1GROFF(7) Miscellaneous Information Manual GROFF(7)
2
6 groff - a short reference for the GNU roff language
7
9 The name groff stands for GNU roff and is the free implementation of
10 the roff type-setting system. See roff(7) for a survey and the back‐
11 ground of the groff system.
12 This document gives only short descriptions of the predefined roff lan‐
14 guage elements as used in groff. Both the classical features and the
15 groff extensions are provided.
16 Historically, the roff language was called troff. groff is compatible
18 with the classical system and provides proper extensions. So in GNU,
19 the terms roff, troff, and groff language could be used as synonyms.
20 However troff slightly tends to refer more to the classical aspects,
21 whereas groff emphasizes the GNU extensions, and roff is the general
22 term for the language.
23 This file is only a short version of the complete documentation that is
25 found in the groff info(1) file, which contains more detailed, actual,
26 and concise information.
27 The general syntax for writing groff documents is relatively easy, but
29 writing extensions to the roff language can be a bit harder.
30 The roff language is line-oriented. There are only two kinds of lines,
32 control lines and text lines. The control lines start with a control
33 character, by default a period “.” or a single quote “'”; all other
34 lines are text lines.
35 Control lines represent commands, optionally with arguments. They have
37 the following syntax. The leading control character can be followed by
38 a command name; arguments, if any, are separated by blanks from the
39 command name and among themselves, for example,
40 .command_name arg1 arg2
42 For indentation, any number of space or tab characters can be inserted
44 between the leading control character and the command name, but the
45 control character must be on the first position of the line.
46 Text lines represent the parts that will be printed. They can be modi‐
48 fied by escape sequences, which are recognized by a leading backslash
49 ‘\’. These are in-line or even in-word formatting elements or func‐
50 tions. Some of these take arguments separated by single quotes “'”,
51 others are regulated by a length encoding introduced by an open paren‐
52 thesis ‘(’ or enclosed in brackets ‘[’ and ‘]’.
53 The roff language provides flexible instruments for writing language
55 extension, such as macros. When interpreting macro definitions, the
56 roff system enters a special operating mode, called the copy mode.
57 The copy mode behavior can be quite tricky, but there are some rules
59 that ensure a safe usage.
60 1. Printable backslashes must be denoted as \e. To be more pre‐
62 cise, \e represents the current escape character. To get a
63 backslash glyph, use \(rs or \[rs].
64 2. Double all backslashes.
66 3. Begin all text lines with the special non-spacing character \&.
68 This does not produce the most efficient code, but it should work as a
70 first measure. For better strategies, see the groff info file and
71 groff_tmac(5).
72 Reading roff source files is easier, just reduce all double backslashes
74 to a single one in all macro definitions.
75
77 The roff language elements add formatting information to a text file.
78 The fundamental elements are predefined commands and variables that
79 make roff a full-blown programming language.
80 There are two kinds of roff commands, possibly with arguments.
82 Requests are written on a line of their own starting with a dot ‘.’ or
83 a “'”, whereas Escape sequences are in-line functions and in-word for‐
84 matting elements starting with a backslash ‘\’.
85 The user can define her own formatting commands using the de request.
87 These commands are called macros, but they are used exactly like
88 requests. Macro packages are pre-defined sets of macros written in the
89 groff language. A user's possibilities to create escape sequences her‐
90 self is very limited, only special characters can be mapped.
91 The groff language provides several kinds of variables with different
93 interfaces. There are pre-defined variables, but the user can define
94 her own variables as well.
95 String variables store character sequences. They are set with the ds
97 request and retrieved by the \* escape sequences. Strings can have
98 variables.
99 Register variables can store numerical values, numbers with a scale
101 unit, and occasionally string-like objects. They are set with the nr
102 request and retrieved by the \n escape sequences.
103 Environments allow the user to temporarily store global formatting
105 parameters like line length, font size, etc. for later reuse. This is
106 done by the ev request.
107 Fonts are identified either by a name or by an internal number. The
109 current font is chosen by the ft request or by the \f escape sequences.
110 Each device has special fonts, but the following fonts are available
111 for all devices. R is the standard font Roman. B is its bold counter‐
112 part. The italic font is called I and is available everywhere, but on
113 text devices it is displayed as an underlined Roman font. For the
114 graphical output devices, there exist constant-width pendants of these
115 fonts, CR, CI, and CB. On text devices, all characters have a constant
116 width anyway.
117 Moreover, there are some advanced roff elements. A diversion stores
119 information into a macro for later usage. A trap is a positional con‐
120 dition like a certain number of lines from page top or in a diversion
121 or in the input. Some action can be prescribed to be run automatically
122 when the condition is met.
123 More detailed information and examples can be found in the groff info
125 file.
126
128 There is a small set of characters that have a special controlling task
129 in certain conditions.
130 . A dot is only special at the beginning of a line or after the
132 condition in the requests if, ie, el, and while. There it is
133 the control character that introduces a request (or macro). The
134 special behavior can be delayed by using the \. escape. By
135 using the cc request, the control character can be set to a dif‐
136 ferent character, making the dot ‘.’ a non-special character.
137 In all other positions, it just means a dot character. In text
139 paragraphs, it is advantageous to start each sentence at a line
140 of its own.
141 ' The single quote has two controlling tasks. At the beginning of
143 a line and in the conditional requests it is the non-breaking
144 control character. That means that it introduces a request like
145 the dot, but with the additional property that this request
146 doesn't cause a linebreak. By using the c2 request, the non-
147 break control character can be set to a different character.
148 As a second task, it is the most commonly used argument separa‐
150 tor in some functional escape sequences (but any pair of charac‐
151 ters not part of the argument will work). In all other posi‐
152 tions, it denotes the single quote or apostrophe character.
153 Groff provides a printable representation with the \(cq escape
154 sequence.
