MAN(7)                    (2020-11-01)                     MAN(7)

     NAME
          man - macros to format man pages

     SYNOPSIS
          groff -Tascii -man file ...

          groff -Tps -man file ...

          man [section] title

     DESCRIPTION
          This manual page explains the groff an.tmac macro package
          (often called the man macro package).  This macro package
          should be used by developers when writing or porting man
          pages for Linux.  It is fairly compatible with other ver-
          sions of this macro package, so porting man pages should not
          be a major problem (exceptions include the NET-2 BSD
          release, which uses a totally different macro package called
          mdoc; see mdoc(7)).

          Note that NET-2 BSD mdoc man pages can be used with groff
          simply by specifying the -mdoc option instead of the -man
          option.  Using the -mandoc option is, however, recommended,
          since this will automatically detect which macro package is
          in use.

          For conventions that should be employed when writing man
          pages for the Linux man-pages package, see man-pages(7).

        Title line
          The first command in a man page (after comment lines, that
          is, lines that start with .\") should be

               .TH title section date source manual

          For details of the arguments that should be supplied to the
          TH command, see man-pages(7).

          Note that BSD mdoc-formatted pages begin with the Dd com-
          mand, not the TH command.

        Sections
          Sections are started with .SH followed by the heading name.

          The only mandatory heading is NAME, which should be the
          first section and be followed on the next line by a one-line
          description of the program:

               .SH NAME
               item \- description

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          It is extremely important that this format is followed, and
          that there is a backslash before the single dash which fol-
          lows the item name.  This syntax is used by the mandb(8)
          program to create a database of short descriptions for the
          whatis(1) and apropos(1) commands.  (See lexgrog(1) for fur-
          ther details on the syntax of the NAME section.)

          For a list of other sections that might appear in a manual
          page, see man-pages(7).

        Fonts
          The commands to select the type face are:

          .B  Bold

          .BI Bold alternating with italics (especially useful for
              function specifications)

          .BR Bold alternating with Roman (especially useful for
              referring to other manual pages)

          .I  Italics

          .IB Italics alternating with bold

          .IR Italics alternating with Roman

          .RB Roman alternating with bold

          .RI Roman alternating with italics

          .SB Small alternating with bold

          .SM Small (useful for acronyms)

          Traditionally, each command can have up to six arguments,
          but the GNU implementation removes this limitation (you
          might still want to limit yourself to 6 arguments for
          portability's sake).  Arguments are delimited by spaces.
          Double quotes can be used to specify an argument which con-
          tains spaces.  For the macros that produce alternating type
          faces, the arguments will be printed next to each other
          without intervening spaces, so that the .BR command can be
          used to specify a word in bold followed by a mark of punctu-
          ation in Roman.  If no arguments are given, the command is
          applied to the following line of text.

        Other macros and strings
          Below are other relevant macros and predefined strings.
          Unless noted otherwise, all macros cause a break (end the
          current line of text).  Many of these macros set or use the
          "prevailing indent."  The "prevailing indent" value is set

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          by any macro with the parameter i below; macros may omit i
          in which case the current prevailing indent will be used.
          As a result, successive indented paragraphs can use the same
          indent without respecifying the indent value.  A normal
          (nonindented) paragraph resets the prevailing indent value
          to its default value (0.5 inches).  By default, a given
          indent is measured in ens; try to use ens or ems as units
          for indents, since these will automatically adjust to font
          size changes.  The other key macro definitions are:

        Normal paragraphs
          .LP      Same as .PP (begin a new paragraph).

          .P       Same as .PP (begin a new paragraph).

          .PP      Begin a new paragraph and reset prevailing indent.

        Relative margin indent
          .RS i    Start relative margin indent: moves the left margin
                   i to the right (if i is omitted, the prevailing
                   indent value is used).  A new prevailing indent is
                   set to 0.5 inches.  As a result, all following
                   paragraph(s) will be indented until the correspond-
                   ing .RE.

          .RE      End relative margin indent and restores the previ-
                   ous value of the prevailing indent.

        Indented paragraph macros
          .HP i    Begin paragraph with a hanging indent (the first
                   line of the paragraph is at the left margin of nor-
                   mal paragraphs, and the rest of the paragraph's
                   lines are indented).

          .IP x i  Indented paragraph with optional hanging tag.  If
                   the tag x is omitted, the entire following para-
                   graph is indented by i. If the tag x is provided,
                   it is hung at the left margin before the following
                   indented paragraph (this is just like .TP except
                   the tag is included with the command instead of
                   being on the following line).  If the tag is too
                   long, the text after the tag will be moved down to
                   the next line (text will not be lost or garbled).
                   For bulleted lists, use this macro with \(bu (bul-
                   let) or \(em (em dash) as the tag, and for numbered
                   lists, use the number or letter followed by a
                   period as the tag; this simplifies translation to
                   other formats.

          .TP i    Begin paragraph with hanging tag.  The tag is given
                   on the next line, but its results are like those of
                   the .IP command.

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        Hypertext link macros
          .UR url
               Insert a hypertext link to the URI (URL) url, with all
               text up to the following .UE macro as the link text.

