Provided by: groff_1.23.0-2_amd64 bug

Name

       groff_man_style - GNU roff man page tutorial and style guide

Synopsis

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

Description

       The  GNU  implementation of the man macro package is part of the groff document formatting
       system.  It is used to produce manual pages (“man pages”) like the one you are reading.

       This document presents the macros thematically; for those needing only a quick  reference,
       the  following  table  lists  them  alphabetically,  with  cross references to appropriate
       subsections below.

       Macro   Meaning                      Subsection
       ───────────────────────────────────────────────────────────────
       .B      Bold                         Font style macros
       .BI     Bold, italic alternating     Font style macros
       .BR     Bold, roman alternating      Font style macros
       .EE     Example end                  Document structure macros
       .EX     Example begin                Document structure macros
       .I      Italic                       Font style macros
       .IB     Italic, bold alternating     Font style macros
       .IP     Indented paragraph           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
       .SB     Small bold                   Font style macros
       .SH     Section heading              Document structure macros
       .SM     Small                        Font style macros
       .SS     Subsection heading           Document structure macros
       .SY     Synopsis start               Command synopsis macros
       .TH     Title heading                Document structure macros
       .TP     Tagged paragraph             Paragraphing macros
       .TQ     Supplemental paragraph tag   Paragraphing macros
       .UE     URI end                      Hyperlink macros
       .UR     URI start                    Hyperlink macros
       .YS     Synopsis end                 Command synopsis macros

       We discuss other macros (.AT, .DT, .HP, .OP,  .PD,  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.

       Man  pages should be encoded using Unicode basic Latin code points exclusively, and employ
       the Unix line-ending convention (U+000A only).

   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 line length (see the -dAD option).  roff(7)
       details these processes.

       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.  We refer to macros in this
       document using this leading dot.  Some macros interpret arguments, words that  follow  the
       macro name.  A newline, unless escaped (see subsection “Portability” below), marks the end
       of the macro call.  An input line consisting of a dot followed by a newline is called  the
       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 topic.  Subsection headings (.SS)  are
       optional  and  permit  sections  that  grow  long  to  develop  in a controlled way.  Many
       technical discussions benefit from examples; lengthy  ones,  especially  those  reflecting
       multiple  lines  of  input to or output from the system, are usefully bracketed by .EX and
       .EE.  When none of the foregoing meets a structural demand, use .RS/.RE to inset a  region
       within a (sub)section.

       .TH topic section [footer-middle] [footer-inside] [header-middle]
              Determine  the contents of the page header and footer.  roff systems refer to these
              collectively as “titles”.  The subject of the man page is topic and the section  of
              the manual to which it belongs is section.  This use of “section” has nothing to do
              with the section headings otherwise discussed in this  page;  it  arises  from  the
              organizational  scheme  of  printed and bound Unix manuals.  See man(1) or intro(1)
              for the manual sectioning  applicable  to  your  system.   topic  and  section  are
              positioned  together  at  the  left  and  right  in  the  header  (with  section in
              parentheses immediately appended to  topic).   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  topic  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.  The macro package may also abbreviate topic and
              footer-inside with ellipses (...) if they would overrun the space available in  the
              header  and  footer,  respectively.   For  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 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, a one-line input
              trap is planted; text on the next line becomes heading-text.  The  left  margin  is
              reset  to zero to set the heading text in bold (or the font specified by the string
              HF), and, on typesetting devices, 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,  setting  the  left margin to the value of the IN register.  Text after heading-
              text is set as an ordinary paragraph (.P).

              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 to be properly indexed.  See man(7) for the conventions prevailing
              on your system.

       .SS [subheading-text]
              Set subheading-text as a subsection heading indented between a section heading  and
              an  ordinary  paragraph  (.P).   If  no argument is given, a one-line input trap is
              planted; text on the next line becomes subheading-text.  The left margin  is  reset
              to  the  value  of  the  SN  register  to set the heading text 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, setting the left margin to  the  value
              of  the  IN  register.   Text after subheading-text is set as an ordinary paragraph
              (.P).

       .EX
       .EE    Begin and end example.   After  .EX,  filling  is  disabled  and  a  constant-width
              (monospaced)  font  is  selected.   Calling  .EE  enables  filling and restores the
              previous font.

              Example regions are useful for formatting  code,  shell  sessions,  and  text  file
              contents.  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  ~, and 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.

