справочная страница GNU roff и руководство по стилю (GNU roff man page tutorial and style guide)
Описание (Description)
The GNU implementation of the man macro package is part of the
groff document formatting system. It is used to produce manual
pages ('man pages') like the one you are reading.
This document presents the macros thematically; for those needing
only a quick reference, the following table lists them
alphabetically, with cross-references to appropriate subsections
below.
Macro Meaning Subsection
────────────────────────────────────────────────────────────────
.B Bold Font style macros
.BI Bold, italic alternating Font style macros
.BR Bold, roman alternating Font style macros
.EE Example end Document structure macros
.EX Example begin Document structure macros
.I Italic Font style macros
.IB Italic, bold alternating Font style macros
.IP Indented paragraph Paragraph macros
.IR Italic, roman alternating Font style macros
.LP (Left) paragraph Paragraph macros
.ME Mail-to end Hyperlink and email macros
.MT Mail-to start Hyperlink and email macros
.OP (Command-line) option Command synopsis macros
.P Paragraph Paragraph macros
.PP Paragraph Paragraph macros
.RB Roman, bold alternating Font style macros
.RE Relative inset end Document structure macros
.RI Roman, italic alternating Font style macros
.RS Relative inset start Document structure macros
.SB Small bold Font style macros
.SH Section heading Document structure macros
.SM Small Font style macros
.SS Subsection heading Document structure macros
.SY Synopsis start Command synopsis macros
.TH Title heading Document structure macros
.TP Tagged paragraph Paragraph macros
.TQ Supplemental paragraph tag Paragraph macros
.UE URL end Hyperlink and email macros
.UR URL start Hyperlink and email macros
.YS Synopsis end Command synopsis macros
Macros whose use we discourage (.AT, .DT, .HP, .PD, and .UC) are
described in subsection 'Deprecated features' below.
Man pages should be encoded using Unicode basic Latin code points
exclusively, and employ the Unix line-ending convention (U+000A
only).
Macro reference preliminaries
Each macro is described in a tagged paragraph. Closely related
macros, such as .EX and .EE, are grouped together.
A macro call appears on a line starting with a dot ('.'),
followed by zero or more spaces and then the macro name. Some
macros accept arguments; each such argument is separated from the
macro name and any subsequent arguments by one or more spaces. A
newline, unless escaped (see subsection 'Portability' below),
terminates the macro call.
Optional macro arguments are indicated by surrounding them with
square brackets. If a macro accepts multiple arguments, those
containing space characters must be double-quoted to be
interpreted correctly. An empty macro argument can be specified
with a pair of double-quotes ('""'), but the man package is
designed such that this should seldom be necessary. See section
'Notes' below for examples of cases where better alternatives to
empty arguments in macro calls are available. Most macro
arguments are strings that will be output as text; exceptions are
noted.
Bear in mind that groff is fundamentally a programming system for
typesetting. Consequently, the verb 'to set' is frequently used
below in the sense 'to typeset'.
Document structure macros
The highest level of organization of a man page is determined by
this group of macros. .TH (title heading) identifies the
document as a man page and defines information enabling its
indexing by mandb(8) or a similar tool. Section headings (.SH),
one of which is mandatory and many of which are standardized,
facilitate quick location of relevant material by the reader and
aid the man page writer to discuss all essential aspects of the
topic. Subsection headings (.SS) are optional and permit
sections that grow long to develop in a controlled way. Many
technical discussions benefit from examples; lengthy ones,
especially those reflecting multiple lines of input to or output
from the system, are usefully bracketed by .EX and .EE. When
none of the foregoing meets a structural demand, a region within
a (sub)section can be manually inset within .RS and .RE macros.
.TH title section [footer-middle] [footer-inside] [header-middle]
Define the title of the man page as title and the section
of the manual volume as section. This use of 'section'
has nothing to do with the section headings otherwise
discussed in this page; it arises from the organizational
scheme of printed and bound Unix manuals. See man(1) for
details on the section numbers and suffixes applicable to
your system. title and section are positioned together at
the left and right in the header line (with section in
parentheses immediately appended to title). footer-middle
is centered in the footer line. The arrangement of the
rest of the footer depends on whether double-sided layout
is enabled with the option -rD1. When disabled (the
default), footer-inside is positioned at the bottom left.
