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groff_man_style(7)  Miscellaneous Information Manual  groff_man_style(7)

Name         top

       groff_man_style - GNU roff man page tutorial and style guide

Synopsis         top

       groff -man [option ...] [file ...]

       groff -m man [option ...] [file ...]

Description         top

       The GNU implementation of the man macro package is part of the
       groff document formatting system.  It is used to compose 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           Paragraphing macros
       .IR     Italic, roman alternating    Font style macros
       .LP     Begin paragraph              Paragraphing macros
       .ME     Mail-to end                  Hyperlink macros
       .MR     Man page cross reference     Hyperlink macros
       .MT     Mail-to start                Hyperlink macros
       .P      Begin paragraph              Paragraphing macros
       .PP     Begin paragraph              Paragraphing 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
       .SH     Section heading              Document structure macros
       .SM     Small                        Font style macros
       .SS     Subsection heading           Document structure macros
       .SY     Synopsis start               Synopsis macros
       .TH     Title heading                Document structure macros
       .TP     Tagged paragraph             Paragraphing macros
       .TQ     Supplemental paragraph tag   Paragraphing macros
       .UE     URI end                      Hyperlink macros
       .UR     URI start                    Hyperlink macros
       .YS     Synopsis end                 Synopsis macros

       We discuss other macros (.AT, .DT, .HP, .OP, .PD, .SB, and .UC)
       in subsection “Deprecated features” below.

       Throughout Unix documentation, a manual entry is referred to
       simply as a “man page”, regardless of its length, without
       gendered implication, and irrespective of the macro package
       selected for its composition.

       A man page employs the Unix line-ending convention (U+000A only).
       Some basic Latin characters have special meaning to roff; see
       subsection “Portability” below.

   Fundamental concepts
       groff is a programming system for typesetting: we thus often use
       the verb “to set” in the sense “to typeset”.  The formatter
       troff(1) collects words from the input and fills output lines
       with as many as will fit.  Words are separated by spaces and
       newlines.  A transition to a new output line is called a break.
       When formatted, a word may be broken at hyphens, at \% or \:
       escape sequences (see subsection “Portability” below), or at
       predetermined locations if automatic hyphenation is enabled (see
       the -rHY option in section “Options” below).  An output line may
       be supplemented with inter-sentence space, and then optionally
       adjusted with more space to a consistent length (see the -dAD
       option).  roff(7) details these processes.  Output is prepared
       for terminals or for more capable typesetters that can change the
       type size and font family.

       An input line that starts with a dot (.) or neutral apostrophe
       (') is a control line.  To call a macro, put its name after a dot
       on a control line.  This document uses the leading dot to
       identify macros.  Some macros interpret arguments, words that
       follow its name.  A newline, unless escaped (see subsection
       “Portability” below), marks the end of the macro call.  A control
       line with no macro name on it is called an empty request; it does
       nothing.  Text lines are input lines that are not control lines.

       We describe below several man macros that plant one-line input
       traps: the next input line that directly produces formatted
       output is treated specially.  For man documents that follow the
       advice in section “Portability” below, this means that control
       lines using the empty request and uncommented input lines ending
       with an escaped newline do not spring the trap; anything else
       does (but see the .TP macro description).

   Macro reference preliminaries
       A tagged paragraph describes each macro.  We present coupled
       pairs together, as with .EX and .EE.  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 will be
       formatted as text in the output; exceptions are noted.

   Document structure macros
       Document structure macros organize a man page's content.  All of
       them break the output line.  .TH (title heading) identifies the
       document as a man page and configures the page headers and
       footers.  Section headings (.SH), one of which is mandatory and
       many of which are conventionally expected, facilitate location of
       material by the reader and aid the man page writer to discuss all
       essential aspects of the subject.  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, use .RS/.RE to inset a region within a

       .TH identifier section [footer-middle [footer-inside [header-
              Populate the page header and footer.  roff systems refer
              to these collectively as “titles”.  Together, identifier
              and the section of the manual to which it belongs can
              uniquely identify a man document on the system.  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) or intro(1) for the manual sectioning
              applicable to your system.  identifier and section are
              positioned at the left and right in the header; the latter
              is set after the former, in parentheses and without space.
              footer-middle is centered in the footer.  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 recto (odd-numbered) pages, and at the bottom right on
              verso (even-numbered) 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
              identifier and section, as in the header.  header-middle
              is centered in the header.  If section is an integer
              between 1 and 9 (inclusive), there is no need to specify
              header-middle; an.tmac will supply text for it.  This
              package may abbreviate identifier and footer-inside with
              ellipses (...) if they would overrun the space available
              in the header and footer, respectively.  In HTML output,
              headers and footers are suppressed.

              Additionally, this macro breaks the page, resetting the
              number to 1 (unless the -rC1 option is given).  This
              feature is intended only for formatting multiple man
              documents in sequence.

              A valid man document calls .TH only once, early in the
              file, prior to any other macro calls.

              By convention, footer-middle is the date of the most
              recent modification to 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.  If no argument is
              given, the macro plants a one-line input trap; text on the
              next line becomes heading-text.  The heading text is set
              in bold (or the font specified by the string HF), and, on
              typesetters, slightly larger than the base type 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.  The inset level is reset to
              1; see subsection “Horizontal and vertical spacing” below.
              Text after heading-text is set as an ordinary paragraph

              The content of heading-text and ordering of sections
              follows a set of common practices, 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
              text of the form
                     topic[, another-topic]... \- summary-description
              for a man page in English to be properly indexed.

       .SS [subheading-text]
              Set subheading-text as a subsection heading indented
              between a section heading and an ordinary paragraph (.P).
              If no argument is given, the macro plants a one-line input
              trap; text on the next line becomes subheading-text.  The
              subheading text 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 subheading-text is mapped to the
              bold-italic style if available in the font family.  The
              inset level is reset to 1; see subsection “Horizontal and
              vertical spacing” below.  Text after subheading-text is
              set as an ordinary paragraph (.P).

       .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.  An example region is
              not a “literal mode” of any sort: special character escape
              sequences must still be used to produce correct glyphs for
              ', -, \, ^, `, and ~ (see subsection “Portability” below).
              Sentence endings are still detected and additional inter-
              sentence space applied.  If the amount of additional
              inter-sentence spacing is altered, the rendering of, for
              instance, regular expressions using . or ? followed by
              multiple spaces can change.  Use the dummy character
              escape sequence \& before the spaces.