              These macros are extensions introduced in Ninth  Edition  Research  Unix.   Systems
              running  that  troff,  or  those from Documenter's Workbench, Heirloom Doctools, or
              Plan 9 troff support them.  To be certain your page will  be  portable  to  systems
              that  do  not,  copy  their  definitions  from  the  an-ext.tmac  file  of  a groff
              installation.

       .RS [inset-amount]
              Start a new relative inset level.  The position of the left margin is  saved,  then
              moved  right  by  inset-amount,  if specified, 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 [level]
              End  a  relative  inset.   The  left  margin  corresponding to inset level level is
              restored.  If no argument is given, the inset level is reduced by 1.

   Paragraphing macros
       An ordinary paragraph (.P) like this one is set without a first-line  indentation  at  the
       current  left  margin.   In man pages and other technical literature, definition lists are
       frequently encountered; these can be set as “tagged paragraphs”, which have one  (.TP)  or
       more  (.TQ)  leading tags followed by a paragraph that has an additional indentation.  The
       indented paragraph (.IP) macro is useful to continue the indented content of  a  narrative
       started  with  .TP,  or to present an itemized or ordered list.  All 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.

       .P
       .LP
       .PP    Begin a new paragraph; these macros are synonymous.  The indentation  is  reset  to
              the default value; the left margin, as affected by .RS and .RE, is not.

       .TP [indentation]
              Set a paragraph with a leading tag, and the remainder of the paragraph indented.  A
              one-line input trap is planted; text on the next line, which can be formatted  with
              a  macro, becomes the tag, which is placed at the current left margin.  The tag can
              be  extended  with  the  \c  escape  sequence.   Subsequent  text  is  indented  by
              indentation,  if specified, and by the amount of the IN register otherwise.  If the
              tag is not as wide as the indentation, the paragraph starts on the same line as the
              tag,  at  the  applicable  indentation,  and  continues  on  the  following  lines.
              Otherwise, the descriptive part of the paragraph begins on the line  following  the
              tag.

              The  line  containing the tag can include a macro call, for instance to set the tag
              in bold with .B.  .TP was used to write the first paragraph of this description  of
              .TP, and .IP the subsequent one.

       .TQ    Set an additional tag for a paragraph tagged with .TP.  An input trap is planted as
              with .TP.

              This macro is a GNU extension not defined on  systems  running  AT&T,  Plan  9,  or
              Solaris troff; see an-ext.tmac in section “Files” below.

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

       .IP [tag] [indentation]
              Set an indented paragraph with an optional tag.  The tag and indentation arguments,
              if present, are handled as with .TP, with the exception that the  tag  argument  to
              .IP cannot include a macro call.

              Two convenient uses for .IP are

                  (1) to  start  a  new  paragraph  with  the  same indentation as an immediately
                      preceding .IP or .TP paragraph, if no indentation argument is given; and

                  (2) to set a paragraph with a short tag that  is  not  semantically  important,
                      such  as  a  bullet  (•)—obtained  with  the  \(bu special character escape
                      sequence—or list enumerator, as seen in this very paragraph.

   Command synopsis macros
       .SY and .YS aid  you  to  construct  a  command  synopsis  that  has  the  classical  Unix
       appearance.  They break the output line.

       These  macros  are  GNU extensions not defined on systems running AT&T, Plan 9, or Solaris
       troff; see an-ext.tmac in section “Files” below.

       .SY command
              Begin synopsis.  A new paragraph begins at the left margin (as with .P) unless  .SY
              has  already been called without a corresponding .YS, in which case only a break is
              performed.  Adjustment and automatic hyphenation are disabled.  command is  set  in
              bold.   If  a break is required, lines after the first are indented by the width of
              command plus a space.

       .YS    End synopsis.  Indentation, adjustment,  and  hyphenation  are  restored  to  their
              previous states.

       Multiple  .SY/.YS  blocks can be specified, for instance to distinguish differing modes of
       operation of a  complex  command  like  tar(1);  each  will  be  vertically  separated  as
       paragraphs are.

       .SY  can  be repeated before .YS to indicate synonymous ways of invoking a particular mode
       of operation.

       groff's own command-line interface serves to illustrate most of the specimens of  synopsis
       syntax one is likely to encounter.

