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groff_man(7)          Miscellaneous Information Manual          groff_man(7)

Name         top

       groff_man - GNU roff macro package for formatting man pages

Synopsis         top

       groff -man [option ...] [input-file ...]
       groff -m man [option ...] [input-file ...]

Description         top

       The man macro package for groff is used to produce manual pages
       (“man pages”) like the one you are reading.

       This document presents the macros thematically; for those needing
       only a quick reference, the following table lists them
       alphabetically, with cross-references to appropriate subsections
       below.

       Macro   Meaning                      Subsection
       ────────────────────────────────────────────────────────────────
       .B      Bold                         Font style macros
       .BI     Bold, italic alternating     Font style macros
       .BR     Bold, roman alternating      Font style macros
       .EE     Example end                  Document structure macros
       .EX     Example begin                Document structure macros
       .I      Italic                       Font style macros
       .IB     Italic, bold alternating     Font style macros
       .IP     Indented paragraph           Paragraph macros
       .IR     Italic, roman alternating    Font style macros
       .LP     (Left) paragraph             Paragraph macros
       .ME     Mail-to end                  Hyperlink and email macros
       .MT     Mail-to start                Hyperlink and email macros
       .OP     (Command-line) option        Command synopsis macros
       .P      Paragraph                    Paragraph macros
       .PP     Paragraph                    Paragraph macros
       .RB     Roman, bold alternating      Font style macros
       .RE     Relative-indent end          Document structure macros
       .RI     Roman, italic alternating    Font style macros
       .RS     Relative-indent start        Document structure macros
       .SB     Small bold                   Font style macros
       .SH     Section heading              Document structure macros
       .SM     Small                        Font style macros
       .SS     Subsection heading           Document structure macros
       .SY     Synopsis start               Command synopsis macros
       .TH     Title heading                Document structure macros
       .TP     Tagged paragraph             Paragraph macros
       .TQ     Supplemental paragraph tag   Paragraph macros
       .UE     URL end                      Hyperlink and email macros
       .UR     URL start                    Hyperlink and email macros
       .YS     Synopsis end                 Command synopsis macros

       Macros whose use we discourage (.AT, .BT, .DT, .HP, .PD, .PT, and
       .UC) are described in subsection “Deprecated features” below.

   Macro reference preliminaries
       Each macro is described in a tagged paragraph.  Closely-related
       macros, such as .EX and .EE, are grouped together.

       A macro call begins on a line starting with a dot (“.”), followed by
       zero or more spaces and then the macro name.  Some macros accept
       arguments; each such argument is separated from the macro name and
       any subsequent arguments by one or more spaces.  A newline, unless
       escaped (see subsection “Portability” below), terminates the macro
       call.

       Optional macro arguments are indicated by surrounding them with
       square brackets.  If a macro accepts multiple arguments, those
       containing space or horizontal tab characters must be double-quoted
       to be interpreted correctly.  An empty macro argument can be
       specified with a pair of double-quotes (“""”), but the man package is
       designed such that this should seldom be necessary.  Unused macro
       arguments are more often simply omitted, or good style suggests that
       a more appropriate macro be chosen, that earlier arguments are more
       important than later ones, or that arguments have identical
       significance such that skipping any is superfluous.  Most macro
       arguments are strings that will be output as text; exceptions are
       noted.

       Bear in mind that groff is fundamentally a programming system for
       typesetting.  Consequently, the verb “to set” is frequently used
       below in the sense “to typeset”.

   Document structure macros
       The highest level of organization of a man page is determined by this
       group of macros.  .TH (title heading) identifies the document as a
       man page and defines information enabling its indexing by mandb(8) or
       a similar tool.  Sections (.SH), one of which is mandatory and many
       of which are standardized, facilitate quick location of relevant
       material by the reader and aid the man page writer to discuss all
       essential aspects of the topic.  Subsections (.SS) are optional and
       permit sections that grow long to develop in a controlled way.  Many
       technical discussions require examples; lengthy ones, especially
       those reflecting multiple lines of input to or output from the
       system, are usefully bracketed by .EX and .EE.  When none of the
       foregoing meets a structural demand, a region within a (sub)section
       can be manually indented within .RS and .RE macros.

       .TH title section
               [footer-middle] [footer-inside] [header-middle] Define the
              title of the man page as title and the section as section.
              See man(1) for details on the section numbers and suffixes
              applicable to your system.  title and section are positioned
              together at the left and right in the header line (with
              section in parentheses immediately appended to title).
              footer-middle is centered in the footer line.  The arragement
              of the rest of the footer depends on whether double-sided
              layout is enabled with the option -rD1.  When disabled (the
              default), footer-inside is positioned at the bottom left.
              Otherwise, footer-inside appears at the bottom left on odd-
              numbered (recto) pages, and at the bottom right on even-
              numbered (verso) pages.  The outside footer is the page
              number, except in the continuous-rendering mode enabled by the
              option -rcR=1, in which case it is the title and section, as
              in the header.  header-middle is centered in the header line.
              If section is a simple integer between 1 and 9 (inclusive), or
              is exactly “3p”, there is no need to specify header-middle;
              the macro package will supply text for it.  For HTML output,
              headers and footers are completely suppressed.

              Additionally, this macro starts a new page; the page number is
              reset to 1 (unless the -rC1 option is given on the command
              line).  This feature is intended only for formatting multiple
              man pages.

