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  develop-
       ers when writing or porting man pages for Linux.  It is fairly compati-
       ble 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 pro-
       gram:

              .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 spec-
           ifications)

       .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 delim-
       ited 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 "prevail-
       ing 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  corre-
                sponding .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 paren-
              thesis and/or end-of-sentence punctuation)  immediately  follow-
              ing.   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: (R)

       \*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 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 char-
       acters 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 posi-
       tive 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 dif-
       ferent 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 condi-
       tion.  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  parame-
       ters).

       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 "cat-
       man" result).

       Many man pages begin with '\" followed by a space and a list of charac-
       ters, indicating how the page is to be preprocessed.  For portability's
       sake to non-troff translators we recommend that you  avoid  using  any-
       thing other than tbl(1), and Linux can detect that automatically.  How-
       ever, 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), groff_mdoc(7),
       whatis(1), groff_man(7), groff_www(7), man-pages(7), mdoc(7)

COLOPHON
       This page is part of release 4.15 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                             2017-09-15                            MAN(7)
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