5 Last update: 10 Nov 2002
7 This file is part of groff, the GNU roff type-setting system.
9 Copyright (C) 2000, 2001, 2002 Free Software Foundation, Inc.
10 written by Bernd Warken <bwarken@mayn.de>
11 maintained by Werner Lemberg <wl@gnu.org>
13 Permission is granted to copy, distribute and/or modify this document
14 under the terms of the GNU Free Documentation License, Version 1.1 or
15 any later version published by the Free Software Foundation; with the
16 Invariant Sections being this .ig-section and AUTHORS, with no
17 Front-Cover Texts, and with no Back-Cover Texts.
19 A copy of the Free Documentation License is included as a file called
20 FDL in the main directory of the groff source package.
23 .\" --------------------------------------------------------------------
25 .\" --------------------------------------------------------------------
41 .\" --------------------------------------------------------------------
42 .\" start of macro definitions
51 .c ---------------------------------------------------------------------
54 .c All arguments are printed as text.
59 .c ---------------------------------------------------------------------
60 .c .ExecFF macro font1 font2 text1 text2 text1 text2 ...
62 .c Concat text arguments using alternating fonts and feed into macro.
63 .c For a trailing punctuation, terminate the call with \c.
78 . as @s \f[\*[@f1]]\*[@a]\f[]\"
83 . as @s \f[\*[@f2]]\*[@a]\f[]\"
86 . \*[@m] "\*[@s]\f[R]"
87 . ft P \" to make \c happy
95 .c --------- command line option ---------
102 .c --------- characters ---------
105 . ExecFF Text CB R \$*
110 . ExecFF Text R CB \[oq] \*[@1] "\[cq]\$*"
116 . ExecFF Text R CB \[lq] \*[@1] "\[rq]\$*"
119 .c --------- requests ---------
121 .c synopsis of a request
127 . ie (\n[.$] = 0) \{\
129 . Text \f[CB]\*[@1]\f[]
133 . Text \f[CB]\*[@1]\~\f[]\f[I]\$*\f[]
137 .c reference of a request
142 .c --------- numerical elements ---------
144 .c number with a trailing unit
146 . Text \$1\^\f[CB]\$2\f[]\$3\f[R]
150 .c representation of units within the text
152 . Text \f[CB]\$1\f[]\$2\f[R]
156 .c representation of mathematical operators within the text
162 .c --------- escape sequences ---------
164 .c ---------------------------------------------------------------------
167 .c Synopsis of an escape sequence, optionally with argument
168 .c Args : 1 or 2; `name' obligatory, `arg' optional
169 .c name : suitable name for an escape sequence (c, (xy, [long])
170 .c arg : arbitrary word
171 .c Result : prints \namearg, where `name' is in CB, `arg' in I
175 . ab .ESC needs 1 or 2 arguments.
176 . ExecFF IP CB I "\[rs]\$1" "\,\$2\/"
178 .c ---------------------------------------------------------------------
181 .c Synopsis for escape sequence with a bracketed long argument
182 .c Args : 2 obligatory
183 .c name : suitable name for an escape sequence (c, (xy, [long])
184 .c arg : arbitrary text
185 .c Result : prints \name[arg], where `name' is in CB, `arg' in I
189 . ab .ESC[] needs exactly 2 arguments.
190 . ExecFF IP CB I "\[rs]\$1\[lB]" "\h'-0.2m'\$2\h'-0.15m'" \[rB]
192 .c ---------------------------------------------------------------------
195 .c Synopsis for escape sequence with a bracketed long argument
196 .c Args : 2 obligatory
197 .c name : suitable name for an escape sequence (c, (xy, [long])
198 .c arg : arbitrary text
199 .c Result : prints \name'arg', where `name' is in CB, `arg' in I
203 . ab .ESCq needs exactly 2 argument.
204 . ExecFF IP CB I "\[rs]\$1\[cq]" "\h'-0.3m'\$2" \[cq]
206 .c ---------------------------------------------------------------------
209 .c Synopsis for escape sequence with a bracketed long argument
210 .c Args : 1 obligatory
211 .c arg : arbitrary text
212 .c Result : prints `\?arg?', where the `?' are in CB, `arg' in I
216 . ab .ESC? needs exactly 1 arguments.
217 . ExecFF IP CB I \[rs]? "\$1" ?
219 .c ---------------------------------------------------------------------
222 .c Reference of an escape sequence (no args), possibly punctuation
223 .c Args : 1 obligatory
224 .c name : suitable name for an escape sequence (c, (xy, [long])
226 .c Result : prints \name, where `name' is in B, `punct' in R
230 . ab .esc needs 1 or 2 arguments.
233 .c ---------------------------------------------------------------------
234 .c .escarg name arg [punct]
236 .c Reference of an escape sequence (no args)
237 .c Args : 1 obligatory, 1 optional
238 .c name : suitable name for an escape sequence (c, (xy, [long])
239 .c arg : arbitrary word
240 .c Result : prints \namearg, where
241 .c `name' is in B, `arg' in I
245 . ab .esc needs 2 or 3 arguments.
