This manual page explains the
macro package (often called the
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
Note that NET-2 BSD mdoc man pages can be used with
simply by specifying the
option instead of the
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
The first command in a man page (after comment lines,
that is, lines that start with .\") should be
.THtitle section date source manual
For details of the arguments that should be supplied to the TH
Note that BSD mdoc-formatted pages begin with the
command, not the
Sections are started with
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:
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
program to create a database of short command descriptions for the
For a list of other sections that might appear in a manual page, see
The commands to select the type face are:
Bold alternating with italics
(especially useful for function specifications)
Bold alternating with Roman
(especially useful for referring to other
Italics alternating with bold
Italics alternating with Roman
Roman alternating with bold
Roman alternating with italics
Small alternating with bold
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
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
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
macros may omit
in which case the current prevailing indent will be used.
As a result, successive indented paragraphs can use the same indent without
re-specifying the indent value.
A normal (non-indented) 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:
(begin a new paragraph).
(begin a new paragraph).
Begin a new paragraph and reset prevailing indent.
Relative Margin Indent
Start relative margin indent: moves the left margin
to the right (if
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
End relative margin indent and
restores the previous value of the prevailing indent.
Indented Paragraph Macros
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
is omitted, the entire following paragraph is indented by
If the tag
is provided, it is hung at the left margin
before the following indented paragraph
(this is just like
except the tag is included with the command instead of being on the
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.
Begin paragraph with hanging tag.
The tag is given on the next line, but
its results are like those of the
Hypertext Link Macros
(Feature supported with
In order to use hypertext link macros, it is necessary to load the
Use the request
to do this.
.URL url link trailer
Inserts a hypertext link to the URI (URL)
as the text of the link.
will be printed immediately afterwards.
When generating HTML this should translate into the HTML command
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
macro in manual pages for the benefit of those viewing it with a roff
viewer other than
That way, the URL, link text, and trailer text (if any) are still visible.
In the above, if
is being used, the
macro package's definition of the URL macro will supersede the locally
A number of other link macros are available.
for more details.
Reset tabs to default tab values (every 0.5 inches);
does not cause a break.
Set inter-paragraph vertical distance to d
(if omitted, d=0.4v);
does not cause a break.
but used for a subsection inside a section).
package has the following predefined strings:
Registration Symbol: ®
Change to default font size
Left angled double quote: ``
Right angled double quote: ''
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
but try to use the
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):
You may also use many troff escape sequences (those sequences beginning
When you need to include the backslash character as normal text,
Other sequences you may use, where x or xx are any characters and N
is any digit, include:
Avoid using the escape sequences for drawing graphics.
Do not use the optional parameter for
Use only positive values for
Don't define a macro
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
should be paired with a matching negative indent
(although you should be using the
The condition test
should only have aqtaq or aqnaq as the condition.
that can be ignored should be used.
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.
By all means include full URLs (or URIs) in the text itself;
some tools such as
can automatically turn them into hypertext links.
You can also use the new
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
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
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:
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
This situation makes it harder to vary the
format for different media,
to make the formatting consistent for a given media, and to automatically
By sticking to the safe subset described above, it should be easier to
automate transitioning to a different reference page format in the future.