155 " The double quote is used to enclose arguments in requests,
157 macros, and strings. In the ds and as requests, a leading dou‐
158 ble quote in the argument will be stripped off, making every‐
159 thing else afterwards the string to be defined (enabling leading
160 whitespace). The escaped double quote \" introduces a comment.
161 Otherwise, it is not special. Groff provides a printable repre‐
162 sentation with the \(dq escape sequence.
163 \ The backslash usually introduces an escape sequence (this can be
165 changed with the ec request). A printed version of the escape
166 character is the \e escape; a backslash glyph can be obtained by
167 \(rs.
168 ( The open parenthesis is only special in escape sequences when
170 introducing an escape name or argument consisting of exactly two
171 characters. In groff, this behavior can be replaced by the []
172 construct.
173 [ The opening bracket is only special in groff escape sequences;
175 there it is used to introduce a long escape name or long escape
176 argument. Otherwise, it is non-special, e.g. in macro calls.
177 ] The closing bracket is only special in groff escape sequences;
179 there it terminates a long escape name or long escape argument.
180 Otherwise, it is non-special.
181 space Space characters are only functional characters. They separate
183 the arguments in requests, macros, and strings, and the words in
184 text lines. They are subject to groff's horizontal spacing cal‐
185 culations. To get a defined space width, escape sequences like
186 ‘\ ’ (this is the escape character followed by a space), \|, \^,
187 or \h should be used.
188 newline
190 In text paragraphs, newlines mostly behave like space charac‐
191 ters. Continuation lines can be specified by an escaped new‐
192 line, i.e., by specifying a backslash ‘\’ as the last character
193 of a line.
194 tab If a tab character occurs during text the interpreter makes a
196 horizontal jump to the next pre-defined tab position. There is
197 a sophisticated interface for handling tab positions.
198
200 A numerical value is a signed or unsigned integer or float with or
201 without an appended scaling indicator. A scaling indicator is a one-
202 character abbreviation for a unit of measurement. A number followed by
203 a scaling indicator signifies a size value. By default, numerical val‐
204 ues do not have a scaling indicator, i.e., they are normal numbers.
205 The roff language defines the following scaling indicators.
207 c Centimeter
209 i Inch
210 P Pica = 1/6 inch
211 p Point = 1/72 inch
212 m Em = the font size in points (width of letter `m')
213 M 100th of an Em
214 n En = Em/2
215 u Basic unit for actual output device
216 v Vertical line space in basic units scaled
217 point = 1/sizescale of a point (defined in font DESC
218 file)
219 f Scale by 65536.
220 Numerical expressions are combinations of the numerical values defined
222 above with the following arithmetical operators already defined in
223 classical troff.
224 + Addition
226 - Subtraction
227 * Multiplication
228 / Division
229 % Modulo
230 = Equals
231 == Equals
232 < Less than
233 > Greater than
234 <= Less or equal
235 >= Greater or equal
236 & Logical and
237 : Logical or
238 ! Logical not
239 ( Grouping of expressions
240 ) Close current grouping
241 Moreover, groff added the following operators for numerical expres‐
243 sions:
244 e1>?e2 The maximum of e1 and e2.
246 e1<?e2 The minimum of e1 and e2.
247 (c;e) Evaluate e using c as the default scaling indicator.
248 For details see the groff info file.
250
252 Conditions occur in tests raised by the if, ie, and the while requests.
253 The following table characterizes the different types of conditions.
254 N A numerical expression N yields true if its value is
256 greater than 0.
257 !N True if the value of I is 0.
258 's1's2' True if string s1 is identical to string s2.
259 !'s1's2' True if string s1 is not identical to string s2.
260 cch True if there is a character ch available.
261 dname True if there is a string, macro, diversion, or
262 request called name.
263 e Current page number is even.
264 o Current page number is odd.
265 mname True if there is a color called name.
266 n Formatter is nroff.
267 rreg True if there is a register named reg.
268 t Formatter is troff.
269
271 This section provides a short reference for the predefined requests.
272 In groff, request and macro names can be arbitrarily long. No bracket‐
273 ing or marking of long names is needed.
274 Most requests take one or more arguments. The arguments are separated
276 by space characters (no tabs!); there is no inherent limit for their
277 length or number. An argument can be enclosed by a pair of double
278 quotes. This is very handy if an argument contains space characters,
279 e.g., "arg with space" denotes a single argument.
280 Some requests have optional arguments with a different behaviour. Not
282 all of these details are outlined here. Refer to the groff info file
283 and groff_diff(7) for all details.
284 In the following request specifications, most argument names were cho‐
286 sen to be descriptive. Only the following denotations need clarifica‐
287 tion.
288 c denotes a single character.
290 font a font either specified as a font name or a font num‐
291 ber.
292 anything all characters up to the end of the line or within \{
293 and \}.
294 n is a numerical expression that evaluates to an integer
295 value.
296 N is an arbitrary numerical expression, signed or
297 unsigned.
298 ±N has three meanings depending on its sign, described
299 below.
300 If an expression defined as ±N starts with a ‘+’ sign the resulting
302 value of the expression will be added to an already existing value
303 inherent to the related request, e.g. adding to a number register. If
304 the expression starts with a ‘-’ the value of the expression will be
305 subtracted from the request value.
306 Without a sign, N replaces the existing value directly. To assign a
308 negative number either prepend 0 or enclose the negative number in
309 parentheses.
310 Request Short Reference
312 . Empty line, ignored. Useful for structuring documents.
313 .\" anything
314 Complete line is a comment.
315 .ab string
316 Print string on standard error, exit program.
317 .ad Begin line adjustment for output lines in current adjust
318 mode.
319 .ad c Start line adjustment in mode c (c=l,r,b,n).
320 .af register c
321 Assign format c to register (c=l,i,I,a,A).
322 .aln alias register
323 Create alias name for register.
324 .als alias object
325 Create alias name for request, string, macro, or diversion
326 object.