246 . Text \f[B]\[rs]\$1\f[]\f[I]\$2\f[]\$3
248 .c ---------------------------------------------------------------------
249 .c .esc[] name arg [punct]
251 .c Reference for escape sequence with a bracketed long argument
252 .c Args : 2 obligatory
253 .c name : suitable name for an escape sequence (c, (xy, [long])
254 .c arg : arbitrary text
255 .c Result : prints \name[arg], where `name' is in CB, `arg' in CI
259 . ab .esc[] needs 2 or 3 arguments.
260 . Text \f[B]\[rs]\$1\[lB]\f[]\f[I]\$2\f[]\f[B]\[rB]\f[]\$3
263 .c ---------------------------------------------------------------------
266 .c Reference for escape sequence with a bracketed long argument
267 .c Args : 2 obligatory
268 .c name : suitable name for an escape sequence (c, (xy, [long])
269 .c arg : arbitrary text
270 .c Result : prints \name'arg', where `name' is in CB, `arg' in CI
274 . ab .escq needs 2 arguments.
275 . Text \f[B]\[rs]\$1\[cq]\f[]\f[I]\$2\f[]\f[B]\[cq]\f[]\$3
278 .c --------- strings ---------
280 .c synopsis for string, with \*[]
285 . ExecFF Text R CB \[rs]*[ \*[@1]\f[]\f[R]] \$*
288 .c synopsis for a long string
292 . Text \f[CB]\[rs]*\[lB]\$1\[rB]\f[]\$2
296 .c --------- registers ---------
298 .c synopsis for registers, with \n[]
303 . ExecFF Text R CB \[rs]n[ \*[@1]\f[]\f[R]] \$*
306 .c reference of a register, without decoration
313 .\" end of macro definitions
316 .\" --------------------------------------------------------------------
318 .\" --------------------------------------------------------------------
320 .TH GROFF @MAN7EXT@ "@MDATE@" "Groff Version @VERSION@"
322 groff \- a short reference for the GNU roff language
325 .\" --------------------------------------------------------------------
327 .\" --------------------------------------------------------------------
333 and is the free implementation of the roff type-setting system.
337 for a survey and the background of the groff system.
340 This document gives only short descriptions of the predefined roff
341 language elements as used in groff.
343 Both the classical features and the groff extensions are provided.
351 is compatible with the classical system and provides proper
359 could be used as synonyms.
363 slightly tends to refer more to the classical aspects, whereas
365 emphasizes the GNU extensions, and
367 is the general term for the language.
370 This file is only a short version of the complete documentation that
374 file, which contains more detailed, actual, and concise information.
377 The general syntax for writing groff documents is relatively easy, but
378 writing extensions to the roff language can be a bit harder.
381 The roff language is line-oriented.
383 There are only two kinds of lines, control lines and text lines.
385 The control lines start with a control character, by default a period
389 all other lines are text lines.
393 represent commands, optionally with arguments.
395 They have the following syntax.
397 The leading control character can be followed by a command name;
398 arguments, if any, are separated by blanks from the command name and
399 among themselves, for example,
403 .Text .command_name arg1 arg2
407 For indentation, any number of space or tab characters can be inserted
408 between the leading control character and the command name, but the
409 control character must be on the first position of the line.
413 represent the parts that will be printed.
414 They can be modified by escape sequences, which are recognized by a
416 .squoted_char \[rs] .
417 These are in-line or even in-word formatting elements or functions.
419 Some of these take arguments separated by single quotes
421 others are regulated by a length encoding introduced by an open
424 or enclosed in brackets
430 The roff language provides flexible instruments for writing language
431 extension, such as macros.
433 When interpreting macro definitions, the roff system enters a special
434 operating mode, called the
438 The copy mode behavior can be quite tricky, but there are some rules
439 that ensure a safe usage.
442 Printable backslashes must be denoted as
446 represents the current escape character.
448 To get a backslash glyph, use
453 Double all backslashes.
455 Begin all text lines with the special non-spacing character
459 This does not produce the most efficient code, but it should work as a
462 For better strategies, see the groff info file and
463 .BR groff_tmac (@MAN5EXT@).
466 Reading roff source files is easier, just reduce all double backslashes
467 to a single one in all macro definitions.
470 .\" --------------------------------------------------------------------
472 .\" --------------------------------------------------------------------
474 The roff language elements add formatting information to a text file.
476 The fundamental elements are predefined commands and variables that
477 make roff a full-blown programming language.
480 There are two kinds of roff commands, possibly with arguments.
482 are written on a line of their own starting with a dot
488 are in-line functions and in-word formatting elements starting with a
490 .squoted_char \[rs] .
493 The user can define her own formatting commands using the
497 These commands are called
499 but they are used exactly like requests.
501 Macro packages are pre-defined sets of macros written in the groff
504 A user's possibilities to create escape sequences herself is very
505 limited, only special characters can be mapped.
508 The groff language provides several kinds of variables with
509 different interfaces.
511 There are pre-defined variables, but the user can define her own
516 variables store character sequences.
518 They are set with the
520 request and retrieved by the
524 Strings can have variables.
528 variables can store numerical values, numbers with a scale unit, and
529 occasionally string-like objects.
531 They are set with the
533 request and retrieved by the
539 allow the user to temporarily store global formatting parameters like
540 line length, font size, etc.\& for later reuse.
548 are identified either by a name or by an internal number.
550 The current font is chosen by the
556 Each device has special fonts, but the following fonts are available
559 is the standard font Roman.
