GROFF(7)                                               GROFF(7)



NAME
       groff - a short reference for the GNU roff language

DESCRIPTION
       The  name  groff  stands  for  GNU  roff and is the free
       implementation of the  roff  type-setting  system.   See
       roff(7)  for  a  survey  and the background of the groff
       system.

       This document gives only short descriptions of the  pre-
       defined  roff  language elements as used in groff.  Both
       the classical features and the groff extensions are pro-
       vided.

       Historically, the roff language was called troff.  groff
       is compatible with the  classical  system  and  provides
       proper  extensions.   So  in GNU, the terms roff, troff,
       and groff language could be used as  synonyms.   However
       troff  slightly  tends  to  refer  more to the classical
       aspects, whereas groff emphasizes  the  GNU  extensions,
       and roff is the general term for the language.

       This  file is only a short version of the complete docu-
       mentation that is found in the groff info(1) file, which
       contains more detailed, actual, and concise information.

       The general syntax for writing groff documents is  rela-
       tively easy, but writing extensions to the roff language
       can be a bit harder.

       The roff language is line-oriented.  There are only  two
       kinds  of lines, control lines and text lines.  The con-
       trol lines start with a control character, by default  a
       period  "."   or a single quote "'"; all other lines are
       text lines.

       Control lines represent commands, optionally with  argu-
       ments.   They  have  the  following syntax.  The leading
       control character can be followed  by  a  command  name;
       arguments,  if any, are separated by spaces (but not tab
       characters) from the command name and among  themselves,
       for example,

              .command_name arg1 arg2

       For  indentation,  any number of space or tab characters
       can be inserted between the  leading  control  character
       and  the command name, but the control character must be
       on the first position of the line.

       Text lines represent the parts that  is  printed.   They
       can  be  modified  by escape sequences, which are recog-
       nized by a leading backslash `\'.  These are in-line  or
       even  in-word formatting elements or functions.  Some of
       these take arguments separated  by  single  quotes  "'",
       others  are regulated by a length encoding introduced by
       an open parenthesis `(' or enclosed in brackets `['  and
       `]'.

       The  roff  language  provides  flexible  instruments for
       writing language extension, such as macros.  When inter-
       preting macro definitions, the roff system enters a spe-
       cial operating mode, called the copy mode.

       The copy mode behavior can be quite  tricky,  but  there
       are some rules that ensure a safe usage.

       1.     Printable  backslashes must be denoted as \e.  To
              be more precise, \e represents the current escape
              character.  To get a backslash glyph, use \(rs or
              \[rs].

       2.     Double all backslashes.

       3.     Begin all text lines with the special non-spacing
              character \&.

       This  does  not  produce the most efficient code, but it
       should work as a first measure.  For better  strategies,
       see the groff info file and groff_tmac(5).

       Reading  roff  source  files  is easier, just reduce all
       double backslashes to a single one in all macro  defini-
       tions.

GROFF ELEMENTS
       The roff language elements add formatting information to
       a text file.  The fundamental  elements  are  predefined
       commands  and variables that make roff a full-blown pro-
       gramming language.

       There are two kinds  of  roff  commands,  possibly  with
       arguments.   Requests are written on a line of their own
       starting with  a  dot  `.'  or  a  "'",  whereas  Escape
       sequences  are  in-line functions and in-word formatting
       elements starting with a backslash `\'.

       The user can define her own  formatting  commands  using
       the  de  request.  These commands are called macros, but
       they are used exactly like requests.  Macro packages are
       pre-defined  sets  of  macros  written in the groff lan-
       guage.   A  user's  possibilities   to   create   escape
       sequences  herself is very limited, only special charac-
       ters can be mapped.

       The groff language provides several kinds  of  variables
       with  different interfaces.  There are pre-defined vari-
       ables, but the user can  define  her  own  variables  as
       well.

       String  variables  store  character sequences.  They are
       set with the ds request and retrieved by the  \*  escape
       sequences.  Strings can have variables.

       Register  variables  can store numerical values, numbers
       with a scale unit, and occasionally string-like objects.
       They are set with the nr request and retrieved by the \n
       escape sequences.

       Environments allow the user to temporarily store  global
       formatting  parameters like line length, font size, etc.
       for later reuse.  This is done by the ev request.

       Fonts are identified either by a name or by an  internal
       number.  The current font is chosen by the ft request or
       by the \f escape sequences.   Each  device  has  special
       fonts,  but  the  following  fonts are available for all
       devices.  R is the standard font Roman.  B is  its  bold
       counterpart.   The italic font is called I and is avail-
       able everywhere, but on text devices it is displayed  as
       an  underlined  Roman  font.   For  the graphical output
       devices, there exist constant-width  pendants  of  these
       fonts, CR, CI, and CB.  On text devices, all glyphs have
       a constant width anyway.

       Glyphs are visual representation  forms  of  characters.
       In  groff, the distinction between those two elements is
       not always obvious (and a full discussion is beyond  the
       scope  of this man page).  A first approximation is that
       glyphs have a specific size and  colour  and  are  taken
       from  a specific font; they can't be modified any more -
       characters are the input, and glyphs are the output.  As
       soon  as an output line has been generated, it no longer
       contains characters but glyphs.  In this  man  page,  we
       use  either  `glyph'  or  `character',  whatever is more
       appropriate.

       Moreover, there are  some  advanced  roff  elements.   A
       diversion  stores  (formatted)  information into a macro
       for later usage.  A trap is a positional condition  like
       a  certain  number of lines from page top or in a diver-
       sion or in the input.  Some action can be prescribed  to
       be run automatically when the condition is met.

       More  detailed  information and examples can be found in
       the groff info file.

CONTROL CHARACTERS
       There is a small set of characters that have  a  special
       controlling task in certain conditions.

       .      A  dot is only special at the beginning of a line
              or after the condition in the  requests  if,  ie,
              el, and while.  There it is the control character
              that introduces a request (or macro).   The  spe-
              cial  behavior  can  be  delayed  by using the \.
              escape.  By using the  cc  request,  the  control
              character  can  be  set to a different character,
              making the dot `.' a non-special character.

              In all other positions, it just means a dot char-
              acter.  In text paragraphs, it is advantageous to
              start each sentence at a line of its own.

       '      The single quote has two controlling  tasks.   At
              the  beginning  of  a line and in the conditional
              requests it is the non-breaking  control  charac-
              ter.   That  means  that  it introduces a request
              like the dot, but with  the  additional  property
              that  this request doesn't cause a linebreak.  By
              using the c2 request, the non-break control char-
              acter can be set to a different character.