              .EX and .EE are extensions introduced in Ninth Edition
              Unix.  Documenter's Workbench, Heirloom Doctools, and
              Plan 9 troffs, and mandoc (since 1.12.2) also support
              them.  Solaris troff does not.  See subsection “Use of
              extensions” below.

       .RS [inset-amount]
              Start a new relative inset level.  The current inset
              amount is saved, then moved right by inset-amount, if
              specified, by the indentation amount of the preceding .IP,
              .TP, or (deprecated) .HP macro call if no (sub-)sectioning
              or ordinary paragraphing macro has intervened, and by the
              amount of the IN register otherwise.  Calls to .RS can be
              nested; each increments by 1 the inset level used by .RE.
              The level prior to any .RS calls is 1.

       .RE [inset-level]
              End a relative inset.  The inset amount corresponding to
              inset-level is restored.  If no argument is given, the
              inset level is reduced by 1.

   Paragraphing macros
       An ordinary paragraph (.P) like this one indents all output lines
       by the same amount.  Definition lists frequently occur in man
       pages; 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 of
       these macros break the output line.  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
       type size and font style to defaults (.TQ again excepted); see
       subsection “Font style macros” below.

       .PP    Begin a new paragraph; these macros are synonymous.  Any
              indentation from use of .IP, .TP, or the deprecated .HP is
              cleared.  The inset amount, as affected by .RS and .RE, is

       .TP [indentation]
              Set a paragraph with a leading tag, and the remainder of
              the paragraph indented.  The macro plants a one-line input
              trap that honors the \c escape sequence; text on the next
              line becomes the tag, set without indentation.  Text on
              subsequent lines is indented by indentation, if specified,
              and by the amount of the IN register otherwise.  If the
              tag, plus the “tag spacing” stored in the TS register (see
              section “Options” below) is wider than the indentation,
              the line is broken after 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 one.

       .TQ    Set an additional tag for a paragraph tagged with .TP,
              planting a one-line input trap as with .TP.

              .TQ is a GNU extension supported by Heirloom Doctools
              troff and mandoc (since 1.14.5) but not by Documenter's
              Workbench, Plan 9, or Solaris troffs.  See subsection “Use
              of extensions” below.

              The descriptions of .P, .LP, and .PP above were written
              using .TP and .TQ.

       .IP [mark [indentation]]
              Set an indented paragraph with an optional mark.
              Arguments, if present, are handled as with .TP, except
              that the mark argument to .IP cannot include a macro call,
              and the tag separation amount stored in the TS register is
              not enforced.

              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 indentation argument is
                       given; and

                  (2)  to set a paragraph with a short mark 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.

   Synopsis macros
       Use .SY and .YS to summarize syntax using familiar Unix
       conventions.  Heirloom Doctools troff and mandoc (since 1.14.5)
       support these GNU extensions; Documenter's Workbench, Plan 9, and
       Solaris troffs do not.  See subsection “Use of extensions” below.

       .SY keyword [suffix]
              Begin synopsis.  Adjustment and automatic hyphenation are
              disabled.  If .SY has already been called without a
              corresponding .YS, a break is performed.  keyword and
              suffix (if any) are set in bold.  If a break is required
              in subsequent text (up to another paragraphing,
              sectioning, or synopsis macro call), lines after the first
              are indented.  The indentation amount is the width of
              keyword plus a space, if that is the only argument, and by
              the sum of the widths of keyword and suffix otherwise.

       .YS [reuse-indentation]
              End synopsis, breaking the line and restoring indentation,
              adjustment, and hyphenation to their previous states.  If
              an argument is given, the indentation corresponding to the
              previous .SY call is reused by the next .SY call instead
              of being computed.

       Interleave multiple .SY/.YS blocks with paragraphing macros to
       distinguish differing modes of operation of a complex command
       like tar(1).  Omit the paragraphing macro to indicate synonymous
       ways of invoking a particular mode of operation.

       groff's own command-line interface illustrates most specimens one
       may encounter.

              .SY groff
              .RB [ \-abcCeEgGijklNpRsStUVXzZ ]
              .RB [ \-d\~\c
              .IR ctext ]
              .RB [ \-d\~\c
              .IB string =\c
              .IR text ]
              .RB [ \-D\~\c
              .IR fallback-encoding ]
              (and so on similarly)
              .RI [ file\~ .\|.\|.]
              .SY groff
              .B \-h
              .SY groff
              .B \-\-help
              .SY groff
              .B \-v
              .RI [ option\~ .\|.\|.\&]
              .RI [ file\~ .\|.\|.]
              .SY groff
              .B \-\-version
              .RI [ option\~ .\|.\|.\&]
              .RI [ file\~ .\|.\|.]

       produces the following output.

              groff [-abcCeEgGijklNpRsStUVXzZ] [-d ctext]
                    [-d string=text] [-D fallback-encoding] [-f font-
                    family] [-F font-directory] [-I inclusion-directory]
                    [-K input-encoding] [-L spooler-argument] [-m macro-
                    package] [-M macro-directory] [-n page-number]
                    [-o page-list] [-P postprocessor-argument]
                    [-r cnumeric-expression] [-r register=numeric-
                    expression] [-T output-device] [-w warning-category]
                    [-W warning-category] [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, vertically spaces
          the input file for readability by the document maintainer.  Do
          not put blank (empty) lines in a man page source document.

       •  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 input.

       •  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 syntactic element may be repeated arbitrarily.
          Where whitespace separates optional arguments, a space
          precedes the ellipsis.

       •  The non-breaking adjustable space escape sequence \~ prevents
          the output line from breaking within the option brackets; see
          subsection “Portability” below.

       •  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 dummy character escape sequence \& follows the ellipsis
          when further text will follow after space on the output line,
          keeping its last period from being interpreted as the end of a
          sentence and causing additional inter-sentence space to be
          placed after it.  See subsection “Portability” below.

