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GROFF_OUT(5)                                                      GROFF_OUT(5)



NAME
       groff_out - groff intermediate output format

DESCRIPTION
       This manual page describes the intermediate output format of the GNU roff(7) text processing system.  This out-
       put is produced by a run of the GNU troff(1) program before it is fed into a device postprocessor program.

       As the GNU roff processor groff(1) is a wrapper program around troff that automatically calls a  postprocessor,
       this  output  does  not  show up normally.  This is why it is called intermediate within the groff system.  The
       groff program provides the option -Z to inhibit postprocessing, such that the produced intermediate  output  is
       sent to standard output just like calling troff manually.

       In  this  document, the term troff output describes what is output by the GNU troff program, while intermediate
       output refers to the language that is accepted by the parser that prepares this output for the  postprocessors.
       This parser is smarter on whitespace and implements obsolete elements for compatibility, otherwise both formats
       are the same.  The pre-groff roff versions are denoted as classical troff.

       The main purpose of the intermediate output concept is to facilitate the development of postprocessors by  pro-
       viding a common programming interface for all devices.  It has a language of its own that is completely differ-
       ent from the groff(7) language.  While the groff language is a high-level programming language  for  text  pro-
       cessing, the intermediate output language is a kind of low-level assembler language by specifying all positions
       on the page for writing and drawing.

       The intermediate output produced by groff is fairly readable, while classical troff output was hard  to  under-
       stand because of strange habits that are still supported, but not used any longer by GNU troff.

LANGUAGE CONCEPTS
       During  the  run  of troff, the roff input is cracked down to the information on what has to be printed at what
       position on the intended device.  So the language of the intermediate output format can be  quite  small.   Its
       only  elements  are  commands with or without arguments.  In this document, the term "command" always refers to
       the intermediate output language, never to the roff language used for document formatting.  There are  commands
       for positioning and text writing, for drawing, and for device controlling.

   Separation
       Classical  troff  output  had  strange  requirements on whitespace.  The groff output parser, however, is smart
       about whitespace by making it maximally optional.  The whitespace characters, i.e. the tab, space, and  newline
       characters,  always  have a syntactical meaning.  They are never printable because spacing within the output is
       always done by positioning commands.

       Any sequence of space or tab characters is treated as a single syntactical space.  It  separates  commands  and
       arguments,  but  is  only required when there would occur a clashing between the command code and the arguments
       without the space.  Most often, this happens when variable length command names, arguments, argument lists,  or
       command  clusters meet.  Commands and arguments with a known, fixed length need not be separated by syntactical
       space.

       A line break is a syntactical element, too.  Every command argument can be followed by whitespace,  a  comment,
       or a newline character.  Thus a syntactical line break is defined to consist of optional syntactical space that
       is optionally followed by a comment, and a newline character.

       The normal commands, those for positioning and text, consist of a single letter taking a fixed number of  argu-
       ments.   For historical reasons, the parser allows to stack such commands on the same line, but fortunately, in
       groff intermediate output, every command with at least one argument is followed by a line break, thus providing
       excellent readability.

       The  other commands -- those for drawing and device controlling -- have a more complicated structure; some recog-
       nize long command names, and some take a variable number of arguments.  So all D and x commands  were  designed
       to  request  a  syntactical line break after their last argument.  Only one command, 'x X' has an argument that
       can stretch over several lines, all other commands must have all of their arguments on the  same  line  as  the
       command, i.e. the arguments may not be splitted by a line break.

       Empty lines, i.e. lines containing only space and/or a comment, can occur everywhere.  They are just ignored.

   Argument Units
       Some commands take integer arguments that are assumed to represent values in a measurement unit, but the letter
       for the corresponding scale indicator is not written with the output command arguments; see  groff(7)  and  the
       groff  info  file  for  more  on this topic.  Most commands assume the scale indicator u, the basic unit of the
       device, some use z, the scaled point unit of the device, while others, such as the color commands expect  plain
       integers.  Note that these scale indicators are relative to the chosen device.  They are defined by the parame-
       ters specified in the device's DESC file; see groff_font(5).