              As  a  second  task, it is the most commonly used
              argument  separator  in  some  functional  escape
              sequences (but any pair of characters not part of
              the argument do work).  In all  other  positions,
              it denotes the single quote or apostrophe charac-
              ter.  Groff provides a  printable  representation
              with the \(cq escape sequence.

       "      The  double quote is used to enclose arguments in
              macros (but not in requests and strings).  In the
              ds and as requests, a leading double quote in the
              argument is stripped off, making everything  else
              afterwards  the  string  to  be defined (enabling
              leading whitespace).  The escaped double quote \"
              introduces  a comment.  Otherwise, it is not spe-
              cial.  Groff provides a printable  representation
              with the \(dq escape sequence.

       \      The   backslash   usually  introduces  an  escape
              sequence  (this  can  be  changed  with  the   ec
              request).   A printed version of the escape char-
              acter is the \e escape; a backslash glyph can  be
              obtained by \(rs.

       (      The  open  parenthesis  is only special in escape
              sequences when  introducing  an  escape  name  or
              argument  consisting  of  exactly two characters.
              In groff, this behavior can be replaced by the []
              construct.

       [      The  opening  bracket  is  only  special in groff
              escape sequences; there it is used to introduce a
              long escape name or long escape argument.  Other-
              wise, it is non-special, e.g. in macro calls.

       ]      The closing bracket  is  only  special  in  groff
              escape  sequences;  there  it  terminates  a long
              escape name or long escape argument.   Otherwise,
              it is non-special.

       space  Space  characters are only functional characters.
              They separate the arguments in requests,  macros,
              and  strings,  and the words in text lines.  They
              are subject to groff's horizontal spacing  calcu-
              lations.   To  get  a defined space width, escape
              sequences like `\ ' (this is the escape character
              followed  by  a  space),  \|, \^, or \h should be
              used.

       newline
              In text paragraphs, newlines mostly  behave  like
              space  characters.   Continuation  lines  can  be
              specified by an escaped newline, i.e., by  speci-
              fying  a backslash `\' as the last character of a
              line.

       tab    If a tab character occurs during text the  inter-
              preter  makes  a horizontal jump to the next pre-
              defined tab position.  There is  a  sophisticated
              interface for handling tab positions.

NUMERICAL EXPRESSIONS
       A  numerical  value  is  a signed or unsigned integer or
       float with or without an appended scaling indicator.   A
       scaling  indicator is a one-character abbreviation for a
       unit of measurement.  A number  followed  by  a  scaling
       indicator signifies a size value.  By default, numerical
       values do not have a scaling indicator, i.e.,  they  are
       normal numbers.

       The  roff language defines the following scaling indica-
       tors.

              c         Centimeter
              i         Inch
              P         Pica = 1/6 inch
              p         Point = 1/72 inch
              m         Em = the font size in  points  (approx.
                        width of letter `m')
              M         100th of an Em
              n         En = Em/2
              u         Basic unit for actual output device
              v         Vertical  line  space  in  basic  units
                        scaled point = 1/sizescale of  a  point
                        (defined in font DESC file)
              f         Scale by 65536.

       Numerical  expressions are combinations of the numerical
       values defined above  with  the  following  arithmetical
       operators already defined in classical troff.

              +         Addition
              -         Subtraction
              *         Multiplication
              /         Division
              %         Modulo
              =         Equals
              ==        Equals
              <         Less than
              >         Greater than
              <=        Less or equal
              >=        Greater or equal
              &         Logical and
              :         Logical or
              !         Logical not
              (         Grouping of expressions
              )         Close current grouping

       Moreover, groff added the following operators for numer-
       ical expressions:

              e1>?e2    The maximum of e1 and e2.
              e1<?e2    The minimum of e1 and e2.
              (c;e)     Evaluate e using c as the default scal-
                        ing indicator.

       For details see the groff info file.

CONDITIONS
       Conditions  occur in tests raised by the if, ie, and the
       while requests.  The following table  characterizes  the
       different types of conditions.

              N         A numerical expression N yields true if
                        its value is greater than 0.
              !N        True if the value of I is 0.
              's1's2'   True  if  string  s1  is  identical  to
                        string s2.
              !'s1's2'  True  if  string s1 is not identical to
                        string s2.
              cch       True if there is a glyph ch  available.
              dname     True  if  there  is  a  string,  macro,
                        diversion, or request called name.
              e         Current page number is even.
              o         Current page number is odd.
              mname     True if there is a color called name.
              n         Formatter is nroff.
              rreg      True if there is a register named  reg.
              t         Formatter is troff.
              Ffont     True if there exists a font named font.
              Sstyle    True if a style named  style  has  been
                        registered.

REQUESTS
       This  section  provides a short reference for the prede-
       fined requests.  In groff, request,  macro,  and  string
       names can be arbitrarily long.  No bracketing or marking
       of long names is needed.

       Most requests take one or more arguments.  The arguments
       are  separated  by space characters (no tabs!); there is
       no inherent limit for their length or number.

       Some requests have optional arguments with  a  different
       behaviour.   Not all of these details are outlined here.
       Refer to the groff info file and groff_diff(7)  for  all
       details.

       In  the  following request specifications, most argument
       names were chosen to be descriptive.  Only the following
       denotations need clarification.

              c         denotes a single character.
              font      a  font either specified as a font name
                        or a font number.
              anything  all characters up to  the  end  of  the
                        line or within \{ and \}.
              n         is  a  numerical expression that evalu-
                        ates to an integer value.
              N         is an arbitrary  numerical  expression,
                        signed or unsigned.
              N        has  three  meanings  depending  on its
                        sign, described below.

       If an expression defined as N starts with  a  `+'  sign
       the  resulting  value  of  the expression is added to an
       already existing value inherent to the related  request,
       e.g.  adding  to  a  number register.  If the expression
       starts with a `-' the value of the  expression  is  sub-
       tracted from the request value.

       Without  a sign, N replaces the existing value directly.
       To assign a negative number either prepend 0 or  enclose
       the negative number in parentheses.