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

       produces the following output.

              groff [-abcCeEgGijklNpRsStUVXzZ] [-d cs] [-d name=string] [-D enc] [-f fam]
                    [-F dir] [-I dir] [-K enc] [-L arg] [-m name] [-M dir] [-n num] [-o list]
                    [-P arg] [-r cn] [-r reg=expr] [-T dev] [-w name] [-W name] [file ...]

              groff -h
              groff --help

              groff -v [option ...] [file ...]
              groff --version [option ...] [file ...]

       Several features of the above example are of note.

       • The  empty  request  (.), which does nothing, is used to vertically space 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 text.

       • Symbols that are neither to be typed literally nor replaced  at  the  user's  discretion
         appear  in  the  roman  style;  brackets  surround  optional  arguments, and an ellipsis
         indicates that the previous syntactical element may be repeated arbitrarily.

       • The non-breaking adjustable space escape sequence \~ is used to prevent the output  line
         from being broken within the option brackets; 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.

   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.  Hyperlinked text is supported
       on HTML and terminal output devices; 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 not defined on systems running AT&T, Plan 9, or
       Solaris troff; see an-ext.tmac in section “Files” below.  Plan 9 from User  Space's  troff
       implements .MR.

       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\:.com/\:fb8afcfbaebc74e\:.cc
       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
              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.  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
                     output.
                     .
                     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,

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

              displays as “Contact Fred Foonly ⟨fred.foonly@fubar.net⟩ 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\:.org/\:software/\:groff/
                     .I groff
                     home page
                     .UE .

              displays  as  “The GNU Project of the Free Software Foundation hosts the groff home
              page ⟨https://www.gnu.org/software/groff/⟩.”.

       The hyperlinking of .TP paragraph tags with .UR/.UE and .MT/.ME is not yet  supported;  if
       attempted,  the  hyperlink will be typeset at the beginning of the indented paragraph even
       on hyperlink-supporting devices.

   Font style macros
       The man macro package is limited in its font styling options,  offering  only  bold  (.B),
       italic  (.I),  and  roman.   Italic  text  is  usually set underscored instead on terminal
       devices.  The .SM and .SB macros set text in roman or bold,  respectively,  at  a  smaller
       type size; these differ visually from regular-sized roman or bold text only on typesetting
       devices.  It is often necessary to set text in different styles without intervening space.
       The  macros  .BI,  .BR,  .IB,  .IR,  .RB,  and .RI, where “B”, “I”, and “R” indicate bold,
       italic, and roman, respectively, set their odd- and even-numbered arguments in alternating
       styles, with no space separating them.

       Because  font  styles are presentational rather than semantic, conflicting traditions have
       arisen regarding which font styles should be used to mark file or path names,  environment
       variables, and inlined literals.

       The  default type size and family for typesetting devices 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, a one-line input trap is planted;  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, a one-line input
              trap is planted; 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 material.

       .SM [text]
              Set text one point smaller than the default type size on typesetting  devices.   If
              no  argument  is  given,  a  one-line input trap is planted; 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.

       .SB [text]
              Set text in bold and (on typesetting devices) one point smaller  than  the  default
              type  size.  If no argument is given, a one-line input trap is planted; text on the
              next line, which can be further formatted with a macro, is set smaller and in bold.
              This macro is an extension introduced in SunOS 4.0.

              Note:  terminals  will render text in bold at the normal size instead.  Do not rely
              upon .SB to communicate semantic information distinct  from  using  bold  style  at
              normal size; it will be hidden from readers using such devices.

       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.  Italic  corrections  are  applied  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.

                     After
                     .B .NH
                     is called,

       .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.

                     if
                     .I file
                     is
                     .RB \[lq] \- \[rq],
                     the standard input stream is read.

       .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
       The indentation argument accepted by .IP, .TP, and the deprecated .HP is a number plus  an
       optional  scaling  unit,  as  is .RS's inset-amount.  If no scaling unit is given, the man
       package assumes “n”; that is, the width of a letter “n” in the font current when the macro
       is called (see section “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 left margin used by ordinary paragraphs set with .P (and its synonyms) not  within  an
       .RS/.RE  relative  inset  is 7.2n for typesetting devices and 7n for terminal devices (but
       see the -rIN option).  Headers, footers (both set with .TH), and  section  headings  (.SH)
       are  set  at the page offset (see groff(7)) and subsection headings (.SS) indented from it
       by 3n (but see the -rSN option).