       Note that single characters can have the eighth bit set, as can the names of fonts and special characters.  The
       names  of characters and fonts can be of arbitrary length.  A character that is to be printed will always be in
       the current font.

       A string argument is always terminated by the next whitespace character (space, tab, or newline); an embedded #
       character  is regarded as part of the argument, not as the beginning of a comment command.  An integer argument
       is already terminated by the next non-digit character, which then is regarded as the  first  character  of  the
       next argument or command.

   Document Parts
       A correct intermediate output document consists of two parts, the prologue and the body.

       The  task  of the prologue is to set the general device parameters using three exactly specified commands.  The
       groff prologue is guaranteed to consist of the following three lines (in that order):

              x T device
              x res n h v
              x init

       with the arguments set as outlined in the section Device Control Commands.  But the parser for the intermediate
       output format is able to swallow additional whitespace and comments as well.

       The body is the main section for processing the document data.  Syntactically, it is a sequence of any commands
       different from the ones used in the prologue.  Processing is terminated as soon as the first x stop command  is
       encountered; the last line of any groff intermediate output always contains such a command.

       Semantically,  the  body  is  page  oriented.  A new page is started by a p command.  Positioning, writing, and
       drawing commands are always done within the current page, so they cannot occur  before  the  first  p  command.
       Absolute  positioning  (by the H and V commands) is done relative to the current page, all other positioning is
       done relative to the current location within this page.

COMMAND REFERENCE
       This section describes all intermediate output commands, the classical commands as well  as  the  groff  exten-
       sions.

   Comment Command
       #anything<end_of_line>
              A comment.  Ignore any characters from the # character up to the next newline character.

       This  command  is the only possibility for commenting in the intermediate output.  Each comment can be preceded
       by arbitrary syntactical space; every command can be terminated by a comment.

   Simple Commands
       The commands in this subsection have a command code consisting of a single character, taking a fixed number  of
       arguments.  Most of them are commands for positioning and text writing.  These commands are smart about whites-
       pace.  Optionally, syntactical space can be inserted before, after, and between  the  command  letter  and  its
       arguments.   All  of  these commands are stackable, i.e., they can be preceded by other simple commands or fol-
       lowed by arbitrary other commands on the same line.  A separating syntactical space is only necessary when  two
       integer arguments would clash or if the preceding argument ends with a string argument.

       C xxx<white_space>
              Print a special groff character named xxx.  The trailing syntactical space or line break is necessary to
              allow character names of arbitrary length.  The character is printed at the current print position;  the
              character's size is read from the font file.  The print position is not changed.

       c c    Print  character  c at the current print position; the character's size is read from the font file.  The
              print position is not changed.

       f n    Set font to font number n (a non-negative integer).

       H n    Move right to the absolute vertical position n (a non-negative integer in basic  units  u)  relative  to
              left edge of current page.

       h n    Move  n  (a  non-negative integer) basic units u horizontally to the right.  [54] allows negative values
              for n also, but groff doesn't use this.

       m color_scheme [component ...]
              Set the color for text (glyphs), line drawing, and the outline of graphic objects using different  color
              schemes;  the  analoguous  command for the filling color of graphic objects is DF.  The color components
              are specified as integer arguments between 0 and 65536.  The number of color components and their  mean-
              ing vary for the different color schemes.  These commands are generated by the groff escape sequence \m.
              No position changing.  These commands are a groff extension.

              mc cyan magenta yellow
                     Set color using the CMY color scheme, having the 3 color components cyan, magenta, and yellow.

              md     Set color to the default color value (black in most cases).  No component arguments.

              mg gray
                     Set color to the shade of gray given by the argument, an integer  between  0  (black)  and  65536
                     (white).

              mk cyan magenta yellow black
                     Set  color  using the CMYK color scheme, having the 4 color components cyan, magenta, yellow, and
                     black.

              mr red green blue
                     Set color using the RGB color scheme, having the 3 color components red, green, and blue.