327 .am macro Append to macro until .. is encountered.
328 .am macro end
329 Append to macro until .end is called.
330 .ami macro
331 Append to a macro whose name is contained in the string reg‐
332 ister macro until .. is encountered.
333 .ami macro end
334 Append to a macro indirectly. macro and end are string reg‐
335 isters whose contents are interpolated for the macro name and
336 the end macro, respectively.
337 .am1 macro
338 Same as .am but with compatibility mode switched off during
339 macro expansion.
340 .am1 macro end
341 Same as .am but with compatibility mode switched off during
342 macro expansion.
343 .as stringvar anything
344 Append anything to stringvar.
345 .asciify diversion
346 Unformat ASCII characters, spaces, and some escape sequences
347 in diversion.
348 .as1 stringvar anything
349 Same as .as but with compatibility mode switched off during
350 string expansion.
351 .backtrace
352 Print a backtrace of the input on stderr.
353 .bd font N
354 Embolden font by N-1 units.
355 .bd S font N
356 Embolden Special Font S when current font is font.
357 .blm Unset the blank line macro.
358 .blm macro
359 Set the blank line macro to macro.
360 .box End current diversion.
361 .box macro
362 Divert to macro, omitting a partially filled line.
363 .boxa End current diversion.
364 .boxa macro
365 Divert and append to macro, omitting a partially filled line.
366 .bp Eject current page and begin new page.
367 .bp ±N Eject current page; next page number ±N.
368 .br Line break.
369 .brp Break and spread output line. Same as \p.
370 .break Break out of a while loop.
371 .c2 Reset no-break control character to “'”.
372 .c2 c Set no-break control character to c.
373 .cc Reset control character to ‘.’.
374 .cc c Set control character to c.
375 .ce Center the next input line.
376 .ce N Center following N input lines.
377 .cf filename
378 Copy contents of file filename unprocessed to stdout or to
379 the diversion.
380 .cflags mode c1 c2 ...
381 Treat characters c1, c2, ... according to mode number.
382 .ch trap N
383 Change trap location to N .
384 .char c anything
385 Define character c as string anything.
386 .chop object
387 Chop the last character off macro, string, or diversion
388 object.
389 .close stream
390 Close the stream.
391 .color Enable colors.
392 .color N If N is zero disable colors, otherwise enable them.
393 .continue Finish the current iteration of a while loop.
394 .cp Enable compatibility mode.
395 .cp N If N is zero disable compatibility mode, otherwise enable it.
396 .cs font N M
397 Set constant character width mode for font to N/36 ems with
398 em M.
399 .cu N Continuous underline in nroff, like .ul in troff.
400 .da End current diversion.
401 .da macro Divert and append to macro.
402 .de macro Define or redefine macro until .. is encountered.
403 .de macro end
404 Define or redefine macro until .end is called.
405 .de1 macro
406 Same as .de but with compatibility mode switched off during
407 macro expansion.
408 .de1 macro end
409 Same as .de but with compatibility mode switched off during
410 macro expansion.
411 .defcolor color scheme component
412 Define or redefine a color with name color. scheme can be
413 rgb, cym, cymk, gray, or grey. component can be single com‐
414 ponents specified as fractions in the range 0 to 1 (default
415 scaling indicator f), as a string of two-digit hexadecimal
416 color components with a leading #, or as a string of four-
417 digit hexadecimal components with two leading #. The color
418 default can't be redefined.
419 .dei macro
420 Define or redefine a macro whose name is contained in the
421 string register macro until .. is encountered.
422 .dei macro end
423 Define or redefine a macro indirectly. macro and end are
424 string registers whose contents are interpolated for the
425 macro name and the end macro, respectively.
426 .di End current diversion.
427 .di macro Divert to macro .
428 .do name Interpret .name with compatibility mode disabled.
429 .ds stringvar anything
430 Set stringvar to anything.
431 .ds1 stringvar anything
432 Same as .ds but with compatibility mode switched off during
433 string expansion.
434 .dt N trap
435 Set diversion trap to position N (default scaling indica‐
436 tor v).
437 .ec Reset escape character to ‘\’.
438 .ec c Set escape character to c.
439 .ecr Restore escape character saved with .ecs.
440 .ecs Save current escape character.
441 .el anything
442 Else part for if-else (ie) request.
443 .em macro The macro will be run after the end of input.
444 .eo Turn off escape character mechanism.
445 .ev Switch to previous environment.
446 .ev env Push down environment number or name env and switch to it.
447 .evc env Copy the contents of environment env to the current environ‐
448 ment. No pushing or popping.
449 .ex Exit from roff processing.
450 .fam Return to previous font family.
451 .fam name Set the current font family to name.
452 .fc Disable field mechanism.
453 .fc a Set field delimiter to a and pad character to space.
454 .fc a b Set field delimiter to a and pad character to b.
455 .fchar c anything
456 Define fallback character c as string anything.
457 .fi Fill output lines.
458 .fl Flush output buffer.
459 .fp n font
460 Mount font on position n.
461 .fp n internal external
462 Mount font with long external name to short internal name on
463 position n.
464 .fspecial font s1 s2 ...
465 When the current font is font, then the fonts s1, s2, ...
466 will be special.
467 .ft Return to previous font. Same as \f[] or \fP.
468 .ft font Change to font name or number font; same as \f[font] escape
469 sequence.
470 .ftr font1 font2
471 Translate font1 to font2.
472 .hc Remove additional hyphenation indicator character.
473 .hc c Set up additional hyphenation indicator character c.
474 .hcode c1 code1 c2 code2 ...
475 Set the hyphenation code of character c1 to code1, that of c2
476 to code2, etc.
477 .hla lang Set the current hyphenation language to lang.
478 .hlm n Set the maximum number of consecutive hyphenated lines to n.