Otherwise, footer-inside appears at the bottom left on
odd-numbered (recto) pages, and at the bottom right on
even-numbered (verso) pages. The outside footer is the
page number, except in the continuous-rendering mode
enabled by the option -rcR=1, in which case it is the
title and section, as in the header. header-middle is
centered in the header line. If section is a simple
integer between 1 and 9 (inclusive), or is exactly '3p',
there is no need to specify header-middle; the macro
package will supply text for it. For HTML output, headers
and footers are completely suppressed.
Additionally, this macro starts a new page; the page
number is reset to 1 (unless the -rC1 option is given).
This feature is intended only for formatting multiple man
pages.
A man page should contain exactly one .TH call at or near
the beginning of the file, prior to any other macro calls.
By convention, footer-middle is the most recent
modification date of the man page source document, and
footer-inside is the name and version or release of the
project providing it.
.SH [heading-text]
Set heading-text as a section heading. The text following
.SH up to the end of the line, or the text on the next
input line if .SH is given no arguments, is set with no
indentation, in bold (or the font specified by the string
HF) and, on typesetter devices, slightly larger than the
base point size. If the heading font \*[HF] is bold, use
of an italic style in heading-text is mapped to the bold-
italic style if available in the font family.
Additionally, the left margin and indentation affecting
subsequent text are reset to their default values. Text
on input lines after heading-text is set as an ordinary
paragraph (.P).
The content of heading-text and ordering of sections has
been standardized by common practice, as has much of the
layout of material within sections. For example, a
section called 'Name' or 'NAME' must exist, must be the
first section after the .TH call, and must contain only a
line of the form
topic[, another-topic]... \- summary-description
for a man page to be properly indexed. See man(7) for the
conventions prevailing on your system.
.SS [subheading-text]
Set subheading-text as a subsection heading indented
between a section heading and an ordinary paragraph (.P).
See subsection 'Horizontal and vertical spacing' below for
the indentation amount. The text following .SS up to the
end of the line, or the text on the next input line if .SS
is given no arguments, is set in bold (or the font
specified by the string HF). If the heading font \*[HF]
is bold, use of an italic style in heading-text is mapped
to the bold-italic style if available in the font family.
Additionally, the left margin and indentation affecting
subsequent text are reset to their default values. Text
on input lines after subheading-text is set as an ordinary
paragraph (.P).
.EX
.EE Begin and end example. After .EX, filling is disabled and
a constant-width (monospaced) font is selected. Calling
.EE enables filling and restores the previous font.
Example regions are useful for formatting code, shell
sessions, and text file contents.
These macros are extensions, introduced in Version 9
Research Unix, to the original man package. Many systems
running AT&T, Heirloom Doctools, or Plan 9 troff support
them. To be certain your page will be portable to systems
that do not, copy their definitions from the an-ext.tmac
file of a groff installation.
.RS [indent]
Start a new relative inset level, moving the left margin
right by indent, if specified, and by a default amount
otherwise; see subsection 'Horizontal and vertical
spacing' below. Calls to .RS can be nested; each call
increments by 1 the inset level used by .RE. The inset
level prior to any .RS calls is 1.
.RE [level]
End a relative inset; move the left margin back to that
corresponding to inset level level. If no argument is
given, move the left margin one level back.
Paragraph macros
An ordinary paragraph (.P) like this one is set without a first-
line indentation at the current left margin, which by default is
indented from the leftmost position of the output device. In man
pages and other technical literature, definition lists are
frequently encountered; these can be set as 'tagged paragraphs',
which have one (.TP) or more (.TQ) leading tags followed by a
paragraph that has an additional indentation. The indented
paragraph (.IP) macro is useful to continue the indented content
of a narrative started with .TP, or to present an itemized or
ordered list. All paragraph macros break the output line at the
current position. If another paragraph macro has occurred since
the previous .SH or .SS, they (except for .TQ) follow the break
with a default amount of vertical space, which can be changed by
the deprecated .PD macro; see subsection 'Horizontal and vertical
spacing' below. They also reset the point size and font style to
defaults (.TQ again excepted); see subsection 'Font style macros'
below.
.P
.LP
.PP Begin a new paragraph; these macros are synonymous. The
indentation is reset to the default value; the left
margin, as affected by .RS and .RE, is not.
.TP [indent]
Set a paragraph with a leading tag, and the remainder of
the paragraph indented. The input line following this
macro, known as the tag, is printed at the current left
margin. Subsequent text is indented by indent, if
specified, and by a default amount otherwise; see
subsection 'Horizontal and vertical spacing' below.