   Request Short Reference
       .         Empty  line,  ignored.  Useful for structuring
                 documents.
       .\" anything
                 Complete line is a comment.
       .ab string
                 Print string on standard error, exit  program.
       .ad       Begin line adjustment for output lines in cur-
                 rent adjust mode.
       .ad c     Start line adjustment in mode c (c=l,r,b,n).
       .af register c
                 Assign format c to register (c=l,i,I,a,A).
       .aln alias register
                 Create alias name for register.
       .als alias object
                 Create alias name for request, string,  macro,
                 or diversion object.
       .am macro Append to macro until .. is encountered.
       .am macro end
                 Append to macro until .end is called.
       .am1 macro
                 Same   as  .am  but  with  compatibility  mode
                 switched off during macro expansion.
       .am1 macro end
                 Same  as  .am  but  with  compatibility   mode
                 switched off during macro expansion.
       .ami macro
                 Append  to  a macro whose name is contained in
                 the string register macro until .. is  encoun-
                 tered.
       .ami macro end
                 Append  to  a macro indirectly.  macro and end
                 are string registers whose contents are inter-
                 polated  for the macro name and the end macro,
                 respectively.
       .ami1 macro
                 Same  as  .ami  but  with  compatibility  mode
                 switched off during macro expansion.
       .ami1 macro end
                 Same  as  .ami  but  with  compatibility  mode
                 switched off during macro expansion.
       .as stringvar anything
                 Append anything to stringvar.
       .as1 stringvar anything
                 Same  as  .as  but  with  compatibility   mode
                 switched off during string expansion.
       .asciify diversion
                 Unformat  ASCII  characters,  spaces, and some
                 escape sequences in diversion.
       .backtrace
                 Print a backtrace of the input on stderr.
       .bd font N
                 Embolden font by N-1 units.
       .bd S font N
                 Embolden Special Font S when current  font  is
                 font.
       .blm      Unset the blank line macro.
       .blm macro
                 Set the blank line macro to macro.
       .box      End current diversion.
       .box macro
                 Divert  to  macro, omitting a partially filled
                 line.
       .boxa     End current diversion.
       .boxa macro
                 Divert and append to macro,  omitting  a  par-
                 tially filled line.
       .bp       Eject current page and begin new page.
       .bp N    Eject current page; next page number N.
       .br       Line break.
       .brp      Break and spread output line.  Same as \p.
       .break    Break out of a while loop.
       .c2       Reset no-break control character to "'".
       .c2 c     Set no-break control character to c.
       .cc       Reset control character to `.'.
       .cc c     Set control character to c.
       .ce       Center the next input line.
       .ce N     Center following N input lines.
       .cf filename
                 Copy  contents of file filename unprocessed to
                 stdout or to the diversion.
       .cflags mode c1 c2 ...
                 Treat characters c1, c2, ... according to mode
                 number.
       .ch trap N
                 Change trap location to N.
       .char c anything
                 Define entity c as string anything.
       .chop object
                 Chop  the last character off macro, string, or
                 diversion object.
       .close stream
                 Close the stream.
       .color    Enable colors.
       .color N  If N is zero disable colors, otherwise  enable
                 them.
       .composite from to
                 Map  glyph  name  from  to glyph name to while
                 constructing a composite glyph name.
       .continue Finish the current iteration of a while  loop.
       .cp       Enable compatibility mode.
       .cp N     If  N is zero disable compatibility mode, oth-
                 erwise enable it.
       .cs font N M
                 Set constant character width mode for font  to
                 N/36 ems with em M.
       .cu N     Continuous  underline  in  nroff,  like .ul in
                 troff.
       .da       End current diversion.
       .da macro Divert and append to macro.
       .de macro Define or redefine macro until ..  is  encoun-
                 tered.
       .de macro end
                 Define or redefine macro until .end is called.
       .de1 macro
                 Same  as  .de  but  with  compatibility   mode
                 switched off during macro expansion.
       .de1 macro end
                 Same   as  .de  but  with  compatibility  mode
                 switched off during macro expansion.
       .defcolor color scheme component
                 Define or redefine a color  with  name  color.
                 scheme  can  be rgb, cym, cymk, gray, or grey.
                 component can be single  components  specified
                 as  fractions  in  the  range  0 to 1 (default
                 scaling indicator f), as a string of two-digit
                 hexadecimal color components with a leading #,
                 or as a string of four-digit hexadecimal  com-
                 ponents with two leading #.  The color default
                 can't be redefined.
       .dei macro
                 Define or redefine a macro whose name is  con-
                 tained  in  the string register macro until ..
                 is encountered.
       .dei macro end
                 Define or redefine a macro indirectly.   macro
                 and  end  are  string registers whose contents
                 are interpolated for the macro  name  and  the
                 end macro, respectively.
       .dei1 macro
                 Same  as  .dei  but  with  compatibility  mode
                 switched off during macro expansion.
       .dei1 macro end
                 Same  as  .dei  but  with  compatibility  mode
                 switched off during macro expansion.
       .device anything
                 Write anything to the intermediate output as a
                 device control function.
       .devicem name
                 Write contents of macro or string  name  unin-
                 terpreted  to  the  intermediate  output  as a
                 device control function.
       .di       End current diversion.
       .di macro Divert to macro.
       .do name  Interpret .name with compatibility  mode  dis-
                 abled.
       .ds stringvar anything
                 Set stringvar to anything.
       .ds1 stringvar anything
                 Same   as  .ds  but  with  compatibility  mode
                 switched off during string expansion.
       .dt N trap
                 Set diversion  trap  to  position  N  (default
                 scaling indicator v).
       .ec       Reset escape character to `\'.
       .ec c     Set escape character to c.
       .ecr      Restore escape character saved with .ecs.
       .ecs      Save current escape character.
       .el anything
                 Else part for if-else (ie) request.
       .em macro The macro is run after the end of input.
       .eo       Turn off escape character mechanism.
       .ev       Switch  to previous environment and pop it off
                 the stack.
       .ev env   Push down environment number or  name  env  to
                 the stack and switch to it.
       .evc env  Copy  the  contents  of environment env to the
                 current environment.  No pushing or popping.
       .ex       Exit from roff processing.
       .fam      Return to previous font family.
       .fam name Set the current font family to name.
       .fc       Disable field mechanism.
       .fc a     Set field delimiter to  a  and  pad  glyph  to
                 space.
       .fc a b   Set field delimiter to a and pad glyph to b.
       .fchar c anything
                 Define  fallback  character  (or  glyph)  c as
                 string anything.
       .fcolor   Set fill color to previous fill color.
       .fcolor c Set fill color to c.
       .fi       Fill output lines.
       .fl       Flush output buffer.
       .fp n font
                 Mount font on position n.
       .fp n internal external
                 Mount font with long external  name  to  short
                 internal name on position n.
       .fschar f c anything
                 Define  fallback  character  (or  glyph) c for
                 font f as string anything.
       .fspecial font
                 Reset list of special fonts  for  font  to  be
                 empty.
       .fspecial font s1 s2 ...
                 When  the current font is font, then the fonts
                 s1, s2, ... are special.
       .ft       Return to previous font.  Same as \f[] or \fP.
       .ft font  Change  to  font  name or number font; same as
                 \f[font] escape sequence.
       .ftr font1 font2
                 Translate font1 to font2.
       .fzoom font
                 Don't magnify font.
       .fzoom font zoom
                 Set zoom factor  for  font  (in  multiples  of
                 1/1000th).
       .gcolor   Set glyph color to previous glyph color.
       .gcolor c Set glyph color to c.
       .hc       Remove  additional hyphenation indicator char-
                 acter.
       .hc c     Set up additional hyphenation indicator  char-
                 acter c.
       .hcode c1 code1 c2 code2 ...
                 Set  the  hyphenation  code of character c1 to
                 code1, that of c2 to code2, etc.
       .hla lang Set the current hyphenation language to  lang.
       .hlm n    Set  the maximum number of consecutive hyphen-
                 ated lines to n.
       .hpf file Read hyphenation patterns from file.
       .hpfa file
                 Append hyphenation patterns from file.
       .hpfcode a b c d ...
                 Set input mapping for .hpf.
       .hw words List of words with exceptional hyphenation.
       .hy N     Switch to hyphenation mode N.
       .hym n    Set the hyphenation margin to n (default scal-
                 ing indicator m).
       .hys n    Set the hyphenation space to n.
       .ie cond anything
                 If cond then anything else goto .el.
       .if cond anything
                 If cond then anything; otherwise do nothing.
       .ig       Ignore text until .. is encountered.
       .ig end   Ignore text until .end is called.
       .in       Change to previous indentation value.
       .in N    Change  indentation  according  to N (default
                 scaling indicator m).
       .it N trap