       We might synopsize the standard C library function bsearch(3) as

              .B void *\c
              .SY bsearch (
              .BI const\~void\~* key ,
              .BI const\~void\~* base ,
              .BI size_t\~ nmemb ,
              .BI int\~(* compar )\c
              .B (const\~void\~*, const\~void\~*));

       man produces the following result.

              void *

              bsearch const void *key, const void *base, size_t nmemb,
                      int (*compar)(const void *, const void *));

   Hyperlink macros
       Man page cross references like ls(1) are best presented with .MR.
       Text may be hyperlinked to email addresses with .MT/.ME or other
       URIs with .UR/.UE.  Not all output devices support hyperlinking
       of text; terminals and pager programs must support ECMA-48 OSC 8
       escape sequences (see grotty(1)).  When device support is
       unavailable or disabled with the U register (see section
       “Options” below), .MT and .UR URIs are rendered between angle
       brackets after the linked text.

       .MT, .ME, .UR, and .UE are GNU extensions supported by Heirloom
       Doctools and mandoc (.UR/.UE since 1.12.3; .MT/.ME since 1.14.2)
       but not by Documenter's Workbench, Plan 9, or Solaris troffs.
       Plan 9 from User Space's troff implements .MR.  See subsection
       “Use of extensions” below.

       The arguments to .MR, .MT, and .UR should be prepared for
       typesetting since they can appear in the output.  Use special
       character escape sequences to encode Unicode basic Latin
       characters where necessary, particularly the hyphen-minus.  (See
       section “Portability” below.)  URIs can be lengthy; rendering
       them can result in jarring adjustment or variations in line
       length, or troff warnings when a hyperlink is longer than an
       output line.  The application of non-printing break point escape
       sequences \: after each slash (or series thereof), and before
       each dot (or series thereof) is recommended as a rule of thumb.
       The former practice avoids forcing a trailing slash in a URI onto
       a separate output line, and the latter helps the reader to avoid
       mistakenly interpreting a dot at the end of a line as a period
       (or multiple dots as an ellipsis).  Thus,
              .UR http://\:example\\:fb8afcfbaebc74e\
       has several potential break points in the URI shown.  Consider
       adding break points before or after at signs in email addresses,
       and question marks, ampersands, and number signs in HTTP(S) URIs.
       The formatter removes \: escape sequences from hyperlinks when
       supplying device control commands to output drivers.

       .MR topic [manual-section [trailing-text]]
              (since groff 1.23) Set a man page cross reference as
              “topic(manual-section)”.  If manual-section is absent, the
              package omits the surrounding parentheses.  If trailing-
              text (typically punctuation) is specified, it follows the
              closing parenthesis without intervening space.
              Hyphenation is disabled while the cross reference is set.
              topic is set in the font specified by the MF string.  If
              manual-section is present, the cross reference hyperlinks
              to a URI of the form “man:topic(manual-section)”.

                     The output driver
                     .MR grops 1
                     produces PostScript from
                     .I troff
                     The Ghostscript program (\c
                     .MR gs 1 )
                     interprets PostScript and PDF.

       .MT address
       .ME [trailing-text]
              Identify address as an RFC 6068 addr-spec for a “mailto:”
              URI with the text between the two macro calls as the link
              text.  An argument to .ME is placed after the link text
              without intervening space.  address may not be visible in
              the rendered document if hyperlinks are enabled and
              supported by the output driver.  If they are not, address
              is set in angle brackets after the link text and before
              trailing-text.  If hyperlinking is enabled but there is no
              link text, address is formatted and hyperlinked without
              angle brackets.

              When rendered by groff to a PostScript device,

                     .MT fred\:.foonly@\:fubar\
                     Fred Foonly
                     for more information.

              displays as “Contact Fred Foonly ⟨⟩
              for more information.”.

       .UR uri
       .UE [trailing-text]
              Identify uri as an RFC 3986 URI hyperlink with the text
              between the two macro calls as the link text.  An argument
              to .UE is placed after the link text without intervening
              space.  uri may not be visible in the rendered document if
              hyperlinks are enabled and supported by the output driver.
              If they are not, uri is set in angle brackets after the
              link text and before trailing-text.  If hyperlinking is
              enabled but there is no link text, uri is formatted and
              hyperlinked without angle brackets.

              When rendered by groff to a PostScript device,

                     The GNU Project of the Free Software Foundation
                     hosts the
                     .UR https://\:www\:.gnu\\:software/\:groff/
                     .I groff
                     home page
                     .UE .

              displays as “The GNU Project of the Free Software
              Foundation hosts the groff home page

       If a .TP call is followed immediately by hyperlinking macros
       .UR/.UE or .MT/.ME, and the device doesn't support hyperlinking,
       the hyperlink is set at the beginning of the indented paragraph,
       not as part of the tag.

   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 terminals.  .SM sets text at a
       smaller type size, which differs visually from regular-sized text
       only on typesetters.  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,
       and inlined literals.

       The default type size and family for typesetters is 10-point
       Times, except on the X75-12 and X100-12 devices where the type
       size is 12 points.  The default style is roman.

       .B [text]
              Set text in bold.  If no argument is given, the macro
              plants a one-line input trap; text on the next line, which
              can be further formatted with a macro, 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 an italic or oblique face.  If no argument is
              given, the macro plants a one-line input trap; text on the
              next line, which can be further formatted with a macro, is
              set in an italic or oblique face.

              Use italics for file and path names, for environment
              variables, for C data types, for enumeration or
              preprocessor constants in C, for variant (user-
              replaceable) portions of syntax synopses, for the first
              occurrence (only) of a technical concept being introduced,
              for names of journals and of literary works longer than an
              article, and anywhere a parameter requiring replacement by
              the user is encountered.  An exception involves variant
              text in a context already typeset in italics, such as file
              or path names with replaceable 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 variant part (see .IR and .RI below), and italics
              again in running roman text when referring to the variant

       .SM [text]
              Set text one point smaller than the default type size on
              typesetters.  If no argument is given, the macro plants a
              one-line input trap; text on the next line, which can be
              further formatted with a macro, 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.

       Observe 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 major works of literature; 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.

       Be frugal with italics for emphasis, and particularly with bold.
       Article titles and 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 escape sequences in
       subsection “Portability” below.