569 and is available everywhere, but on text devices it is displayed as an
570 underlined Roman font.
572 For the graphical output devices, there exist constant-width pendants
578 On text devices, all characters have a constant width anyway.
581 Moreover, there are some advanced roff elements.
585 stores information into a macro for later usage.
589 is a positional condition like a certain number of lines from page top
590 or in a diversion or in the input.
592 Some action can be prescribed to be run automatically when the
596 More detailed information and examples can be found in the groff info
600 .\" --------------------------------------------------------------------
601 .SH "CONTROL CHARACTERS"
602 .\" --------------------------------------------------------------------
604 There is a small set of characters that have a special controlling
605 task in certain conditions.
609 A dot is only special at the beginning of a line or after the
610 condition in the requests
616 There it is the control character that introduces a request (or macro).
618 The special behavior can be delayed by using the
624 request, the control character can be set to a different character,
627 a non-special character.
629 In all other positions, it just means a dot character.
631 In text paragraphs, it is advantageous to start each sentence at a
636 The single quote has two controlling tasks.
638 At the beginning of a line and in the conditional requests it is the
639 non-breaking control character.
641 That means that it introduces a request like the dot, but with the
642 additional property that this request doesn't cause a linebreak.
646 request, the non-break control character can be set to a different
650 As a second task, it is the most commonly used argument separator in
651 some functional escape sequences (but any pair of characters not part
652 of the argument will work).
654 In all other positions, it denotes the single quote or apostrophe
657 Groff provides a printable representation with the
663 The double quote is used to enclose arguments in requests, macros, and
670 requests, a leading double quote in the argument will be stripped off,
671 making everything else afterwards the string to be defined (enabling
674 The escaped double quote
676 introduces a comment.
678 Otherwise, it is not special.
680 Groff provides a printable representation with the
686 The backslash usually introduces an escape sequence (this can be
691 A printed version of the escape character is the
693 escape; a backslash glyph can be obtained by
697 The open parenthesis is only special in escape sequences when
698 introducing an escape name or argument consisting of exactly two
701 In groff, this behavior can be replaced by the \f[CB][]\f[] construct.
704 The opening bracket is only special in groff escape sequences; there
705 it is used to introduce a long escape name or long escape argument.
707 Otherwise, it is non-special, e.g.\& in macro calls.
710 The closing bracket is only special in groff escape sequences; there
711 it terminates a long escape name or long escape argument.
713 Otherwise, it is non-special.
716 Space characters are only functional characters.
718 They separate the arguments in requests, macros, and strings, and the words
721 They are subject to groff's horizontal spacing calculations.
723 To get a defined space width, escape sequences like
724 .squoted_char "\[rs]\ "
725 (this is the escape character followed by a space),
732 .IP \f[CI]newline\f[]
733 In text paragraphs, newlines mostly behave like space characters.
735 Continuation lines can be specified by an escaped newline, i.e., by
736 specifying a backslash
738 as the last character of a line.
740 If a tab character occurs during text the interpreter makes a
741 horizontal jump to the next pre-defined tab position.
743 There is a sophisticated interface for handling tab positions.
746 .\" --------------------------------------------------------------------
747 .SH "NUMERICAL EXPRESSIONS"
748 .\" --------------------------------------------------------------------
752 is a signed or unsigned integer or float with or without an appended
757 is a one-character abbreviation for a unit of measurement.
759 A number followed by a scaling indicator signifies a size value.
761 By default, numerical values do not have a scaling indicator, i.e., they
767 language defines the following scaling indicators.
784 Pica\ \[eq]\ 1/6\ inch
788 Point\ \[eq]\ 1/72\ inch
792 Em\ \[eq]\ \f[R]the font size in points (width of letter `\f[CR]m\f[R]')
796 100\^th \f[R]of an \f[CR]Em
804 Basic unit for actual output device
808 Vertical line space in basic units
809 scaled point\ \[eq]\ 1/\f[CI]sizescale\f[R] of a point (defined in
810 font \f[I]DESC\f[] file)
819 .B Numerical expressions
820 are combinations of the numerical values defined above with the
821 following arithmetical operators already defined in classical troff.
885 Grouping of expressions
889 Close current grouping
897 added the following operators for numerical expressions:
904 .ExecFF Text I CB e1 >? e2
911 .ExecFF Text I CB e1 <? e2
918 .ExecFF Text CB I ( c ; e )
923 as the default scaling indicator.
929 For details see the groff info file.
932 .\" --------------------------------------------------------------------
934 .\" --------------------------------------------------------------------
937 occur in tests raised by the
944 The following table characterizes the different types of conditions.
952 A numerical expression
954 yields true if its value is greater than\~0.
966 is identical to string\~\c
973 is not identical to string\~\c
978 True if there is a character\~\c
984 True if there is a string, macro, diversion, or request called
989 Current page number is even.
993 Current page number is odd.
997 True if there is a color called
1007 True if there is a register named
1019 .\" --------------------------------------------------------------------
1021 .\" --------------------------------------------------------------------
1023 This section provides a short reference for the predefined requests.
1025 In groff, request and macro names can be arbitrarily long.
1027 No bracketing or marking of long names is needed.
1030 Most requests take one or more arguments.
1032 The arguments are separated by space characters (no tabs!); there is
1033 no inherent limit for their length or number.