If the tag is not as wide as the indentation, the
paragraph starts on the same line as the tag, at the
applicable indentation, and continues on the following
lines. Otherwise, the descriptive part of the paragraph
begins on the line following the tag.
The line containing the tag can include a macro call, for
instance to set the tag in bold with .B. .TP was used to
write the first paragraph of this description of .TP, and
.IP the subsequent ones.
.TQ Set an additional tag for a paragraph tagged with .TP.
The pending output line is broken. The tag on the input
line following this macro and subsequent lines are handled
as with .TP.
This macro is a GNU extension not defined on systems
running AT&T, Plan 9, or Solaris troff; see an-ext.tmac in
section 'Files' below.
The descriptions of .P, .LP, and .PP above were written
using .TP and .TQ.
.IP [tag] [indent]
Set an indented paragraph with an optional tag. The tag
and indent arguments, if present, are handled as with .TP,
with the exception that the tag argument to .IP cannot
include a macro call.
Two convenient uses for .IP are
(1) to start a new paragraph with the same
indentation as an immediately preceding .IP or
.TP paragraph, if no indent argument is given;
and
(2) to set a paragraph with a short tag that is not
semantically important, such as a bullet
(•)—obtained with the \(bu special character
escape sequence—or list enumerator, as seen in
this very paragraph.
Command synopsis macros
Command synopses are a staple of section 1 and 8 man pages.
These macros aid you to construct one that has the classical Unix
appearance. A command synopsis is wrapped in .SY/.YS calls, with
command-line options of some formats indicated by .OP.
These macros are extensions (.OP from Documenter's Workbench
troff, .SY and .YS from GNU) not defined on systems running AT&T,
Plan 9, or Solaris troff; see an-ext.tmac in section 'Files'
below.
.SY command
Begin synopsis. A new paragraph is begun at the left
margin (like .P and its aliases) unless .SY has already
been called without a corresponding .YS, in which case
only a break is performed. Hyphenation is turned off.
The command argument is set in bold. The output line is
filled as normal, but if a break is required, subsequent
output lines are indented by the width of command plus a
space.
.OP option-name [option-argument]
Indicate an optional command parameter called option-name,
which is set in bold. If the option takes an argument,
specify option-argument using a noun, abbreviation, or
hyphenated noun phrase. If present, option-argument is
preceded by a space and set in italics. Square brackets
in roman surround both arguments.
.YS End synopsis. Restore previous indentation and initial
hyphenation mode.
Multiple .SY/.YS blocks can be specified, for instance to
distinguish differing modes of operation of a complex command
like tar(1); each will be vertically separated as paragraphs are.
.SY can also be repeated multiple times before a closing .YS,
which is useful to indicate synonymous ways of invoking a
particular mode of operation.
groff's own command-line interface serves to illustrate most of
the specimens of synopsis syntax one is likely to encounter.
.SY groff
.RB [ \-abcCeEgGijklNpRsStUVXzZ ]
.RB [ \-d\~\c
.IR cs ]
.RB [ \-d\~\c
.IB name =\c
.IR string ]
.RB [ \-D\~\c
.IR enc ]
(and so on similarly)
.RI [ file\~ .\|.\|.]
.YS
.
.
.SY groff
.B \-h
.
.SY groff
.B \-\-help
.YS
.
.
.SY groff
.B \-v
.RI [ option\~ .\|.\|.\&]
.RI [ file\~ .\|.\|.]
.
.SY groff
.B \-\-version
.RI [ option\~ .\|.\|.\&]
.RI [ file\~ .\|.\|.]
.YS
produces the following output.
groff [-abcCeEgGijklNpRsStUVXzZ] [-d cs] [-d name=string]
[-D enc] [-f fam] [-F dir] [-I dir] [-K enc]
[-L arg] [-m name] [-M dir] [-n num] [-o list]
[-P arg] [-r cn] [-r reg=expr] [-T dev] [-w name]
[-W name] [file ...]
groff -h
groff --help
groff -v [option ...] [file ...]
groff --version [option ...] [file ...]
Several features of the above example are of note.
• The empty request (.), which does nothing, is used for
vertical spacing in the input file for readability by the
document maintainer. Do not put blank (empty) lines in a
man page source document.
• The command and option names are presented in bold to cue
the user that they should be input literally.
• Option dashes are specified with the \- escape sequence;
this is an important practice to make them clearly visible
and to facilitate copy-and-paste from the rendered man
page to a shell prompt or text file.