              A man page should contain exactly one .TH call at or near the
              beginning of the file, prior to any other macro calls.

              By convention, footer-middle is the most recent modification
              date of the man page source document, and footer-inside is the
              name and version or release of the project providing it.

       .SH [  heading-text] Set heading-text as a section heading flush
              left.  The text following .SH up to the end of the line, or
              the text on the next input line if .SH is given no arguments,
              is set in bold (or the font specified by the string HF) and,
              on typesetter devices, slightly larger than the base point
              size.  Additionally, the left margin and indentation affecting
              subsequent text are reset to their default values.  Text on
              input lines after heading-text is set as a normal paragraph
              (.PP).

              The content of heading-text and ordering of sections has been
              standardized by common practice, as has much of the layout of
              material within sections.  For example, a section called
              “Name” or “NAME” must exist, must be the first section after
              the .TH call, and must contain only a line of the form
                     topic[, another-topic]... \- summary-description
              for a man page to be properly indexed.  See man(7) for the
              conventions prevailing on your system.

       .SS [  subheading-text] Set subheading-text as a subsection heading
              indented partway between a section heading and a normally-
              indented paragraph (.PP).  See subsection “Horizontal and
              vertical spacing” below for the precise indentation amount.
              The text following .SS up to the end of the line, or the text
              on the next input line if .SS is given no arguments, is set in
              bold (or the font specified by the string HF).  Additionally,
              the left margin and indentation affecting subsequent text are
              reset to their default values.  Text on input lines after
              subheading-text is set as a normal paragraph (.PP).

       .EX
       .EE    Begin and end example.  After .EX, filling and hyphenation are
              disabled and a constant-width (monospaced) font is selected.
              Calling .EE enables filling and restores the previous font and
              initial hyphenation mode.

              Example regions are useful for formatting code, shell
              sessions, and text file contents.

              These macros are extensions, introduced in Version 9 Unix, to
              the original man package.  Many systems running AT&T, Heirloom
              Doctools, or Plan 9 troff support them.  To be certain your
              page will be portable to systems that do not, copy their
              definitions from the an-ext.tmac file of a groff installation.

       .RS [  indent] Move the left margin to the right by the value indent,
              if specified, and by a default amount otherwise; see
              subsection “Horizontal and vertical spacing” below.  Calls to
              .RS can be nested; each call increments by 1 the indentation
              level used by .RE.  The indentation level prior to any .RS
              calls is 1.

       .RE [  level] Move the left margin back to that corresponding to
              indentation level level.  If no argument is given, move the
              left margin one level back.

   Paragraph macros
       An ordinary paragraph (.PP) like this one is set without a first-line
       indent at the current left margin, which by default is indented from
       the leftmost position of the output device.  In man pages and other
       technical literature, definition lists are frequently encountered;
       these can be set as “tagged paragraphs” (.TP and .TQ), which have one
       or more leading tags followed by a paragraph that has an additional
       left indent.  The indented paragraph (.IP) macro is useful to
       continue the indented content of a narrative started with .TP, or to
       present an itemized or ordered list.  All paragraph macros break the
       output line at the current position.  If another paragraph macro has
       occurred since the previous .SH or .SS, they (except for .TQ) follow
       the break with a default amount of vertical space, which can be
       changed by the deprecated .PD macro; see subsection “Horizontal and
       vertical spacing” below.  They also reset the point size and font
       style to defaults (.TQ again excepted); see subsection “Font style
       macros” below.

       .LP
       .PP
       .P     Begin a new paragraph; these macros are synonymous.  The left
              margin and indentation are reset to default values.

       .TP [  indent] Set a tagged, indented paragraph.  The input line
              following this macro, known as the tag, is printed at the
              current left margin.  Subsequent text is indented by indent,
              if specified, and by a default amount otherwise; see
              subsection “Horizontal and vertical spacing” below.

              If the tag is not as wide as the indentation, the paragraph
              starts on the same line as the tag, at the applicable
              indentation, and continues on the following lines.  Otherwise,
              the descriptive part of the paragraph begins on the line
              following the tag, entirely indented.  The line containing the
              tag can include a macro call, for instance to set the tag in
              bold with .B.

              .TP was used to write the first paragraph of this description
              of .TP, and .IP the subsequent ones.

       .TQ    Set an additional tag for a paragraph tagged with .TP.  The
              pending output line is broken.  The tag on the input line
              following this macro and subsequent lines are handled as with
              .TP.

              This macro is not defined on systems running AT&T or Plan 9
              troff.  To be certain your page will be portable to those
              systems, copy its definition from the an-ext.tmac file of a
              groff installation.

              The descriptions of .LP, .PP, and .P above were written using
              .TP and .TQ.

       .IP [  tag] [indent] Set an indented paragraph with an optional tag.
              The tag and indent arguments, if present, are handled as with
              .TP, with the exception that the tag argument to .IP cannot
              include a macro call.

              Two convenient use cases for .IP are

                     (1) to start a new paragraph with the same indentation
                         as an immediately preceding .IP or .TP paragraph,
                         if no indent argument is given; and

                     (2) to set a paragraph with a short tag that is not
                         semantically important, such as a bullet
                         (·)—obtained with the \(bu special character
                         escape—or list enumerator, as seen in this very
                         paragraph.

