man

MAN(7)                      Linux Programmer's Manual                     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 versions 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 command, 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

       It is extremely important that this format is followed, and that there is
       a backslash before the single dash which follows 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 further 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
       contains spaces.  All of 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 punctuation 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 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 corresponding
                .RE.

       .RE      End relative margin indent and restores the previous 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 normal 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 paragraph 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 (bullet)
                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.

   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: ®

       \*S    Change to default font size

       \*(Tm  Trademark Symbol: ™

       \*(lq  Left angled double quote: “

       \*(rq  Right angled double quote: ”

   Safe subset
       Although technically man is a troff macro package, in reality 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 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: \', \`, \-, \., \", \%, \*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 't' or 'n' 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.,
       ⟨http://www.kernel.org⟩) to ensure that tools can automatically find the
       URLs.

       Tools processing these files should open the file and examine the first
       nonwhitespace character.  A period (.) or single quote (') 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 '\" followed by a space and a list of
       characters, indicating how the page is to be preprocessed.  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 definitions 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 markings).  This situation makes it harder to vary the man
       format 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), whatis(1),
       groff_man(7), groff_www(7), man-pages(7), mdoc(7)

COLOPHON
       This page is part of release 5.08 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/.



Linux                              2019-03-06                             MAN(7)