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   groff_man_style    ( 7 )

справочная страница GNU roff и руководство по стилю (GNU roff man page tutorial and style guide)

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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.