.\" $Id: man.7,v 1.124 2014/02/16 14:26:55 schwarze Exp $ .\" .\" Copyright (c) 2009, 2010, 2011, 2012 Kristaps Dzonsons .\" Copyright (c) 2011, 2012, 2013 Ingo Schwarze .\" Copyright (c) 2010 Joerg Sonnenberger .\" .\" Permission to use, copy, modify, and distribute this software for any .\" purpose with or without fee is hereby granted, provided that the above .\" copyright notice and this permission notice appear in all copies. .\" .\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES .\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF .\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR .\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES .\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. .\" .Dd $Mdocdate: February 16 2014 $ .Dt MAN 7 .Os .Sh NAME .Nm man .Nd legacy formatting language for manual pages .Sh DESCRIPTION Traditionally, the .Nm man language has been used to write .Ux manuals for the .Xr man 1 utility. It supports limited control of presentational details like fonts, indentation and spacing. This reference document describes the structure of manual pages and the syntax and usage of the man language. .Pp .Bf -emphasis Do not use .Nm to write your manuals: .Ef It lacks support for semantic markup. Use the .Xr mdoc 7 language, instead. .Pp In a .Nm document, lines beginning with the control character .Sq \&. are called .Dq macro lines . The first word is the macro name. It usually consists of two capital letters. For a list of available macros, see .Sx MACRO OVERVIEW . The words following the macro name are arguments to the macro. .Pp Lines not beginning with the control character are called .Dq text lines . They provide free-form text to be printed; the formatting of the text depends on the respective processing context: .Bd -literal -offset indent \&.SH Macro lines change control state. Text lines are interpreted within the current state. .Ed .Pp Many aspects of the basic syntax of the .Nm language are based on the .Xr roff 7 language; see the .Em LANGUAGE SYNTAX and .Em MACRO SYNTAX sections in the .Xr roff 7 manual for details, in particular regarding comments, escape sequences, whitespace, and quoting. .Sh MANUAL STRUCTURE Each .Nm document must contain the .Sx \&TH macro describing the document's section and title. It may occur anywhere in the document, although conventionally it appears as the first macro. .Pp Beyond .Sx \&TH , at least one macro or text line must appear in the document. .Pp The following is a well-formed skeleton .Nm file for a utility .Qq progname : .Bd -literal -offset indent \&.TH PROGNAME 1 2009-10-10 \&.SH NAME \efBprogname\efR \e(en one line about what it does \&.\e\(dq .SH LIBRARY \&.\e\(dq For sections 2, 3, and 9 only. \&.\e\(dq Not used in OpenBSD. \&.SH SYNOPSIS \efBprogname\efR [\efB\e-options\efR] \efIfile ...\efR \&.SH DESCRIPTION The \efBfoo\efR utility processes files ... \&.\e\(dq .SH IMPLEMENTATION NOTES \&.\e\(dq Not used in OpenBSD. \&.\e\(dq .SH RETURN VALUES \&.\e\(dq For sections 2, 3, and 9 function return values only. \&.\e\(dq .SH ENVIRONMENT \&.\e\(dq For sections 1, 6, 7, and 8 only. \&.\e\(dq .SH FILES \&.\e\(dq .SH EXIT STATUS \&.\e\(dq For sections 1, 6, and 8 only. \&.\e\(dq .SH EXAMPLES \&.\e\(dq .SH DIAGNOSTICS \&.\e\(dq For sections 1, 4, 6, 7, 8, and 9 printf/stderr messages only. \&.\e\(dq .SH ERRORS \&.\e\(dq For sections 2, 3, 4, and 9 errno settings only. \&.\e\(dq .SH SEE ALSO \&.\e\(dq .BR foobar ( 1 ) \&.\e\(dq .SH STANDARDS \&.\e\(dq .SH HISTORY \&.\e\(dq .SH AUTHORS \&.\e\(dq .SH CAVEATS \&.\e\(dq .SH BUGS \&.\e\(dq .SH SECURITY CONSIDERATIONS \&.