   Command synopsis macros
       Command synopses are a staple of section 1 and 8 man pages.  These
       macros aid you to construct one that has the classical Unix
       appearance.  A command synopsis is wrapped in .SY/.YS calls, with
       command-line options of some formats indicated by .OP.

       These macros are not defined on systems running AT&T or Plan 9 troff.
       To be certain your page will be portable to those systems, copy their
       definitions from the an-ext.tmac file of a groff installation.

       .SY command
              Begin synopsis.  Hyphenation is turned off.  The command
              argument is set in bold.  The output line is filled as normal,
              but if a break is required, subsequent output lines are
              indented by the width of command plus a space.

       .OP option-name
               [option-argument] Indicate an optional command parameter
              called option-name, which is set in bold.  If the option takes
              an argument, specify option-argument using a noun,
              abbreviation, or hyphenated noun phrase.  If present, option-
              argument is preceded by a space and set in italics.  Square
              brackets in roman surround both arguments.

       .YS    End synopsis.  Restore previous indentation amount and initial
              hyphenation mode.

       Multiple .SY/.YS blocks can be specified, for instance to distinguish
       differing modes of operation of a complex command like tar(1); each
       will be separated by a paragraph space.

       .SY can also be repeated multiple times before a closing .YS, which
       is useful to indicate synonymous ways of invoking a particular mode
       of operation.

       For example,

              .SY groff
              .OP \-abcegiklpstzCEGNRSUVXZ
              .OP \-d cs
              .OP \-f fam
              .OP \-F dir
              .OP \-I dir
              .OP \-K arg
              .OP \-L arg
              .OP \-m name
              .OP \-M dir
              .OP \-n num
              .OP \-o list
              .OP \-P arg
              .OP \-r cn
              .OP \-T dev
              .OP \-w name
              .OP \-W name
              .RI [ file
              \&.\|.\|.\&]
              .YS
              .
              .SY groff
              .B \-h
              .SY groff
              .B \-\-help
              .YS

       produces the following output.

              groff [-abcegiklpstzCEGNRSUVXZ] [-d cs] [-f fam] [-F dir]
                    [-I dir] [-K arg] [-L arg] [-m name] [-M dir] [-n num]
                    [-o list] [-P arg] [-r cn] [-T dev] [-w name] [-W name]
                    [file ...]

              groff -h
              groff --help

       Several features of the above example are of note.

       ·      The empty request (.), which does nothing, is used for verti‐
              cal spacing in the input file for readability by the document
              maintainer.  Do not put blank (i.e., empty) lines in a roff
              source document.

       ·      The command and option names are presented in bold to cue the
              user that they should be input literally.

       ·      Option dashes are specified with the \- escape sequence; this
              is an important practice to make them clearly visible and to
              facilitate cut-and-paste from the rendered man page to a shell
              prompt or text file.

       ·      Option arguments and command operands are presented in italics
              (but see subsection “Font style macros” below regarding termi‐
              nals) to cue the user that they must be replaced with appro‐
              priate text.

       ·      Symbols that are neither to be typed literally nor simply
              replaced appear in the roman style; brackets surround optional
              arguments, and an ellipsis indicates that the previous syntac‐
              tical element may be repeated arbitrarily.

              Authors of man pages should note the use of the zero-width
              space escape sequence \& preceding the ellipsis, which pre‐
              vents it from being misinterpreted as an invalid control line,
              and after it, which prevents it from being misinterpreted as
              the end of a sentence.  See subsection “Portability” below.

   Hyperlink and email macros
       Email addresses are bracketed with .MT/.ME and URL hyperlinks with
       .UR/.UE.

       These macros are not defined on systems running AT&T or Plan 9 troff.
       To be certain your page will be portable to those systems, copy their
       definitions from the an-ext.tmac file of a groff installation.

       .MT address
       .ME [  punctuation] Identify address as an RFC 6068 addr-spec for a
              “mailto:” URI with the text between the two macro calls as the
              link text.  A punctuation argument to .ME is placed at the end
              of the link text without intervening space.  Note that address
              may not be visible in the output text, particularly if the man
              page is being viewed as HTML.  On a device that is not a
              browser, address is set in angle brackets after the link text
              and before punctuation.

              When rendered by groff to a terminal or PostScript device,

                     Contact
                     .MT fred.foonly@\:fubar.net
                     Fred Foonly
                     .ME
                     for more information.

              displays as “Contact Fred Foonly ⟨fred.foonly@fubar.net⟩ for
              more information.”.

              The use of \: to insert hyphenless discretionary breaks is a
              GNU extension and can be omitted.

       .UR URL
       .UE [  punctuation] Identify URL as an RFC 3986 URI hyperlink with
              the text between the two macro calls as the link text.  A
              punctuation argument to .UE is placed at the end of the link
              text without intervening space.  Note that URL may not be vis‐
              ible in the output text, particularly if the man page is being
              viewed as HTML.  On a device that is not a browser, URL is set
              in angle brackets after the link text and before punctuation.

              When rendered by groff to a terminal or PostScript device,

                     The GNU Project of the Free Software Foundation
                     hosts the
                     .UR https://\:www.gnu.org/\:software/\:groff/
                     groff home page
                     .UE .

              displays as “The GNU Project of the Free Software Foundation
              hosts the groff home page ⟨https://www.gnu.org/soft‐
              ware/groff/⟩.”.