479 .hpf file Read hyphenation patterns from file.
480 .hpfa file
481 Append hyphenation patterns from file.
482 .hpfcode file
483 Set input mapping for .hpf.
484 .hw words List of words with exceptional hyphenation.
485 .hy N Switch to hyphenation mode N.
486 .hym n Set the hyphenation margin to n (default scaling indica‐
487 tor m).
488 .hys n Set the hyphenation space to n.
489 .ie cond anything
490 If cond then anything else goto .el.
491 .if cond anything
492 If cond then anything; otherwise do nothing.
493 .ig Ignore text until .. is encountered.
494 .ig end Ignore text until .end.
495 .in Change to previous indent value.
496 .in ±N Change indent according to ±N (default scaling indicator m).
497 .it N trap
498 Set an input-line count trap for the next N lines.
499 .itc N trap
500 Same as .it but count lines interrupted with \c as one line.
501 .kern Enable pairwise kerning.
502 .kern n If n is zero, disable pairwise kerning, otherwise enable it.
503 .lc Remove leader repetition character.
504 .lc c Set leader repetition character to c.
505 .length register anything
506 Write the length of the string anything in register.
507 .linetabs Enable line-tabs mode (i.e., calculate tab positions relative
508 to output line).
509 .linetabs n
510 If n is zero, disable line-tabs mode, otherwise enable it.
511 .lf N file
512 Set input line number to N and filename to file.
513 .lg N Ligature mode on if N>0.
514 .ll Change to previous line length.
515 .ll ±N Set line length according to ±N (default size 6.5i, default
516 scaling indicator m).
517 .ls Change to the previous value of additional intra-line skip.
518 .ls N Set additional intra-line skip value to N, i.e., N-1 blank
519 lines are inserted after each text output line.
520 .lt ±N Length of title (default scaling indicator m).
521 .mc Margin character off.
522 .mc c Print character c after each text line at actual distance
523 from right margin.
524 .mc c N Set margin character to c and distance to N from right margin
525 (default scaling indicator m).
526 .mk register
527 Mark current vertical position in register.
528 .mso file The same as the .so request except that file is searched in
529 the tmac directories.
530 .na No output-line adjusting.
531 .ne Need a one-line vertical space.
532 .ne N Need N vertical space (default scaling indicator v).
533 .nf No filling or adjusting of output-lines.
534 .nh No hyphenation.
535 .nm Number mode off.
536 .nm ±N [M [S [I]]]
537 In line number mode, set number, multiple, spacing, and
538 indent.
539 .nn Do not number next line.
540 .nn N Do not number next N lines.
541 .nop anything
542 Always execute anything.
543 .nr register ±N M
544 Define or modify register using ±N with auto-increment M.
545 .nroff Make the built-in condition n true and t false.
546 .ns Turn no-space mode on.
547 .nx Immediately jump to end of current file.
548 .nx filename
549 Next file.
550 .open stream filename
551 Open register filename for writing and associate the stream
552 named register stream with it.
553 .opena stream filename
554 Like .open but append to it.
555 .os Output vertical distance that was saved by the sv request.
556 .output string
557 Emit string directly to intermediate output, allowing leading
558 whitespace if string starts with " (which will be stripped
559 off).
560 .pc Reset page number character to ‘%’.
561 .pc c Page number character.
562 .pi program
563 Pipe output to program (nroff only).
564 .pl Set page length to default 11i. The current page length is
565 stored in register .p.
566 .pl ±N Change page length to ±N (default scaling indicator v).
567 .pm Print macro names and sizes (number of blocks of 128 bytes).
568 .pm t Print only total of sizes of macros (number of 128 bytes
569 blocks).
570 .pn ±N Next page number N.
571 .pnr Print the names and contents of all currently defined number
572 registers on stderr.
573 .po Change to previous page offset. The current page offset is
574 available in register .o.
575 .po ±N Page offset N.
576 .ps Return to previous point-size.
577 .ps ±N Point size; same as \s[±N].
578 .psbb filename
579 Get the bounding box of a PostScript image filename.
580 .pso command
581 This behaves like the so request except that input comes from
582 the standard output of command.
583 .ptr Print the names and positions of all traps (not including
584 input line traps and diversion traps) on stderr.
585 .pvs Change to previous post-vertical line spacing.
586 .pvs ±N Change post-vertical line spacing according to ±N (default
587 scaling indicator p).
588 .rchar c1 c2 ...
589 Remove the definitions of characters c1, c2, ...
590 .rd prompt
591 Read insertion.
592 .return Return from a macro.
593 .rj n Right justify the next n input lines.
594 .rm name Remove request, macro, or string name.
595 .rn old new
596 Rename request, macro, or string old to new.
597 .rnn reg1 reg2
598 Rename register reg1 to reg2.
599 .rr register
600 Remove register.
601 .rs Restore spacing; turn no-space mode off.
602 .rt ±N Return (upward only) to marked vertical place (default scal‐
603 ing indicator v).
604 .shc Reset soft hyphen character to \(hy.
605 .shc c Set the soft hyphen character to c.
606 .shift n In a macro, shift the arguments by n positions.
607 .sizes s1 s2 ... sn [0]
608 Set available font sizes similar to the sizes command in a
609 DESC file.
610 .so filename
611 Include source file.
612 .sp Skip one line vertically.
613 .sp N Space vertical distance N up or down according to sign of N
614 (default scaling indicator v).
615 .special s1 s2 ...
616 Fonts s1, s2, etc. are special and will be searched for char‐
617 acters not in the current font.
618 .spreadwarn
619 Toggle the spread warning on and off without changing its
620 value.
621 .spreadwarn limit
622 Emit a warning if each space in an output line is widened by
623 limit or more (default scaling indicator m).
624 .ss N Space-character size set to N/12 of the spacewidth in the
625 current font.