       It may be helpful to think of the left margin and  indentation  as  related  but  distinct
       concepts;  groff's  implementation  of  the man macro package tracks them separately.  The
       left margin is manipulated by .RS and .RE (and by .SH and  .SS,  which  reset  it  to  the
       default).   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 (in other words, moved the left  margin)  with
              .RS and started another ordinary paragraph with .P.

              tag    This  tagged  paragraph,  set  with .TP, is still within the .RS region, but
                     lines after the first have a supplementary indentation that the tag lacks.

                     A paragraph like this one, set with .IP, will appear to the reader  as  also
                     associated  with the tag above, because .IP re-uses the previous paragraph's
                     indentation unless given an  argument  to  change  it.   This  paragraph  is
                     affected both by the moved left margin (.RS) and indentation (.IP).

                     ┌─────────────────────────────────┐
                     │This table is affected both by   │
                     │the left margin and indentation. │
                     └─────────────────────────────────┘
              •      This  indented paragraph has a bullet for a tag, making it more obvious that
                     the left margin and indentation are distinct; only the  former  affects  the
                     tag, but both affect the text of the paragraph.

              This  ordinary  (.P) paragraph resets the indentation, but the left margin is still
              inset.

              ┌────────────────────────────┐
              │This table is affected only │
              │by the left margin.         │
              └────────────────────────────┘
       Finally, we have ended the relative inset by using .RE, which (because we  used  only  one
       .RS/.RE pair) has reset the left margin to the default.  This is an ordinary .P paragraph.

       Resist the temptation to mock up tabular or multi-column output with tab characters or the
       indentation arguments to .IP, .TP, .RS, or the deprecated .HP; the result may  not  render
       comprehensibly on an output device you fail to check, or which is developed in the future.
       The table preprocessor tbl(1) can likely meet your needs.

       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 is 1v for
       terminal devices and 0.4v for typesetting devices (“v” is a  unit  of  vertical  distance,
       where  1v  is  the  distance between adjacent text baselines in a single-spaced document).
       (The deprecated macro .PD can change this vertical spacing, but its use  is  discouraged.)
       Between .EX and .EE calls, the inter-paragraph spacing is 1v regardless of output device.

   Registers
       Registers  are  described  in  section  “Options”  below.  They can be set not only on the
       command line but in the site man.local file as well; see section “Files” below.

   Strings
       The following strings are defined  for  use  in  man  pages.   Others  are  supported  for
       configuration of rendering parameters; see section “Options” below.

       \*R    interpolates  a  special character escape sequence for the “registered sign” glyph,
              \(rg, if available, and “(Reg.)” otherwise.

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

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

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

       None of the above is necessary in a contemporary man page.  \*S is superfluous, since type
       size  changes  are  invisible  on  terminal  devices and macros that change it restore its
       original value afterward.  Better alternatives exist for the rest; simply  use  the  \(rg,
       \(lq,  \(rq,  and  \(tm  special  character  escape sequences directly.  Unless a man page
       author is aiming for a pathological level of portability, such as the composition of pages
       for  consumption  on  simulators  of  1980s Unix systems (or Solaris troff, though even it
       supports \(rg), the above strings should be avoided.

   Portability
       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.  A similar restriction applied to the  .B,  .I,  .SM,  and  font  style  alternation
       macros.

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

       However, using raw groff requests (apart from the empty request “.”)  is  likely  to  make
       your  page render poorly when processed by other tools; many of these attempt to interpret
       page sources directly for conversion to HTML.  Some  requests  make  implicit  assumptions
       about things like character and page sizes that may not hold in an HTML environment; also,
       many of these viewers don't interpret the full groff vocabulary, a problem that  can  lead
       to portions of your text being omitted or presented incomprehensibly.

       For  portability  to  modern viewers, it is best to write your page solely with the macros
       described in this page (except for the ones identified  as  deprecated,  which  should  be
       avoided).   The  macros  we  have described as extensions (.EX/.EE, .SY/.YS, .TQ, .UR/.UE,
       .MT/.ME, .MR, and .SB) should be used with caution, as they may not be built  in  to  some
       viewer that is important to your audience.  See an-ext.tmac in section “Files” below.

       Similar caveats apply to escape sequences.  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 syntactically—namely, any of the set ' - \ ^ ` ~ (apostrophe, dash
       or minus, backslash, caret, grave accent, tilde).