              The use of \: to insert hyphenless discretionary breaks is a
              GNU extension and can be omitted.

   Font style macros
       The man macro package is limited in its font styling options, offer‐
       ing only bold (.B), italic (.I), and roman.  Italic text is usually
       set underscored instead on terminal devices.  The .SM and .SB macros
       set text in roman or bold, respectively, at a smaller point size;
       these differ visually from regular-sized roman or bold text only on
       typesetter devices.  It is often necessary to set text in different
       styles without intervening space.  The macros .BI, .BR, .IB, .IR,
       .RB, and .RI, where “B”, “I”, and “R” indicate bold, italic, and
       roman, respectively, set their odd- and even-numbered arguments in
       alternating styles, with no space separating them.

       Because font styles are presentational rather than semantic, con‐
       flicting traditions have arisen regarding which font styles should be
       used to mark file or path names, environment variables, in-line lit‐
       erals, and man page cross-references.

       The default point size and family (for typesetter devices) is
       10-point Times.  The default style is roman.

       .B [   text] Set text in bold.  If the macro is given no arguments,
              the text of the next input line is set in bold.

              Use bold for literal portions of syntax synopses, for command-
              line options in running text, and for literals that are major
              topics of the subject under discussion; for example, this page
              uses bold for macro, string, and register names.  In .EX/.EE
              examples of interactive I/O (such as a shell session), set
              only user input in bold.

       .I [   text] Set text in italics.  If the macro is given no argu‐
              ments, the text of the next input line is set in italics.

              Use italics for file and path names, for environment vari‐
              ables, for enumeration or preprocessor constants in C, for
              variable (user-determined) portions of syntax synopses, for
              the first occurrence (only) of a technical concept being
              introduced, for names of works of software (including commands
              and functions, but excluding names of operating systems or
              their kernels), and anywhere a parameter requiring replacement
              by the user is encountered.  An exception involves variable
              text in a context that is already marked up in italics, such
              as file or path names with variable components; in such cases,
              follow the convention of mathematical typography: set the file
              or path name in italics as usual but use roman for the vari‐
              able part (see .IR and .RI below), and italics again in run‐
              ning roman text when referring to the variable material.

       .SM [  text] Set text one point smaller than the default point size.
              If the macro is given no arguments, the text of the next input
              line is set smaller.

              Note: terminals will render text at normal size instead.  Do
              not rely upon .SM to communicate semantic information distinct
              from using roman style at normal size; it will be hidden from
              readers using such devices.

       .SB [  text] Set text in bold, one point smaller than the default
              point size.  If the macro is given no arguments, the text of
              the next input line is set smaller and in bold.

              Note: terminals will render text in bold at the normal size
              instead.  Do not rely upon .SB to communicate semantic infor‐
              mation distinct from using bold style at normal size; it will
              be hidden from readers using such devices.

       Note what is not prescribed for setting in bold or italics above:
       elements of “synopsis language” such as ellipses and brackets around
       options; proper names and adjectives; titles of anything other than
       works of literature or software; identifiers for standards documents
       or technical reports such as CSTR #54, RFC 1918, Unicode 11.0, or
       POSIX.1-2017; acronyms; and occurrences after the first of a techni‐
       cal term or piece of jargon.  Again, the names of operating systems
       and their kernels are, by practically universal convention, set in
       roman.

       Be frugal with the use of italics for emphasis, and particularly with
       the use of bold.  Brief runs of literal text, such as references to
       individual characters or short strings, including section and subsec‐
       tion headings of man pages, are suitable objects for quotation; see
       the \(lq, \(rq, \(oq, and \(cq escapes in subsection “Portability”
       below.

       Unlike the above font style macros, the font style alternation macros
       below accept only arguments on the same line as the macro call.  If
       space is required within one of the arguments, first consider whether
       the same result could be achieved with as much clarity by using the
       single-style macros on separate input lines.  When it cannot, double-
       quote an argument containing embedded space characters.  Setting all
       three different styles within a word presents challenges; it is pos‐
       sible with the \c and/or \f escapes, but see subsection “Portability”
       below for caveats.

       .BI bold-text italic-text
               ... Set each argument in bold and italics, alternately.

                     .BI \-r name = n

       .BR bold-text roman-text
               ... Set each argument in bold and roman, alternately.

                     Any such change becomes effective with the first
                     use of
                     .BR .NH ,
                     .I after
                     the new alias is defined.

       .IB italic-text bold-text
               ... Set each argument in italics and bold, alternately.

                     All macro package files must be named
                     .IB name .tmac
                     to fully use the
                     .I tmac
                     mechanism.

       .IR italic-text roman-text
               ... Set each argument in italics and roman, alternately.

                     This is the first command of the
                     .IR prologue .

       .RB roman-text bold-text
               ... Set each argument in roman and bold, alternately.

                     Also,
                     the statement
                     .RB \(oq "delim on" \(cq
                     is not handled specially.

       .RI roman-text italic-text
               ... Set each argument in roman and italics, alternately.