       Unlike the above font style macros, the font style alternation
       macros below set no input traps; they must be given arguments to
       have effect.  They apply italic corrections as appropriate.  If a
       space is required within an argument, first consider whether the
       same result could be achieved with as much clarity by using
       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.  See subsection “Portability” below for approaches.

       .BI bold-text italic-text ...
              Set each argument in bold and italics, alternately.

                     .BI -r\~ register = numeric-expression

       .BR bold-text roman-text ...
              Set each argument in bold and roman, alternately.

                     Set an ellipsis on the math axis with the GNU extension macro
                     .BR cdots .

       .IB italic-text bold-text ...
              Set each argument in italics and bold, alternately.

                     In places where
                     .IB n th
                     is allowed,

       .IR italic-text roman-text ...
              Set each argument in italics and roman, alternately.

                     Use GNU
                     .IR pic 's
                     .B figname
                     command to change the name of the vbox.

       .RB roman-text bold-text ...
              Set each argument in roman and bold, alternately.

                     .I file
                     .RB \[lq] - \[rq],
                     .I groff
                     reads the standard input stream.

       .RI roman-text italic-text ...
              Set each argument in roman and italics, alternately.

                     .RI ( tpic
                     was a fork of AT&T
                     .I pic
                     by Tim Morgan of the University of California at Irvine

   Horizontal and vertical spacing
       All text is rendered with respect to the page offset; see
       register PO in section “Options” below.  Headers, footers (both
       set with .TH), and section headings (.SH) are set with no further
       indentation.  Subsection headings (.SS) are indented by the
       amount in the SN register.

       Ordinary paragraphs not within an .RS/.RE inset region are inset
       by the amount stored in the BP register; see section “Options”
       below.  The IN register configures the default indentation amount
       used by .RS (as the inset-amount), .IP, .TP, and the deprecated
       .HP; an overriding argument is a number plus an optional scaling
       unit.  If no scaling unit is given, the man package assumes “n”;
       that is, roughly the width of a letter “n” in the font current
       when the macro is called—see section “Measurements” 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
       indentation argument, or (2) .SH, .SS, or .P or its synonyms is
       called; these clear the indentation entirely.

       The inset amount and indentation are related but distinct
       parameters with the same defaults.  The former is manipulated by
       .RS and .RE (and by .SH and .SS, which reset it to the default).
       Indentation is controlled by the paragraphing macros (though,
       again, .SH and .SS reset it); it 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 with .RS and started
              another ordinary paragraph with .P.  We observe that all
              of its lines are inset and indented the same; contrast
              with a first-line indentation.

              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

                     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.  Both the inset amount (.RS) and
                     indentation (.IP) affect this paragraph.
                     │ This table is affected both by    │
                     │ the inset amount and indentation. │

              •      This indented paragraph is marked with a bullet,
                     contrasting the inset amount and the indentation;
                     only the former affects the mark, but both affect
                     the text of the paragraph.

              This ordinary (.P) paragraph resets the indentation, but
              the inset amount is unchanged.
              │ This table is affected only │
              │ by the inset amount.        │

       Finally, we have ended the relative inset by using .RE, which
       (because we used only one .RS/.RE pair) has restored the inset
       amount to its initial value.  This is an ordinary .P paragraph.

       Resist the temptation to mock up tabular or multi-column output
       with tab characters or the indentation arguments to .IP, .TP,
       .RS, or the deprecated .HP; the result may not be comprehensible
       on an output device you fail to check, or which is developed in
       the future.  Consider the table preprocessor tbl(1) instead.

       Several macros insert vertical space: .SH, .SS, .TP, .P (and its
       synonyms), .IP, and the deprecated .HP.  The default inter-
       section and inter-paragraph spacing is 1v for terminals and 0.4v
       for typesetters.  “v” is a unit of vertical distance, where 1v is
       the distance between adjacent text baselines.  (The deprecated
       macro .PD can change this vertical spacing, but we discourage its
       use.)  Between .EX and .EE calls, the inter-paragraph spacing is
       1v regardless of output device.

       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.

       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.)”

       \*S    interpolates an escape sequence setting the type size to
              the document default.

       \*(rq  interpolate special character escape sequences for left
              and right double-quotation marks, \(lq and \(rq,

       \*(Tm  interpolates a special character escape sequence for the
              “trade mark sign” glyph, \(tm, if available, and “(TM)”

       None of the above is necessary in a contemporary man page.  \*S
       is superfluous, since type size changes are invisible on
       terminals 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 you are aiming for a pathological level of
       portability—perhaps composing a man page for consumption on
       simulators of 1980s Unix systems (or Solaris troff, though even
       it supports \(rg)—avoid using the above strings.

   Use of extensions
       To ensure that your man page formats reliably on a wide variety
       of viewers, write it solely with the macros described in this
       page (except for the ones identified as deprecated, which you
       should avoid).  The macros we have described as extensions might
       not be supported by a formatter that is important to your
       audience.  Nevertheless, groff's extensions are present because
       they perform tasks that are otherwise difficult or tedious to
       achieve portably.  If you require an extension but also expect
       your man page to be rendered on a system that doesn't support it,
       consider writing a configuration test that measures a property of
       the system, and use m4(1), sed(1), or a similar tool to generate
       a .man file from a file, defining page-local versions of
       extension macros only where necessary.  You can copy extension
       macro definitions from groff; see an-ext.tmac in section “Files”

       For example, we might put a line
       in our man document at the end of the “Name” section, test a
       system for the availability of the groff man .MR macro, remove
       the line if the macro is present, and “inline” a definition
       otherwise, as follows.  (This version is slightly simplified and
       does not attempt to disable hyphenation when setting arguments to
              have_MR=$(echo .pm | troff -man 2>&1 | grep MR)
              if [ -n "$have_MR" ]
                sed '/@DEFINE_MR@/d' >
                sed 's/@DEFINE_MR@/.de MR\
              .  ie \\\\n(.$=1 .I \\\\$1\
              .  el .IR \\\\$1 (\\\\$2)\\\\$3\
              ../' >
       (The profusion of backslashes is due to its status as an escape
       character in both roff and sed.)

       If the foregoing method is too much trouble, you could apply the
       radical technique of reading your man page using every formatter
       of interest, confirming satisfactory output from each.  Test
       documentation for syntactic validity and semantic correctness,
       just as you would test code.