626 .ss N M Space-character size set to N/12 and sentence space size set
627 to M/12 of the spacewidth in the current font (=1/3 em).
628 .sty n style
629 Associate style with font position n.
630 .substring xx n1 n2
631 Replace the string named xx with the substring defined by the
632 indices n1 and n2.
633 .sv Save 1v of vertical space.
634 .sv N Save the vertical distance N for later output with os
635 request.
636 .sy command-line
637 Execute program command-line.
638 .ta T N Set tabs after every position that is a multiple of N
639 (default scaling indicator m).
640 .ta n1 n2 ... nn T r1 r2 ... rn
641 Set tabs at positions n1, n2, ..., nn, then set tabs at
642 nn+r1, nn+r2, ..., nn+rn, then at nn+rn+r1, nn+rn+r2, ...,
643 nn+rn+rn, and so on.
644 .tc Remove tab repition character.
645 .tc c Set tab repetition character to c.
646 .ti ±N Temporary indent next line (default scaling indicator m).
647 .tkf font s1 n1 s2 n2
648 Enable track kerning for font.
649 .tl ’left’center’right’
650 Three-part title.
651 .tm anything
652 Print anything on terminal (UNIX standard message output).
653 .tm1 anything
654 Print anything on terminal (UNIX standard message output),
655 allowing leading whitespace if anything starts with " (which
656 will be stripped off).
657 .tmc anything
658 Similar to .tm1 without emitting a final newline.
659 .tr abcd...
660 Translate a to b, c to d, etc. on output.
661 .trf filename
662 Transparently output the contents of file filename.
663 .trin abcd...
664 This is the same as the tr request except that the asciify
665 request will use the character code (if any) before the char‐
666 acter translation.
667 .trnt abcd...
668 This is the same as the tr request except that the transla‐
669 tions do not apply to text that is transparently throughput
670 into a diversion with \!.
671 .troff Make the built-in condition t true and n false.
672 .uf font Underline font set to font (to be switched to by .ul).
673 .ul N Underline (italicize in troff) N input lines.
674 .unformat diversion
675 Unformat space characters and tabs, preserving font informa‐
676 tion in diversion.
677 .vpt n Enable vertical position traps if n is non-zero, disable them
678 otherwise.
679 .vs Change to previous vertical base line spacing.
680 .vs ±N Set vertical base line spacing according to ±N (default scal‐
681 ing indicator p). Default value is 12p.
682 .warn n Set warnings code to n.
683 .warnscale si
684 Set scaling indicator used in warnings to si.
685 .wh N Remove (first) trap at position N.
686 .wh N trap
687 Set location trap; negative means from page bottom.
688 .while cond anything
689 While condition cond is true, accept anything as input.
690 .write stream anything
691 Write anything to the stream named stream.
692 .writec stream anything
693 Similar to .write without emitting a final newline.
694 .writem stream xx
695 Write contents of macro or string xx to the stream named
696 stream.
697 Besides these standard groff requests, there might be further macro
699 calls. They can originate from a macro package (see roff(7) for an
700 overview) or from a preprocessor.
701 Preprocessor macros are easy to be recognized. They enclose their code
703 into a pair of characteristic macros.
704 ┌─────────────┬─────────────┬────────────┐
706 │preprocessor │ start macro │ end macro │
707 ├─────────────┼─────────────┼────────────┤
708 │ eqn │ .PS │ .PE │
709 │ grap │ .G1 │ .G2 │
710 │ grn │ .GS │ .GE │
711 │ pic │ .PS │ .PE │
712 │ refer │ .R1 │ .R2 │
713 │ soelim │ none │ none │
714 │ tbl │ .TS │ .TE │
715 └─────────────┴─────────────┴────────────┘
717 Escape sequences are in-line language elements usually introduced by a
718 backslash ‘\’ and followed by an escape name and sometimes by a
719 required argument. Input processing is continued directly after the
720 escaped character or the argument resp. without an intervening separa‐
721 tion character. So there must be a way to determine the end of the
722 escape name and the end of the argument.
723 This is done by enclosing names (escape name and arguments consisting
725 of a variable name) by a pair of brackets [name] and constant arguments
726 (number expressions and characters) by apostrophes (ASCII 0x27) like
727 ’constant’.
728 There are abbreviations for short names. Two character escape names
730 can be specified by an opening parenthesis like \(xy without a closing
731 counterpart. And all one-character names different from the special
732 characters ‘[’ and ‘(’ can even be specified without a marker in the
733 form \c.
734 Constant arguments of length 1 can omit the marker apostrophes, too,
736 but there is no two-character analogue.
737 While 1-character escape sequences are mainly used for in-line func‐
739 tions and system related tasks, the 2-letter names following the \(
740 construct are used for special characters predefined by the roff sys‐
741 tem. Escapes sequences with names of more than two characters \[name]
742 denote user defined named characters (see the char request).
743 Single Character Escapes
745 \" Beginning of a comment. Everything up to the end of the line is
746 ignored.
747 \# Everything up to and including the next newline is ignored.
748 This is interpreted in copy mode. This is like \" except that
749 the terminating newline is ignored as well.
750 \*s The string stored in the string variable with 1-character name
751 s.
752 \*(st The string stored in the string variable with 2-character name
753 st.
754 \*[stringvar arg1 arg2 ...]
755 The string stored in the string variable with arbitrary length
756 name stringvar, taking arg1, arg2, ... as arguments.
757 \$0 The name by which the current macro was invoked. The als
758 request can make a macro have more than one name.
759 \$x Macro or string argument with 1-place number x, where x is a
760 digit between 1 and 9.
761 \$(xy Macro or string argument with 2-digit number xy.
762 \$[nexp]
763 Macro or string argument with number nexp, where nexp is a
764 numerical expression evaluating to an integer ≥1.
765 \$* In a macro or string, the concatenation of all the arguments
766 separated by spaces.