       \"     Comment.   Everything  after  the  double-quote  to  the  end  of the input line is
              ignored.  Whole-line comments should be placed immediately after the empty  request
              (“.”).

       \newline
              Join  the  next  input line to the current one.  Except for the update of the input
              line counter (used for diagnostic messages and related purposes), a series of lines
              ending  in  backslash-newline  appears  to  groff as a single input line.  Use this
              escape sequence to 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.  This escape sequence  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 example.

              This escape sequence is a groff extension also supported by Heirloom Doctools troff
              050915 (September 2005), mandoc 1.14.5 (2019-03-10), 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 unit(s).

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

              This escape sequence is a groff extension also supported by Heirloom Doctools troff
              050915 (September 2005), mandoc 1.9.5  (2009-09-21),  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 typesetting devices 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 be broken there (if not, an  adjustable  space  is  inserted);  if  filling  is
              disabled,  the line will be broken 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.

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

              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 current 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 implementation.

              \fP reliably returns to the style in use  immediately  preceding  the  previous  \f
              escape  sequence  only  if  no  sectioning,  paragraph,  or  style macro calls have
              intervened.

              As long as at most two styles are needed in a word, style macros like  .B  and  .BI
              usually result in more readable roff source than \f 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).

       \-     Minus sign or basic Latin hyphen-minus.  This escape  sequence  produces  the  Unix
              command-line option dash in the output.  “-” is a hyphen in the roff language; some
              output devices replace it with U+2010 (hyphen) or similar.

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

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

       \(dq   Basic Latin quotation mark (double quote).  Use in macro calls to prevent ‘"”  from
              being interpreted as beginning a quoted argument, or simply for readability.

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

       \(lq
       \(rq   Left  and  right  double  quotation marks.  Use these for paired directional double
              quotes, “like this”.

       \(em   Em-dash.  Use for an interruption—such as this one—in a sentence.

       \(en   En-dash.  Use to separate the ends of a range, particularly  between  numbers;  for
              example, “the digits 1–9”.

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

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

       \(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)  or
              similar.

       For  maximum  portability,  escape  sequences  and special characters not listed above are
       better avoided in man pages.

   Hooks
       Two macros, both GNU extensions, are called internally by the groff man package to  format
       page  headers  and footers and can be redefined by the administrator in a site's man.local
       file (see section “Files” below).  The 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 discouraged.

       .AT [system [release]]
              Alter  the  footer for use with legacy AT&T man pages, overriding any definition of
              the footer-inside argument to .TH.  This macro exists only to render man pages from
              historical systems.

              system can be any of the following.

                     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 is desirable to restore them, you should probably be composing a table  using
              tbl(1) instead.

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

              Use of this presentation-oriented  macro  is  deprecated.   A  hanging  indentation
              cannot  be expressed naturally under HTML, 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 flexibility.

       .PD [vertical-space]
              Define  the  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” above.

              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.

       .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.

              version can be any of the following.

                     3      3rd Berkeley Distribution (default)

                     4      4th Berkeley Distribution

                     5      4.2 Berkeley Distribution

                     6      4.3 Berkeley Distribution

                     7      4.4 Berkeley Distribution

   History
       M. Douglas McIlroy ⟨m.douglas.mcilroy@dartmouth.edu⟩ 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
       documented.

       .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
       Research Unix (1986) introduced .EX and .EE.  SunOS 4.0 (1988) added .SB.

       The foregoing features were what James Clark  implemented  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

       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.

       -dAD=adjustment-mode
              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.

       -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  terminal  devices;  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 topic (the first argument to .TH) in full capitals in headers and
              footers.   This  transformation  is  off  by  default  because  it  discards   case
              distinction information.

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

       -rFT=footer-distance
              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.

       -dHF=heading-font
              Set  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).

       -rIN=standard-indentation
              Set the amount of indentation used for ordinary paragraphs (.P  and  its  synonyms)
              and  the  default indentation amount used by .IP, .RS, .TP, and the deprecated .HP.
              See subsection “Horizontal and  vertical  spacing”  above  for  the  default.   For
              terminal devices, standard-indentation should always be an integer multiple of unit
              “n” to get consistent indentation.

       -rLL=line-length
              Set line length; the default is 78n for terminal devices and 6.5i  for  typesetting
              devices.