       An installed man page should contain Unicode basic Latin code
       points exclusively.  One can maintain it in a more convenient
       encoding, using preconv(1) to produce a basic Latin version that
       employs special character escape sequences to access code points
       necessary in non-English text.

       The two major features that control formatting in the roff
       language are requests and escape sequences.  Since the man macros
       are implemented in terms of these, one can, in principle,
       supplement the functionality of man with these lower-level
       elements where necessary.

       However, use of roff requests (apart from the empty request “.”)
       risks poor rendering when your page is processed by tools other
       than roff formatters that attempt to interpret page sources.
       (Historically, this was commonly attempted for HTML conversion.)
       Requests might make assumptions about line length that do not
       hold in an HTML environment.  Many of these programs don't
       interpret the full roff language (let alone extensions): they may
       be incapable of handling numeric expressions, control structures,
       or register, string, and macro definitions.  Such limitations can
       lead to portions of a document being presented incomprehensibly
       or omitted altogether.

       It is wise to quote multi-word section and subsection headings;
       the .SH and .SS macros of man(7) implementations descended from
       Seventh Edition Unix supported six arguments at most.  This
       restriction also applied to the .B, .I, .SM, and font style
       alternation macros.

       Exercise restraint with escape sequences as with requests.  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 escape sequences below must
       be used to render them correctly and portably when documenting
       material that uses them as literals—namely, any of the set ' - \
       ^ ` ~ (apostrophe, dash or hyphen-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 split
                 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
                 hyphenation breaks within except those specified with

       \:        Insert a non-printing break point.  A word can break at
                 such a point, but a hyphen glyph is not written to the
                 output if it does.  \: is an input word boundary, so
                 the remainder of the word is subject to hyphenation as
                 normal.  You can use \: and \% in combination to
                 control breaking of a file name or URI or to permit
                 hyphenation only after certain explicit hyphens within
                 a word.  See subsection “Hyperlink macros” above for an

                 \: is a GNU extension also supported by Heirloom
                 Doctools troff 050915 (September 2005), mandoc 1.13.1
                 (2014-08-10), and neatroff (commit 399a4936,
                 2014-02-17), but not by Plan 9, Solaris, or
                 Documenter's Workbench troffs.

       \~        Adjustable non-breaking space.  Use this escape
                 sequence to prevent a break inside a short phrase or
                 between a numerical quantity and its corresponding

                        Before starting the motor,
                        set the output speed to\~1.
                        There are 1,024\~bytes in 1\~KiB.
                        CSTR\~#8 documents the B\~language.

                 \~ is a GNU extension also supported by Heirloom
                 Doctools troff 050915 (September 2005), mandoc 1.9.14
                 (2009-11-16), neatroff (commit 1c6ab0f6e, 2016-09-13),
                 and Plan 9 from User Space troff (commit 93f8143600,
                 2022-08-12), but not by Solaris or Documenter's
                 Workbench troffs.

       \&        Dummy character.  Insert at the beginning of an input
                 line to prevent a dot or apostrophe from being
                 interpreted as beginning a roff control line.  Append
                 to an end-of-sentence punctuation sequence to keep it
                 from being recognized as such.

       \|        Thin space (one-sixth em on typesetters, zero-width on
                 terminals); a non-breaking space.  Used primarily in
                 ellipses (“.\|.\|.”) to space the dots more pleasantly
                 on typesetters like dvi, pdf, and ps.

       \c        End a text line without inserting space or attempting a
                 break.  Normally, if filling is enabled, the end of a
                 text line is treated like a space; an output line may
                 break there (if it does not, troff inserts an
                 adjustable space); if filling is disabled, the line
                 will break there, as in .EX/.EE examples.  The next
                 line is interpreted as usual and can include a macro
                 call (contrast with \newline).  \c is useful when three
                 font styles are needed in a single word, as in a
                 command synopsis.

                        .RB [ \-\-stylesheet=\c
                        .IR name ]

                 It also helps when changing font styles in .EX/.EE
                 examples, since they are not filled.

                        $ \c
                        .B groff \-T utf8 \-Z \c
                        .I file \c
                        .B | grotty \-i

                 Alternatively, and perhaps with better portability, the
                 \f font selection escape sequence can be used; see
                 below.  Using \c to continue a .TP paragraph tag across
                 multiple input lines will render incorrectly with groff
                 1.22.3, mandoc 1.14.1, older versions of these
                 programs, and perhaps with some other formatters.

       \e        Format the roff escape character on the output; widely
                 used in man pages to render a backslash 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 escape sequences 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

                 \fP reliably returns to the style in use immediately
                 preceding the previous \f escape sequence only if no
                 sectioning, paragraph, example, 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 escape sequences do.

       Several special characters are also widely portable.  Except for
       \-, \(em, and \(ga, AT&T troff did not consistently define the
       characters listed below, but its descendants, like Plan 9 or
       Solaris troff, can be made to support them by defining them in
       font description files, making them aliases of existing glyphs if
       necessary; see groff_font(5).  groff's extended notation for
       special characters, \[xx], is also supported by mandoc(1),
       Heirloom Doctools troff, and neatroff, but not Documenter's
       Workbench, Plan 9, or Solaris troff.

       \-     Minus sign.  \- produces the basic Latin hyphen-minus
              (U+002D) specifying Unix command-line options and
              frequently used in file names.  “-” is a hyphen in roff;
              some output devices format it as U+2010 (hyphen).

       \(aq   Basic Latin neutral apostrophe.  Some output devices
              format “'” as a right single quotation mark.

       \(cq   Opening (left) and closing (right) single quotation marks.
              Use these for paired directional single quotes, ‘like

       \(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.

                     .BI "split \(dq" text \(dq

       \(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

       \(en   En dash.  Use to separate the ends of a range,
              particularly between numbers; for example, “the digits

       \(ga   Basic Latin grave accent.  Some output devices format “`”
              as a left single quotation mark.

       \(ha   Basic Latin circumflex accent (“hat”).  Some output
              devices format “^” as U+02C6 (modifier letter circumflex

       \(rs   Reverse solidus (backslash).  The backslash is the default
              escape character in the roff language, so it does not
              represent itself in output.  Also see \e above.

       \(ti   Basic Latin tilde.  Some output devices format “~” as
              U+02DC (small tilde).