       N n    Print character with index n (a non-negative integer) of the current font.  The print  position  is  not
              changed.  This command is a groff extension.

       n b a  Inform  the  device about a line break, but no positioning is done by this command.  In classical troff,
              the integer arguments b and a informed about the space before and after the current  line  to  make  the
              intermediate output more human readable without performing any action.  In groff, they are just ignored,
              but they must be provided for compatibility reasons.

       p n    Begin a new page in the outprint.  The page number is set to n.  This page is completely independent  of
              pages formerly processed even if those have the same page number.  The vertical position on the outprint
              is automatically set to 0.  All positioning, writing, and drawing is always done relative to a page,  so
              a p command must be issued before any of these commands.

       s n    Set  point  size to n scaled points (this is unit z in GNU troff).  Classical troff used the unit points
              (p) instead; see section COMPATIBILITY.

       t xxx<white_space>
       t xxx dummy_arg<white_space>
              Print a word, i.e. a sequence of characters xxx terminated by a space character  or  a  line  break;  an
              optional  second  integer  argument  is ignored (this allows the formatter to generate an even number of
              arguments).  The first character should be printed at the current position, the current horizontal posi-
              tion  should  then  be increased by the width of the first character, and so on for each character.  The
              widths of the characters are read from the font file, scaled for the current point size, and rounded  to
              a  multiple  of the horizontal resolution.  Special characters cannot be printed using this command (use
              the C command for named characters).  This command is a groff extension; it is  only  used  for  devices
              whose DESC file contains the tcommand keyword; see groff_font(5).

       u n xxx<white_space>
              Print  word with track kerning.  This is the same as the t command except that after printing each char-
              acter, the current horizontal position is increased by the sum of the width of that character and n  (an
              integer  in  basic  units u).  This command is a groff extension; it is only used for devices whose DESC
              file contains the tcommand keyword; see groff_font(5).

       V n    Move down to the absolute vertical position n (a non-negative integer in  basic  units  u)  relative  to
              upper edge of current page.

       v n    Move  n  basic  units u down (n is a non-negative integer).  [54] allows negative values for n also, but
              groff doesn't use this.

       w      Informs about a paddable whitespace to increase readability.   The  spacing  itself  must  be  performed
              explicitly by a move command.

   Graphics Commands
       Each  graphics  or  drawing  command in the intermediate output starts with the letter D followed by one or two
       characters that specify a subcommand; this is followed by a fixed or variable number of integer arguments  that
       are separated by a single space character.  A D command may not be followed by another command on the same line
       (apart from a comment), so each D command is terminated by a syntactical line break.

       troff output follows the classical spacing rules (no space between command and subcommand,  all  arguments  are
       preceded  by  a  single  space character), but the parser allows optional space between the command letters and
       makes the space before the first argument optional.  As usual, each space can be any sequence of tab and  space
       characters.

       Some graphics commands can take a variable number of arguments.  In this case, they are integers representing a
       size measured in basic units u.  The arguments called h1, h2, ..., hn h1, h2, ..., hn stand for horizontal dis-
       tances  where  positive means right, negative left.  The arguments called v1, v2, ..., vn v1, v2, ..., vn stand
       for vertical distances where positive means down, negative up.  All these distances are offsets relative to the
       current location.

       Unless  indicated  otherwise, each graphics command directly corresponds to a similar groff \D escape sequence;
       see groff(7).

       Unknown D commands are assumed to be device-specific.  Its arguments are parsed as strings; the whole  informa-
       tion is then sent to the postprocessor.

       In  the  following command reference, the syntax element <line_break> means a syntactical line break as defined
       in section Separation.

