1GROFF_OUT(5) File Formats Manual GROFF_OUT(5)
2
6 groff_out - groff intermediate output format
7
9 This manual page describes the intermediate output format of the GNU
10 roff(7) text processing system. This output is produced by a run of
11 the GNU troff(1) program before it is fed into a device postprocessor
12 program.
13 As the GNU roff processor groff(1) is a wrapper program around troff
15 that automatically calls a postprocessor, this output does not show up
16 normally. This is why it is called intermediate within the groff sys‐
17 tem. The groff program provides the option -Z to inhibit postprocess‐
18 ing, such that the produced intermediate output is sent to standard
19 output just like calling troff manually.
20 In this document, the term troff output describes what is output by the
22 GNU troff program, while intermediate output refers to the language
23 that is accepted by the parser that prepares this output for the post‐
24 processors. This parser is smarter on whitespace and implements obso‐
25 lete elements for compatibility, otherwise both formats are the same.
26 The pre-groff roff versions are denoted as classical troff.
27 The main purpose of the intermediate output concept is to facilitate
29 the development of postprocessors by providing a common programming
30 interface for all devices. It has a language of its own that is com‐
31 pletely different from the groff(7) language. While the groff language
32 is a high-level programming language for text processing, the interme‐
33 diate output language is a kind of low-level assembler language by
34 specifying all positions on the page for writing and drawing.
35 The intermediate output produced by groff is fairly readable, while
37 classical troff output was hard to understand because of strange habits
38 that are still supported, but not used any longer by GNU troff.
39
41 During the run of troff, the roff input is cracked down to the informa‐
42 tion on what has to be printed at what position on the intended device.
43 So the language of the intermediate output format can be quite small.
44 Its only elements are commands with or without arguments. In this doc‐
45 ument, the term "command" always refers to the intermediate output lan‐
46 guage, never to the roff language used for document formatting. There
47 are commands for positioning and text writing, for drawing, and for
48 device controlling.
49 Separation
51 Classical troff output had strange requirements on whitespace. The
52 groff output parser, however, is smart about whitespace by making it
53 maximally optional. The whitespace characters, i.e. the tab, space,
54 and newline characters, always have a syntactical meaning. They are
55 never printable because spacing within the output is always done by
56 positioning commands.
57 Any sequence of space or tab characters is treated as a single syntac‐
59 tical space. It separates commands and arguments, but is only required
60 when there would occur a clashing between the command code and the
61 arguments without the space. Most often, this happens when variable
62 length command names, arguments, argument lists, or command clusters
63 meet. Commands and arguments with a known, fixed length need not be
64 separated by syntactical space.
65 A line break is a syntactical element, too. Every command argument can
67 be followed by whitespace, a comment, or a newline character. Thus a
68 syntactical line break is defined to consist of optional syntactical
69 space that is optionally followed by a comment, and a newline charac‐
70 ter.
71 The normal commands, those for positioning and text, consist of a sin‐
73 gle letter taking a fixed number of arguments. For historical reasons,
74 the parser allows to stack such commands on the same line, but fortu‐
75 nately, in groff intermediate output, every command with at least one
76 argument is followed by a line break, thus providing excellent read‐
77 ability.
78 The other commands — those for drawing and device controlling — have a
80 more complicated structure; some recognize long command names, and some
81 take a variable number of arguments. So all D and x commands were
82 designed to request a syntactical line break after their last argument.
83 Only one command, `x X' has an argument that can stretch over several
84 lines, all other commands must have all of their arguments on the same
85 line as the command, i.e. the arguments may not be splitted by a line
86 break.
87 Empty lines, i.e. lines containing only space and/or a comment, can
89 occur everywhere. They are just ignored.
90 Argument Units
92 Some commands take integer arguments that are assumed to represent val‐
93 ues in a measurement unit, but the letter for the corresponding scale
94 indicator is not written with the output command arguments; see
95 groff(7) and the groff info file for more on this topic. Most commands
96 assume the scale indicator u, the basic unit of the device, some use z,
97 the scaled point unit of the device, while others, such as the color
98 commands expect plain integers. Note that these scale indicators are
99 relative to the chosen device. They are defined by the parameters
100 specified in the device's DESC file; see groff_font(5).