1035 An argument can be enclosed by a pair of double quotes.
1037 This is very handy if an argument contains space characters, e.g.,
1038 .RI \[dq] "arg with space" \[dq]
1039 denotes a single argument.
1042 Some requests have optional arguments with a different behaviour.
1044 Not all of these details are outlined here.
1046 Refer to the groff info file and
1047 .BR groff_diff (@MAN7EXT@)
1051 In the following request specifications, most argument names were
1052 chosen to be descriptive.
1054 Only the following denotations need clarification.
1062 denotes a single character.
1066 a font either specified as a font name or a font number.
1070 all characters up to the end of the line or within
1077 is a numerical expression that evaluates to an integer value.
1081 is an arbitrary numerical expression, signed or unsigned.
1085 has three meanings depending on its sign, described below.
1091 If an expression defined as
1095 sign the resulting value of the expression will be added to an already
1096 existing value inherent to the related request, e.g.\& adding to a number
1099 If the expression starts with a
1101 the value of the expression will be subtracted from the request value.
1106 replaces the existing value directly.
1108 To assign a negative number either prepend\~0 or enclose the negative
1109 number in parentheses.
1112 .\" --------------------------------------------------------------------
1113 .SS "Request Short Reference"
1114 .\" --------------------------------------------------------------------
1119 Empty line, ignored.
1121 Useful for structuring documents.
1123 .REQ .\[rs]\[dq] anything
1124 Complete line is a comment.
1129 on standard error, exit program.
1132 Begin line adjustment for output lines in current adjust mode.
1135 Start line adjustment in mode
1137 (\f[CI]c\f[]\f[CR]\|\^\[eq]\|l,r,b,n\f[]).
1144 (\f[CI]c\f[]\f[CR]\|\^\[eq]\|l,i,I,a,A\f[]).
1146 .REQ .aln alias register
1147 Create alias name for
1150 .REQ .als alias object
1151 Create alias name for request, string, macro, or diversion
1169 Append to a macro whose name is contained in the string register
1176 Append to a macro indirectly.
1180 are string registers whose contents are interpolated for the macro name
1181 and the end macro, respectively.
1186 but with compatibility mode switched off during macro expansion.
1191 but with compatibility mode switched off during macro expansion.
1193 .REQ .as stringvar anything
1199 .REQ .asciify diversion
1200 Unformat ASCII characters, spaces, and some escape sequences in
1203 .REQ .as1 stringvar anything
1206 but with compatibility mode switched off during string expansion.
1209 Print a backtrace of the input on stderr.
1219 Embolden Special Font
1221 when current font is
1225 Unset the blank line macro.
1228 Set the blank line macro to
1232 End current diversion.
1237 omitting a partially filled line.
1240 End current diversion.
1243 Divert and append to
1245 omitting a partially filled line.
1248 Eject current page and begin new page.
1251 Eject current page; next page number
1258 Break and spread output line.
1263 Break out of a while loop.
1266 Reset no-break control character to
1270 Set no-break control character to
1274 Reset control character to
1278 Set control character to
1282 Center the next input line.
1290 Copy contents of file
1292 unprocessed to stdout or to the diversion.
1294 .REQ .cflags mode c1 c2 .\|.\|.\&
1310 .REQ .char c anything
1317 Chop the last character off macro, string, or diversion
1330 is zero disable colors, otherwise enable them.
1333 Finish the current iteration of a while loop.
1336 Enable compatibility mode.
1341 is zero disable compatibility mode, otherwise enable it.
1344 Set constant character width mode for
1352 Continuous underline in nroff, like
1357 End current diversion.
1360 Divert and append to
1380 but with compatibility mode switched off during macro expansion.
1385 but with compatibility mode switched off during macro expansion.
1387 .REQ .defcolor color scheme component
1388 Define or redefine a color with name
1399 can be single components specified as fractions in the range 0 to 1
1400 (default scaling indicator\~\c
1401 .scaleindicator f ),
1402 as a string of two-digit hexadecimal color components with a leading
1404 or as a string of four-digit hexadecimal components with two leading
1411 Define or redefine a macro whose name is contained in the string register
1418 Define or redefine a macro indirectly.
1422 are string registers whose contents are interpolated for the macro name
1423 and the end macro, respectively.
1426 End current diversion.
1435 with compatibility mode disabled.
1437 .REQ .ds stringvar anything
1443 .REQ .ds1 stringvar anything
1446 but with compatibility mode switched off during string expansion.
1449 Set diversion trap to position
1451 (default scaling indicator\~\c
1452 .scaleindicator v ).
1455 Reset escape character to
1456 .squoted_char \[rs] .
1459 Set escape character to
1463 Restore escape character saved with
1467 Save current escape character.
1470 Else part for if-else (\c
1477 will be run after the end of input.
1480 Turn off escape character mechanism.
1483 Switch to previous environment.
1486 Push down environment number or name
1491 Copy the contents of environment
1493 to the current environment.
1494 No pushing or popping.
1497 Exit from roff processing.
1500 Return to previous font family.
1503 Set the current font family to
1507 Disable field mechanism.
1510 Set field delimiter to
1512 and pad character to space.