                     .RI [ file
                     \&.\|.\|.\&]

   Horizontal and vertical spacing
       The indent argument accepted by .RS, .IP, .TP, and the deprecated .HP
       is a number plus an optional scaling indicator.  If no scaling indi‐
       cator is given, the man package assumes “n”; that is, the width of a
       letter “n” in the font current when the macro is called (see section
       “Numerical Expressions” in groff(7)).  An indent specified in a call
       to .IP, .TP, or the deprecated .HP persists until (1) another of
       these macros is called with an explicit indent argument, or (2) .SH,
       .SS, or .PP or its synonyms is called; these clear the indent
       entirely.

       Indents set by .RS move the left margin and persist until .RS, .RE,
       .SH, or .SS is called.  The default indentation, exhibited by ordi‐
       nary .PP paragraphs not within an .RS/.RE relative indent, is 7.2n
       for typesetter devices and 7n for terminal devices.  The HTML output
       device is an exception; it ignores indentation completely.  This same
       indentation is used again (additively) for the defaults of .IP, .TP,
       .RS, and the deprecated .HP.  Headers, footers (both set with .TH),
       and section headings (.SH) are set flush left and subsection headings
       (.SS) are indented 3n (but see the -rSN option).

       Resist the temptation to mock up tabular or multi-column output with
       horizontal tab characters or the indentation arguments to .IP, .TP,
       .RS, or the deprecated .HP; the result may not render comprehensibly
       on an output device you fail to check, or which is developed in the
       future.  The table preprocessor tbl(1) can likely meet your needs.

       The following macros break the output line and insert vertical space:
       .SH, .SS, .TP, .PP (and its synonyms), .IP, and the deprecated .HP.
       The default inter-section and inter-paragraph spacing is is 1v for
       terminal devices and 0.4v for typesetter devices (“v” is a unit of
       vertical distance, where 1v is the distance between adjacent text
       baselines in a single-spaced document).  In .EX/.EE sections, the
       inter-paragraph spacing is 1v regardless of output device.  (The dep‐
       recated macro .PD can change this vertical spacing, but its use is
       discouraged.)  The macros .RS, .RE, .EX, .EE, and .TQ also cause a
       break but no insertion of vertical space.

   Number registers
       Number registers are described in section “Options” below.

   Strings
       The following strings are defined.

       \*R    expands to the special character escape for the “registered
              sign” glyph, \(rg, if available, and “(Reg.)” otherwise.

       \*S    expands to an escape setting the point size to the document
              default.

       \*(HF  expands to the font identifier used to print headings and sub‐
              headings.  The default is “B”.  This string is a GNU exten‐
              sion.

       \*(lq
       \*(rq  expand to the special character escapes for left and right
              double-quotation marks, \(lq and \(rq, respectively.

       \*(Tm  expands to the special character escape for the “trade mark
              sign” glyph, \(tm, if available, and “(TM)” otherwise.

   Interaction with preprocessors
       When a preprocessor like tbl or eqn is needed, a hint can be given to
       the man page formatter by making the first line of a man page look
       like this:

              '\" word

       Note that the line starts with an apostrophe ('), not a dot, and that
       a single space character follows the double quote.  The word consists
       of one letter for each needed preprocessor: “e” for eqn, “r” for
       refer, and “t” for tbl.  Modern implementations of the man program
       interpret this first line and automatically call the right preproces‐
       sor(s).

       The usual tbl and eqn macros for table and equation inclusion, .TS,
       .T&, .TE, .EQ, and .EN, may be used freely.  Note that terminal
       devices are extremely limited in presentation of mathematical equa‐
       tions.

   Portability
       The two major syntactical categories of roff languages are requests
       and escapes.  Since the man macros are implemented in terms of groff
       requests and escapes, one can, in principle, supplement the function‐
       ality of man with these lower-level elements where necessary.

       Note, however, that using raw groff requests (apart from the empty
       request “.”) is likely to make your page render poorly when processed
       by other tools; many of these attempt to interpret page sources
       directly for conversion to HTML.  Some requests make implicit assump‐
       tions about things like character and page sizes that may not hold in
       an HTML environment; also, many of these viewers don't interpret the
       full groff vocabulary, a problem that can lead to portions of your
       text being omitted or presented incomprehensibly.

       For portability to modern viewers, it is best to write your page
       entirely with the macros described in this page (except for the ones
       identified as deprecated, which should be avoided).  The macros we
       have described as extensions (.EX/.EE, .SY/.OP/.YS, .UR/.UE, and
       .MT/.ME) should be used with caution, as they may not yet be built in
       to some viewer that is important to your audience.  If in doubt, copy
       the implementation into your page—after the .TH call and the “Name”
       section, to accommodate timid mandb implementations.

       Similar caveats apply to escapes.  Some escape sequences are however
       required for correct typesetting even in man pages and usually do not
       cause portability problems.  Several of these render glyphs corre‐
       sponding to punctuation characters in the Unicode basic Latin range
       (U+0000–U+007F) that are handled specially in roff input; the escapes
       below must be used to render them correctly and portably when docu‐
       menting material that uses them syntactically—namely, any of the set
       ' - ^ ` ~ (apostrophe, dash, caret, grave accent, tilde).

       \"     Comment.  Everything after the double-quote to the end of the
              input line is ignored.  Whole-line comments are frequently
              placed immediately after the empty request “.”).

       \newline
              Join the next input line to the current one.  Except for the
              update of the input line counter (used for diagnostic messages
              and related purposes), a series of lines ending in backslash-
              newline appears to groff as a single input line.  Use this
              escape to break excessively long input lines for document
              maintenance.

