x or xx are any characters and N is any digit, include: \', \`, \-, \., \ , \%, \*x, \*(xx, \(xx, \$N,
x
,
(xx
, \fx, and \f(xx. Avoid using the escape sequences for drawing graphics.

Do not use the optional parameter for bp (break page). Use only positive values for sp (vertical space). Don't define a macro (de) with the same name as a macro in this or the mdoc macro package with a different meaning; it's likely that such redefinitions will be ignored. Every positive indent (in) should be paired with a matching negative indent (although you should be using the RS and RE macros instead). The condition test (if,ie) should only have aqtaq or aqnaq as the condition. Only translations (tr) that can be ignored should be used. Font changes (ft and the \f escape sequence) should only have the values 1, 2, 3, 4, R, I, B, P, or CW (the ft command may also have no parameters).

If you use capabilities beyond these, check the results carefully on several tools. Once you've confirmed that the additional capability is safe, let the maintainer of this document know about the safe command or sequence that should be added to this list.  

FILES

/usr/share/groff/[*/]tmac/an.tmac
/usr/man/whatis  

NOTES

By all means include full URLs (or URIs) in the text itself; some tools such as m(1) can automatically turn them into hypertext links. You can also use the new URL macro to identify links to related information. If you include URLs, use the full URL (e.g., <http://www.kernelnotes.org>) to ensure that tools can automatically find the URLs.

Tools processing these files should open the file and examine the first nonwhitespace character. A period (.) or single quote (') at the beginning of a line indicates a troff-based file (such as man or mdoc). A left angle bracket (<) indicates an SGML/XML-based file (such as HTML or Docbook). Anything else suggests simple ASCII text (e.g., a "catman" result).

Many man pages begin with '\" followed by a space and a list of characters, indicating how the page is to be preprocessed. For portability's sake to non-troff translators we recommend that you avoid using anything other than tbl(1), and Linux can detect that automatically. However, you might want to include this information so your man page can be handled by other (less capable) systems. Here are the definitions of the preprocessors invoked by these characters:

e
eqn(1)
g
grap(1)
p
pic(1)
r
refer(1)
t
tbl(1)
v
vgrind(1)
 

BUGS

Most of the macros describe formatting (e.g., font type and spacing) instead of marking semantic content (e.g., this text is a reference to another page), compared to formats like mdoc and DocBook (even HTML has more semantic markings). This situation makes it harder to vary the man format for different media, to make the formatting consistent for a given media, and to automatically insert cross-references. By sticking to the safe subset described above, it should be easier to automate transitioning to a different reference page format in the future.

The Sun macro TX is not implemented.  

SEE ALSO

apropos(1), groff(1), man(1), m(1), whatis(1), groff_man(7), groff_www(7), man-pages(7), mdoc(7), mdoc.samples(7)  

COLOPHON

This page is part of release 3.32 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.


 

Index

NAME
SYNOPSIS
DESCRIPTION
Title line
Sections
Fonts
Other Macros and Strings
Normal Paragraphs
Relative Margin Indent
Indented Paragraph Macros
Hypertext Link Macros
Miscellaneous Macros
Predefined Strings
Safe Subset
FILES
NOTES
BUGS
SEE ALSO
COLOPHON

This document was created by man2html using the manual pages.
Time: 17:31:37 GMT, October 23, 2013

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