767 \$@ In a macro or string, the concatenation of all the arguments
768 with each surrounded by double quotes, and separated by spaces.
769 \\ reduces to a single backslash; useful to delay its interpreta‐
770 tion as escape character in copy mode. For a printable back‐
771 slash, use \e, or even better \[rs], to be independent from the
772 current escape character.
773 \’ The acute accent ´; same as \(aa. Unescaped: apostrophe, right
774 quotation mark, single quote (ASCII 0x27).
775 \` The grave accent `; same as \(ga. Unescaped: left quote, back‐
776 quote (ASCII 0x60).
777 \- The - sign in the current font.
778 \. An uninterpreted dot (period), even at start of line.
779 \% Default optional hyphenation character.
780 \! Transparent line indicator.
781 \?anything?
782 In a diversion, this will transparently embed anything in the
783 diversion. anything is read in copy mode. See also the escape
784 sequences \! and \?.
785 \space Unpaddable space-size space character (no line break).
786 \0 Digit width.
787 \| 1/6 em narrow space character; zero width in nroff.
788 \^ 1/12 em half-narrow space character; zero width in nroff.
789 \& Non-printable, zero width character.
790 \) Like \& except that it behaves like a character declared with
791 the cflags request to be transparent for the purposes of end of
792 sentence recognition.
793 \/ Increases the width of the preceding character so that the spac‐
794 ing between that character and the following character will be
795 correct if the following character is a roman character.
796 \, Modifies the spacing of the following character so that the
797 spacing between that character and the preceding character will
798 correct if the preceding character is a roman character.
799 \~ Unbreakable space that stretches like a normal inter-word space
800 when a line is adjusted.
801 \: Inserts a zero-width break point (similar to \% but without a
802 soft hyphen character).
803 \newline
804 Ignored newline, for continuation lines.
805 \{ Begin conditional input.
806 \} End conditional input.
807 \(sc The special character with 2-character name sc, see section Spe‐
808 cial Characters.
809 \[name]
810 The named character with arbitrary length name name.
811 \a Non-interpreted leader character.
812 \A’anything’
813 If anything is acceptable as a name of a string, macro, diver‐
814 sion, register, environment or font it expands to 1, and to 0
815 otherwise.
816 \b’abc...’
817 Bracket building function.
818 \B’anything’
819 If anything is acceptable as a valid numeric expression it
820 expands to 1, and to 0 otherwise.
821 \c Interrupt text processing.
822 \C’char’
823 The character called char; same as \[char], but compatible to
824 other roff versions.
825 \d Forward (down) 1/2 em vertical unit (1/2 line in nroff).
826 \D’charseq’
827 Draw a graphical element defined by the characters in charseq;
828 see groff info file for details.
829 \e Printable version of the current escape character.
830 \E Equivalent to an escape character, but is not interpreted in
831 copy-mode.
832 \fF Change to font with 1-character name or 1-digit number F.
833 \fP Switch back to previous font.
834 \f(fo Change to font with 2-character name or 2-digit number fo.
835 \f[font]
836 Change to font with arbitrary length name or number expression
837 font.
838 \f[] Switch back to previous font.
839 \Ff Change to font family with 1-character name f.
840 \F(fm Change to font family with 2-character name fm.
841 \F[fam]
842 Change to font family with arbitrary length name fam.
843 \F[] Switch back to previous font family.
844 \g[reg]
845 Return format of register with name reg suitable for .af.
846 Alternative forms \g(xy and \gx.
847 \h’N’ Local horizontal motion; move right N (left if negative).
848 \H’N’ Set height of current font to N.
849 \k[reg]
850 Mark horizontal input place in register with arbitrary length
851 name reg. Alternative forms \k(xy and \kx.
852 \l’Nc’ Horizontal line drawing function (optionally using character c).
853 \L’Nc’ Vertical line drawing function (optionally using character c).
854 \m[color]
855 Change to color color. Alternative forms \m(co and \mc.
856 \m[] Switch back to previous color.
857 \M[color]
858 Change filling color for closed drawn objects to color color.
859 Alternative forms \M(co and \Mc.
860 \M[] Switch to previous fill color.
861 \nr The numerical value stored in the register variable with the
862 1-character name r.
863 \n(re The numerical value stored in the register variable with the
864 2-character name re.
865 \n[reg]
866 The numerical value stored in the register variable with arbi‐
867 trary length name reg.
868 \N’n’ Typeset the character with code n in the current font, no spe‐
869 cial fonts are searched. Useful for adding characters to a font
870 using the char request.
871 \o’abc...’
872 Overstrike characters a, b, c, etc.
873 \O0 Disable glyph output. Mainly for internal use.
874 \O1 Enable glyph output. Mainly for internal use.
875 \p Break and spread output line.
876 \r Reverse 1 em vertical motion (reverse line in nroff).
877 \R’name ±n’
878 The same as .nr name ±n.
879 \s[±N] Set the point size to N scaled points. Note the alternative
880 forms \s±[N], \s'±N', \s±'N', \s(±xy, \s±(xy, \s±x. Same as ps
881 request.
882 \S’N’ Slant output N degrees.
883 \t Non-interpreted horizontal tab.
884 \u Reverse (up) 1/2 em vertical motion (1/2 line in nroff).
885 \v’N’ Local vertical motion; move down N (up if negative).
886 \V[env]
887 The contents of the environment variable env. Alternative forms
888 \V(xy and \Vx.
889 \w’string’
890 The width of the character sequence string.
891 \x’N’ Extra line-space function (negative before, positive after).
892 \X’string’
893 Output string as device control function.
894 \Y[name]
895 Output string variable or macro name uninterpreted as device
896 control function. Alternative forms \Y(xy and \Yx.
897 \zc Print c with zero width (without spacing).
898 \Z’anything’
899 Print anything and then restore the horizontal and vertical
900 position; anything may not contain tabs or leaders.
