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

       man - macros to format man pages

       groff -Tascii -man file ...

       groff -Tps -man file ...

       man [section] title

       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

       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 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-

              .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

       The commands to select the type face are:

       .B  Bold

       .BI Bold alternating with italics (especially useful for function spec-

       .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
       (Feature  supported  with  groff only.)  In order to use hypertext link
       macros, it is necessary to load the www.tmac macro  package.   Use  the
       request .mso www.tmac to do this.

       .URL url link trailer
                Inserts  a  hypertext  link to the URI (URL) url, with link as
                the text of the link.  The trailer will be printed immediately
                afterward.   When  generating  HTML this should translate into
                the HTML command <A HREF="url">link</A>trailer.

                This and other related macros are new, and many tools won't do
                anything  with  them,  but  since many tools (including troff)
                will simply ignore undefined macros (or at worst insert  their
                text) these are safe to insert.

                It  can be useful to define your own URL macro in manual pages
                for the benefit of those viewing it with a roff  viewer  other
                than  groff.   That  way, the URL, link text, and trailer text
                (if any) are still visible.

                Here's an example:
                      .de URL
                      \\$2 \(laURL: \\$1 \(ra\\$3
                      .if \n[.g] .mso www.tmac
                      .TH ...
                      (later in the page)
                      This software comes from the
                      .URL "" "GNU Project" " of the"
                      .URL "" "Free Software Foundation" .

                In the above, if groff is being used, the www.tmac macro pack-
                age's  definition  of the URL macro will supersede the locally
                defined one.

       A number of other link macros are available.  See groff_www(7) for more

   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

   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-

       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.


       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 new URL macro to identify links to related infor-
       mation.    If   you   include   URLs,   use   the   full   URL   (e.g.,
       <>)  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)

       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.

       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)

       This  page  is  part of release 4.04 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

Linux                             2012-08-05                            MAN(7)
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