\e\(dq Not used in OpenBSD. .Ed .Pp The sections in a .Nm document are conventionally ordered as they appear above. Sections should be composed as follows: .Bl -ohang -offset indent .It Em NAME The name(s) and a short description of the documented material. The syntax for this is generally as follows: .Pp .D1 \efBname\efR \e(en description .It Em LIBRARY The name of the library containing the documented material, which is assumed to be a function in a section 2 or 3 manual. For functions in the C library, this may be as follows: .Pp .D1 Standard C Library (libc, -lc) .It Em SYNOPSIS Documents the utility invocation syntax, function call syntax, or device configuration. .Pp For the first, utilities (sections 1, 6, and 8), this is generally structured as follows: .Pp .D1 \efBname\efR [-\efBab\efR] [-\efBc\efR\efIarg\efR] \efBpath\efR... .Pp For the second, function calls (sections 2, 3, 9): .Pp .D1 \&.B char *name(char *\efIarg\efR); .Pp And for the third, configurations (section 4): .Pp .D1 \&.B name* at cardbus ? function ? .Pp Manuals not in these sections generally don't need a .Em SYNOPSIS . .It Em DESCRIPTION This expands upon the brief, one-line description in .Em NAME . It usually contains a break-down of the options (if documenting a command). .It Em IMPLEMENTATION NOTES Implementation-specific notes should be kept here. This is useful when implementing standard functions that may have side effects or notable algorithmic implications. .It Em RETURN VALUES This section documents the return values of functions in sections 2, 3, and 9. .It Em ENVIRONMENT Documents any usages of environment variables, e.g., .Xr environ 7 . .It Em FILES Documents files used. It's helpful to document both the file name and a short description of how the file is used (created, modified, etc.). .It Em EXIT STATUS This section documents the command exit status for section 1, 6, and 8 utilities. Historically, this information was described in .Em DIAGNOSTICS , a practise that is now discouraged. .It Em EXAMPLES Example usages. This often contains snippets of well-formed, well-tested invocations. Make sure that examples work properly! .It Em DIAGNOSTICS Documents error conditions. In section 4 and 9 manuals, these are usually messages printed by the kernel to the console and to the kernel log. In section 1, 6, 7, and 8, these are usually messages printed by userland programs to the standard error output. .Pp Historically, this section was used in place of .Em EXIT STATUS for manuals in sections 1, 6, and 8; however, this practise is discouraged. .It Em ERRORS Documents .Xr errno 2 settings in sections 2, 3, 4, and 9. .It Em SEE ALSO References other manuals with related topics. This section should exist for most manuals. .Pp .D1 \&.BR bar \&( 1 \&), .Pp Cross-references should conventionally be ordered first by section, then alphabetically. .It Em STANDARDS References any standards implemented or used, such as .Pp .D1 IEEE Std 1003.2 (\e(lqPOSIX.2\e(rq) .Pp If not adhering to any standards, the .Em HISTORY section should be used. .It Em HISTORY A brief history of the subject, including where support first appeared. .It Em AUTHORS Credits to the person or persons who wrote the code and/or documentation. Authors should generally be noted by both name and email address. .It Em CAVEATS Common misuses and misunderstandings should be explained in this section. .It Em BUGS Known bugs, limitations, and work-arounds should be described in this section. .It Em SECURITY CONSIDERATIONS Documents any security precautions that operators should consider. .El .Sh MACRO OVERVIEW This overview is sorted such that macros of similar purpose are listed together, to help find the best macro for any given purpose. Deprecated macros are not included in the overview, but can be found in the alphabetical reference below. .Ss Page header and footer meta-data .Bl -column "PP, LP, P" description .It Sx TH Ta set the title: Ar title section date Op Ar source Op Ar volume .It Sx AT Ta display AT&T UNIX version in the page footer (<= 1 argument) .It Sx UC Ta display BSD version in the page footer (<= 1 argument) .El .Ss Sections and paragraphs .Bl -column "PP, LP, P" description .It Sx SH Ta section header (one line) .It Sx SS Ta subsection header (one line) .It Sx PP , LP , P Ta start an undecorated paragraph (no arguments) .It Sx RS , RE Ta reset the left margin: Op