1515 Set field delimiter to
1517 and pad character to
1520 .REQ .fchar c anything
1521 Define fallback character
1530 Flush output buffer.
1538 .REQ .fp n internal external
1539 Mount font with long
1547 Reset list of special fonts for
1551 .REQ .fspecial font s1 s2 .\|.\|.\&
1552 When the current font is
1561 Return to previous font.
1568 Change to font name or number
1574 .REQ .ftr font1 font2
1581 Remove additional hyphenation indicator character.
1584 Set up additional hyphenation indicator character\~\c
1587 .REQ .hcode c1 code1 c2 code2 .\|.\|.\&
1588 Set the hyphenation code of character
1599 Set the current hyphenation language to
1603 Set the maximum number of consecutive hyphenated lines to
1607 Read hyphenation patterns from
1611 Append hyphenation patterns from
1615 Set input mapping for
1621 with exceptional hyphenation.
1624 Switch to hyphenation mode
1628 Set the hyphenation margin to
1630 (default scaling indicator\~\c
1631 .scaleindicator m ).
1634 Set the hyphenation space to
1637 .REQ .ie cond anything
1645 .REQ .if cond anything
1650 otherwise do nothing.
1662 Change to previous indent value.
1665 Change indent according to
1667 (default scaling indicator\~\c
1668 .scaleindicator m ).
1671 Set an input-line count trap for the next
1678 but count lines interrupted with
1683 Enable pairwise kerning.
1688 is zero, disable pairwise kerning, otherwise enable it.
1691 Remove leader repetition character.
1694 Set leader repetition character to\~\c
1697 .REQ .length register anything
1698 Write the length of the string
1704 Enable line-tabs mode (i.e., calculate tab positions relative to output
1710 is zero, disable line-tabs mode, otherwise enable it.
1713 Set input line number to
1723 Change to previous line length.
1726 Set line length according to
1729 .scalednumber 6.5 i ,
1730 default scaling indicator\~\c
1731 .scaleindicator m ).
1734 Change to the previous value of additional intra-line skip.
1737 Set additional intra-line skip value to
1741 blank lines are inserted after each text output line.
1744 Length of title (default scaling indicator\~\c
1745 .scaleindicator m ).
1748 Margin character off.
1753 after each text line at actual distance from right margin.
1756 Set margin character to
1760 from right margin (default scaling indicator\~\c
1761 .scaleindicator m ).
1764 Mark current vertical position in
1768 The same as the .so request except that
1770 is searched in the tmac directories.
1773 No output-line adjusting.
1776 Need a one-line vertical space.
1781 vertical space (default scaling indicator\~\c
1782 .scaleindicator v ).
1785 No filling or adjusting of output-lines.
1793 .REQ .nm \[+-]N \fR[\fPM \fR[\fPS \fR[\fPI\fR]]]\fP
1794 In line number mode, set number, multiple, spacing, and indent.
1797 Do not number next line.
1808 .REQ .nr register \[+-]N M
1817 Make the built-in condition
1824 Turn no-space mode on.
1827 Immediately jump to end of current file.
1832 .REQ .open stream filename
1835 for writing and associate the stream named
1839 .REQ .opena stream filename
1845 Output vertical distance that was saved by the
1852 directly to intermediate output, allowing leading whitespace if
1856 (which will be stripped off).
1859 Reset page number character to\~\c
1863 Page number character.
1871 Set page length to default
1872 .scalednumber 11 i .
1873 The current page length is stored in
1877 Change page length to
1879 (default scaling indicator\~\c
1880 .scaleindicator v ).
1883 Print macro names and sizes (number of blocks of 128 bytes).
1886 Print only total of sizes of macros (number of 128 bytes blocks).
1893 Print the names and contents of all currently defined number registers
1897 Change to previous page offset.
1899 The current page offset is available in
1907 Return to previous point-size.
1913 Get the bounding box of a PostScript image
1917 This behaves like the
1919 request except that input comes from the standard output of
1923 Print the names and positions of all traps (not including input line
1924 traps and diversion traps) on stderr.
1927 Change to previous post-vertical line spacing.
1930 Change post-vertical line spacing according to
1932 (default scaling indicator\~\c
1933 .scaleindicator p ).
1935 .REQ .rchar c1 c2 .\|.\|.\&
1936 Remove the definitions of characters
1945 Return from a macro.
1948 Right justify the next
1953 Remove request, macro, or string
1957 Rename request, macro, or string
1973 Restore spacing; turn no-space mode off.
1978 to marked vertical place (default scaling indicator\~\c
1979 .scaleindicator v ).
1982 Reset soft hyphen character to
1986 Set the soft hyphen character to
1990 In a macro, shift the arguments by
1994 .REQ .sizes s1 s2 .\|.\|.\& sn \fB[0]\fP
1995 Set available font sizes similar to the
2002 Include source file.
2005 Skip one line vertically.
2008 Space vertical distance
2010 up or down according to sign of
2012 (default scaling indicator\~\c
2013 .scaleindicator v ).
2016 Reset global list of special fonts to empty.
2018 .REQ .special s1 s2 .\|.\|.\&
2022 etc.\& are special and will be searched for characters not in the
2026 Toggle the spread warning on and off without changing its value.
2028 .REQ .spreadwarn limit
2029 Emit a warning if each space in an output line is widened by
2031 or more (default scaling indicator\~\c
2032 .scaleindicator m ).
2035 Space-character size set to
2037 of the spacewidth in the current font.