       For maximum portability, avoid escape sequences (including
       special characters) not listed above.

       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 presentation of .TH above describes
       the default headers and footers.  Because these macros are hooks
       for groff man internals, man pages have no reason to call them.
       Such hook definitions will likely consist of “.sp” and “.tl”
       requests.  They must also increase the page length with “.pl”
       requests in continuous rendering mode; .PT furthermore has the
       responsibility of emitting a PDF bookmark after writing the first
       page header in a document.  Consult the existing implementations
       in an.tmac when drafting replacements.

       .BT    Set the page footer text (“bottom trap”).

       .PT    Set the page header text (“page trap”).

       To remove a page header or footer entirely, define the
       appropriate macro as empty rather than deleting it.

   Deprecated features
       Use of the following in man pages for public distribution is

       .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 to render man pages from
              historical systems.

              The inside footer is populated per the value of system.

                     3      7th edition (default)

                     4      System III

                     5      System V

              The optional release argument specifies the release
              number, as in “System V Release 3”.

       .DT    Reset tab stops to the default (every 0.5i [inches]).

              Use of this presentation-oriented 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 tab stops to
              express are likely to be lost.  If you feel tempted to
              change the tab stops such that calling this macro later to
              restore them is desirable, consider composing a table
              using tbl(1) instead.

       .HP [indentation]
              Set up a paragraph with a hanging left indentation.
              indentation, if present, is handled as with .TP.

              Use of this presentation-oriented macro is deprecated.  A
              hanging indentation cannot be expressed naturally in HTML,
              a hanging paragraph is not distinguishable from an
              ordinary one if it formats on only one output line, and
              non-roff-based man page interpreters may treat .HP as an
              ordinary paragraph.  Thus, information or distinctions you
              mean to express with indentation may be lost.

       .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.

              Use of this quasi-semantic macro, an extension originating
              in Documenter's Workbench troff, is deprecated.  It cannot
              easily be used to annotate options that take optional
              arguments or options whose arguments have internal
              structure (such as a mixture of literal and variable
              components).  One could work around these limitations with
              font selection escape sequences, but it is preferable to
              use font style alternation macros, which afford greater

       .PD [vertical-space]
              Configure the amount of vertical space between paragraphs
              or (sub)sections.  The optional argument vertical-space
              specifies the amount; the default scaling unit is “v”.
              Without an argument, the spacing is reset to its default
              value; see subsection “Horizontal and vertical spacing”

              Use of this presentation-oriented 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.

       .SB [text]
              Set text in bold and (on typesetters) one point smaller
              than the default type size.  If no argument is given, the
              macro plants a one-line input trap; text on the next line,
              which can be further formatted with a macro, is set
              smaller and in bold.  Use of this macro, an extension
              originating in SunOS 4.0 troff, is deprecated.  .SM
              without an argument, followed immediately by “.B text”,
              produces the same output more portably.  The macros' order
              is interchangeable; put text with the latter.

              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

       .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 to render man pages from
              historical systems.

              The inside footer is populated per the value of version.

                     3      3rd Berkeley Distribution (default)

                     4      4th Berkeley Distribution

                     5      4.2 Berkeley Distribution

                     6      4.3 Berkeley Distribution

                     7      4.4 Berkeley Distribution

       M. Douglas McIlroy ⟨⟩ designed,
       implemented, and documented the AT&T man macros for Unix
       Version 7 (1979) and employed them to edit the first volume of
       its Programmer's Manual, a compilation of all man pages supplied
       by the system.  That man supported the macros listed in this page
       not described as extensions, except .P and the deprecated .AT and
       .UC.  The only strings defined were R and S; no registers were

       .UC appeared in 3BSD (1980).  Unix System III (1980) introduced
       .P and exposed the registers IN and LL, which had been internal
       to Seventh Edition Unix man.  PWB/UNIX 2.0 (1980) added the Tm
       string.  4BSD (1980) added lq and rq strings.  SunOS 2.0 (1985)
       recognized C, D, P, and X registers.  4.3BSD (1986) added .AT and
       .P.  Ninth Edition Unix (1986) introduced .EX and .EE.  SunOS 4.0
       (1988) added .SB.

       James Clark implemented the foregoing features in early versions
       of groff.  Later, groff 1.20 (2009) originated .SY/.YS, .TQ,
       .MT/.ME, and .UR/.UE.  Plan 9 from User Space's troff introduced
       .MR in 2020.

Options         top

       The following groff options set registers (with -r) and strings
       (with -d) recognized and used by the man macro package.  To
       ensure rendering consistent with output device capabilities and
       reader preferences, man pages should never manipulate them.

              Set line adjustment to adjustment-mode, which is typically
              “b” for adjustment to both margins (the default), or “l”
              for left alignment (ragged right margin).  Any valid
              argument to groff's “.ad” request may be used.  See
              groff(7) for less-common choices.

              Set the inset amount for ordinary paragraphs not within an
              .RS/.RE inset.  The default is 5n.

       -rcR=1 Enable continuous rendering.  Output is not paginated;
              instead, one (potentially very long) page is produced.
              This is the default for terminal and HTML devices.  Use
              -rcR=0 to disable it on terminals; on HTML devices, it
              cannot be disabled.

       -rC1   Number output pages consecutively, in strictly increasing
              sequence, rather than resetting the page number to 1 (or
              the value of register P) with each new man document.

       -rCS=1 Set section headings (the argument(s) to .SH) in full
              capitals.  This transformation is off by default because
              it discards case distinction information.

       -rCT=1 Set the man page identifier (the first argument to .TH) in
              full capitals in headers and footers.  This transformation
              is off by default because it discards case distinction

       -rD1   Enable double-sided layout, formatting footers for even
              and odd pages differently; see the description of .TH in
              subsection “Document structure macros” above.

              Set distance of the footer relative to the bottom of the
              page to footer-distance; this amount is always negative.
              At one half-inch above this location, the page text is
              broken before writing the footer.  Ignored if continuous
              rendering is enabled.  The default is “-0.5i - 1v”.

              Select the font used for section and subsection headings;
              the default is “B” (bold style of the default family).
              Any valid argument to groff's “.ft” request may be used.
              See groff(7).

