man(7) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | FILES | NOTES | BUGS | SEE ALSO | COLOPHON

MAN(7)                  Linux Programmer's Manual                 MAN(7)

NAME         top

       man - macros to format man pages

SYNOPSIS         top

       groff -Tascii -man file ...
       groff -Tps -man file ...

       man [section] title

DESCRIPTION         top

       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.  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 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         top

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

NOTES         top

       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         top

       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         top

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

COLOPHON         top

       This page is part of release 5.13 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                          2021-03-22                         MAN(7)

Pages that refer to this page: dh_installman(1)groffer(1)man(1)groff_man(7)groff_man_style(7)man-pages(7)uri(7)