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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

       It is extremely important that this format is followed, and that there is a backslash before  the  single  dash
       which follows the command name.  This syntax is used by the makewhatis(8) program to create a database of short
       command descriptions for the whatis(1) and apropos(1) commands.

       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 fol-
       lowing 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 re-specifying
       the  indent  value.   A normal (non-indented) 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
       (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  afterwards.  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 "http://www.gnu.org/" "GNU Project" " of the"
                      .URL "http://www.fsf.org/" "Free Software Foundation" .

                In the above, if groff is being used, the www.tmac macro package'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 details.

   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 prepro-
       cessors (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 new URL macro to identify links to  related  information.
       If  you  include URLs, use the full URL (e.g., <http://www.kernelnotes.org>;) to ensure that tools can automati-
       cally find the URLs.

       Tools processing these files should open the file and examine the first non-whitespace 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 seman-
       tic  markings).  This situation makes it harder to vary the man format for different media, to make the format-
       ting consistent for a given media, and to automatically insert cross-references.  By sticking to the safe  sub-
       set  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),  man(1),  man2html(1),  whatis(1),  groff_man(7),  groff_www(7),  man-pages(7),  mdoc(7),
       mdoc.samples(7)

COLOPHON
       This  page  is part of release 3.22 of the Linux man-pages project.  A description of the project, and informa-
       tion about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.



Linux                             2007-05-30                            MAN(7)