101 Note that single characters can have the eighth bit set, as can the
103 names of fonts and special characters. The names of characters and
104 fonts can be of arbitrary length. A character that is to be printed
105 will always be in the current font.
106 A string argument is always terminated by the next whitespace character
108 (space, tab, or newline); an embedded # character is regarded as part
109 of the argument, not as the beginning of a comment command. An integer
110 argument is already terminated by the next non-digit character, which
111 then is regarded as the first character of the next argument or com‐
112 mand.
113 Document Parts
115 A correct intermediate output document consists of two parts, the pro‐
116 logue and the body.
117 The task of the prologue is to set the general device parameters using
119 three exactly specified commands. The groff prologue is guaranteed to
120 consist of the following three lines (in that order):
121 x T device
123 x res n h v
124 x init
125 with the arguments set as outlined in the section Device Control Com‐
127 mands. But the parser for the intermediate output format is able to
128 swallow additional whitespace and comments as well.
129 The body is the main section for processing the document data. Syntac‐
131 tically, it is a sequence of any commands different from the ones used
132 in the prologue. Processing is terminated as soon as the first x stop
133 command is encountered; the last line of any groff intermediate output
134 always contains such a command.
135 Semantically, the body is page oriented. A new page is started by a
137 p command. Positioning, writing, and drawing commands are always done
138 within the current page, so they cannot occur before the first p com‐
139 mand. Absolute positioning (by the H and V commands) is done relative
140 to the current page, all other positioning is done relative to the cur‐
141 rent location within this page.
142
144 This section describes all intermediate output commands, the classical
145 commands as well as the groff extensions.
146 Comment Command
148 #anything⟨end_of_line⟩
149 A comment. Ignore any characters from the # character up to the
150 next newline character.
151 This command is the only possibility for commenting in the intermediate
153 output. Each comment can be preceded by arbitrary syntactical space;
154 every command can be terminated by a comment.
155 Simple Commands
157 The commands in this subsection have a command code consisting of a
158 single character, taking a fixed number of arguments. Most of them are
159 commands for positioning and text writing. These commands are smart
160 about whitespace. Optionally, syntactical space can be inserted
161 before, after, and between the command letter and its arguments. All
162 of these commands are stackable, i.e., they can be preceded by other
163 simple commands or followed by arbitrary other commands on the same
164 line. A separating syntactical space is only necessary when two inte‐
165 ger arguments would clash or if the preceding argument ends with a
166 string argument.
167 C xxx⟨white_space⟩
169 Print a special groff character named xxx. The trailing syntac‐
170 tical space or line break is necessary to allow character names
171 of arbitrary length. The character is printed at the current
172 print position; the character's size is read from the font file.
173 The print position is not changed.
174 c c Print character c at the current print position; the character's
176 size is read from the font file. The print position is not
177 changed.
178 f n Set font to font number n (a non-negative integer).
180 H n Move right to the absolute vertical position n (a non-negative
182 integer in basic units u) relative to left edge of current page.
183 h n Move n (a non-negative integer) basic units u horizontally to
185 the right. [54] allows negative values for n also, but groff
186 doesn't use this.
187 m color_scheme [component ...]
189 Set the color for text (glyphs), line drawing, and the outline
190 of graphic objects using different color schemes; the analoguous
191 command for the filling color of graphic objects is DF. The
192 color components are specified as integer arguments between 0
193 and 65536. The number of color components and their meaning
194 vary for the different color schemes. These commands are gener‐
195 ated by the groff escape sequence \m. No position changing.
196 These commands are a groff extension.
197 mc cyan magenta yellow
199 Set color using the CMY color scheme, having the 3 color
200 components cyan, magenta, and yellow.
201 md Set color to the default color value (black in most
203 cases). No component arguments.
204 mg gray
206 Set color to the shade of gray given by the argument, an
207 integer between 0 (black) and 65536 (white).
208 mk cyan magenta yellow black
210 Set color using the CMYK color scheme, having the 4 color
211 components cyan, magenta, yellow, and black.