                 Set an input-line count trap for  the  next  N
                 lines.
       .itc N trap
                 Same  as  .it but count lines interrupted with
                 \c as one line.
       .kern     Enable pairwise kerning.
       .kern n   If n is zero, disable pairwise kerning, other-
                 wise enable it.
       .lc       Remove leader repetition glyph.
       .lc c     Set leader repetition glyph to c.
       .length register anything
                 Write  the  length  of  the string anything to
                 register.
       .linetabs Enable line-tabs  mode  (i.e.,  calculate  tab
                 positions relative to output line).
       .linetabs n
                 If  n  is zero, disable line-tabs mode, other-
                 wise enable it.
       .lf N     Set input line number to N.
       .lf N file
                 Set input line number to  N  and  filename  to
                 file.
       .lg N     Ligature mode on if N>0.
       .ll       Change to previous line length.
       .ll N    Set  line  length  according  to  N  (default
                 length 6.5i, default scaling indicator m).
       .ls       Change to the  previous  value  of  additional
                 intra-line skip.
       .ls N     Set  additional  intra-line  skip  value to N,
                 i.e., N-1 blank lines are inserted after  each
                 text output line.
       .lt N    Length of title (default scaling indicator m).
       .mc       Margin glyph off.
       .mc c     Print glyph c after each text line  at  actual
                 distance from right margin.
       .mc c N   Set  margin  glyph to c and distance to N from
                 right margin (default scaling indicator m).
       .mk register
                 Mark current vertical position in register.
       .mso file The same as .so except that file  is  searched
                 in the tmac directories.
       .na       No output-line adjusting.
       .ne       Need a one-line vertical space.
       .ne N     Need N vertical space (default scaling indica-
                 tor v).
       .nf       No filling or adjusting of output-lines.
       .nh       No hyphenation.
       .nm       Number mode off.
       .nm N [M [S [I]]]
                 In line number  mode,  set  number,  multiple,
                 spacing, and indentation.
       .nn       Do not number next line.
       .nn N     Do not number next N lines.
       .nop anything
                 Always process anything.
       .nr register N [M]
                 Define  or modify register using N with auto-
                 increment M.
       .nroff    Make the built-in  conditions  n  true  and  t
                 false.
       .ns       Turn on no-space mode.
       .nx       Immediately jump to end of current file.
       .nx filename
                 Immediately   continue  processing  with  file
                 file.
       .open stream filename
                 Open filename for writing  and  associate  the
                 stream named stream with it.
       .opena stream filename
                 Like .open but append to it.
       .os       Output vertical distance that was saved by the
                 sv request.
       .output string
                 Emit string directly to  intermediate  output,
                 allowing  leading  whitespace if string starts
                 with " (which is stripped off).
       .pc       Reset page number character to `%'.
       .pc c     Page number character.
       .pev      Print the current environment and each defined
                 environment state to stderr.
       .pi program
                 Pipe output to program (nroff only).
       .pl       Set  page  length to default 11i.  The current
                 page length is stored in register .p.
       .pl N    Change page  length  to  N  (default  scaling
                 indicator v).
       .pm       Print  macro names and sizes (number of blocks
                 of 128 bytes).
       .pm t     Print only total of sizes of macros (number of
                 128 bytes blocks).
       .pn N    Next page number N.
       .pnr      Print  the names and contents of all currently
                 defined number registers on stderr.
       .po       Change to previous page offset.   The  current
                 page offset is available in register .o.
       .po N    Page offset N.
       .ps       Return to previous point size.
       .ps N    Point size; same as \s[N].
       .psbb filename
                 Get  the  bounding  box  of a PostScript image
                 filename.
       .pso command
                 This behaves like the so request  except  that
                 input  comes  from the standard output of com-
                 mand.
       .ptr      Print the names and  positions  of  all  traps
                 (not  including input line traps and diversion
                 traps) on stderr.
       .pvs      Change to previous post-vertical line spacing.
       .pvs N   Change post-vertical line spacing according to
                 N (default scaling indicator p).
       .rchar c1 c2 ...
                 Remove the definitions of entities c1, c2, ...
       .rd prompt
                 Read insertion.
       .return   Return from a macro.
       .return anything
                 Return  twice,  namely  from  the macro at the
                 current level and from  the  macro  one  level
                 higher.
       .rfschar f c1 c2 ...
                 Remove the definitions of entities c1, c2, ...
                 for font f.
       .rj n     Right justify the next n input lines.
       .rm name  Remove request, macro, or string name.
       .rn old new
                 Rename request, macro, or string old to new.
       .rnn reg1 reg2
                 Rename register reg1 to reg2.
       .rr register
                 Remove register.
       .rs       Restore spacing; turn no-space mode off.
       .rt N    Return (upward only) to marked vertical  place
                 (default scaling indicator v).
       .schar c anything
                 Define  global fallback character (or glyph) c
                 as string anything.
       .shc      Reset soft hyphen glyph to \(hy.
       .shc c    Set the soft hyphen glyph to c.
       .shift n  In a macro, shift the  arguments  by  n  posi-
                 tions.
       .sizes s1 s2 ... sn [0]
                 Set  available font sizes similar to the sizes
                 command in a DESC file.
       .so filename
                 Include source file.
       .sp       Skip one line vertically.
       .sp N     Space vertical distance N up or down according
                 to sign of N (default scaling indicator v).
       .special  Reset  global  list  of  special  fonts  to be
                 empty.
       .special s1 s2 ...
                 Fonts  s1,  s2,  etc.  are  special  and   are
                 searched for glyphs not in the current font.
       .spreadwarn
                 Toggle  the  spread warning on and off without
                 changing its value.
       .spreadwarn limit
                 Emit a warning if each space in an output line
                 is  widened  by limit or more (default scaling
                 indicator m).
       .ss N     Set space glyph size  to  N/12  of  the  space
                 width in the current font.
       .ss N M   Set  space  glyph  size  to  N/12 and sentence
                 space size set to M/12 of the space  width  in
                 the current font.
       .sty n style
                 Associate style with font position n.
       .substring xx n1 n2
                 Replace the string named xx with the substring
                 defined by the indices n1 and n2.
       .sv       Save 1 v of vertical space.
       .sv N     Save the vertical distance N for later  output
                 with os request (default scaling indicator v).
       .sy command-line
                 Execute program command-line.
       .ta T N   Set tabs after every position that is a multi-
                 ple of N (default scaling indicator m).
       .ta n1 n2 ... nn T r1 r2 ... rn
                 Set  tabs  at  positions n1, n2, ..., nn, then
                 set tabs at nn+r1, nn+r2, ..., nn+rn, then  at
                 nn+rn+r1,  nn+rn+r2, ..., nn+rn+rn, and so on.
       .tc       Remove tab repetition glyph.
       .tc c     Set tab repetition glyph to c.
       .ti N    Temporary indent next  line  (default  scaling
                 indicator m).
       .tkf font s1 n1 s2 n2
                 Enable track kerning for font.
       .tl 'left'center'right'
                 Three-part title.
       .tm anything
                 Print anything on stdout.
       .tm1 anything
                 Print  anything  on  stdout,  allowing leading
                 whitespace if anything starts with " (which is
                 stripped off).
       .tmc anything
                 Similar  to .tm1 without emitting a final new-
                 line.
       .tr abcd...
                 Translate a to b, c to d, etc. on output.
       .trf filename
                 Transparently  output  the  contents  of  file
                 filename.
       .trin abcd...
                 This is the same as the tr request except that
                 the asciify request uses  the  character  code
                 (if any) before the character translation.
       .trnt abcd...
                 This is the same as the tr request except that
                 the translations do not apply to text that  is
                 transparently throughput into a diversion with
                 \!.
       .troff    Make the built-in  conditions  t  true  and  n
                 false.
       .uf font  Set  underline font to font (to be switched to
                 by .ul).
       .ul N     Underline (italicize in troff) N input  lines.
       .unformat diversion
                 Unformat  space  characters and tabs in diver-
                 sion, preserving font information.
       .vpt n    Enable vertical position traps if  n  is  non-
                 zero, disable them otherwise.
       .vs       Change to previous vertical base line spacing.
       .vs N    Set vertical base line spacing to N  (default
                 scaling indicator p).
       .warn n   Set warnings code to n.
       .warnscale si
                 Set  scaling indicator used in warnings to si.
       .wh N     Remove (first) trap at position N.
       .wh N trap
                 Set location trap; negative  means  from  page
                 bottom.
       .while cond anything
                 While  condition cond is true, accept anything
                 as input.
       .write stream anything
                 Write anything to the stream named stream.
       .writec stream anything
                 Similar to .write  without  emitting  a  final
                 newline.
       .writem stream xx
                 Write  contents  of  macro or string xx to the
                 stream named stream.