       -rLT=title-length
              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).

       -dMF=man-page-topic-font
              Set the font used for man page topics named in .TH and .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.

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

       -rStype-size
              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.

       -rSN=subsection-indentation
              Set indentation of subsection headings to subsection-indentation.   See  subsection
              “Horizontal and vertical spacing” above for the default.

       -rU1   Enable  generation  of  URI  hyperlinks  in  the grohtml and grotty output drivers.
              grohtml enables them by default; grotty does not,  pending  more  widespread  pager
              support for OSC 8 escape sequences.  Use -rU0 to disable hyperlinks; this will make
              the arguments to MT and UR calls visible in the document  text  produced  by  link-
              capable drivers.

       -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

       /usr/share/groff/1.23.0/tmac/an.tmac
              Most man  macros  are  defined  in  this  file.   It  also  loads  extensions  from
              an-ext.tmac (see below).

       /usr/share/groff/1.23.0/tmac/andoc.tmac
              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 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.

       /usr/share/groff/1.23.0/tmac/an-ext.tmac
              Except for .SB, definitions of macros described above as extensions  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.

              The  definitions  for  these  macros  are read after a page calls .TH, so they will
              replace any macros of the same names preceding it in your file.  If  you  use  your
              own  implementations  of  these macros, they must be defined after .TH is called to
              have any effect.  Furthermore, it is wise to define such page-local macros  (if  at
              all)   after   the   “Name”  section  to  accommodate  timid  makewhatis  or  mandb
              implementations that may give up their scan for indexing material early.

       /usr/share/groff/1.23.0/tmac/man.tmac
              This is a wrapper that loads an.tmac.

       /usr/share/groff/1.23.0/tmac/mandoc.tmac
              This is a wrapper that loads andoc.tmac.

       /usr/share/groff/site-tmac/man.local
              Put site-local changes and customizations into this file.

                     .\" Use narrower indentation on terminals and similar.
                     .if n .nr IN 4n
                     .\" 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]>78n .nr LL 78n
                     .\" Ensure hyperlinks are enabled for terminals.
                     .nr U 1

              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

       Some tips on troubleshooting your man pages follow.

       • 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 marker 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 forms.

       • .RS doesn't indent relative to my indented paragraph.
              The .RS macro sets the left margin; that is, the  position  at  which  an  ordinary
              paragraph  (.P and its synonyms) will be set.  .IP, .TP, and the deprecated .HP use
              the same default indentation.  If not given an argument, .RS moves the left  margin
              by  this  same  amount.  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 .P paragraph.   See  subsection  “Horizontal  and  vertical
              spacing” above for the values.

              Another  approach  you  can  use  with  tagged  paragraphs  is to place an .RS call
              immediately after the paragraph tag; this will also force a break regardless of the
              width  of  the  tag, 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.
       • warning: scaling unit invalid in context
       • warning: register 'an-saved-marginn' not defined
       • warning: register 'an-saved-prevailing-indentn' not defined
              The .RS macro takes an indentation amount as an argument; the .RE macro's  argument
              is  a  specific  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.

              After calls to the .SH and .SS sectioning macros, all relative insets  are  cleared
              and calls to .RE have no effect until .RS is used again.

       • Do I need to keep typing the indentation in a series of .IP calls?
              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  “Command  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...              ...do 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 cause
              great confusion.  Dots and space are universally supported.

Authors

       The initial GNU implementation of the man  macro  package  was  written  by  James  Clark.
       Later,  Werner  Lemberg  ⟨wl@gnu.org⟩  supplied  the  S,  LT, and cR registers, the last a
       4.3BSD-Reno mdoc(7) feature.  Larry Kollar ⟨kollar@alltel.net⟩ added the FT,  HY,  and  SN
       registers;  the  HF  string;  and  the  PT  and BT macros.  G. Branden Robinson ⟨g.branden
       .robinson@gmail.com⟩ implemented the AD and MF strings; CS, CT, and U registers;  and  the
       MR  macro.   Except for .SB, the extension macros were written by Lemberg, Eric S. Raymond
       ⟨esr@thyrsus.com⟩, and Robinson.

       This document was originally written for the Debian GNU/Linux system by Susan G. Kleinmann
       ⟨sgk@debian.org⟩.   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 ⟨schwarze@usta.de⟩ contributed most of the material on
       escape sequences.

See also

       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), man(7)