       D~ h1 v1 h2 v2 ... hn vn<line_break>
              Draw B-spline from current position to offset (h1, v1), then to offset (h2, v2) if  given,  etc.  up  to
              (hn, vn).  This  command takes a variable number of argument pairs; the current position is moved to the
              terminal point of the drawn curve.

       Da h1 v1 h2 v2<line_break>
              Draw arc from current position to (h1, v1)+(h2, v2) with center at (h1, v1); then move the current posi-
              tion to the final point of the arc.

       DC d<line_break>
       DC d dummy_arg<line_break>
              Draw  a  solid circle using the current fill color with diameter d (integer in basic units u) with left-
              most point at the current position; then move the current position to the rightmost point of the circle.
              An  optional second integer argument is ignored (this allows to the formatter to generate an even number
              of arguments).  This command is a groff extension.

       Dc d<line_break>
              Draw circle line with diameter d (integer in basic units u) with leftmost point at the current position;
              then move the current position to the rightmost point of the circle.

       DE h v<line_break>
              Draw  a  solid ellipse in the current fill color with a horizontal diameter of h and a vertical diameter
              of v (both integers in basic units u) with the leftmost point at the current position; then move to  the
              rightmost point of the ellipse.  This command is a groff extension.

       De h v<line_break>
              Draw  an outlined ellipse with a horizontal diameter of h and a vertical diameter of v (both integers in
              basic units u) with the leftmost point at current position; then move to  the  rightmost  point  of  the
              ellipse.

       DF color_scheme [component ...]<line_break>
              Set  fill color for solid drawing objects using different color schemes; the analoguous command for set-
              ting the color of text, line graphics, and the outline of graphic objects is m.   The  color  components
              are  specified as integer arguments between 0 and 65536.  The number of color components and their mean-
              ing vary for the different color schemes.  These commands are generated by the  groff  escape  sequences
              \D'F ...'   and \M (with no other corresponding graphics commands).  No position changing.  This command
              is a groff extension.

              DFc cyan magenta yellow<line_break>
                     Set fill color for solid drawing objects using the CMY color scheme, having the  3  color  compo-
                     nents cyan, magenta, and yellow.

              DFd <line_break>
                     Set  fill  color for solid drawing objects to the default fill color value (black in most cases).
                     No component arguments.

              DFg gray<line_break>
                     Set fill color for solid drawing objects to the shade of gray given by the argument,  an  integer
                     between 0 (black) and 65536 (white).

              DFk cyan magenta yellow black<line_break>
                     Set  fill  color for solid drawing objects using the CMYK color scheme, having the 4 color compo-
                     nents cyan, magenta, yellow, and black.

              DFr red green blue<line_break>
                     Set fill color for solid drawing objects using the RGB color scheme, having the  3  color  compo-
                     nents red, green, and blue.

       Df n<line_break>
              The argument n must be an integer in the range -32767 to 32767.

              0 <= n <= 1000
                     Set  the color for filling solid drawing objects to a shade of gray, where 0 corresponds to solid
                     white, 1000 (the default) to solid black, and values in between to intermediate shades  of  gray;
                     this is obsoleted by command DFg.

              n < 0 or n > 1000
                     Set the filling color to the color that is currently being used for the text and the outline, see
                     command m.  For example, the command sequence
                             mg 0 0 65536
                             Df -1
                     sets all colors to blue.

              No position changing.  This command is a groff extension.

       Dl h v<line_break>
              Draw line from current position to offset (h, v) (integers in basic units u); then set current  position
              to the end of the drawn line.

       Dp h1 v1 h2 v2 ... hn vn<line_break>
              Draw  a polygon line from current position to offset (h1, v1), from there to offset (h2, v2), etc. up to
              offset (hn, vn), and from there back to the starting position.  For historical reasons, the position  is
              changed by adding the sum of all arguments with odd index to the actual horizontal position and the even
              ones to the vertical position.  Although this doesn't make sense it is  kept  for  compatibility.   This
              command is a groff extension.