Ar width .It Sx IP Ta indented paragraph: Op Ar head Op Ar width .It Sx TP Ta tagged paragraph: Op Ar width .It Sx HP Ta hanged paragraph: Op Ar width .It Sx PD Ta set vertical paragraph distance: Op Ar height .It Sx \&br Ta force output line break in text mode (no arguments) .It Sx \&sp Ta force vertical space: Op Ar height .It Sx fi , nf Ta fill mode and no-fill mode (no arguments) .It Sx in Ta additional indent: Op Ar width .El .Ss Physical markup .Bl -column "PP, LP, P" description .It Sx B Ta boldface font .It Sx I Ta italic font .It Sx R Ta roman (default) font .It Sx SB Ta small boldface font .It Sx SM Ta small roman font .It Sx BI Ta alternate between boldface and italic fonts .It Sx BR Ta alternate between boldface and roman fonts .It Sx IB Ta alternate between italic and boldface fonts .It Sx IR Ta alternate between italic and roman fonts .It Sx RB Ta alternate between roman and boldface fonts .It Sx RI Ta alternate between roman and italic fonts .El .Sh MACRO REFERENCE This section is a canonical reference to all macros, arranged alphabetically. For the scoping of individual macros, see .Sx MACRO SYNTAX . .Ss \&AT Sets the volume for the footer for compatibility with man pages from .At releases. The optional arguments specify which release it is from. .Ss \&B Text is rendered in bold face. .Pp See also .Sx \&I and .Sx \&R . .Ss \&BI Text is rendered alternately in bold face and italic. Thus, .Sq .BI this word and that causes .Sq this and .Sq and to render in bold face, while .Sq word and .Sq that render in italics. Whitespace between arguments is omitted in output. .Pp Examples: .Pp .Dl \&.BI bold italic bold italic .Pp The output of this example will be emboldened .Dq bold and italicised .Dq italic , with spaces stripped between arguments. .Pp See also .Sx \&IB , .Sx \&BR , .Sx \&RB , .Sx \&RI , and .Sx \&IR . .Ss \&BR Text is rendered alternately in bold face and roman (the default font). Whitespace between arguments is omitted in output. .Pp See .Sx \&BI for an equivalent example. .Pp See also .Sx \&BI , .Sx \&IB , .Sx \&RB , .Sx \&RI , and .Sx \&IR . .Ss \&DT Has no effect. Included for compatibility. .Ss \&EE This is a non-standard GNU extension, included only for compatibility. In .Xr mandoc 1 , it does the same as .Sx \&fi . .Ss \&EX This is a non-standard GNU extension, included only for compatibility. In .Xr mandoc 1 , it does the same as .Sx \&nf . .Ss \&HP Begin a paragraph whose initial output line is left-justified, but subsequent output lines are indented, with the following syntax: .Bd -filled -offset indent .Pf \. Sx \&HP .Op Cm width .Ed .Pp The .Cm width argument is a .Xr roff 7 scaling width. If specified, it's saved for later paragraph left-margins; if unspecified, the saved or default width is used. .Pp See also .Sx \&IP , .Sx \&LP , .Sx \&P , .Sx \&PP , and .Sx \&TP . .Ss \&I Text is rendered in italics. .Pp See also .Sx \&B and .Sx \&R . .Ss \&IB Text is rendered alternately in italics and bold face. Whitespace between arguments is omitted in output. .Pp See .Sx \&BI for an equivalent example. .Pp See also .Sx \&BI , .Sx \&BR , .Sx \&RB , .Sx \&RI , and .Sx \&IR . .Ss \&IP Begin an indented paragraph with the following syntax: .Bd -filled -offset indent .Pf \. Sx \&IP .Op Cm head Op Cm width .Ed .Pp The .Cm width argument is a .Xr roff 7 scaling width defining the left margin. It's saved for later paragraph left-margins; if unspecified, the saved or default width is used. .Pp The .Cm head argument is used as a leading term, flushed to the left margin. This is useful for bulleted paragraphs and so on. .Pp See also .Sx \&HP , .Sx \&LP , .Sx \&P , .Sx \&PP , and .Sx \&TP . .Ss \&IR Text is rendered alternately in italics and roman (the default font). Whitespace between arguments is omitted in output. .Pp See .Sx \&BI for an equivalent example. .Pp See also .Sx \&BI , .Sx \&IB , .Sx \&BR , .Sx \&RB , and .Sx \&RI . .Ss \&LP Begin an undecorated paragraph. The scope of a paragraph is closed by a subsequent