2040 Space-character size set to
2042 and sentence space size set to
2044 of the spacewidth in the current font (\f[CR]\[eq]1/3 em\f[]).
2052 .REQ .substring xx n1 n2
2053 Replace the string named
2055 with the substring defined by the indices
2066 Save the vertical distance
2068 for later output with
2072 .REQ .sy command-line
2077 Set tabs after every position that is a multiple of
2079 (default scaling indicator\~\c
2080 .scaleindicator m ).
2081 .REQ .ta n1 n2 .\|.\|.\& nn \f[CB]T\f[] r1 r2 .\|.\|.\& rn
2082 Set tabs at positions
2100 .\"Restore internally saved tab positions.
2103 .\"Save tab positions internally.
2106 Remove tab repition character.
2108 Set tab repetition character to\~\c
2112 Temporary indent next line (default scaling indicator\~\c
2113 .scaleindicator m ).
2115 .REQ .tkf font s1 n1 s2 n2
2116 Enable track kerning for
2119 .REQ .tl \f[CB]\[cq]\f[]left\f[CB]\[cq]\f[]center\f[CB]\[cq]\f[]right\f[CB]\[cq]\f[]
2125 on terminal (UNIX standard message output).
2130 on terminal (UNIX standard message output), allowing leading
2135 (which will be stripped off).
2140 without emitting a final newline.
2142 .REQ .tr abcd.\|.\|.\&
2153 Transparently output the contents of file
2156 .REQ .trin abcd.\|.\|.\&
2157 This is the same as the
2159 request except that the
2161 request will use the character code (if any) before the character
2164 .REQ .trnt abcd.\|.\|.\&
2165 This is the same as the
2167 request except that the translations do not apply to text that is
2168 transparently throughput into a diversion with
2172 Make the built-in condition
2179 Underline font set to
2181 (to be switched to by
2185 Underline (italicize in troff)
2189 .REQ .unformat diversion
2190 Unformat space characters and tabs, preserving font information in
2193 Enable vertical position traps if
2195 is non-zero, disable them otherwise.
2198 Change to previous vertical base line spacing.
2201 Set vertical base line spacing according to
2203 (default scaling indicator\~\c
2204 .scaleindicator p ).
2206 .scalednumber 12 p .
2209 Set warnings code to
2213 Set scaling indicator used in warnings to
2217 Remove (first) trap at position
2221 Set location trap; negative means from page bottom.
2223 .REQ .while cond anything
2230 .REQ .write stream anything
2236 .REQ .writec stream anything
2239 without emitting a final newline.
2241 .REQ .writem stream xx
2242 Write contents of macro or string
2250 Besides these standard groff requests, there might be further macro
2252 They can originate from a macro package (see
2253 .BR roff (@MAN7EXT@)
2254 for an overview) or from a preprocessor.
2257 Preprocessor macros are easy to be recognized.
2259 They enclose their code into a pair of characteristic macros.
2263 box, center, tab (@);
2266 preprocessor@start macro@ end macro
2273 soelim@\f[I]none@\f[I]none
2279 .\" --------------------------------------------------------------------
2280 .SH "ESCAPE SEQUENCES"
2281 .\" --------------------------------------------------------------------
2283 Escape sequences are in-line language elements usually introduced by a
2286 and followed by an escape name and sometimes by a required argument.
2288 Input processing is continued directly after the escaped character or
2289 the argument resp.\& without an intervening separation character.
2291 So there must be a way to determine the end of the escape name and the
2292 end of the argument.
2295 This is done by enclosing names (escape name and arguments consisting
2296 of a variable name) by a pair of brackets
2297 .BI \[lB] name \[rB]
2298 and constant arguments (number expressions and characters) by
2299 apostrophes (ASCII 0x27) like
2300 .BI \[cq] constant \[cq] \f[R].
2303 There are abbreviations for short names.
2305 Two character escape names can be specified by an opening parenthesis
2308 without a closing counterpart.
2310 And all one-character names different from the special characters
2314 can even be specified without a marker in the form
2318 Constant arguments of length\~1 can omit the marker apostrophes, too,
2319 but there is no two-character analogue.
2322 While 1-character escape sequences are mainly used for in-line
2323 functions and system related tasks, the 2-letter names following the
2325 construct are used for special characters predefined by the roff system.
2327 Escapes sequences with names of more than two characters
2329 denote user defined named characters (see the
2334 .\" --------------------------------------------------------------------
2335 .SS "Single Character Escapes"
2336 .\" --------------------------------------------------------------------
2340 .\" --------- comments ---------
2343 Beginning of a comment.
2345 Everything up to the end of the line is ignored.
2348 Everything up to and including the next newline is ignored.
2350 This is interpreted in copy mode.
2354 except that the terminating newline is ignored as well.
2356 .\" --------- strings ---------
2359 The string stored in the string variable with 1-character name
2363 The string stored in the string variable with 2-character name
2366 .ESC[] * "stringvar arg1 arg2 .\|.\|."
2367 The string stored in the string variable with arbitrary length name
2375 .\" --------- macro arguments ---------
2378 The name by which the current macro was invoked.
2382 request can make a macro have more than one name.
2385 Macro or string argument with 1-place number
2389 is a digit between 1 and 9.
2392 Macro or string argument with 2-digit number
2396 Macro or string argument with number
2400 is a numerical expression evaluating to an integer \[>=]1.