212 mr red green blue
214 Set color using the RGB color scheme, having the 3 color
215 components red, green, and blue.
216 N n Print character with index n (a non-negative integer) of the
218 current font. The print position is not changed. This command
219 is a groff extension.
220 n b a Inform the device about a line break, but no positioning is done
222 by this command. In classical troff, the integer arguments b
223 and a informed about the space before and after the current line
224 to make the intermediate output more human readable without per‐
225 forming any action. In groff, they are just ignored, but they
226 must be provided for compatibility reasons.
227 p n Begin a new page in the outprint. The page number is set to n.
229 This page is completely independent of pages formerly processed
230 even if those have the same page number. The vertical position
231 on the outprint is automatically set to 0. All positioning,
232 writing, and drawing is always done relative to a page, so a
233 p command must be issued before any of these commands.
234 s n Set point size to n scaled points (this is unit z in GNU troff).
236 Classical troff used the unit points (p) instead; see section
237 COMPATIBILITY.
238 t xxx⟨white_space⟩
240 t xxx dummy_arg⟨white_space⟩
241 Print a word, i.e. a sequence of characters xxx terminated by a
242 space character or a line break; an optional second integer
243 argument is ignored (this allows the formatter to generate an
244 even number of arguments). The first character should be
245 printed at the current position, the current horizontal position
246 should then be increased by the width of the first character,
247 and so on for each character. The widths of the characters are
248 read from the font file, scaled for the current point size, and
249 rounded to a multiple of the horizontal resolution. Special
250 characters cannot be printed using this command (use the C com‐
251 mand for named characters). This command is a groff extension;
252 it is only used for devices whose DESC file contains the tcom‐
253 mand keyword; see groff_font(5).
254 u n xxx⟨white_space⟩
256 Print word with track kerning. This is the same as the t com‐
257 mand except that after printing each character, the current hor‐
258 izontal position is increased by the sum of the width of that
259 character and n (an integer in basic units u). This command is
260 a groff extension; it is only used for devices whose DESC file
261 contains the tcommand keyword; see groff_font(5).
262 V n Move down to the absolute vertical position n (a non-negative
264 integer in basic units u) relative to upper edge of current
265 page.
266 v n Move n basic units u down (n is a non-negative integer). [54]
268 allows negative values for n also, but groff doesn't use this.
269 w Informs about a paddable whitespace to increase readability.
271 The spacing itself must be performed explicitly by a move com‐
272 mand.
273 Graphics Commands
275 Each graphics or drawing command in the intermediate output starts with
276 the letter D followed by one or two characters that specify a subcom‐
277 mand; this is followed by a fixed or variable number of integer argu‐
278 ments that are separated by a single space character. A D command may
279 not be followed by another command on the same line (apart from a com‐
280 ment), so each D command is terminated by a syntactical line break.
281 troff output follows the classical spacing rules (no space between com‐
283 mand and subcommand, all arguments are preceded by a single space char‐
284 acter), but the parser allows optional space between the command let‐
285 ters and makes the space before the first argument optional. As usual,
286 each space can be any sequence of tab and space characters.
287 Some graphics commands can take a variable number of arguments. In
289 this case, they are integers representing a size measured in basic
290 units u. The arguments called h1, h2, ..., hn h1, h2, ..., hn stand
291 for horizontal distances where positive means right, negative left.
292 The arguments called v1, v2, ..., vn v1, v2, ..., vn stand for vertical
293 distances where positive means down, negative up. All these distances
294 are offsets relative to the current location.
295 Unless indicated otherwise, each graphics command directly corresponds
297 to a similar groff \D escape sequence; see groff(7).
298 Unknown D commands are assumed to be device-specific. Its arguments
300 are parsed as strings; the whole information is then sent to the post‐
301 processor.
302 In the following command reference, the syntax element ⟨line_break⟩
304 means a syntactical line break as defined in section Separation.
305 D~ h1 v1 h2 v2 ... hn vn⟨line_break⟩
307 Draw B-spline from current position to offset (h1, v1), then to
308 offset (h2, v2) if given, etc. up to (hn, vn). This command
309 takes a variable number of argument pairs; the current position
310 is moved to the terminal point of the drawn curve.