paragraph, sub-section, section, or end of file. The saved paragraph left-margin width is reset to the default. .Pp See also .Sx \&HP , .Sx \&IP , .Sx \&P , .Sx \&PP , and .Sx \&TP . .Ss \&OP Optional command-line argument. This is a non-standard GNU extension, included only for compatibility. It has the following syntax: .Bd -filled -offset indent .Pf \. Sx \&OP .Cm key Op Cm value .Ed .Pp The .Cm key is usually a command-line flag and .Cm value its argument. .Ss \&P Synonym for .Sx \&LP . .Pp See also .Sx \&HP , .Sx \&IP , .Sx \&LP , .Sx \&PP , and .Sx \&TP . .Ss \&PD Specify the vertical space to be inserted before each new paragraph. .br The syntax is as follows: .Bd -filled -offset indent .Pf \. Sx \&PD .Op Cm height .Ed .Pp The .Cm height argument is a .Xr roff 7 scaling width. It defaults to .Cm 1v . If the unit is omitted, .Cm v is assumed. .Pp This macro affects the spacing before any subsequent instances of .Sx \&HP , .Sx \&IP , .Sx \&LP , .Sx \&P , .Sx \&PP , .Sx \&SH , .Sx \&SS , and .Sx \&TP . .Ss \&PP Synonym for .Sx \&LP . .Pp See also .Sx \&HP , .Sx \&IP , .Sx \&LP , .Sx \&P , and .Sx \&TP . .Ss \&R Text is rendered in roman (the default font). .Pp See also .Sx \&I and .Sx \&B . .Ss \&RB Text is rendered alternately in roman (the default font) and bold face. Whitespace between arguments is omitted in output. .Pp See .Sx \&BI for an equivalent example. .Pp See also .Sx \&BI , .Sx \&IB , .Sx \&BR , .Sx \&RI , and .Sx \&IR . .Ss \&RE Explicitly close out the scope of a prior .Sx \&RS . The default left margin is restored to the state of the original .Sx \&RS invocation. .Ss \&RI Text is rendered alternately in roman (the default font) and italics. Whitespace between arguments is omitted in output. .Pp See .Sx \&BI for an equivalent example. .Pp See also .Sx \&BI , .Sx \&IB , .Sx \&BR , .Sx \&RB , and .Sx \&IR . .Ss \&RS Temporarily reset the default left margin. This has the following syntax: .Bd -filled -offset indent .Pf \. Sx \&RS .Op Cm width .Ed .Pp The .Cm width argument is a .Xr roff 7 scaling width. If not specified, the saved or default width is used. .Pp See also .Sx \&RE . .Ss \&SB Text is rendered in small size (one point smaller than the default font) bold face. .Ss \&SH Begin a section. The scope of a section is only closed by another section or the end of file. The paragraph left-margin width is reset to the default. .Ss \&SM Text is rendered in small size (one point smaller than the default font). .Ss \&SS Begin a sub-section. The scope of a sub-section is closed by a subsequent sub-section, section, or end of file. The paragraph left-margin width is reset to the default. .Ss \&TH Sets the title of the manual page with the following syntax: .Bd -filled -offset indent .Pf \. Sx \&TH .Ar title section date .Op Ar source Op Ar volume .Ed .Pp Conventionally, the document .Ar title is given in all caps. The recommended .Ar date format is .Sy YYYY-MM-DD as specified in the ISO-8601 standard; if the argument does not conform, it is printed verbatim. If the .Ar date is empty or not specified, the current date is used. The optional .Ar source string specifies the organisation providing the utility. The .Ar volume string replaces the default rendered volume, which is dictated by the manual section. .Pp Examples: .Pp .Dl \&.TH CVS 5 "1992-02-12" GNU .Ss \&TP Begin a paragraph where the head, if exceeding the indentation width, is followed by a newline; if not, the body follows on the same line after a buffer to the indentation width. Subsequent output lines are indented. The syntax is as follows: .Bd -filled -offset indent .Pf \. Sx \&TP .Op Cm width .Ed .Pp The .Cm width argument is a .Xr roff 7 scaling width. If specified, it's saved for later paragraph left-margins; if unspecified, the saved or default width is used. .Pp See also .Sx \&HP , .Sx \&IP , .Sx \&LP , .Sx \&P , and .Sx \&PP . .Ss \&UC Sets the volume for the footer for compatibility with man pages from .Bx releases. The optional first argument specifies