       \%     Control hyphenation.  If hyphenation is enabled, the location
              of this escape within a word marks a hyphenation point, over‐
              riding groff's hyphenation patterns.  Use at the beginning of
              a word to suppress its hyphenation entirely.

       \~     Adjustable, non-breaking space character.  Use this escape to
              prevent a break inside a short phrase or between a numerical
              quantity and its corresponding unit(s).

                     Before starting the motor,
                     set the output speed to\~1.
                     There are 1,024\~bytes in 1\~KiB.
                     CSTR\~#8 documents the B\~language.

       \&     Zero-width non-breaking space.  Insert at the beginning of an
              input line to prevent a dot or apostrophe from being inter‐
              preted as the beginning of a roff request.  Append to an end-
              of-sentence punctuation sequence to keep it from being recog‐
              nized as such.

       \|     Narrow (one-sixth em on typesetters, zero-width on terminals)
              non-breaking space.  Used primarily in ellipses (“.\|.\|.”)
              to achieve more pleasant spacing on typesetter devices like
              PostScript and PDF.

       \-     Minus sign or basic Latin hyphen-minus.  “-” is a hyphen to
              roff; some output devices replace it with U+2010 (hyphen) or
              similar.

       \(aq   Basic Latin apostrophe.  Some output devices replace “'” with
              a right single quotation mark.

       \(oq   Opening single quotation mark.
       \(cq   Closing single quotation mark.

              Use these for paired directional single quotes, ‘like this’.

       \(dq   Basic Latin double-quote.  Use in macro calls to prevent ‘"”
              from being interpreted as beginning a quoted argument.

                     .BI split\~\(dq text \(dq

       \(lq   Left double quotation mark.
       \(rq   Right double quotation mark.

              Use these for paired directional double quotes, “like this”.

       \(em   Em-dash.  Use for an interruption—such as this one—in a sen‐
              tence.

       \(en   En-dash.  Use to separate the ends of a range, particularly
              between numbers; for example, “the digits 1–9”.

       \(ga   Basic Latin grave accent.  Some output devices replace “`”
              with a left single quotation mark.

       \(ha   Basic Latin circumflex accent (“hat”).  Some output devices
              replace “^” with U+02C6 (modifier letter circumflex accent) or
              similar.

       \(ti   Basic Latin tilde.  Some output devices replace “~” with
              U+02DC (small tilde) or similar.

       \c     Suppress break at the end of the input line.  Normally, the
              end of an input line is treated like a space; an output line
              may be broken there and will be in .EX/.EE examples.  Anything
              after \c on the input line is discarded.  The next line,
              including macro calls, is interpreted as usual (contrast with
              \newline).  This is occasionally useful when three different
              fonts are needed in a single word.

                     Normally,
                     the final output file should be named
                     .IB file .pdf\c
                     \&.

              Note that when using this trick with the .BI or .RI macros,
              you will need to manually add an italic correction escape
              “\/”, a GNU extension, before the \c due to way macros expand
              their arguments—if you value the improved typesetter output
              quality over the potential reduction in document portability.

                     Files processed with
                     .B groff \-mom
                     (or
                     .BI "\-m " mom\/\c
                     ) produce PostScript output by default.

              Alternatively, and perhaps with better portability, the \f
              font style escape sequence can be used; see below.  Using \c
              to include the output from more than one input line into the
              next-line argument of a .TP macro will render incorrectly with
              groff 1.22.3, mandoc 1.14.1, older versions of these programs,
              and perhaps with some other formatters.

       \e     Widely used in man pages to represent a backslash output
              glyph.  It works reliably as long as the .ec request is not
              used, which should never happen in man pages, and it is
              slightly more portable than the more exact \(rs (“reverse
              solidus”) special character escape sequence.

       \fB, \fI, \fR, \fP
              Switch to bold, italic, roman, or back to the previous style,
              respectively.  Either \f or \c is needed when three different
              font styles are required in a word.

                     .RB [ \-\-reference\-dictionary=\fI\,name\/\fP ]

                     .RB [ \-\-reference\-dictionary=\c
                     .IR name ]

              Style escapes may be more portable than \c.  As shown above,
              it is up to you to account for italic corrections with “\/”
              and “\,”, which are themselves GNU extensions, if desired and
              if supported by your implementation.

              Note that \fP reliably returns to the style in use immediately
              preceding the previous \f escape only if no sectioning, para‐
              graph, or style macro calls have intervened.

              As long as at most two styles are needed in a word, style
              macros like .B and .BI usually result in more readable roff
              source than \f escapes do.

       For maximum portability, escape sequences and special characters not
       listed above are better avoided in man pages.

   Deprecated features
       Use of the following in man pages for public distribution is discour‐
       aged.

       .AT [  system [release]] Alter the footer for use with legacy AT&T
              man pages, overriding any definition of the footer-inside
              argument to .TH.  This macro exists only for compatibility, to
              render man pages from historical systems.

              The first argument system can be:

                     3      7th edition (default)

                     4      System III

                     5      System V

              The optional second argument release specifies the release
              number, such as in “System V Release 3”.

       .BT    Set the page footer.  By redefining this macro (a GNU exten‐
              sion) in a man.local file (see section “Files” below), an
              adminsitrator can customize the footer for a site.