• Option arguments and command operands are presented in
italics (but see subsection 'Font style macros' below
regarding terminals) to cue the user that they must be
replaced with appropriate text.
• Symbols that are neither to be typed literally nor
replaced at the user's discretion appear in the roman
style; brackets surround optional arguments, and an
ellipsis indicates that the previous syntactical element
may be repeated arbitrarily.
• The non-breaking adjustable space escape sequence \~ is
used to prevent the output line from being broken within
the option brackets.
• The output line continuation escape sequence \c is used
with font style alternation macros to allow all three font
styles to be set without (breakable) space among them; see
subsection 'Portability' below.
• The non-printing input break escape sequence \& follows
the ellipsis when further text will follow after space on
the output line. This keeps the ellipsis's last period
from being interpreted as the end of a sentence,
preventing its last period from marking the end of a
sentence, which would cause additional inter-sentence
space to be placed after it. See subsection 'Portability'
below.
Hyperlink and email macros
Email addresses are bracketed with .MT/.ME and URL hyperlinks
with .UR/.UE.
These macros are GNU extensions not defined on systems running
AT&T, Plan 9, or Solaris troff; see an-ext.tmac in section
'Files' below.
.MT address
.ME [punctuation]
Identify address as an RFC 6068 addr-spec for a 'mailto:'
URI with the text between the two macro calls as the link
text. A punctuation argument to .ME is placed at the end
of the link text without intervening space. address may
not be visible in the output text, particularly if the man
page is being viewed as HTML. On a device that is not a
browser, address is set in angle brackets after the link
text and before punctuation.
When rendered by groff to a terminal or PostScript device,
Contact
.MT fred\:.foonly@\:fubar\:.net
Fred Foonly
.ME
for more information.
displays as 'Contact Fred Foonly ⟨fred.foonly@fubar.net⟩
for more information.'.
The use of \: to insert non-printing break points is a GNU
extension and can be omitted. We place them before each
period so that the reader does not mistake them for
sentence endings.
.UR URL
.UE [punctuation]
Identify URL as an RFC 3986 URI hyperlink with the text
between the two macro calls as the link text. A
punctuation argument to .UE is placed at the end of the
link text without intervening space. URL may not be
visible in the output text, particularly if the man page
is being viewed as HTML. On a device that is not a
browser, URL is set in angle brackets after the link text
and before punctuation.
When rendered by groff to a terminal or PostScript device,
The GNU Project of the Free Software Foundation
hosts the
.UR https://\:www\:.gnu\:.org/\:software/\:groff/
.I groff
home page
.UE .
displays as 'The GNU Project of the Free Software
Foundation hosts the groff home page
⟨https://www.gnu.org/software/groff/⟩.'.
The use of \: to insert non-printing break points is a GNU
extension and can be omitted. We place a break point
before each period so that the reader does not interpret
the period as ending a sentence.
Font style macros
The man macro package is limited in its font styling options,
offering only bold (.B), italic (.I), and roman. Italic text is
usually set underscored instead on terminal devices. The .SM and
.SB macros set text in roman or bold, respectively, at a smaller
point size; these differ visually from regular-sized roman or
bold text only on typesetter devices. It is often necessary to
set text in different styles without intervening space. The
macros .BI, .BR, .IB, .IR, .RB, and .RI, where 'B', 'I', and 'R'
indicate bold, italic, and roman, respectively, set their odd-
and even-numbered arguments in alternating styles, with no space
separating them.
Because font styles are presentational rather than semantic,
conflicting traditions have arisen regarding which font styles
should be used to mark file or path names, environment variables,
in-line literals, and man page cross-references.
The default point size and family for typesetter devices is
10-point Times, except on the X75-12 and X100-12 devices where
the point size is 12. The default style is roman.
.B [text]
Set text in bold. If the macro is given no arguments, the
text of the next input line is set in bold.
Use bold for literal portions of syntax synopses, for
command-line options in running text, and for literals
that are major topics of the subject under discussion; for
example, this page uses bold for macro, string, and
register names. In an .EX/.EE example of interactive I/O
(such as a shell session), set only user input in bold.
.I [text]
Set text in italics. If the macro is given no arguments,
the text of the next input line is set in italics.
Use italics for file and path names, for environment
variables, for enumeration or preprocessor constants in C,
for variable (user-determined) portions of syntax
synopses, for the first occurrence (only) of a technical
concept being introduced, for names of works of software
(including commands and functions, but excluding names of
operating systems or their kernels), and anywhere a
parameter requiring replacement by the user is
encountered. An exception involves variable text in a
context that is already marked up in italics, such as file
or path names with variable components; in such cases,
follow the convention of mathematical typography: set the
file or path name in italics as usual but use roman for
the variable part (see .IR and .RI below), and italics
again in running roman text when referring to the variable
material.