       Besides these standard groff requests,  there  might  be
       further  macro  calls.   They can originate from a macro
       package (see roff(7) for an overview)  or  from  a  pre-
       processor.

       Preprocessor  macros  are  easy  to be recognized.  They
       enclose their code into a pair of characteristic macros.


              +-------------+-------------+------------+
              |preprocessor | start macro |  end macro |
              +-------------+-------------+------------+
              |    eqn      |     .EQ     |    .EN     |
              |    grap     |     .G1     |    .G2     |
              |    grn      |     .GS     |    .GE     |
              |    pic      |     .PS     |    .PE     |
              |   refer     |     .R1     |    .R2     |
              |   soelim    |    none     |    none    |
              |    tbl      |     .TS     |    .TE     |
              +-------------+-------------+------------+

ESCAPE SEQUENCES
       Escape  sequences  are in-line language elements usually
       introduced by a backslash `\' and followed by an  escape
       name  and  sometimes by a required argument.  Input pro-
       cessing is continued directly after the escaped  charac-
       ter  or  the argument (without an intervening separation
       character).  So there must be a way to determine the end
       of the escape name and the end of the argument.

       This  is  done by enclosing names (escape name and argu-
       ments consisting of a variable name) by a pair of brack-
       ets  [name]  and  constant arguments (number expressions
       and characters) by apostrophes (ASCII 0x27)  like  'con-
       stant'.

       There  are abbreviations for short names.  Two-character
       escape names can be specified by an opening  parenthesis
       like  \(xy  or \*(xy without a closing counterpart.  And
       all one-character names different from the special char-
       acters  `['  and  `('  can  even  be specified without a
       marker, for example \nc or \$c.

       Constant arguments of length 1 can omit the marker apos-
       trophes, too, but there is no two-character analogue.

       While one-character escape sequences are mainly used for
       in-line functions and system related tasks, the two-let-
       ter  names  following the \( construct are glyphs prede-
       fined by the roff  system;  these  are  called  `Special
       Characters'  in  the  classical  documentation.  Escapes
       sequences of the form \[name] denote glyphs too.

