MAN(7)                    Linux Programmer's Manual                   MAN(7)

## NAME         top

man - macros to format man pages

## SYNOPSIS         top

groff -Tascii -man file ...

groff -Tps -man file ...

man [section] title

## DESCRIPTION         top

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

.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.

(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.

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

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

\*(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         top

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

## NOTES         top

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 char‐
acters, indicating how the page is to be preprocessed.  For portabil‐
ity'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 defini‐
tions 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         top

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.