311 Da h1 v1 h2 v2⟨line_break⟩
313 Draw arc from current position to (h1, v1)+(h2, v2) with center
314 at (h1, v1); then move the current position to the final point
315 of the arc.
316 DC d⟨line_break⟩
318 DC d dummy_arg⟨line_break⟩
319 Draw a solid circle using the current fill color with diameter d
320 (integer in basic units u) with leftmost point at the current
321 position; then move the current position to the rightmost point
322 of the circle. An optional second integer argument is ignored
323 (this allows to the formatter to generate an even number of
324 arguments). This command is a groff extension.
325 Dc d⟨line_break⟩
327 Draw circle line with diameter d (integer in basic units u) with
328 leftmost point at the current position; then move the current
329 position to the rightmost point of the circle.
330 DE h v⟨line_break⟩
332 Draw a solid ellipse in the current fill color with a horizontal
333 diameter of h and a vertical diameter of v (both integers in
334 basic units u) with the leftmost point at the current position;
335 then move to the rightmost point of the ellipse. This command
336 is a groff extension.
337 De h v⟨line_break⟩
339 Draw an outlined ellipse with a horizontal diameter of h and a
340 vertical diameter of v (both integers in basic units u) with the
341 leftmost point at current position; then move to the rightmost
342 point of the ellipse.
343 DF color_scheme [component ...]⟨line_break⟩
345 Set fill color for solid drawing objects using different color
346 schemes; the analoguous command for setting the color of text,
347 line graphics, and the outline of graphic objects is m. The
348 color components are specified as integer arguments between 0
349 and 65536. The number of color components and their meaning
350 vary for the different color schemes. These commands are gener‐
351 ated by the groff escape sequences \D'F ...' and \M (with no
352 other corresponding graphics commands). No position changing.
353 This command is a groff extension.
354 DFc cyan magenta yellow⟨line_break⟩
356 Set fill color for solid drawing objects using the CMY
357 color scheme, having the 3 color components cyan,
358 magenta, and yellow.
359 DFd ⟨line_break⟩
361 Set fill color for solid drawing objects to the default
362 fill color value (black in most cases). No component
363 arguments.
364 DFg gray⟨line_break⟩
366 Set fill color for solid drawing objects to the shade of
367 gray given by the argument, an integer between 0 (black)
368 and 65536 (white).
369 DFk cyan magenta yellow black⟨line_break⟩
371 Set fill color for solid drawing objects using the CMYK
372 color scheme, having the 4 color components cyan,
373 magenta, yellow, and black.
374 DFr red green blue⟨line_break⟩
376 Set fill color for solid drawing objects using the RGB
377 color scheme, having the 3 color components red, green,
378 and blue.
379 Df n⟨line_break⟩
381 The argument n must be an integer in the range -32767 to 32767.
382 0 ≤ n ≤ 1000
384 Set the color for filling solid drawing objects to a
385 shade of gray, where 0 corresponds to solid white, 1000
386 (the default) to solid black, and values in between to
387 intermediate shades of gray; this is obsoleted by command
388 DFg.
389 n < 0 or n > 1000
391 Set the filling color to the color that is currently
392 being used for the text and the outline, see command m.
393 For example, the command sequence
394 mg 0 0 65536
395 Df -1
396 sets all colors to blue.
397 No position changing. This command is a groff extension.
399 Dl h v⟨line_break⟩
401 Draw line from current position to offset (h, v) (integers in
402 basic units u); then set current position to the end of the
403 drawn line.
404 Dp h1 v1 h2 v2 ... hn vn⟨line_break⟩
406 Draw a polygon line from current position to offset (h1, v1),
407 from there to offset (h2, v2), etc. up to offset (hn, vn), and
408 from there back to the starting position. For historical rea‐
409 sons, the position is changed by adding the sum of all arguments
410 with odd index to the actual horizontal position and the even
411 ones to the vertical position. Although this doesn't make sense
412 it is kept for compatibility. This command is a groff exten‐
413 sion.
