Ubuntu Manpage: man - macros to format man pages

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
item \- description

It is extremely important that this format is followed, and that there is a backslash before the single
dash which follows the item name. This syntax is used by the mandb(8) program to create a database of
short descriptions for the whatis(1) and apropos(1) commands. (See lexgrog(1) for further details on the
syntax of the NAME section.)

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 \n[.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, \nx, \n(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 't' or 'n' 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 man2html(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.

COLOPHON

       This  page  is  part  of  release  4.04  of  the  Linux man-pages project.  A description of the project,
       information  about  reporting  bugs,  and  the  latest  version  of  this   page,   can   be   found   at
       http://www.kernel.org/doc/man-pages/.

Linux                                              2012-08-05                                             MAN(7)