901 The escape sequences \e, \., \", \$, \*, \a, \n, \t, \g, and \newline
903 are interpreted in copy mode.
904 Escape sequences starting with \( or \[ do not represent single charac‐
906 ter escape sequences, but introduce escape names with two or more char‐
907 acters.
908 If a backslash is followed by a character that does not constitute a
910 defined escape sequence the backslash is silently ignored and the char‐
911 acter maps to itself.
912 Special Characters
914 Common special characters are predefined by escape sequences of the
915 form \(xy with characters x and y. Some of these exist in the usual
916 font while most of them are only available in the special font. Below
917 you'll find a selection of the most important glyphs; a complete list
918 can be found in groff_char(7).
919 \(bu Bullet sign
921 \(co Copyright
922 \(ct Cent
923 \(dd Double dagger
924 \(de Degree
925 \(dg Dagger
926 \(rs Printable double quote
927 \(em Em-dash
928 \(hy Hyphen
929 \(rg Registered sign
930 \(rs Printable backslash character
931 \(sc Section sign
932 \(ul Underline character
933 \(== Identical
934 \(>= Larger or equal
935 \(<= Less or equal
936 \(!= Not equal
937 \(-> Right arrow
938 \(<- Left arrow
939 \(+- Plus-minus sign
940 Strings
942 Strings are defined by the ds request and can be retrieved by the \*
943 escape sequence.
944 Strings share their name space with macros. So strings and macros
946 without arguments are roughly equivalent; it is possible to call a
947 string like a macro and vice-versa, but this often leads to unpre‐
948 dictable results. The following strings are predefined in groff.
949 \*[.T] The name of the current output device as specified by the -T
951 command line option.
952
954 Registers are variables that store a value. In groff, most registers
955 store numerical values (see section NUMERICAL EXPRESSIONS above), but
956 some can also hold a string value.
957 Each register is given a name. Arbitrary registers can be defined and
959 set with the request nr register.
960 The value stored in a register can be retrieved by the escape sequences
962 introduced by \n.
963 Most useful are predefined registers. In the following the notation
965 name is used to refer to a register called register name to make clear
966 that we speak about registers. Please keep in mind that the \n[] deco‐
967 ration is not part of the register name.
968 Read-only Registers
970 The following registers have predefined values that should not be modi‐
971 fied by the user (usually, registers starting with a dot a read-only).
972 Mostly, they provide information on the current settings or store
973 results from request calls.
974 \n[.$] Number of arguments in the current macro or string.
976 \n[.a] Post-line extra line-space most recently utilized using
977 \x’N’.
978 \n[.A] Set to 1 in troff if option -A is used; always 1 in nroff.
979 \n[.c] Current input line number.
980 \n[.C] 1 if compatibility mode is in effect, 0 otherwise.
981 \n[.cdp] The depth of the last character added to the current environ‐
982 ment. It is positive if the character extends below the
983 baseline.
984 \n[.ce] The number of lines remaining to be centered, as set by the
985 ce request.
986 \n[.cht] The height of the last character added to the current envi‐
987 ronment. It is positive if the character extends above the
988 baseline.
989 \n[.color]
990 1 if colors are enabled, 0 otherwise.
991 \n[.csk] The skew of the last character added to the current environ‐
992 ment. The skew of a character is how far to the right of the
993 center of a character the center of an accent over that char‐
994 acter should be placed.
995 \n[.d] Current vertical place in current diversion; equal to regis‐
996 ter register nl.
997 \n[.ev] The name or number of the current environment (string-val‐
998 ued).
999 \n[.f] Current font number.
1000 \n[.fam] The current font family (string-valued).
1001 \n[.fn] The current (internal) real font name (string-valued).
1002 \n[.fp] The number of the next free font position.
1003 \n[.g] Always 1 in GNU troff. Macros should use it to test if run‐
1004 ning under groff.
1005 \n[.h] Text base-line high-water mark on current page or diversion.
1006 \n[.H] Available horizontal resolution in basic units.
1007 \n[.hla] The current hyphenation language as set by the .hla request.
1008 \n[.hlc] The number of immediately preceding consecutive hyphenated
1009 lines.
1010 \n[.hlm] The maximum allowed number of consecutive hyphenated lines,
1011 as set by the hlm request.
1012 \n[.hy] The current hyphenation flags (as set by the hy request).
1013 \n[.hym] The current hyphenation margin (as set by the hym request).
1014 \n[.hys] The current hyphenation space (as set by the hys request).
1015 \n[.i] Current ident.
1016 \n[.in] The indent that applies to the current output line.
1017 \n[.int] Positive if last output line contains \c.
1018 \n[.kern] 1 if pairwise kerning is enabled, 0 otherwise.
1019 \n[.l] Current line length.
1020 \n[.lg] The current ligature mode (as set by the lg request).
1021 \n[.linetabs]
1022 The current line-tabs mode (as set by the linetabs request).
1023 \n[.ll] The line length that applies to the current output line.
1024 \n[.lt] The title length (as set by the lt request).
1025 \n[.n] Length of text portion on previous output line.
1026 \n[.ne] The amount of space that was needed in the last ne request
1027 that caused a trap to be sprung. Useful in conjunction with
1028 register .trunc.
1029 \n[.ns] 1 if in no-space mode, 0 otherwise.
1030 \n[.o] Current page offset.
1031 \n[.p] Current page length.
1032 \n[.pn] The number of the next page: either the value set by a pn
1033 request, or the number of the current page plus 1.
1034 \n[.ps] The current pointsize in scaled points.
1035 \n[.psr] The last-requested pointsize in scaled points.
1036 \n[.pvs] The current post-vertical line spacing.
1037 \n[.rj] The number of lines to be right-justified as set by the rj
1038 request.
1039 \n[.s] Current point size as a decimal fraction.