.SM [text]
Set text one point smaller than the default point size on
typesetter devices. If the macro is given no arguments,
the text of the next input line is set smaller.
Note: terminals will render text at normal size instead.
Do not rely upon .SM to communicate semantic information
distinct from using roman style at normal size; it will be
hidden from readers using such devices.
.SB [text]
Set text in bold and (on typesetter devices) one point
smaller than the default point size. If the macro is
given no arguments, the text of the next input line is set
smaller and in bold.
Note: terminals will render text in bold at the normal
size instead. Do not rely upon .SB to communicate
semantic information distinct from using bold style at
normal size; it will be hidden from readers using such
devices.
Note what is not prescribed for setting in bold or italics above:
elements of 'synopsis language' such as ellipses and brackets
around options; proper names and adjectives; titles of anything
other than works of literature or software; identifiers for
standards documents or technical reports such as CSTR #54,
RFC 1918, Unicode 13.0, or POSIX.1-2017; acronyms; and
occurrences after the first of a technical term or piece of
jargon. Again, the names of operating systems and their kernels
are, by practically universal convention, set in roman.
Be frugal with italics for emphasis, and particularly with bold.
Brief runs of literal text, such as references to individual
characters or short strings, including section and subsection
headings of man pages, are suitable objects for quotation; see
the \(lq, \(rq, \(oq, and \(cq escapes in subsection
'Portability' below.
Unlike the above font style macros, the font style alternation
macros below accept only arguments on the same line as the macro
call. Italic corrections are applied as appropriate. If space
is required within one of the arguments, first consider whether
the same result could be achieved with as much clarity by using
the single-style macros on separate input lines. When it cannot,
double-quote an argument containing embedded space characters.
Setting all three different styles within a word presents
challenges; it is possible with the \c and/or \f escape
sequences, but see subsection 'Portability' below for caveats.
.BI bold-text italic-text ...
Set each argument in bold and italics, alternately.
.BI \-r\~ reg = n
.BR bold-text roman-text ...
Set each argument in bold and roman, alternately.
After invocation of
.BR .NH ,
the assigned number is made available in the strings
.IB italic-text bold-text ...
Set each argument in italics and bold, alternately.
.I groff
copes with this situation by searching for both
.IB anything .tmac
and
.BI tmac. anything
.IR italic-text roman-text ...
Set each argument in italics and roman, alternately.
The
.I groff
font file is written to
.IR font .
.RB roman-text bold-text ...
Set each argument in roman and bold, alternately.
and do not handle the
.RB \(lq "delim on" \(rq
statement specially.
.RI roman-text italic-text ...
Set each argument in roman and italics, alternately.
.RI [ file\~ .\|.\|.]
Horizontal and vertical spacing
The indent argument accepted by .RS, .IP, .TP, and the deprecated
.HP is a number plus an optional scaling indicator. If no
scaling indicator is given, the man package assumes 'n'; that is,
the width of a letter 'n' in the font current when the macro is
called (see section 'Numerical Expressions' in groff(7)). An
indentation specified in a call to .IP, .TP, or the deprecated
.HP persists until (1) another of these macros is called with an
explicit indent argument, or (2) .SH, .SS, or .P or its synonyms
is called; these clear the indentation entirely. Relative insets
created by .RS move the left margin and persist until .RS, .RE,
.SH, or .SS is called.
The indentation amount exhibited by ordinary paragraphs set with
.P (and its synonyms) not within an .RS/.RE relative inset, and
the default used when .IP, .RS, .TP, and the deprecated .HP are
not given an indentation argument, is 7.2n for typesetter devices
and 7n for terminal devices (but see the -rIN option). Headers,
footers (both set with .TH), and section headings (.SH) are set
with no indentation and subsection headings (.SS) are indented 3n
(but see the -rSN option). However, the HTML output device
ignores indentation completely.
It may be helpful to think of the left margin and indentation as
related but distinct concepts; groff's implementation of the man
macro package tracks them separately. The left margin is
manipulated by .RS and .RE (and by .SH and .SS, which reset it to
the default). The other kind of indentation is controlled by the
paragraphing macros (though, again, .SH and .SS reset it).