       -rHY=0 Disable automatic hyphenation.  Normally, it is
              enabled (1).  The hyphenation mode is determined by the
              groff locale; see section “Localization“ of groff(7).

              Set the default indentation amount used by .IP, .TP, and
              the deprecated .HP, and the inset amount used by .RS.  The
              default is 7n on terminals and 7.2n on typesetters.  Use
              only integer multiples of unit “n” on terminals for
              consistent indentation.

              Set line length; the default is 80n on terminals and 6.5i
              on typesetters.

              Set the line length for titles.  (“Titles” is the roff
              term for headers and footers.)  By default, it is set to
              the line length (see -rLL above).

              Select the font used for man page identifiers in .TH calls
              and topics named in .MR calls; the default is “I” (italic
              style of the default family).  Any valid argument to
              groff's “.ft” request may be used.  If the MF string ends
              in “I”, it is assumed to be an oblique typeface, and
              italic corrections are applied before and after man page
              topics and identifiers.

       -rPn   Start enumeration of pages at n.  The default is 1.

              Set page offset; the default is 0 on terminals and 1i on

              Use type-size for the document's body text; acceptable
              values are 10, 11, or 12 points.  See subsection “Font
              style macros” above for the default.

              Set indentation of subsection headings to subsection-
              indentation.  The default is 3n.

              Require the given separation between a TP paragraph's tag
              and its body.  The default is 2n.

       -rU0   Disable generation of URI hyperlinks in output drivers
              capable of them, making the arguments to MT and UR calls
              visible as formatted text.  grohtml(1), gropdf(1), and
              grotty(1) enable hyperlinks by default (the last only if
              not in legacy output mode).

       -rXp   Number successors of page p as pa, pb, pc, and so forth.
              The register tracking the suffixed page letter uses format
              “a” (see the “.af” request in groff(7)).  For example, the
              option -rX2 produces the following page numbers: 1, 2, 2a,
              2b, ..., 2aa, 2ab, and so on.

Files         top

              Most man macros are defined in this file.  It also loads
              extensions from an-ext.tmac (see below).

              This brief groff program detects whether the man or mdoc
              macro package is being used by a document and loads the
              correct macro definitions, taking advantage of the fact
              that pages using them must call .TH or .Dd, respectively,
              before any other macros.  A man program or a user typing,
              for example, “groff -mandoc page.1”, need not know which
              package the file page.1 uses.  Multiple man pages, in
              either format, can be handled; andoc reloads each macro
              package as necessary.  Page-local redefinitions of names
              used by the man or mdoc packages prior to .TH or .Dd calls
              will be “clobbered” by the reloading process.  If you want
              to provide your own definition of an extension macro to
              ensure its availability, the an-ext.tmac entry below
              offers advice.

              Definitions of macros described above as extensions (and
              not deprecated) are contained in this file; in some cases,
              they are simpler versions of definitions appearing in
              an.tmac, and are ignored if the formatter is GNU troff.
              They are written to be compatible with AT&T troff and
              permissively licensed—not copylefted.  To reduce the risk
              of name space collisions, string and register names begin
              only with “m.  We encourage man page authors who are
              concerned about portability to legacy Unix systems to copy
              these definitions into their pages, and maintainers of
              troff implementations or work-alike systems that format
              man pages to re-use them.  To ensure reliable rendering,
              define them after your page calls .TH; see the discussion
              of andoc.tmac above.  Further, it is wise to define such
              page-local macros (if at all) after the “Name” section to
              accommodate timid makewhatis(8) or mandb(8)
              implementations that easily give up scanning for indexing

              is a wrapper enabling the package to be loaded with the
              option “-m man”.

              is a wrapper enabling andoc.tmac to be loaded with the
              option “-m mandoc”.

              Put site-local changes and customizations into this file.

                     .\" Put only one space after the end of a sentence.
                     .ss 12 0 \" See groff(7).
                     .\" Keep pages narrow even on wide terminals.
                     .if n .if \n[LL]>80n .nr LL 80n

              On multi-user systems, it is more considerate to users
              whose preferences may differ from the administrator's to
              be less aggressive with such settings, or to permit their
              override with a user-specific man.local file.  Place the
              requests below at the end of the site-local file to
              manifest courtesy.
                     .soquiet \V[XDG_CONFIG_HOME]/man.local
                     .soquiet \V[HOME]/.man.local
              However, a security-sandboxed man(1) program may lack
              permission to open such files.

Notes         top

       Some tips on composing and troubleshooting your man pages follow.

       • What's the difference between a man page topic and identifier?

         A single man page may document several related but distinct
         topics.  For example, printf(3) and fprintf(3) are often
         presented together.  Further, multiple programming languages
         have functions named “printf”, and may document these in a man
         page.  The identifier is intended to (with the section)
         uniquely identify a page on the system; it may furthermore
         correspond closely to the file name of the document.

         The man(1) librarian makes access to man pages convenient by
         resolving topics to man page identifiers.  Thus, you can type
         “man fprintf”, and other pages can refer to it, without knowing
         whether the installed document uses “printf”, “fprintf”, or
         even “c_printf” as an identifier.

       • Some ASCII characters look funny or copy and paste wrong.

         On devices with large glyph repertoires, like UTF-8-capable
         terminals and PDF, several keyboard glyphs are mapped to code
         points outside the Unicode basic Latin range because that
         usually results in better typography in the general case.  When
         documenting GNU/Linux command or C language syntax, however,
         this translation is sometimes not desirable.

         To get a “literal”...   ...should be input.
                             '   \(aq
                             -   \-
                             \   \(rs
                             ^   \(ha
                             `   \(ga
                             ~   \(ti

         Additionally, if a neutral double quote (") is needed in a
         macro argument, you can use \(dq to get it.  You should not use
         \(aq for an ordinary apostrophe (as in “can't”) or \- for an
         ordinary hyphen (as in “word-aligned”).  Review subsection
         “Portability” above.

       • Do I ever need to use an empty macro argument ("")?

         Probably not.  When this seems necessary, often a shorter or
         clearer alternative is available.