          .UE  [trailer] Terminate the link text of the preceding .UR
               macro, with the optional trailer (if present, usually a
               closing parenthesis and/or end-of-sentence punctuation)
               immediately following.  For non-HTML output devices
               (e.g., man -Tutf8), the link text is followed by the
               URL in angle brackets; if there is no link text, the
               URL is printed as its own link text, surrounded by
               angle brackets.  (Angle brackets may not be available
               on all output devices.)  For the HTML output device,
               the link text is hyperlinked to the URL; if there is no
               link text, the URL is printed as its own link text.

          These macros have been supported since GNU Troff 1.20
          (2009-01-05) and Heirloom Doctools Troff since 160217
          (2016-02-17).

        Miscellaneous macros
          .DT      Reset tabs to default tab values (every 0.5
                   inches); does not cause a break.

          .PD d    Set inter-paragraph vertical distance to d (if
                   omitted, d=0.4v); does not cause a break.

          .SS t    Subheading t (like .SH, but used for a subsection
                   inside a section).

        Predefined strings
          The man package has the following predefined strings:

          \*R  Registration Symbol: (Reg.)

          \*S  Change to default font size

          \*(Tm
               Trademark Symbol: TM

          \*(lq
               Left angled double quote:

          \*(rq
               Right angled double quote:

        Safe subset
          Although technically man is a troff macro package, in real-
          ity a large number of other tools process man page files
          that don't implement all of troff's abilities.  Thus, it's
          best to avoid some of troff's more exotic abilities where

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          possible to permit these other tools to work correctly.
          Avoid using the various troff preprocessors (if you must, go
          ahead and use tbl(1), but try to use the IP and TP commands
          instead for two-column tables).  Avoid using computations;
          most other tools can't process them.  Use simple commands
          that are easy to translate to other formats.  The following
          troff macros are believed to be safe (though in many cases
          they will be ignored by translators): \ ," " " " " " ., ad,
          bp, br, ce, de, ds, el, ie, if, fi, ft, hy, ig, in, na, ne,
          nf, nh, ps, so, sp, ti, tr.

          You may also use many troff escape sequences (those
          sequences beginning with \).  When you need to include the
          backslash character as normal text, use \e.  Other sequences
          you may use, where x or xx are any characters and N is any
          digit, include: \aq, \`, \-, \., \ ," " " " " " \%, \*x,
          \*(xx, \(xx, \$N, \nx, \n(xx, \fx, and \f(xx.  Avoid using
          the escape sequences for drawing graphics.

          Do not use the optional parameter for bp (break page).  Use
          only positive values for sp (vertical space).  Don't define
          a macro (de) with the same name as a macro in this or the
          mdoc macro package with a different meaning; it's likely
          that such redefinitions will be ignored.  Every positive
          indent (in) should be paired with a matching negative indent
          (although you should be using the RS and RE macros instead).
          The condition test (if,ie) should only have aqtaq or aqnaq as
          the condition.  Only translations (tr) that can be ignored
          should be used.  Font changes (ft and the \f escape
          sequence) should only have the values 1, 2, 3, 4, R, I, B,
          P, or CW (the ft command may also have no parameters).

          If you use capabilities beyond these, check the results
          carefully on several tools.  Once you've confirmed that the
          additional capability is safe, let the maintainer of this
          document know about the safe command or sequence that should
          be added to this list.

     FILES
          /usr/share/groff/[*/]tmac/an.tmac
          /usr/man/whatis

     NOTES
          By all means include full URLs (or URIs) in the text itself;
          some tools such as man2html(1) can automatically turn them
          into hypertext links.  You can also use the UR and UE macros
          to identify links to related information.  If you include
          URLs, use the full URL (e.g., to ensure that tools can auto-
          matically find the URLs.

          Tools processing these files should open the file and exam-
          ine the first nonwhitespace character.  A period (.) or

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          single quote (aq) at the beginning of a line indicates a
          troff-based file (such as man or mdoc).  A left angle
          bracket (<) indicates an SGML/XML-based file (such as HTML
          or Docbook).  Anything else suggests simple ASCII text
          (e.g., a "catman" result).

          Many man pages begin with aq\" followed by a space and a list
          of characters, indicating how the page is to be prepro-
          cessed.  For portability's sake to non-troff translators we
          recommend that you avoid using anything other than tbl(1),
          and Linux can detect that automatically.  However, you might
          want to include this information so your man page can be
          handled by other (less capable) systems.  Here are the defi-
          nitions of the preprocessors invoked by these characters:

          e  eqn(1)

          g  grap(1)

          p  pic(1)

          r  refer(1)

          t  tbl(1)

          v  vgrind(1)

     BUGS
          Most of the macros describe formatting (e.g., font type and
          spacing) instead of marking semantic content (e.g., this
          text is a reference to another page), compared to formats
          like mdoc and DocBook (even HTML has more semantic mark-
          ings).  This situation makes it harder to vary the man for-
          mat for different media, to make the formatting consistent
          for a given media, and to automatically insert cross-
          references.  By sticking to the safe subset described above,
          it should be easier to automate transitioning to a different
          reference page format in the future.

          The Sun macro TX is not implemented.

     SEE ALSO
          apropos(1), groff(1), lexgrog(1), man(1), man2html(1),
          groff_mdoc(7), whatis(1), groff_man(7), groff_www(7),
          man-pages(7), mdoc(7)

     COLOPHON
          This page is part of release 5.10 of the Linux man-pages
          project.  A description of the project, information about
          reporting bugs, and the latest version of this page, can be
          found at https://www.kernel.org/doc/man-pages/.

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