414 DP h1 v1 h2 v2 ... hn vn⟨line_break⟩
416 The same macro as the corresponding Dp command with the same
417 arguments, but draws a solid polygon in the current fill color
418 rather than an outlined polygon. The position is changed in the
419 same way as with Dp. This command is a groff extension.
420 Dt n⟨line_break⟩
422 Set the current line thickness to n (an integer in basic
423 units u) if n>0; if n=0 select the smallest available line
424 thickness; if n<0 set the line thickness proportional to the
425 point size (this is the default before the first Dt command was
426 specified). For historical reasons, the horizontal position is
427 changed by adding the argument to the actual horizontal posi‐
428 tion, while the vertical position is not changed. Although this
429 doesn't make sense it is kept for compatibility. This command
430 is a groff extension.
431 Device Control Commands
433 Each device control command starts with the letter x followed by a
434 space character (optional or arbitrary space/tab in groff) and a sub‐
435 command letter or word; each argument (if any) must be preceded by a
436 syntactical space. All x commands are terminated by a syntactical line
437 break; no device control command can be followed by another command on
438 the same line (except a comment).
439 The subcommand is basically a single letter, but to increase readabil‐
441 ity, it can be written as a word, i.e. an arbitrary sequence of charac‐
442 ters terminated by the next tab, space, or newline character. All
443 characters of the subcommand word but the first are simply ignored.
444 For example, troff outputs the initialization command x i as x init and
445 the resolution command x r as x res. But writings like x i_like_groff
446 and x roff_is_groff resp. are accepted as well to mean the same com‐
447 mands.
448 In the following, the syntax element ⟨line_break⟩ means a syntactical
450 line break as defined in section Separation.
451 xF name⟨line_break⟩
453 (Filename control command)
454 Use name as the intended name for the current file in error
455 reports. This is useful for remembering the original file name
456 when groff uses an internal piping mechanism. The input file is
457 not changed by this command. This command is a groff extension.
458 xf n s⟨line_break⟩
460 (font control command)
461 Mount font position n (a non-negative integer) with font named s
462 (a text word), cf. groff_font(5).
463 xH n⟨line_break⟩
465 (Height control command)
466 Set character height to n (a positive integer in scaled
467 points z). Classical troff used the unit points (p) instead;
468 see section COMPATIBILITY.
469 xi⟨line_break⟩
471 (init control command)
472 Initialize device. This is the third command of the prologue.
473 xp⟨line_break⟩
475 (pause control command)
476 Parsed but ignored. The classical documentation reads pause
477 device, can be restarted.
478 xr n h v⟨line_break⟩
480 (resolution control command)
481 Resolution is n, while h is the minimal horizontal motion, and v
482 the minimal vertical motion possible with this device; all argu‐
483 ments are positive integers in basic units u per inch. This is
484 the second command of the prologue.
485 xS n⟨line_break⟩
487 (Slant control command)
488 Set slant to n (an integer in basic units u).
489 xs⟨line_break⟩
491 (stop control command)
492 Terminates the processing of the current file; issued as the
493 last command of any intermediate troff output.
494 xt⟨line_break⟩
496 (trailer control command)
497 Generate trailer information, if any. In groff, this is actu‐
498 ally just ignored.
499 xT xxx⟨line_break⟩
501 (Typesetter control command)
502 Set name of device to word xxx, a sequence of characters ended
503 by the next whitespace character. The possible device names
504 coincide with those from the groff -T option. This is the first
505 command of the prologue.
506 xu n⟨line_break⟩
508 (underline control command)
509 Configure underlining of spaces. If n is 1, start underlining
510 of spaces; if n is 0, stop underlining of spaces. This is
511 needed for the cu request in nroff mode and is ignored other‐
512 wise. This command is a groff extension.
513 xX anything⟨line_break⟩
515 (X-escape control command)
516 Send string anything uninterpreted to the device. If the line
517 following this command starts with a + character this line is
518 interpreted as a continuation line in the following sense. The
519 + is ignored, but a newline character is sent instead to the
520 device, the rest of the line is sent uninterpreted. The same
521 applies to all following lines until the first character of a
522 line is not a + character. This command is generated by the
523 groff escape sequence \X. The line-continuing feature is a
524 groff extension.