       DP h1 v1 h2 v2 ... hn vn<line_break>
              The same macro as the corresponding Dp command with the same arguments, but draws a solid polygon in the
              current fill color rather than an outlined polygon.  The position is changed in the same way as with Dp.
              This command is a groff extension.

       Dt n<line_break>
              Set  the  current  line  thickness to n (an integer in basic units u) if n>0; if n=0 select the smallest
              available line thickness; if n<0 set the line thickness proportional to the  point  size  (this  is  the
              default  before the first Dt command was specified).  For historical reasons, the horizontal position is
              changed by adding the argument to the actual horizontal position, while the  vertical  position  is  not
              changed.  Although this doesn't make sense it is kept for compatibility.  This command is a groff exten-
              sion.

   Device Control Commands
       Each device control command starts with the letter x followed by  a  space  character  (optional  or  arbitrary
       space/tab  in  groff) and a subcommand letter or word; each argument (if any) must be preceded by a syntactical
       space.  All x commands are terminated by a syntactical line break; no device control command can be followed by
       another command on the same line (except a comment).

       The  subcommand is basically a single letter, but to increase readability, it can be written as a word, i.e. an
       arbitrary sequence of characters terminated by the next tab, space, or newline character.   All  characters  of
       the  subcommand  word  but the first are simply ignored.  For example, troff outputs the initialization command
       x i as x init and the resolution command x r as x res.  But writings like  x i_like_groff  and  x roff_is_groff
       resp. are accepted as well to mean the same commands.

       In  the following, the syntax element <line_break> means a syntactical line break as defined in section Separa-
       tion.

       xF name<line_break>
              (Filename control command)
              Use name as the intended name for the current file in error reports.  This is useful for remembering the
              original  file name when groff uses an internal piping mechanism.  The input file is not changed by this
              command.  This command is a groff extension.

       xf n s<line_break>
              (font control command)
              Mount font position n (a non-negative integer) with font named s (a text word), cf.  groff_font(5).

       xH n<line_break>
              (Height control command)
              Set character height to n (a positive integer in scaled points z).  Classical troff used the unit points
              (p) instead; see section COMPATIBILITY.

       xi<line_break>
              (init control command)
              Initialize device.  This is the third command of the prologue.

       xp<line_break>
              (pause control command)
              Parsed but ignored.  The classical documentation reads pause device, can be restarted.

       xr n h v<line_break>
              (resolution control command)
              Resolution  is  n,  while h is the minimal horizontal motion, and v the minimal vertical motion possible
              with this device; all arguments are positive integers in basic units u per inch.   This  is  the  second
              command of the prologue.

       xS n<line_break>
              (Slant control command)
              Set slant to n (an integer in basic units u).

       xs<line_break>
              (stop control command)
              Terminates the processing of the current file; issued as the last command of any intermediate troff out-
              put.

       xt<line_break>
              (trailer control command)
              Generate trailer information, if any.  In groff, this is actually just ignored.

       xT xxx<line_break>
              (Typesetter control command)
              Set name of device to word xxx, a sequence of characters ended by the next  whitespace  character.   The
              possible  device  names  coincide with those from the groff -T option.  This is the first command of the
              prologue.

       xu n<line_break>
              (underline control command)
              Configure underlining of spaces.  If n is 1, start underlining of spaces; if n is 0, stop underlining of
              spaces.   This  is  needed for the cu request in nroff mode and is ignored otherwise.  This command is a
              groff extension.

       xX anything<line_break>
              (X-escape control command)
              Send string anything uninterpreted to the device.  If the line following this command starts  with  a  +
              character this line is interpreted as a continuation line in the following sense.  The + is ignored, but
              a newline character is sent instead to the device, the rest of the line is sent uninterpreted.  The same
              applies  to  all following lines until the first character of a line is not a + character.  This command
              is generated by the groff escape sequence \X.  The line-continuing feature is a groff extension.