Indentation is imposed by the .TP, .IP, and deprecated .HP
macros, and cancelled by .P and its synonyms. An extensive
example follows.
This ordinary (.P) paragraph is not in a relative inset nor does
it possess an indentation.
Now we have created a relative inset (in other words,
moved the left margin) with .RS and started another
ordinary paragraph with .P.
tag This tagged paragraph, set with .TP, is still
within the .RS region, but lines after the first
have a supplementary indentation that the tag
lacks.
A paragraph like this one, set with .IP, will
appear to the reader as also associated with the
tag above, because .IP re-uses the previous
paragraph's indentation unless given an argument to
change it. This paragraph is affected both by the
moved left margin (.RS) and indentation (.IP).
┌─────────────────────────────────┐
│This table is affected both by │
│the left margin and indentation. │
└─────────────────────────────────┘
• This indented paragraph has a bullet for a tag,
making it more obvious that the left margin and the
paragraph indentation are distinct; only the former
affects the tag, but both affect the text of the
paragraph.
This ordinary (.P) paragraph resets the indentation, but
the left margin is still inset.
┌────────────────────────────┐
│This table is affected only │
│by the left margin. │
└────────────────────────────┘
Finally, we have ended the relative inset by using .RE, which
(because we only used one .RS/.RE pair) has reset the left margin
to the default. This is an ordinary .P paragraph.
Resist the temptation to mock up tabular or multi-column output
with horizontal tab characters or the indentation arguments to
.IP, .TP, .RS, or the deprecated .HP; the result may not render
comprehensibly on an output device you fail to check, or which is
developed in the future. The table preprocessor tbl(1) can
likely meet your needs.
The following macros break the output line and insert vertical
space: .SH, .SS, .TP, .P (and its synonyms), .IP, and the
deprecated .HP. The default inter-section and inter-paragraph
spacing is is 1v for terminal devices and 0.4v for typesetter
devices ('v' is a unit of vertical distance, where 1v is the
distance between adjacent text baselines in a single-spaced
document). In .EX/.EE sections, the inter-paragraph spacing is
1v regardless of output device. (The deprecated macro .PD can
change this vertical spacing, but its use is discouraged.) The
macros .RS, .RE, .EX, .EE, and .TQ also cause a break but no
insertion of vertical space.
Registers
Registers are described in section 'Options' below. They can be
set not only on the command line but in the site man.local file
as well; see section 'Files' below.
Strings
The following strings are defined for use in man pages. Others
are supported for configuration of rendering parameters; see
section 'Options' below.
\*R interpolates a special character escape sequence for the
'registered sign' glyph, \(rg, if available, and '(Reg.)'
otherwise.
\*S interpolates an escape sequence setting the point size to
the document default.
\*(lq
\*(rq interpolate special character escape sequences for left
and right double-quotation marks, \(lq and \(rq,
respectively.
\*(Tm interpolate special character escape sequences for the
'trade mark sign' glyph, \(tm, if available, and '(TM)'
otherwise.
None of the above is necessary in a contemporary man page. \*S
is superfluous, since point size changes are invisible on
terminal devices and macros that change it restore its original
value afterward. Better alternatives exist for the rest; simply
use the \(rg, \(lq, \(rq, and \(tm special character escape
sequences directly. Unless a man page author is aiming for a
pathological level of portability, such as the composition of
pages for consumption on simulators of 1980s Unix systems (or
Solaris troff, though even it supports \rg), the above strings
should be avoided.
Interaction with preprocessors
When a preprocessor like tbl or eqn is needed, a hint can be
given to the man page librarian by making the first line of a man
page look like this:
'\" word
The line starts with an apostrophe ('), not a dot, and a single
space character follows the double quote. The word consists of
one letter for each needed preprocessor: 'e' for eqn, 'r' for
refer, and 't' for tbl. Modern implementations of the man
program can use this information to automatically call the
required preprocessor(s) in the right order.
The usual tbl and eqn macros for table and equation inclusion,
.TS, .T&, .TE, .EQ, and .EN, may be used freely. Terminal
devices are extremely limited in presentation of mathematical
equations.
Portability
The two major syntactical categories of roff languages are
requests and escapes. Since the man macros are implemented in
terms of groff requests and escapes, one can, in principle,
supplement the functionality of man with these lower-level
elements where necessary.