                Instead of...               ...should be considered.
         .TP ""                         .TP
         .BI "" italic-text bold-text   .IB italic-text bold-text
         .TH foo 1 "" "foo 1.2.3"       .TH foo 1 yyyy-mm-dd "foo 1.2.3"
         .IP "" 4n                      .IP
         .IP "" 4n                      .RS 4n
         paragraph                      .P
         ...                            paragraph
         ...                            .RE
         .B one two "" three            .B one two three

         In the title heading (.TH), the date of the page's last
         revision is more important than packaging information; it
         should not be omitted.  Ideally, a page maintainer will keep
         both up to date.

         .IP is sometimes ill-understood and misused, especially when no
         mark argument is supplied—an indentation argument is not
         required.  By setting an explicit indentation, you may be
         overriding the reader's preference as set with the -rIN option.
         If your page renders adequately without one, use the simpler
         form.  If you need to indent multiple (unmarked) paragraphs,
         consider setting an inset region with .RS and .RE instead.

         In the last example, the empty argument does have a subtly
         different effect than its suggested replacement: the empty
         argument causes an additional space character to be
         interpolated between the arguments “two” and “three”—but it is
         a regular breaking space, so it can be discarded at the end of
         an output line.  It is better not to be subtle, particularly
         with space, which can be overlooked in source and rendered

       • .RS doesn't indent relative to my indented paragraph.

         The .RS macro determines the inset amount, the position at
         which an ordinary paragraph (.P and its synonyms) will be set;
         the value of the IN register determines its default amount.
         This register also determines the default indentation used by
         .IP, .TP, and the deprecated .HP.  To create an inset relative
         to an indented paragraph, call .RS repeatedly until an
         acceptable indentation is achieved, or give .RS an indentation
         argument that is at least as much as the paragraph's
         indentation amount relative to an adjacent ordinary (.P)

         Another approach to tagged paragraphs places an .RS call
         immediately after the tag; this will also force a break
         regardless of the tag's width, which some authors prefer.
         Follow-up paragraphs under the tag can then be set with .P
         instead of .IP.  Remember to use .RE to end the indented region
         before starting the next tagged paragraph (at the appropriate
         nesting level).

       • .RE doesn't move the inset back to the expected level.

         The .RS macro takes an inset amount as an argument; the .RE
         macro's argument is an inset level.  .RE 1 goes to the level
         before any .RS macros were called, .RE 2 goes to the level of
         the first .RS call you made, and so forth.  If you desire
         symmetry in your macro calls, simply issue one .RE without an
         argument for each .RS that precedes it.

         Calling the .SH or .SS sectioning macros clears all relative
         insets and .RE calls have no effect until .RS is used again.

       • Do I need to keep typing the indentation in a series of .IP

         Not if you don't want to change it.  Review subsection
         “Horizontal and vertical spacing” above.

           Instead of...     ...should be considered.
         .IP \(bu 4n         .IP \(bu 4n
         paragraph           paragraph
         .IP \(bu 4n         .IP \(bu
         another-paragraph   another-paragraph

       • Why doesn't the package provide a string to insert an ellipsis?

         Examples of ellipsis usage are shown above, in subsection
         “Synopsis macros”.  The idiomatic roff ellipsis is three dots
         (periods) with thin space escape sequences \| internally
         separating them.  Since dots both begin control lines and are
         candidate end-of-sentence characters, however, it is sometimes
         necessary to prefix and/or suffix an ellipsis with the dummy
         character escape sequence \&.  That fact stands even if a
         string is defined to contain the sequence; further, if the
         string ends with \&, end-of-sentence detection is defeated when
         you use the string at the end of an actual sentence.  (Ending a
         sentence with an ellipsis is often poor style, but not always.)
         A hypothetical string EL that contained an ellipsis, but not
         the trailing dummy character \&, would then need to be suffixed
         with the latter when not ending a sentence.

             Instead of...     this.
         .ds EL \&.\|.\|.         Arguments are
         Arguments are            .IR src-file\~ .\|.\|.\&
         .IR src-file\~ \*(EL\&   .IR dest-dir .
         .IR dest-dir .

         The first column practices a false economy; the savings in
         typing is offset by the cost of obscuring even the suggestion
         of an ellipsis to a casual reader of the source document, and
         reduced portability to non-roff man page formatters that cannot
         handle string definitions.

         There is an ellipsis code point in Unicode, and some fonts have
         an ellipsis glyph, which some man pages have accessed in a non-
         portable way with the font-dependent \N escape sequence.  We
         discourage the use of these; on terminals, they may crowd the
         dots into a half-width character cell, and will not render at
         all if the output device doesn't have the glyph.  In syntax
         synopses, missing ellipses can mislead the reader.  Dots and
         space are universally supported.

Authors         top

       The initial GNU implementation of the man macro package was
       written by James Clark.  Later, Werner Lemberg ⟨⟩
       supplied the S, LT, and cR registers, the last a 4.3BSD-Reno
       mdoc(7) feature.  Larry Kollar ⟨⟩ added the FT,
       HY, and SN registers; the HF string; and the PT and BT macros.
       G. Branden Robinson ⟨⟩ implemented
       the AD and MF strings; BP, CS, CT, PO, TS, and U registers; and
       the MR macro.  Extension macros since groff 1.20 were written by
       Lemberg, Eric S. Raymond ⟨⟩, and Robinson.

       This document was originally written for the Debian GNU/Linux
       system by Susan G. Kleinmann ⟨⟩.  It was corrected
       and updated by Lemberg and Robinson.  The extension macros were
       documented by Raymond and Robinson.  Raymond also originated the
       portability section, to which Ingo Schwarze ⟨⟩
       contributed most of the material on escape sequences.

See also         top

       tbl(1), eqn(1), and refer(1) are preprocessors used with man
       pages.  man(1) describes the man page librarian on your system.
       groff_mdoc(7) details the groff version of the BSD-originated
       alternative macro package for man pages.

       groff_man(7), groff(7), groff_char(7)

COLOPHON         top

       This page is part of the groff (GNU troff) project.  Information
       about the project can be found at 
       ⟨⟩.  If you have a bug report
       for this manual page, see ⟨⟩.
       This page was obtained from the project's upstream Git repository
       ⟨⟩ on 2024-06-14.  (At
       that time, the date of the most recent commit that was found in
       the repository was 2024-06-10.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
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       (which is not part of the original manual page), send a mail to

groff   6 June 2024            groff_man_style(7)