   Obsolete Command
       In classical troff output, the writing of a single character was mostly done by a  very  strange  command  that
       combined  a horizontal move and the printing of a character.  It didn't have a command code, but is represented
       by a 3-character argument consisting of exactly 2 digits and a character.

       ddc    Move right dd (exactly two decimal digits) basic units u, then print character c.

              In groff, arbitrary syntactical space around and within this command is allowed to be added.  Only  when
              a  preceding  command  on  the  same line ends with an argument of variable length a separating space is
              obligatory.  In classical troff, large clusters of these and other commands were  used,  mostly  without
              spaces; this made such output almost unreadable.

       For  modern  high-resolution  devices, this command does not make sense because the width of the characters can
       become much larger than two decimal digits.  In groff, this is only used for the devices X75, X75-12, X100, and
       X100-12.  For other devices, the commands t and u provide a better functionality.

POSTPROCESSING
       The  roff postprocessors are programs that have the task to translate the intermediate output into actions that
       are sent to a device.  A device can be some piece of hardware such as a printer,  or  a  software  file  format
       suitable  for graphical or text processing.  The groff system provides powerful means that make the programming
       of such postprocessors an easy task.

       There is a library function that parses the intermediate output and  sends  the  information  obtained  to  the
       device  via  methods  of  a  class with a common interface for each device.  So a groff postprocessor must only
       redefine the methods of this class.  For details, see the reference in section FILES.

EXAMPLES
       This section presents the intermediate output generated from the same input for three different  devices.   The
       input is the sentence hell world fed into groff on the command line.

       ? High-resolution device ps

         shell> echo hell world | groff -Z -T ps

         x T ps
         x res 72000 1 1
         x init
         p1
         x font 5 TR
         f5
         s10000
         V12000
         H72000
         thell
         wh2500
         tw
         H96620
         torld
         n12000 0
         x trailer
         V792000
         x stop

       This output can be fed into the postprocessor grops(1) to get its representation as a PostScript file.

       ? Low-resolution device latin1

         This  is  similar  to  the high-resolution device except that the positioning is done at a minor scale.  Some
         comments (lines starting with #) were added for clarification; they were not generated by the formatter.

         shell> echo hell world | groff -Z -T latin1

         # prologue
         x T latin1
         x res 240 24 40
         x init
         # begin a new page
         p1
         # font setup
         x font 1 R
         f1
         s10
         # initial positioning on the page
         V40
         H0
         # write text 'hell'
         thell
         # inform about a space, and do it by a horizontal jump
         wh24
         # write text 'world'
         tworld
         # announce line break, but do nothing because ...
         n40 0
         # ... the end of the document has been reached
         x trailer
         V2640
         x stop

       This output can be fed into the postprocessor grotty(1) to get a formatted text document.

       ? Classical style output

         As a computer monitor has a very low resolution compared to modern printers the intermediate output  for  the
         X devices can use the jump-and-write command with its 2-digit displacements.

         shell> echo hell world | groff -Z -T X100

         x T X100
         x res 100 1 1
         x init
         p1
         x font 5 TR
         f5
         s10
         V16
         H100
         # write text with old-style jump-and-write command
         ch07e07l03lw06w11o07r05l03dh7
         n16 0
         x trailer
         V1100
         x stop

       This output can be fed into the postprocessor xditview(1x) or gxditview(1) for displaying in X.

       Due to the obsolete jump-and-write command, the text clusters in the classical output are almost unreadable.

COMPATIBILITY
       The  intermediate  output language of the classical troff was first documented in [97].  The groff intermediate
       output format is compatible with this specification except for the following features.

       ? The classical quasi device independence is not yet implemented.