However, using raw groff requests (apart from the empty request
'.') is likely to make your page render poorly when processed by
other tools; many of these attempt to interpret page sources
directly for conversion to HTML. Some requests make implicit
assumptions about things like character and page sizes that may
not hold in an HTML environment; also, many of these viewers
don't interpret the full groff vocabulary, a problem that can
lead to portions of your text being omitted or presented
incomprehensibly.
For portability to modern viewers, it is best to write your page
entirely with the macros described in this page (except for the
ones identified as deprecated, which should be avoided). The
macros we have described as extensions (.EX/.EE, .SY/.OP/.YS,
.TQ, .UR/.UE, and .MT/.ME) should be used with caution, as they
may not yet be built in to some viewer that is important to your
audience. See an-ext.tmac in section 'Files' below.
Similar caveats apply to escapes. Some escape sequences are
however required for correct typesetting even in man pages and
usually do not cause portability problems. Several of these
render glyphs corresponding to punctuation code points in the
Unicode basic Latin range (U+0000–U+007F) that are handled
specially in roff input; the escapes below must be used to render
them correctly and portably when documenting material that uses
them syntactically—namely, any of the set ' - \ ^ ` ~
(apostrophe, dash or minus, backslash, caret, grave accent,
tilde).
\" Comment. Everything after the double-quote to the end of
the input line is ignored. Whole-line comments should be
placed immediately after the empty request '.').
\newline
Join the next input line to the current one. Except for
the update of the input line counter (used for diagnostic
messages and related purposes), a series of lines ending
in backslash-newline appears to groff as a single input
line. Use this escape sequence to break excessively long
input lines for document maintenance.
\% Control hyphenation. The location of this escape sequence
within a word marks a hyphenation point, supplementing
groff's automatic hyphenation patterns. At the beginning
of a word, it suppresses any automatic hyphenation points
within; any specified with \% are still honored.
\~ Adjustable non-breaking space. Use this escape sequence
to prevent a break inside a short phrase or between a
numerical quantity and its corresponding unit(s).
Before starting the motor,
set the output speed to\~1.
There are 1,024\~bytes in 1\~KiB.
CSTR\~#8 documents the B\~language.
\& Non-printing input break. Insert at the beginning of an
input line to prevent a dot or apostrophe from being
interpreted as the beginning of a roff request. Append to
an end-of-sentence punctuation sequence to keep it from
being recognized as such.
\| Narrow (one-sixth em on typesetters, zero-width on
terminals) non-breaking space. Used primarily in ellipses
('.\|.\|.') to space the dots more pleasantly on
typesetter devices like PostScript and PDF.
\- Minus sign or basic Latin hyphen-minus. This escape
sequence produces the Unix command-line option dash in the
output. '-' is a hyphen to roff; some output devices
replace it with U+2010 (hyphen) or similar.
\(aq Basic Latin apostrophe. Some output devices replace '''
with a right single quotation mark.
\(oq
\(cq Opening and closing single quotation marks. Use these for
paired directional single quotes, 'like this'.
\(dq Basic Latin quotation mark (double quote). Use in macro
calls to prevent '"' from being interpreted as beginning a
quoted argument, or simply for readability.
.TP
.BI "split \(dq" text \(dq
\(lq
\(rq Left and right double quotation marks. Use these for
paired directional double quotes, 'like this'.
\(em Em-dash. Use for an interruption—such as this one—in a
sentence.
\(en En-dash. Use to separate the ends of a range,
particularly between numbers; for example, 'the digits
1–9'.
\(ga Basic Latin grave accent. Some output devices replace '`'
with a left single quotation mark.
\(ha Basic Latin circumflex accent ('hat'). Some output
devices replace '^' with U+02C6 (modifier letter
circumflex accent) or similar.
\(rs Reverse solidus (backslash). The backslash is the default
groff escape character, so it does not represent itself in
output. Also see \e below.
\(ti Basic Latin tilde. Some output devices replace '~' with
U+02DC (small tilde) or similar.
\c End an input line without inserting space or attempting a
break. Normally, the end of an input line is treated like
a space; an output line may be broken there if filling is
enabled (if not, an adjustable space is inserted), and
will be broken there when filling is disabled, as in
.EX/.EE examples. Anything after \c on the input line is
ignored. The next line is interpreted as usual and can
include a macro call (contrast with \newline). This
escape sequence is useful when three different font styles
are needed in a single word, as in a command synopsis,
.RB [ \-\-stylesheet=\c
.IR name ]
or on a single line, as in .EX/.EE examples.