   Single-Character Escapes
       \"     Start of a comment.  Everything up to the end  of
              the line is ignored.
       \#     Everything  up  to and including the next newline
              is ignored.  This is interpreted  in  copy  mode.
              This  is like \" except that the terminating new-
              line is ignored as well.
       \*s    The string stored in  the  string  variable  with
              one-character name s.
       \*(st  The  string  stored  in  the string variable with
              two-character name st.
       \*[string]
              The string stored in  the  string  variable  with
              name string (with arbitrary length).
       \*[stringvar arg1 arg2 ...]
              The  string  stored  in  the string variable with
              arbitrarily long  name  stringvar,  taking  arg1,
              arg2, ... as arguments.
       \$0    The  name by which the current macro was invoked.
              The als request can make a macro have  more  than
              one name.
       \$x    Macro  or string argument with one-digit number x
              in the range 1 to 9.
       \$(xy  Macro or string argument with two-digit number xy
              (larger than zero).
       \$[nexp]
              Macro  or string argument with number nexp, where
              nexp is a numerical expression evaluating  to  an
              integer >=1.
       \$*    In  a  macro  or string, the concatenation of all
              the arguments separated by spaces.
       \$@    In a macro or string, the  concatenation  of  all
              the  arguments  with  each  surrounded  by double
              quotes, and separated by spaces.
       \$^    In a macro, the representation of all  parameters
              as if they were an argument to the ds request.
       \\     reduces  to  a  single backslash; useful to delay
              its interpretation as escape  character  in  copy
              mode.  For a printable backslash, use \e, or even
              better \[rs], to be independent from the  current
              escape character.
       \'     The  acute  accent  ;  same as \(aa.  Unescaped:
              apostrophe, right quotation  mark,  single  quote
              (ASCII 0x27).
       \`     The  grave  accent  `;  same as \(ga.  Unescaped:
              left quote, backquote (ASCII 0x60).
       \-     The - (minus) sign in the current font.
       \_     The same as \(ul, the underline character.
       \.     An uninterpreted dot (period), even at  start  of
              line.
       \%     Default optional hyphenation character.
       \!     Transparent line indicator.
       \?anything?
              In  a  diversion,  this transparently embeds any-
              thing in the diversion.  anything is read in copy
              mode.   See also the escape sequences \!  and \?.
       \space Unpaddable  space  size  space  glyph  (no   line
              break).
       \0     Digit-width space.
       \|     1/6 em narrow space glyph; zero width in nroff.
       \^     1/12 em  half-narrow  space  glyph; zero width in
              nroff.
       \&     Non-printable, zero-width glyph.
       \)     Like \& except  that  it  behaves  like  a  glyph
              declared  with the cflags request to be transpar-
              ent for the purposes of end-of-sentence  recogni-
              tion.
       \/     Increases  the  width  of  the preceding glyph so
              that the spacing between that glyph and the  fol-
              lowing glyph is correct if the following glyph is
              a roman glyph.
       \,     Modifies the spacing of the  following  glyph  so
              that  the spacing between that glyph and the pre-
              ceding glyph is correct if the preceding glyph is
              a roman glyph.
       \~     Unbreakable  space  that  stretches like a normal
              inter-word space when a line is adjusted.
       \:     Inserts a zero-width break point (similar  to  \%
              but without a soft hyphen character).
       \newline
              Ignored newline, for continuation lines.
       \{     Begin conditional input.
       \}     End conditional input.
       \(sc   A  glyph  with two-character name sc; see section
              Special Characters.
       \[name]
              A glyph with name name (of arbitrary length).
       \[comp1 comp2 ...]
              A composite glyph with components  comp1,  comp2,
              ...
       \a     Non-interpreted leader character.
       \A'anything'
              If  anything is acceptable as a name of a string,
              macro, diversion, register, environment  or  font
              it expands to 1, and to 0 otherwise.
       \b'abc...'
              Bracket building function.
       \B'anything'
              If  anything  is  acceptable  as  a valid numeric
              expression it expands to 1, and to 0 otherwise.
       \c     Interrupt text processing.
       \C'glyph'
              The glyph called glyph;  same  as  \[glyph],  but
              compatible to other roff versions.
       \d     Forward (down) 1/2 em (1/2 line in nroff).
       \D'charseq'
              Draw  a  graphical element defined by the charac-
              ters in charseq; see  the  groff  info  file  for
              details.
       \e     Printable  version  of the current escape charac-
              ter.
       \E     Equivalent to an escape  character,  but  is  not
              interpreted in copy mode.
       \fF    Change  to  font  with one-character name or one-
              digit number F.
       \fP    Switch back to previous font.
       \f(fo  Change to font with two-character  name  or  two-
              digit number fo.
       \f[font]
              Change to font with arbitrarily long name or num-
              ber expression font.
       \f[]   Switch back to previous font.
       \Ff    Change to font family with one-character name  f.
       \F(fm  Change to font family with two-character name fm.
       \F[fam]
              Change to font family with arbitrarily long  name
              fam.
       \F[]   Switch back to previous font family.
       \gr    Return  format  of  register  with  one-character
              name r suitable for af request.
       \g(rg  Return format of register with two-character name
              rg suitable for af request.
       \g[reg]
              Return  format  of register with arbitrarily long
              name reg suitable for af request.
       \h'N'  Local horizontal motion; move right  N  (left  if
              negative).
       \H'N'  Set height of current font to N.
       \kr    Mark horizontal input place in one-character reg-
              ister r.
       \k(rg  Mark horizontal input place in two-character reg-
              ister rg.
       \k[reg]
              Mark  horizontal  input  place  in  register with
              arbitrarily long name reg.
       \l'Nc' Horizontal  line  drawing  function   (optionally
              using character c).
       \L'Nc' Vertical  line drawing function (optionally using
              character c).
       \mc    Change to color with one-character name c.
       \m(cl  Change to color with two-character name cl.
       \m[color]
              Change to color with arbitrarily long name color.
       \m[]   Switch back to previous color.
       \Mc    Change  filling color for closed drawn objects to
              color with one-character name c.
       \M(cl  Change filling color for closed drawn objects  to
              color with two-character name cl.
       \M[color]
              Change  filling color for closed drawn objects to
              color with arbitrarily long name color.
       \M[]   Switch to previous fill color.
       \nr    The numerical value stored in the register  vari-
              able with the one-character name r.
       \n(re  The  numerical value stored in the register vari-
              able with the two-character name re.
       \n[reg]
              The numerical value stored in the register  vari-
              able with arbitrarily long name reg.
       \N'n'  Typeset  the  glyph  with  index n in the current
              font.  No special fonts are searched.  Useful for
              adding  (named)  entities to a document using the
              char request and friends.
       \o'abc...'
              Overstrike glyphs a, b, c, etc.
       \O0    Disable glyph output.  Mainly for internal use.
       \O1    Enable glyph output.  Mainly for internal use.
       \p     Break and spread output line.
       \r     Reverse 1 em vertical  motion  (reverse  line  in
              nroff).
       \R'name n'
              The same as .nr name n.
       \sN   Set/increase/decrease  the  point  size  to/by  N
              scaled points; N is a  one-digit  number  in  the
              range 1 to 9.  Same as ps request.
       \s(N  \s(N  Set/increase/decrease the point size to/by
              N scaled points; N is  a  two-digit  number  >=1.
              Same as ps request.
       \s[N] \s[N]  \s'N'  \s'N'  Set/increase/decrease the
              point size to/by N scaled  points.   Same  as  ps
              request.
       \S'N'  Slant output by N degrees.
       \t     Non-interpreted horizontal tab.
       \u     Reverse  (up) 1/2 em vertical motion (1/2 line in
              nroff).
       \v'N'  Local vertical motion; move down N (up  if  nega-
              tive).
       \Ve    The  contents  of  the  environment variable with
              one-character name e.
       \V(ev  The contents of  the  environment  variable  with
              two-character name ev.
       \V[env]
              The  contents  of  the  environment variable with
              arbitrarily long name env.
       \w'string'
              The width of the glyph sequence string.
       \x'N'  Extra line-space function (negative before, posi-
              tive after).
       \X'string'
              Output string as device control function.
       \Yn    Output  string variable or macro with one-charac-
              ter name n uninterpreted as device control  func-
              tion.
       \Y(nm  Output  string variable or macro with two-charac-
              ter name nm uninterpreted as device control func-
              tion.
       \Y[name]
              Output  string variable or macro with arbitrarily
              long name name uninterpreted  as  device  control
              function.
       \zc    Print c with zero width (without spacing).
       \Z'anything'
              Print  anything  and  then restore the horizontal
              and vertical position; anything may  not  contain
              tabs or leaders.