       ? The old hardware was very different from what we use today.  So the groff devices are also fundamentally dif-
         ferent  from  the  ones in classical troff.  For example, the classical PostScript device was called post and
         had a resolution of 720 units per inch, while groff's ps device has a resolution of  72000  units  per  inch.
         Maybe,  by  implementing  some  rescaling mechanism similar to the classical quasi device independence, these
         could be integrated into modern groff.

       ? The B-spline command D~ is correctly handled by the intermediate output  parser,  but  the  drawing  routines
         aren't implemented in some of the postprocessor programs.

       ? The  argument  of the commands s and x H has the implicit unit scaled point z in groff, while classical troff
         had point (p).  This isn't an incompatibility, but a compatible extension, for both units  coincide  for  all
         devices  without  a  sizescale  parameter, including all classical and the groff text devices.  The few groff
         devices with a sizescale parameter either did not exist, had a different name, or seem to have had a  differ-
         ent resolution.  So conflicts with classical devices are very unlikely.

       ? The  position changing after the commands Dp, DP, and Dt is illogical, but as old versions of groff used this
         feature it is kept for compatibility reasons.

       The differences between groff and classical troff are documented in groff_diff(7).

FILES
       /usr/share/groff/1.18.1.4/font/devname/DESC
              Device description file for device name.

       <groff_source_dir>/src/libs/libdriver/input.cc
              Defines the parser and postprocessor for the intermediate output.  It is located  relative  to  the  top
              directory of the groff source tree, e.g.  @GROFFSRCDIR@.  This parser is the definitive specification of
              the groff intermediate output format.

SEE ALSO
       A reference like groff(7) refers to a manual page; here groff in section 7 of the man-page  documentation  sys-
       tem.  To read the example, look up section 7 in your desktop help system or call from the shell prompt

              shell> man 7 groff

       For more details, see man(1).

       groff(1)
              option -Z and further readings on groff.

       groff(7)
              for details of the groff language such as numerical units and escape sequences.

       groff_font(5)
              for details on the device scaling parameters of the DESC file.

       troff(1)
              generates the device-independent intermediate output.

       roff(7)
              for historical aspects and the general structure of roff systems.

       groff_diff(7)
              The differences between the intermediate output in groff and classical troff.

       grodvi(1), grohtml(1), grolbp(1), grolj4(1), grops(1), grotty(1)
              the groff postprocessor programs.

       For  a  treatment of all aspects of the groff system within a single document, see the groff info file.  It can
       be read within the integrated help systems, within emacs(1) or from the shell prompt by
              shell> info groff

       The classical troff output language is described in two AT&T Bell Labs CSTR documents available on-line at Bell
       Labs CSTR site <http://cm.bell-labs.com/cm/cs/cstr.html>;.

       [CSTR #97]
              A  Typesetter-independent TROFF by Brian Kernighan is the original and most concise documentation on the
              output language; see CSTR #97 <http://cm.bell-labs.com/cm/cs/cstr/97.ps.gz>;.

       [CSTR #54]
              The 1992 revision of the Nroff/Troff User's Manual by J. F. Osanna and Brian Kernighan isn't as  concise
              as [CSTR #97] regarding the output language; see CSTR #54 <http://cm.bell-labs.com/cm/cs/cstr/54.ps.gz>;.

AUTHORS
       Copyright (C) 1989, 2001, 2002 Free Software Foundation, Inc.

       This document is distributed under the terms of the FDL (GNU Free Documentation License) version 1.1 or  later.
       You  should have received a copy of the FDL with this package; it is also available on-line at the GNU copyleft
       site <http://www.gnu.org/copyleft/fdl.html>;.

       This document is part of groff, the GNU roff distribution.  It is based on a former version -  published  under
       the GPL - that described only parts of the groff extensions of the output language.  It has been rewritten 2002
       by Bernd Warken <bwarkenATmayn.de> and is maintained by Werner Lemberg <wlATgnu.org>.



Groff Version 1.18.1.4         12 September 2002                  GROFF_OUT(5)