2403 In a macro or string, the concatenation of all the arguments separated
2407 In a macro or string, the concatenation of all the arguments with each
2408 surrounded by double quotes, and separated by spaces.
2410 .\" --------- escaped characters ---------
2413 reduces to a single backslash; useful to delay its interpretation as
2414 escape character in copy mode.
2416 For a printable backslash, use
2420 to be independent from the current escape character.
2423 The acute accent \[aa]; same as
2425 Unescaped: apostrophe, right quotation mark, single quote (ASCII 0x27).
2428 The grave accent \[ga]; same as
2430 Unescaped: left quote, backquote (ASCII 0x60).
2433 The \- sign in the current font.
2436 An uninterpreted dot (period), even at start of line.
2439 Default optional hyphenation character.
2442 Transparent line indicator.
2445 In a diversion, this will transparently embed
2449 is read in copy mode.
2451 See also the escape sequences
2457 .\" --------- spacing ---------
2460 Unpaddable space-size space character (no line break).
2466 1/6\ em narrow space character; zero width in nroff.
2469 1/12\ em half-narrow space character; zero width in nroff.
2472 Non-printable, zero width character.
2477 except that it behaves like a character declared with the cflags
2478 request to be transparent for the purposes of end of sentence
2482 Increases the width of the preceding character so that the spacing
2483 between that character and the following character will be correct if
2484 the following character is a roman character.
2487 Modifies the spacing of the following character so that the spacing
2488 between that character and the preceding character will correct if the
2489 preceding character is a roman character.
2492 Unbreakable space that stretches like a normal inter-word space when a
2496 Inserts a zero-width break point (similar to
2498 but without a soft hyphen character).
2501 Ignored newline, for continuation lines.
2503 .\" --------- structuring ---------
2506 Begin conditional input.
2509 End conditional input.
2511 .\" --------- longer escape names ---------
2514 The special character with 2-character name
2517 .BR "Special Characters" .
2520 The named character with arbitrary length name
2523 .\" --------- alphabetical escapes ---------
2526 Non-interpreted leader character.
2531 is acceptable as a name of a string, macro, diversion, register,
2532 environment or font it expands to\~1, and to\~0 otherwise.
2534 .ESCq b abc.\|.\|.\&
2535 Bracket building function.
2540 is acceptable as a valid numeric expression it expands to\~1, and
2544 Interrupt text processing.
2547 The character called
2551 but compatible to other roff versions.
2554 Forward (down) 1/2 em vertical unit (1/2 line in nroff).
2557 Draw a graphical element defined by the characters in
2559 see groff info file for details.
2562 Printable version of the current escape character.
2565 Equivalent to an escape character, but is not interpreted in copy-mode.
2568 Change to font with 1-character name or 1-digit number
2572 Switch back to previous font.
2575 Change to font with 2-character name or 2-digit number
2579 Change to font with arbitrary length name or number expression
2583 Switch back to previous font.
2586 Change to font family with 1-character name
2590 Change to font family with 2-character name
2594 Change to font family with arbitrary length name
2598 Switch back to previous font family.
2601 Return format of register with name
2612 Local horizontal motion; move right
2617 Set height of current font to
2621 Mark horizontal input place in register with arbitrary length name
2629 Horizontal line drawing function (optionally using character
2633 Vertical line drawing function (optionally using character
2646 Switch back to previous color.
2649 Change filling color for closed drawn objects to color
2658 Switch to previous fill color.
2661 The numerical value stored in the register variable with the
2666 The numerical value stored in the register variable with the
2671 The numerical value stored in the register variable with arbitrary
2676 Typeset the character with code
2678 in the current font, no special fonts are searched.
2680 Useful for adding characters to a font using the
2684 .ESCq o abc.\|.\|.\&
2685 Overstrike characters
2692 Disable glyph output.
2694 Mainly for internal use.
2697 Enable glyph output.
2699 Mainly for internal use.
2702 Break and spread output line.
2705 Reverse 1\ em vertical motion (reverse line in nroff).
2707 .ESCq R "name\~\[+-]n"
2714 Set the point size to
2718 Note the alternative forms
2719 .BI \[rs]s \[+-] [ N ]\c
2721 .BI \[rs]s' \[+-]N '\c
2723 .BI \[rs]s \[+-] ' N '\c
2725 .escarg s( \[+-]xy\c
2727 .BI \[rs]s \[+-] ( xy\c
2740 Non-interpreted horizontal tab.
2743 Reverse (up) 1/2 em vertical motion (1/2 line in nroff).
2746 Local vertical motion; move down
2751 The contents of the environment variable
2760 The width of the character sequence
2764 Extra line-space function (negative before, positive after).
2769 as device control function.
2772 Output string variable or macro
2774 uninterpreted as device control function.
2784 with zero width (without spacing).
2789 and then restore the horizontal and vertical position;
2791 may not contain tabs or leaders.
2795 The escape sequences
2807 are interpreted in copy mode.
2810 Escape sequences starting with
2814 do not represent single character escape sequences, but introduce escape
2815 names with two or more characters.
2818 If a backslash is followed by a character that does not constitute a
2819 defined escape sequence the backslash is silently ignored and the
2820 character maps to itself.