       The escape sequences \e, \., \", \$, \*, \a, \n, \t, \g,
       and \newline are interpreted in copy mode.

       Escape sequences starting with \( or \[ do not represent
       single  character escape sequences, but introduce escape
       names with two or more characters.

       If a backslash is followed by a character that does  not
       constitute  a  defined escape sequence, the backslash is
       silently ignored and the character maps to itself.

   Special Characters
       [Note: `Special Characters' is a misnomer;  those  enti-
       ties are (output) glyphs, not (input) characters.]

       Common  special  characters  are  predefined  by  escape
       sequences of the form \(xy  with  characters  x  and  y.
       Some of these exist in the usual font while most of them
       are only available in the special font.  Below  you  can
       find  a  selection  of the most important glyphs; a com-
       plete list can be found in groff_char(7).

              \(bu   Bullet sign
              \(co   Copyright
              \(ct   Cent
              \(dd   Double dagger
              \(de   Degree
              \(dg   Dagger
              \(rq   Printable double quote
              \(em   Em-dash
              \(hy   Hyphen
              \(rg   Registered sign
              \(rs   Printable backslash character
              \(sc   Section sign
              \(ul   Underline character
              \(==   Identical
              \(>=   Larger or equal
              \(<=   Less or equal
              \(!=   Not equal
              \(->   Right arrow
              \(<-   Left arrow
              \(+-   Plus-minus sign

   Strings
       Strings are  defined  by  the  ds  request  and  can  be
       retrieved by the \* escape sequence.

       Strings  share their name space with macros.  So strings
       and macros without arguments are roughly equivalent;  it
       is  possible  to  call  a  string like a macro and vice-
       versa, but this often leads  to  unpredictable  results.
       The  following  string  is  the  only  one predefined in
       groff.

       \*[.T]    The name of the current output device as spec-
                 ified by the -T command line option.

REGISTERS
       Registers  are  variables that store a value.  In groff,
       most  registers  store  numerical  values  (see  section
       NUMERICAL  EXPRESSIONS  above), but some can also hold a
       string value.

       Each register is given a name.  Arbitrary registers  can
       be defined and set with the nr request.

       The  value  stored in a register can be retrieved by the
       escape sequences introduced by \n.

       Most useful are predefined registers.  In the  following
       the  notation  name is used to refer to register name to
       make clear that we speak about registers.   Please  keep
       in mind that the \n[] decoration is not part of the reg-
       ister name.

   Read-only Registers
       The following  registers  have  predefined  values  that
       should  not  be modified by the user (usually, registers
       starting with a dot a read-only).  Mostly, they  provide
       information  on  the  current  settings or store results
       from request calls.

       \n[.$]    Number of arguments in the  current  macro  or
                 string.
       \n[.a]    Post-line  extra line-space most recently uti-
                 lized using \x.
       \n[.A]    Set to 1  in  troff  if  option  -A  is  used;
                 always 1 in nroff.
       \n[.br]   Within  a macro, set to 1 if macro called with
                 the `normal' control character, and to 0  oth-
                 erwise.
       \n[.c]    Current input line number.
       \n[.C]    1 if compatibility mode is in effect, 0 other-
                 wise.
       \n[.cdp]  The depth of the last glyph added to the  cur-
                 rent environment.  It is positive if the glyph
                 extends below the baseline.
       \n[.ce]   The number of lines remaining to be  centered,
                 as set by the ce request.
       \n[.cht]  The height of the last glyph added to the cur-
                 rent environment.  It is positive if the glyph
                 extends above the baseline.
       \n[.color]
                 1 if colors are enabled, 0 otherwise.
       \n[.csk]  The  skew  of the last glyph added to the cur-
                 rent environment.  The skew of a glyph is  how
                 far  to the right of the center of a glyph the
                 center of an accent over that glyph should  be
                 placed.
       \n[.d]    Current  vertical  place in current diversion;
                 equal to register nl.
       \n[.ev]   The name or number of the current  environment
                 (string-valued).
       \n[.f]    Current font number.
       \n[.fam]  The current font family (string-valued).
       \n[.fn]   The current (internal) real font name (string-
                 valued).
       \n[.fp]   The number of the next free font position.
       \n[.g]    Always 1 in GNU troff.  Macros should  use  it
                 to test if running under groff.
       \n[.h]    Text base-line high-water mark on current page
                 or diversion.
       \n[.H]    Available  horizontal  resolution   in   basic
                 units.
       \n[.height]
                 The current font height as set with \H.
       \n[.hla]  The current hyphenation language as set by the
                 hla request.
       \n[.hlc]  The number of immediately  preceding  consecu-
                 tive hyphenated lines.
       \n[.hlm]  The  maximum  allowed  number  of  consecutive
                 hyphenated lines, as set by the hlm request.
       \n[.hy]   The current hyphenation flags (as set  by  the
                 hy request).
       \n[.hym]  The  current hyphenation margin (as set by the
                 hym request).
       \n[.hys]  The current hyphenation space (as set  by  the
                 hys request).
       \n[.i]    Current indentation.
       \n[.in]   The  indentation  that  applies to the current
                 output line.
       \n[.int]  Positive if last output line contains \c.
       \n[.kern] 1 if pairwise kerning is enabled, 0 otherwise.
       \n[.l]    Current line length.
       \n[.lg]   The  current  ligature  mode (as set by the lg
                 request).
       \n[.linetabs]
                 The current line-tabs  mode  (as  set  by  the
                 linetabs request).
       \n[.ll]   The  line  length  that applies to the current
                 output line.
       \n[.lt]   The title length (as set by the lt request).
       \n[.m]    The current drawing color (string-valued).
       \n[.M]    The current background color  (string-valued).
       \n[.n]    Length  of  text  portion  on  previous output
                 line.
       \n[.ne]   The amount of space that  was  needed  in  the
                 last  ne  request  that  caused  a  trap to be
                 sprung.  Useful in conjunction  with  register
                 .trunc.
       \n[.ns]   1 if in no-space mode, 0 otherwise.
       \n[.o]    Current page offset.
       \n[.p]    Current page length.
       \n[.pe]   1 during page ejection, 0 otherwise.
       \n[.pn]   The  number of the next page: either the value
                 set by a pn request, or the number of the cur-
                 rent page plus 1.
       \n[.ps]   The current point size in scaled points.
       \n[.psr]  The   last-requested   point  size  in  scaled
                 points.
       \n[.pvs]  The current post-vertical line spacing.
       \n[.rj]   The number of lines to be  right-justified  as
                 set by the rj request.
       \n[.s]    Current point size as a decimal fraction.
       \n[.slant]
                 The  slant of the current font as set with \S.
       \n[.sr]   The last requested point size in points  as  a
                 decimal fraction (string-valued).
       \n[.ss]   The  value  of the parameters set by the first
                 argument of the ss request.
       \n[.sss]  The value of the parameters set by the  second
                 argument of the ss request.
       \n[.sty]  The current font style (string-valued).
       \n[.t]    Vertical distance to the next trap.
       \n[.T]    Set to 1 if option -T is used.
       \n[.tabs] A  string  representation  of  the current tab
                 settings suitable for use as  an  argument  to
                 the ta request.
       \n[.trunc]
                 The  amount of vertical space truncated by the
                 most recently sprung vertical  position  trap,
                 or,  if  the  trap was sprung by a ne request,
                 minus the amount of vertical  motion  produced
                 by .ne.  Useful in conjunction with the regis-
                 ter .ne.
       \n[.u]    Equal to 1 in fill mode and 0 in no-fill mode.
       \n[.U]    Equal to 1 in safer mode and 0 in unsafe mode.
       \n[.v]    Current vertical line spacing.
       \n[.V]    Available vertical resolution in basic  units.
       \n[.vpt]  1  if  vertical  position  traps  are enabled,
                 0 otherwise.
       \n[.w]    Width of previous glyph.
       \n[.warn] The sum of the number codes of  the  currently
                 enabled warnings.
       \n[.x]    The major version number.
       \n[.y]    The minor version number.
       \n[.Y]    The revision number of groff.
       \n[.z]    Name of current diversion.
       \n[.zoom] Zoom  factor for current font (in multiples of
                 1/1000th; zero if no magnification).