which release it is from. .Ss \&UE End a uniform resource identifier block. This is a non-standard GNU extension, included only for compatibility. See .Sx \&UE . .Ss \&UR Begin a uniform resource identifier block. This is a non-standard GNU extension, included only for compatibility. It has the following syntax: .Bd -literal -offset indent .Pf \. Sx \&UR Ar uri link description to be shown .Pf \. Sx UE .Ed .Ss \&br Breaks the current line. Consecutive invocations have no further effect. .Pp See also .Sx \&sp . .Ss \&fi End literal mode begun by .Sx \&nf . .Ss \&ft Change the current font mode. See .Sx Text Decoration for a listing of available font modes. .Ss \&in Indent relative to the current indentation: .Pp .D1 Pf \. Sx \&in Op Cm width .Pp If .Cm width is signed, the new offset is relative. Otherwise, it is absolute. This value is reset upon the next paragraph, section, or sub-section. .Ss \&na Don't align to the right margin. .Ss \&nf Begin literal mode: all subsequent free-form lines have their end of line boundaries preserved. May be ended by .Sx \&fi . Literal mode is implicitly ended by .Sx \&SH or .Sx \&SS . .Ss \&sp Insert vertical spaces into output with the following syntax: .Bd -filled -offset indent .Pf \. Sx \&sp .Op Cm height .Ed .Pp The .Cm height argument is a scaling width as described in .Xr roff 7 . If 0, this is equivalent to the .Sx \&br macro. Defaults to 1, if unspecified. .Pp See also .Sx \&br . .Sh MACRO SYNTAX The .Nm macros are classified by scope: line scope or block scope. Line macros are only scoped to the current line (and, in some situations, the subsequent line). Block macros are scoped to the current line and subsequent lines until closed by another block macro. .Ss Line Macros Line macros are generally scoped to the current line, with the body consisting of zero or more arguments. If a macro is scoped to the next line and the line arguments are empty, the next line, which must be text, is used instead. Thus: .Bd -literal -offset indent \&.I foo .Ed .Pp is equivalent to .Sq \&.I foo . If next-line macros are invoked consecutively, only the last is used. If a next-line macro is followed by a non-next-line macro, an error is raised, except for .Sx \&br , .Sx \&sp , and .Sx \&na . .Pp The syntax is as follows: .Bd -literal -offset indent \&.YO \(lBbody...\(rB \(lBbody...\(rB .Ed .Bl -column "MacroX" "ArgumentsX" "ScopeXXXXX" "CompatX" -offset indent .It Em Macro Ta Em Arguments Ta Em Scope Ta Em Notes .It Sx \&AT Ta <=1 Ta current Ta \& .It Sx \&B Ta n Ta next-line Ta \& .It Sx \&BI Ta n Ta current Ta \& .It Sx \&BR Ta n Ta current Ta \& .It Sx \&DT Ta 0 Ta current Ta \& .It Sx \&EE Ta 0 Ta current Ta compat .It Sx \&EX Ta 0 Ta current Ta compat .It Sx \&I Ta n Ta next-line Ta \& .It Sx \&IB Ta n Ta current Ta \& .It Sx \&IR Ta n Ta current Ta \& .It Sx \&OP Ta 0, 1 Ta current Ta compat .It Sx \&PD Ta 1 Ta current Ta \& .It Sx \&R Ta n Ta next-line Ta \& .It Sx \&RB Ta n Ta current Ta \& .It Sx \&RI Ta n Ta current Ta \& .It Sx \&SB Ta n Ta next-line Ta \& .It Sx \&SM Ta n Ta next-line Ta \& .It Sx \&TH Ta >1, <6 Ta current Ta \& .It Sx \&UC Ta <=1 Ta current Ta \& .It Sx \&br Ta 0 Ta current Ta compat .It Sx \&fi Ta 0 Ta current Ta compat .It Sx \&ft Ta 1 Ta current Ta compat .It Sx \&in Ta 1 Ta current Ta compat .It Sx \&na Ta 0 Ta current Ta compat .It Sx \&nf Ta 0 Ta current Ta compat .It Sx \&sp Ta 1 Ta current Ta compat .El .Pp Macros marked as .Qq compat are included for compatibility with the significant corpus of existing manuals that mix dialects of roff. These macros should not be used for portable .Nm manuals. .Ss Block Macros Block macros comprise a head and body. As with in-line macros, the head is scoped to the current line and, in one circumstance, the next line (the next-line stipulations as in .Sx Line Macros apply here as well). .Pp The syntax is as follows: .Bd -literal -offset indent \&.YO \(lBhead...\(rB \(lBhead...\(rB \(lBbody...