.EX
$ \c
.B groff \-T utf8 \-Z \c
.I file \c
.B | grotty \-i
.EE
Alternatively, and perhaps with better portability, the \f
font style escape sequence can be used; see below. Using
\c to include the output from more than one input line
into the next-line argument of a .TP macro will render
incorrectly with groff 1.22.3, mandoc 1.14.1, older
versions of these programs, and perhaps with some other
formatters.
\e Widely used in man pages to represent a backslash output
glyph. It works reliably as long as the '.ec' request is
not used, which should never happen in man pages, and it
is slightly more portable than the more explicit \(rs
('reverse solidus') special character escape sequence.
\fB, \fI, \fR, \fP
Switch to bold, italic, roman, or back to the previous
style, respectively. Either \f or \c is needed when three
different font styles are required in a word.
.RB [ \-\-reference\-dictionary=\fI\,name\/\fP ]
.RB [ \-\-reference\-dictionary=\c
.IR name ]
Style escapes may be more portable than \c. As shown
above, it is up to you to account for italic corrections
with '\/' and '\,', which are themselves GNU extensions,
if desired and if supported by your implementation.
\fP reliably returns to the style in use immediately
preceding the previous \f escape sequence only if no
sectioning, paragraph, or style macro calls have
intervened.
As long as at most two styles are needed in a word, style
macros like .B and .BI usually result in more readable
roff source than \f escapes do.
For maximum portability, escape sequences and special characters
not listed above are better avoided in man pages.
Hooks
Two macros, both GNU extensions, are called internally by the
groff man package to format page headers and footers and can be
redefined by the administrator in a site's man.local file (see
section 'Files' below). The default headers and footers are
documented in the description of .TH above. Because these macros
are hooks for groff man internals, man pages have no reason to
call them. A macro definition for these hooks typically consists
of a '.tl' request.
.BT Set the page footer text ('bottom trap').
.PT Set the page header text ('page trap').
Deprecated features
Use of the following in man pages for public distribution is
discouraged.
.AT [system [release]]
Alter the footer for use with legacy AT&T man pages,
overriding any definition of the footer-inside argument to
.TH. This macro exists only for compatibility, to render
man pages from historical systems.
The first argument system can be:
3 7th edition (default)
4 System III
5 System V
The optional second argument release specifies the release
number, such as in 'System V Release 3'.
.DT Set tab stops every 0.5i (inches). Since this macro is
called by .TH, it would make sense to call it only if a
man page changes the tab stops.
Use of this presentation-level macro is deprecated. It
translates poorly to HTML, under which exact space control
and tabulation are not readily available. Thus,
information or distinctions that you use .DT to express
are likely to be lost. If you feel tempted to use it, you
should probably be composing a table using tbl(1) markup
instead.
.HP [indent]
Set up a paragraph with a hanging left indentation. The
indent argument, if present, is handled as with .TP.
Use of this presentation-level macro is deprecated. A
hanging indentation cannot be expressed naturally under
HTML, and HTML-based man page processors may interpret it
as starting an ordinary paragraph. Thus, any information
or distinction you mean to express with the indentation
may be lost.
.PD [vertical-space]
Define the vertical space between paragraphs or
(sub)sections. The optional argument vertical-space
specifies the amount; the default scaling indicator is
'v'. Without an argument, the spacing is reset to its
default value; see subsection 'Horizontal and vertical
spacing' above.
Use of this presentation-level macro is deprecated. It
translates poorly to HTML, under which exact control of
inter-paragraph spacing is not readily available. Thus,
information or distinctions that you use .PD to express
are likely to be lost.
.UC [version]
Alter the footer for use with legacy BSD man pages,
overriding any definition of the footer-inside argument to
.TH. This macro exists only for compatibility, to render
man pages from historical systems.
The argument version can be:
3 3rd Berkeley Distribution (default)
4 4th Berkeley Distribution
5 4.2 Berkeley Distribution
6 4.3 Berkeley Distribution
7 4.4 Berkeley Distribution
History
Version 7 Unix (1979) introduced the man macro package and
supported all of the macros described in this page not listed as
extensions, except .P, .SB, and the deprecated .AT and .UC. The
only strings defined were R and S; no registers were documented.
.UC appeared in 3BSD (1980) and .P in Unix System III (1980).
PWB/UNIX 2.0 (1980) added the Tm string. 4BSD (1980) added lq
and rq strings. 4.3BSD (1986) added .AT and .P. Version 9 Unix
(1986) introduced .EX and .EE. SunOS 4.0 (1988) may have been
the first to support .SB.