   Writable Registers
       The following registers can be read and written  by  the
       user.   They  have  predefined default values, but these
       can be modified for customizing a document.

       \n[%]     Current page number.
       \n[c.]    Current input line number.
       \n[ct]    Character type (set by width function \w).
       \n[dl]    Maximal width of last completed diversion.
       \n[dn]    Height of last completed diversion.
       \n[dw]    Current day of week (1-7).
       \n[dy]    Current day of month (1-31).
       \n[hours] The number of hours past  midnight.   Initial-
                 ized at start-up.
       \n[hp]    Current horizontal position at input line.
       \n[llx]   Lower  left x-coordinate (in PostScript units)
                 of a given PostScript image (set by .psbb).
       \n[lly]   Lower left y-coordinate (in PostScript  units)
                 of a given PostScript image (set by .psbb).
       \n[ln]    Output line number.
       \n[minutes]
                 The  number  of  minutes after the hour.  Ini-
                 tialized at start-up.
       \n[mo]    Current month (1-12).
       \n[nl]    Vertical position of last printed  text  base-
                 line.
       \n[rsb]   Like  register  sb,  but  takes account of the
                 heights and depths of glyphs.
       \n[rst]   Like register st, but  takes  account  of  the
                 heights and depths of glyphs.
       \n[sb]    Depth  of string below base line (generated by
                 width function \w).
       \n[seconds]
                 The number of seconds after the minute.   Ini-
                 tialized at start-up.
       \n[skw]   Right  skip  width from the center of the last
                 glyph in the \w argument.
       \n[slimit]
                 If greater  than  0,  the  maximum  number  of
                 objects  on  the input stack.  If <=0 there is
                 no limit, i.e., recursion can  continue  until
                 virtual memory is exhausted.
       \n[ssc]   The amount of horizontal space (possibly nega-
                 tive) that should be added to the  last  glyph
                 before  a  subscript (generated by width func-
                 tion \w).
       \n[st]    Height of string above base line (generated by
                 width function \w).
       \n[systat]
                 The return value of the system() function exe-
                 cuted by the last sy request.
       \n[urx]   Upper right x-coordinate (in PostScript units)
                 of a given PostScript image (set by .psbb).
       \n[ury]   Upper right y-coordinate (in PostScript units)
                 of a given PostScript image (set by .psbb).
       \n[year]  The current year (year 2000 compliant).
       \n[yr]    Current year minus 1900.  For  Y2K  compliance
                 use register year instead.

COMPATIBILITY
       The  differences  of the groff language in comparison to
       classical troff as defined by [CSTR #54] are  documented
       in groff_diff(7).

       The  groff  system  provides  a  compatibility mode, see
       groff(1) on how to invoke this.

BUGS
       Report bugs to the groff bug mailing list Include a com-
       plete, self-contained example that will allow the bug to
       be reproduced, and say which version of  groff  you  are
       using.

AUTHORS
       Copyright  (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006,
       2007, 2008, 2009 Free Software Foundation, Inc.

       This document is distributed under the terms of the  FDL
       (GNU  Free  Documentation License) version 1.3 or later.
       You should have received a copy of the FDL on your  sys-
       tem,  it  is  also available on-line at the GNU copyleft
       site

       This document is part of groff, the GNU  roff  distribu-
       tion.   It  was written by Bernd Warken it is maintained
       by Werner Lemberg

SEE ALSO
       The main source of information for the groff language is
       the  groff  info(1)  file.  Besides the gory details, it
       contains many examples.

       groff(1)
              the usage of the groff program  and  pointers  to
              the  documentation  and availability of the groff
              system.

       groff_diff(7)
              the differences of the groff language as compared
              to  classical  roff.   This  is the authoritative
              document for  the  predefined  language  elements
              that are specific to groff.

       groff_char(7)
              the predefined groff special characters (glyphs).

       groff_font(5)
              the specification of fonts and the DESC file.

       roff(7)
              the history of roff, the common parts  shared  by
              all  roff  systems, and pointers to further docu-
              mentation.

       [CSTR #54]
              Nroff/Troff User's Manual by Ossanna &  Kernighan
              -- the bible for classical troff.



Groff Version 1.20       5 January 2009                GROFF(7)