       .DT    Set tab stops every 0.5 inches.  Since this macro is always
              called during a .TH macro, it makes sense to call it only if
              the tab stops have been changed.

              Use of this presentation-level macro is deprecated.  It trans‐
              lates poorly to HTML, under which exact space control and tab‐
              ulation are not readily available.  Thus, information or dis‐
              tinctions that you use .DT to express are likely to be lost.
              If you feel tempted to use it, you should probably be compos‐
              ing a table using tbl(1) markup instead.

       .HP [  indent] Set up a paragraph with a hanging left indentation.
              The indent argument, if present, is handled as with .TP.

              Use of this presentation-level macro is deprecated.  While it
              is universally portable to legacy Unix systems, a hanging
              indentation cannot be expressed naturally under HTML, and
              HTML-based man page processors may interpret it as starting a
              normal paragraph.  Thus, any information or distinction you
              tried to express with the indentation may be lost.

       .PD [  vertical-space] Define the vertical space between paragraphs
              or (sub)sections.  The optional argument vertical-space speci‐
              fies the amount of space; the default scaling is ‘v’).  With‐
              out an argument, the spacing is reset to its default value;
              see subsection “Horizontal and vertical spacing” above.

              Use of this presentation-level macro is deprecated.  It trans‐
              lates poorly to HTML, under which exact control of inter-para‐
              graph spacing is not readily available.  Thus, information or
              distinctions that you use .PD to express are likely to be
              lost.

       .PT    Set the page header.  By redefining this macro (a GNU exten‐
              sion) in a man.local file (see section “Files” below), an
              adminsitrator can customize the header for a site.

       .UC [  version] Alter the footer for use with legacy BSD man pages,
              overriding any definition of the footer-inside argument to
              .TH.  This macro exists only for compatibility, to render man
              pages from historical systems.

              The argument version can be:

                     3      3rd Berkeley Distribution (default)

                     4      4th Berkeley Distribution

                     5      4.2 Berkeley Distribution

                     6      4.3 Berkeley Distribution

                     7      4.4 Berkeley Distribution

   History
       Version 7 Unix (1979) introduced the man macro package and supported
       all of the macros described in this page not listed as extensions,
       except .P, .SB, and the deprecated .AT and .UC.  The only strings
       defined were R and S; no number registers were documented.  .UC
       appeared in 3BSD (1980) and .P in Unix System III (1980).  4BSD
       (1980) added lq and rq strings.  4.3BSD (1986) added .AT and .P.
       Version 9 Unix (1986) introduced .EX and .EE.  Ultrix 11 (1988) added
       the Tm string.  SunOS 4.0 (1988) may have been the first to support
       .SB.

Options         top

       The following groff options set number registers recognized and used
       by the man macro package.

       -rcR=1 Continuous rendering.  Do not paginate the output; produce one
              (potentially very long) output page.  This is the default for
              terminal and HTML devices.  Use -rcR=0 to disable it.

       -rC1   Number output pages continuously.  If multiple man pages are
              processed, number the output pages in strictly increasing
              sequence, rather than resetting the page number to 1 at each
              new man page.

       -rCS=1 Capitalize section headings.  Set section headings (the
              argument(s) to .SH) in full capitals.  This transformation is
              off by default because it discards case distinction
              information.

       -rCT=1 Capitalize titles.  Set the man page title (the first argument
              to .TH) in full capitals in headers and footers.  This
              transformation is off by default because it discards case
              distinction information.

       -rD1   Enable double-sided layout.  Format footers for even and odd
              pages differently; see the description of .TH in subsection
              “Document structure macros” above.

       -rFT=footer-distance
              Set distance of the footer, relative to the bottom of the page
              if negative or top if positive, to footer-distance.  The
              default is -0.5i.

       -rHY=mode
              Set hyphenation mode, as documented in section “Hyphenation”
              of groff(7).  The default is 4 if continuous rendering is
              enabled (-rcR=1 above), and 6 otherwise.

       -rIN=indent
              Set the body text indentation (for normal paragraphs) to
              indent.  See subsection “Horizontal and vertical spacing”
              above for the default indentation value.  For terminal
              devices, indent should always be an integer multiple of unit
              ‘n’ to get consistent indentation.

       -rLL=line-length
              Set line length.  If this option is not given, the line length
              is set to respect any value set by a prior “.ll” request
              (which must be in effect when the .TH macro is invoked), if
              this differs from the built-in default for the formatter;
              otherwise it defaults to 78n for terminal devices and 6.5i for
              typesetter devices.

              Note that the use of a “.ll” request to initialize the line
              length is supported for backward compatibility with some
              versions of the man program; direct initialization of the LL
              register should always be preferred to the use of such a
              request.  In particular, note that a “.ll 65n” request does
              not preserve the default nroff line length (the man default
              initialization to 78n prevails), whereas the -rLL=65n option,
              or an equivalent “.nr LL 65n” request preceding the use of the
              .TH macro, does set a line length of 65n.

       -rLT=title-length
              Set title length, used for headers and footers.  If this
              option is not given, the title length defaults to the line
              length.

       -rPn   Start enumeration of pages at n rather than 1.

       -rSpoint-size
              Use point-size as the base document point size.  Acceptable
              values are 10, 11, or 12.  See subsection “Font style macros”
              above for the default.