\(rB .Ed .Pp The closure of body scope may be to the section, where a macro is closed by .Sx \&SH ; sub-section, closed by a section or .Sx \&SS ; part, closed by a section, sub-section, or .Sx \&RE ; or paragraph, closed by a section, sub-section, part, .Sx \&HP , .Sx \&IP , .Sx \&LP , .Sx \&P , .Sx \&PP , or .Sx \&TP . No closure refers to an explicit block closing macro. .Pp As a rule, block macros may not be nested; thus, calling a block macro while another block macro scope is open, and the open scope is not implicitly closed, is syntactically incorrect. .Bl -column "MacroX" "ArgumentsX" "Head ScopeX" "sub-sectionX" "compatX" -offset indent .It Em Macro Ta Em Arguments Ta Em Head Scope Ta Em Body Scope Ta Em Notes .It Sx \&HP Ta <2 Ta current Ta paragraph Ta \& .It Sx \&IP Ta <3 Ta current Ta paragraph Ta \& .It Sx \&LP Ta 0 Ta current Ta paragraph Ta \& .It Sx \&P Ta 0 Ta current Ta paragraph Ta \& .It Sx \&PP Ta 0 Ta current Ta paragraph Ta \& .It Sx \&RE Ta 0 Ta current Ta none Ta compat .It Sx \&RS Ta 1 Ta current Ta part Ta compat .It Sx \&SH Ta >0 Ta next-line Ta section Ta \& .It Sx \&SS Ta >0 Ta next-line Ta sub-section Ta \& .It Sx \&TP Ta n Ta next-line Ta paragraph Ta \& .It Sx \&UE Ta 0 Ta current Ta none Ta compat .It Sx \&UR Ta 1 Ta current Ta part Ta compat .El .Pp Macros marked .Qq compat are as mentioned in .Sx Line Macros . .Pp If a block macro is next-line scoped, it may only be followed by in-line macros for decorating text. .Ss Font handling In .Nm documents, both .Sx Physical markup macros and .Xr roff 7 .Ql \ef font escape sequences can be used to choose fonts. In text lines, the effect of manual font selection by escape sequences only lasts until the next macro invocation; in macro lines, it only lasts until the end of the macro scope. Note that macros like .Sx \&BR open and close a font scope for each argument. .Sh COMPATIBILITY This section documents areas of questionable portability between implementations of the .Nm language. .Pp .Bl -dash -compact .It Do not depend on .Sx \&SH or .Sx \&SS to close out a literal context opened with .Sx \&nf . This behaviour may not be portable. .It In quoted literals, GNU troff allowed pair-wise double-quotes to produce a standalone double-quote in formatted output. It is not known whether this behaviour is exhibited by other formatters. .It troff suppresses a newline before .Sq \(aq macro output; in mandoc, it is an alias for the standard .Sq \&. control character. .It The .Sq \eh .Pq horizontal position , .Sq \ev .Pq vertical position , .Sq \em .Pq text colour , .Sq \eM .Pq text filling colour , .Sq \ez .Pq zero-length character , .Sq \ew .Pq string length , .Sq \ek .Pq horizontal position marker , .Sq \eo .Pq text overstrike , and .Sq \es .Pq text size escape sequences are all discarded in mandoc. .It The .Sq \ef scaling unit is accepted by mandoc, but rendered as the default unit. .It The .Sx \&sp macro does not accept negative values in mandoc. In GNU troff, this would result in strange behaviour. .It In page header lines, GNU troff versions up to and including 1.21 only print .Ar volume names explicitly specified in the .Sx \&TH macro; mandoc and newer groff print the default volume name corresponding to the .Ar section number when no .Ar volume is given, like in .Xr mdoc 7 . .El .Pp The .Sx OP macro is part of the extended .Nm macro set, and may not be portable to non-GNU troff implementations. .Sh SEE ALSO .Xr man 1 , .Xr mandoc 1 , .Xr eqn 7 , .Xr mandoc_char 7 , .Xr mdoc 7 , .Xr roff 7 , .Xr tbl 7 .Sh HISTORY The .Nm language first appeared as a macro package for the roff typesetting system in .At v7 . It was later rewritten by James Clark as a macro package for groff. Eric S. Raymond wrote the extended .Nm macros for groff in 2007. The stand-alone implementation that is part of the .Xr mandoc 1 utility written by Kristaps Dzonsons appeared in .Ox 4.6 . .Sh AUTHORS This .Nm reference was written by .An Kristaps Dzonsons Aq Mt kristaps@bsd.lv . .Sh CAVEATS Do not use this language. Use .Xr mdoc 7 , instead.