1040 \n[.sr] The last requested pointsize in points as a decimal fraction
1041 (string-valued).
1042 \n[.t] Distance to the next trap.
1043 \n[.T] Set to 1 if option -T is used.
1044 \n[.tabs] A string representation of the current tab settings suitable
1045 for use as an argument to the ta request.
1046 \n[.trunc]
1047 The amount of vertical space truncated by the most recently
1048 sprung vertical position trap, or, if the trap was sprung by
1049 a ne request, minus the amount of vertical motion produced by
1050 .ne. In other words, at the point a trap is sprung, it rep‐
1051 resents the difference of what the vertical position would
1052 have been but for the trap, and what the vertical position
1053 actually is. Useful in conjunction with the register .ne
1054 register.
1055 \n[.ss] The value of the parameters set by the first argument of the
1056 ss request.
1057 \n[.sss] The value of the parameters set by the second argument of the
1058 ss request.
1059 \n[.u] Equal to 1 bin fill mode and 0 in nofill mode.
1060 \n[.v] Current vertical line spacing.
1061 \n[.V] Available vertical resolution in basic units.
1062 \n[.vpt] 1 if vertical position traps are enabled, 0 otherwise.
1063 \n[.w] Width of previous character.
1064 \n[.warn] The sum of the number codes of the currently enabled warn‐
1065 ings.
1066 \n[.x] The major version number.
1067 \n[.y] The minor version number.
1068 \n[.Y] The revision number of groff.
1069 \n[.z] Name of current diversion.
1070 Writable Registers
1072 The following registers can be read and written by the user. They have
1073 predefined default values, but these can be modified for customizing a
1074 document.
1075 \n[%] Current page number.
1077 \n[c.] Current input line number.
1078 \n[ct] Character type (set by width function \w).
1079 \n[dl] Maximal width of last completed diversion.
1080 \n[dn] Height of last completed diversion.
1081 \n[dw] Current day of week (1-7).
1082 \n[dy] Current day of month (1-31).
1083 \n[hours] The number of hours past midnight. Initialized at start-up.
1084 \n[hp] Current horizontal position at input line.
1085 \n[llx] Lower left x-coordinate (in PostScript units) of a given
1086 PostScript image (set by .psbb).
1087 \n[lly] Lower left y-coordinate (in PostScript units) of a given
1088 PostScript image (set by .psbb).
1089 \n[ln] Output line number.
1090 \n[minutes]
1091 The number of minutes after the hour. Initialized at start-
1092 up.
1093 \n[mo] Current month (1-12).
1094 \n[nl] Vertical position of last printed text base-line.
1095 \n[rsb] Like register sb, but takes account of the heights and depths
1096 of characters.
1097 \n[rst] Like register st, but takes account of the heights and depths
1098 of characters.
1099 \n[sb] Depth of string below base line (generated by width function
1100 \w).
1101 \n[seconds]
1102 The number of seconds after the minute. Initialized at
1103 start-up.
1104 \n[skw] Right skip width from the center of the last character in the
1105 \w argument.
1106 \n[slimit]
1107 If greater than 0, the maximum number of objects on the input
1108 stack. If ≤0 there is no limit, i.e., recursion can continue
1109 until virtual memory is exhausted.
1110 \n[ssc] The amount of horizontal space (possibly negative) that
1111 should be added to the last character before a subscript
1112 (generated by width function \w).
1113 \n[st] Height of string above base line (generated by width function
1114 \w).
1115 \n[systat]
1116 The return value of the system() function executed by the
1117 last sy request.
1118 \n[urx] Upper right x-coordinate (in PostScript units) of a given
1119 PostScript image (set by .psbb).
1120 \n[ury] Upper right y-coordinate (in PostScript units) of a given
1121 PostScript image (set by .psbb).
1122 \n[year] The current year (year 2000 compliant).
1123 \n[yr] Current year minus 1900. For Y2K compliance use register
1124 register year instead.
1125
1127 The differences of the groff language in comparison to classical troff
1128 as defined by [CSTR #54] are documented in groff_diff(7).
1129 The groff system provides a compatibility mode, see groff(1) on how to
1131 invoke this.
1132
1134 Report bugs to the groff bug mailing list ⟨bug-groff@gnu.org⟩. Include
1135 a complete, self-contained example that will allow the bug to be repro‐
1136 duced, and say which version of groff you are using.
1137
1139 Copyright (C) 2000, 2001, 2002 Free Software Foundation, Inc.
1140 This document is distributed under the terms of the FDL (GNU Free Docu‐
1142 mentation License) version 1.1 or later. You should have received a
1143 copy of the FDL on your system, it is also available on-line at the GNU
1144 copyleft site ⟨http://www.gnu.org/copyleft/fdl.html⟩.
1145 This document is part of groff, the GNU roff distribution. It was
1147 written by Bernd Warken ⟨bwarken@mayn.de⟩; it is maintained by Werner
1148 Lemberg ⟨wl@gnu.org⟩.
1149
1151 The main source of information for the groff language is the groff
1152 info(1) file. Besides the gory details, it contains many examples.
1153 groff(1)
1155 the usage of the groff program and pointers to the documentation
1156 and availability of the groff system.
1157 groff_diff(7)
1159 the differences of the groff language as compared to classical
1160 roff. This is the authoritative document for the predefined
1161 language elements that are specific to groff.
1162 groff_char(7)
1164 the predefined groff characters (glyphs).
1165 groff_font(5)
1167 the specification of fonts and the DESC file.
1168 roff(7)
1170 the history of roff, the common parts shared by all roff sys‐
1171 tems, and pointers to further documentation.
1172 [CSTR #54]
1174 Nroff/Troff User's Manual by Osanna & Kernighan ⟨http://
1175 cm.bell-labs.com/cm/cs/54.ps⟩ — the bible for classical troff.
1176Groff Version 1.18.1.4 29 June 2002 GROFF(7)