       -rSN=subsection-indent
              Set subsection indentation to subsection-indent.  See
              subsection “Horizontal and vertical spacing” above for the
              default indentation value.

       -rXp   After page p, number pages as pa, pb, pc, and so forth.  For
              example, the option -rX2 produces the following page numbers:
              1, 2, 2a, 2b, 2c, and so on.

Files         top

       /usr/local/share/groff/1.22.4/tmac/man.tmac
       /usr/local/share/groff/1.22.4/tmac/an.tmac
              These are wrapper files to call andoc.tmac.

       /usr/local/share/groff/1.22.4/tmac/andoc.tmac
              This brief groff program detects whether the man or mdoc macro
              package is being used by a document and loads the correct
              macro definitions, taking advantage of the fact that pages
              using them must call .TH or .Dd, respectively, as their first
              macro.  Because the wrappers above load this file, a man
              program or user typing, for example, “groff -man page.1”, need
              not know which package the file page.1 uses.  Multiple man
              pages, in either format, can be handled.

       /usr/local/share/groff/1.22.4/tmac/an-old.tmac
              Most man macros are contained in this file.  It also loads the
              extensions from an-ext.tmac (see below).

       /usr/local/share/groff/1.22.4/tmac/an-ext.tmac
              The extension macro definitions for .SY, .OP, .YS, .TQ,
              .EX/.EE, .UR/.UE, and .MT/.ME are contained in this file,
              which is written to be compatible with AT&T troff and
              permissively licensed—not copylefted.  Man page authors
              concerned about portability to legacy Unix systems are
              encouraged to copy these definitions into their pages, and
              maintainers of troff implementations or work-alike systems
              that format man pages are encouraged to re-use them.

              Note that the definitions for these macros are read after the
              call of .TH, so they will replace any macros of the same names
              preceding it in your file.  If you use your own
              implementations of these macros, they must be defined after
              calling .TH to have any effect.

       /usr/local/share/groff/site-tmac/man.local
              Local changes and customizations should be put into this file.

Notes         top

       Some tips on troubleshooting your man pages follow.

       · .RS doesn't indent relative to my indented paragraph
              The .RS macro sets the indentation relative to that of a
              normal paragraph (.PP and its synonyms).  .RS, .IP, .TP, and
              the deprecated .HP all use the same default indentation.  To
              indent relative to an indented paragraph, call .RS repeatedly
              until an acceptable indentation is achieved, or give .RS an
              indentation argument that is at least as much as the
              paragraph's indentation amount relative to an adjacent .PP
              paragraph.  See subsection “Horizontal and vertical spacing”
              above for the values.

       · .RE doesn't reset the indent to the expected level
       · warning: scale indicator invalid in this context
       · warning: number register 'an-saved-margin
              n' not defined
       · warning: number register 'an-saved-prevailing-indent
              n' not defined The .RS macro takes an indentation amount as an
              argument; the .RE macro's argument is a specific indentation
              level.  .RE 1 goes to the level before any .RS macros were
              called, .RE 2 goes to the level of the first .RS call you
              made, and so forth.  If you desire symmetry in your macro
              calls, simply issue one .RE without an argument for each .RS
              that precedes it.

              After calls to the .SH and .SS sectioning macros, all relative
              indents are cleared and calls to .RE have no effect until .RS
              is used again.

Authors         top

       The GNU version of the man macro package was written by James Clark
       and contributors.  The extension macros were written by Werner
       Lemberg ⟨wl@gnu.org⟩ and Eric S. Raymond ⟨esr@thyrsus.com⟩.

       This document was originally written for the Debian GNU/Linux system
       by Susan G. Kleinmann ⟨sgk@debian.org⟩.  It was corrected and updated
       by Werner Lemberg and G. Branden Robinson.  The extension macros were
       documented by Eric S. Raymond; he also originated the portability
       section, to which Ingo Schwarze contributed most of the material on
       escape sequences.

See Also         top

       Groff: The GNU Implementation of troff, by Trent A. Fisher and Werner
       Lemberg, is the main groff documentation.  You can browse it
       interactively with “info groff”.

       tbl(1), eqn(1), and refer(1) are preprocessors used with man pages.

       man(1) describes the man page formatter on your system.

       groff_mdoc(7) describes the groff version of the BSD-originated
       alternative macro package for man pages.

       groff(7), groff_char(7), man(7)

COLOPHON         top

       This page is part of the groff (GNU troff) project.  Information
       about the project can be found at 
       ⟨http://www.gnu.org/software/groff/⟩.  If you have a bug report for
       this manual page, see ⟨http://www.gnu.org/software/groff/⟩.  This
       page was obtained from the project's upstream Git repository
       ⟨https://git.savannah.gnu.org/git/groff.git⟩ on 2020-07-14.  (At that
       time, the date of the most recent commit that was found in the repos‐
       itory was 2020-07-12.)  If you discover any rendering problems in
       this HTML version of the page, or you believe there is a better or
       more up-to-date source for the page, or you have corrections or
       improvements to the information in this COLOPHON (which is not part
       of the original manual page), send a mail to man-pages@man7.org

groff 1.22.4.234-3ba6           14 July 2020                    groff_man(7)

Pages that refer to this page: groff(1)grotty(1)groff_tmac(5)man(7)man-pages(7)