525 Obsolete Command
527 In classical troff output, the writing of a single character was mostly
528 done by a very strange command that combined a horizontal move and the
529 printing of a character. It didn't have a command code, but is repre‐
530 sented by a 3-character argument consisting of exactly 2 digits and a
531 character.
532 ddc Move right dd (exactly two decimal digits) basic units u, then
534 print character c.
535 In groff, arbitrary syntactical space around and within this
537 command is allowed to be added. Only when a preceding command
538 on the same line ends with an argument of variable length a sep‐
539 arating space is obligatory. In classical troff, large clusters
540 of these and other commands were used, mostly without spaces;
541 this made such output almost unreadable.
542 For modern high-resolution devices, this command does not make sense
544 because the width of the characters can become much larger than two
545 decimal digits. In groff, this is only used for the devices X75,
546 X75-12, X100, and X100-12. For other devices, the commands t and u
547 provide a better functionality.
548
550 The roff postprocessors are programs that have the task to translate
551 the intermediate output into actions that are sent to a device. A
552 device can be some piece of hardware such as a printer, or a software
553 file format suitable for graphical or text processing. The groff sys‐
554 tem provides powerful means that make the programming of such postpro‐
555 cessors an easy task.
556 There is a library function that parses the intermediate output and
558 sends the information obtained to the device via methods of a class
559 with a common interface for each device. So a groff postprocessor must
560 only redefine the methods of this class. For details, see the refer‐
561 ence in section FILES.
562
564 This section presents the intermediate output generated from the same
565 input for three different devices. The input is the sentence hell
566 world fed into groff on the command line.
567 · High-resolution device ps
569 shell> echo hell world | groff -Z -T ps
571 x T ps
573 x res 72000 1 1
574 x init
575 p1
576 x font 5 TR
577 f5
578 s10000
579 V12000
580 H72000
581 thell
582 wh2500
583 tw
584 H96620
585 torld
586 n12000 0
587 x trailer
588 V792000
589 x stop
590 This output can be fed into the postprocessor grops(1) to get its rep‐
592 resentation as a PostScript file.
593 · Low-resolution device latin1
595 This is similar to the high-resolution device except that the posi‐
597 tioning is done at a minor scale. Some comments (lines starting with
598 #) were added for clarification; they were not generated by the for‐
599 matter.
600 shell> echo hell world | groff -Z -T latin1
602 # prologue
604 x T latin1
605 x res 240 24 40
606 x init
607 # begin a new page
608 p1
609 # font setup
610 x font 1 R
611 f1
612 s10
613 # initial positioning on the page
614 V40
615 H0
616 # write text `hell'
617 thell
618 # inform about a space, and do it by a horizontal jump
619 wh24
620 # write text `world'
621 tworld
622 # announce line break, but do nothing because ...
623 n40 0
624 # ... the end of the document has been reached
625 x trailer
626 V2640
627 x stop
628 This output can be fed into the postprocessor grotty(1) to get a for‐
630 matted text document.
631 · Classical style output
633 As a computer monitor has a very low resolution compared to modern
635 printers the intermediate output for the X devices can use the jump-
636 and-write command with its 2-digit displacements.
637 shell> echo hell world | groff -Z -T X100
639 x T X100
641 x res 100 1 1
642 x init
643 p1
644 x font 5 TR
645 f5
646 s10
647 V16
648 H100
649 # write text with old-style jump-and-write command
650 ch07e07l03lw06w11o07r05l03dh7
651 n16 0
652 x trailer
653 V1100
654 x stop
655 This output can be fed into the postprocessor xditview(1x) or
657 gxditview(1) for displaying in X.
658 Due to the obsolete jump-and-write command, the text clusters in the
660 classical output are almost unreadable.
661
663 The intermediate output language of the classical troff was first docu‐
664 mented in [97]. The groff intermediate output format is compatible
665 with this specification except for the following features.
666 · The classical quasi device independence is not yet implemented.
668 · The old hardware was very different from what we use today. So the
670 groff devices are also fundamentally different from the ones in clas‐
671 sical troff. For example, the classical PostScript device was called
672 post and had a resolution of 720 units per inch, while groff's ps
673 device has a resolution of 72000 units per inch. Maybe, by imple‐
674 menting some rescaling mechanism similar to the classical quasi
675 device independence, these could be integrated into modern groff.
676 · The B-spline command D~ is correctly handled by the intermediate out‐
678 put parser, but the drawing routines aren't implemented in some of
679 the postprocessor programs.
680 · The argument of the commands s and x H has the implicit unit scaled
682 point z in groff, while classical troff had point (p). This isn't an
683 incompatibility, but a compatible extension, for both units coincide
684 for all devices without a sizescale parameter, including all classi‐
685 cal and the groff text devices. The few groff devices with a
686 sizescale parameter either did not exist, had a different name, or
687 seem to have had a different resolution. So conflicts with classical
688 devices are very unlikely.
689 · The position changing after the commands Dp, DP, and Dt is illogical,
691 but as old versions of groff used this feature it is kept for compat‐
692 ibility reasons.
693 The differences between groff and classical troff are documented in
695 groff_diff(7).
696
698 /usr/share/groff/1.18.1.4/font/devname/DESC
699 Device description file for device name.
700 ⟨groff_source_dir⟩/src/libs/libdriver/input.cc
702 Defines the parser and postprocessor for the intermediate out‐
703 put. It is located relative to the top directory of the groff
704 source tree, e.g. @GROFFSRCDIR@. This parser is the definitive
705 specification of the groff intermediate output format.
706
708 A reference like groff(7) refers to a manual page; here groff in sec‐
709 tion 7 of the man-page documentation system. To read the example, look
710 up section 7 in your desktop help system or call from the shell prompt
711 shell> man 7 groff
713 For more details, see man(1).
715 groff(1)
717 option -Z and further readings on groff.
718 groff(7)
720 for details of the groff language such as numerical units and
721 escape sequences.
722 groff_font(5)
724 for details on the device scaling parameters of the DESC file.
725 troff(1)
727 generates the device-independent intermediate output.
728 roff(7)
730 for historical aspects and the general structure of roff sys‐
731 tems.
732 groff_diff(7)
734 The differences between the intermediate output in groff and
735 classical troff.
736 grodvi(1), grohtml(1), grolbp(1), grolj4(1), grops(1), grotty(1)
738 the groff postprocessor programs.
739 For a treatment of all aspects of the groff system within a single doc‐
741 ument, see the groff info file. It can be read within the integrated
742 help systems, within emacs(1) or from the shell prompt by
743 shell> info groff
744 The classical troff output language is described in two AT&T Bell Labs
746 CSTR documents available on-line at Bell Labs CSTR site ⟨http://
747 cm.bell-labs.com/cm/cs/cstr.html⟩.
748 [CSTR #97]
750 A Typesetter-independent TROFF by Brian Kernighan is the origi‐
751 nal and most concise documentation on the output language; see
752 CSTR #97 ⟨http://cm.bell-labs.com/cm/cs/cstr/97.ps.gz⟩.
753 [CSTR #54]
755 The 1992 revision of the Nroff/Troff User's Manual by J. F.
756 Osanna and Brian Kernighan isn't as concise as [CSTR #97]
757 regarding the output language; see CSTR #54 ⟨http://
758 cm.bell-labs.com/cm/cs/cstr/54.ps.gz⟩.
759
761 Copyright (C) 1989, 2001, 2002 Free Software Foundation, Inc.
762 This document is distributed under the terms of the FDL (GNU Free Docu‐
764 mentation License) version 1.1 or later. You should have received a
765 copy of the FDL with this package; it is also available on-line at the
766 GNU copyleft site ⟨http://www.gnu.org/copyleft/fdl.html⟩.
767 This document is part of groff, the GNU roff distribution. It is based
769 on a former version - published under the GPL - that described only
770 parts of the groff extensions of the output language. It has been
771 rewritten 2002 by Bernd Warken ⟨bwarken@mayn.de⟩ and is maintained by
772 Werner Lemberg ⟨wl@gnu.org⟩.
773Groff Version 1.18.1.4 12 September 2002 GROFF_OUT(5)