2823 .\" --------------------------------------------------------------------
2824 .SS "Special Characters"
2825 .\" --------------------------------------------------------------------
2827 Common special characters are predefined by escape sequences of the
2835 Some of these exist in the usual font while most of them are only
2836 available in the special font.
2838 Below you'll find a selection of the most important glyphs; a complete
2839 list can be found in
2840 .BR groff_char (@MAN7EXT@).
2858 Printable double quote
2866 Printable backslash character
2889 .\" --------------------------------------------------------------------
2891 .\" --------------------------------------------------------------------
2893 Strings are defined by the
2895 request and can be retrieved by the
2900 Strings share their name space with macros.
2902 So strings and macros without arguments are roughly equivalent; it is
2903 possible to call a string like a macro and vice-versa, but this often
2904 leads to unpredictable results.
2906 The following strings are predefined in groff.
2909 The name of the current output device as specified by the
2911 command line option.
2914 .\" --------------------------------------------------------------------
2916 .\" --------------------------------------------------------------------
2918 Registers are variables that store a value.
2919 In groff, most registers store numerical values (see section
2920 .B NUMERICAL EXPRESSIONS
2921 above), but some can also hold a string value.
2924 Each register is given a name.
2925 Arbitrary registers can be defined and set with the request
2930 The value stored in a register can be retrieved by the escape sequences
2935 Most useful are predefined registers.
2937 In the following the notation
2939 is used to refer to a register called
2941 to make clear that we speak about registers.
2943 Please keep in mind that the
2945 decoration is not part of the register name.
2948 .\" --------------------------------------------------------------------
2949 .SS "Read-only Registers"
2950 .\" --------------------------------------------------------------------
2952 The following registers have predefined values that should not be
2953 modified by the user (usually, registers starting with a dot a
2956 Mostly, they provide information on the current settings or store
2957 results from request calls.
2963 Number of arguments in the current macro or string.
2966 Post-line extra line-space most recently utilized using
2974 is used; always\~1 in
2978 Current input line number.
2981 1\~if compatibility mode is in effect, 0\~otherwise.
2984 The depth of the last character added to the current environment.
2985 It is positive if the character extends below the baseline.
2988 The number of lines remaining to be centered, as set by the
2993 The height of the last character added to the current environment.
2994 It is positive if the character extends above the baseline.
2997 1\~if colors are enabled, 0\~otherwise.
3000 The skew of the last character added to the current environment.
3001 The skew of a character is how far to the right of the center of a character
3002 the center of an accent over that character should be placed.
3005 Current vertical place in current diversion; equal to register
3009 The name or number of the current environment (string-valued).
3012 Current font number.
3015 The current font family (string-valued).
3018 The current (internal) real font name (string-valued).
3021 The number of the next free font position.
3024 Always 1 in GNU troff.
3026 Macros should use it to test if running under groff.
3029 Text base-line high-water mark on current page or diversion.
3032 Available horizontal resolution in basic units.
3035 The current hyphenation language as set by the
3040 The number of immediately preceding consecutive hyphenated lines.
3043 The maximum allowed number of consecutive hyphenated lines, as set by
3049 The current hyphenation flags (as set by the
3054 The current hyphenation margin (as set by the
3059 The current hyphenation space (as set by the
3067 The indent that applies to the current output line.
3070 Positive if last output line contains
3074 1\~if pairwise kerning is enabled, 0\~otherwise.
3077 Current line length.
3080 The current ligature mode (as set by the
3085 The current line-tabs mode (as set by the
3090 The line length that applies to the current output line.
3093 The title length (as set by the
3098 Length of text portion on previous output line.
3101 The amount of space that was needed in the last
3103 request that caused a trap to be sprung.
3105 Useful in conjunction with
3109 1\~if in no-space mode, 0\~otherwise.
3112 Current page offset.
3115 Current page length.
3118 The number of the next page: either the value set by a
3120 request, or the number of the current page plus\ 1.
3123 The current pointsize in scaled points.
3126 The last-requested pointsize in scaled points.
3129 The current post-vertical line spacing.
3132 The number of lines to be right-justified as set by the rj request.
3135 Current point size as a decimal fraction.
3138 The last requested pointsize in points as a decimal fraction
3142 Distance to the next trap.
3151 A string representation of the current tab settings suitable for use
3152 as an argument to the
3157 The amount of vertical space truncated by the most recently sprung
3158 vertical position trap, or, if the trap was sprung by a
3160 request, minus the amount of vertical motion produced by
3163 In other words, at the point a trap is sprung, it represents
3164 the difference of what the vertical position would have been but for
3165 the trap, and what the vertical position actually is.
3167 Useful in conjunction with the
3172 The value of the parameters set by the first argument of the
3177 The value of the parameters set by the second argument of the
3182 Equal to 1 bin fill mode and 0 in nofill mode.
3185 Current vertical line spacing.
3188 Available vertical resolution in basic units.
3191 1\~ if vertical position traps are enabled, 0\~otherwise.
3194 Width of previous character.
3197 The sum of the number codes of the currently enabled warnings.
3200 The major version number.
3203 The minor version number.
3206 The revision number of groff.
3209 Name of current diversion.
3213 .\" --------------------------------------------------------------------
3214 .SS "Writable Registers"
3215 .\" --------------------------------------------------------------------
3217 The following registers can be read and written by the user.
3218 They have predefined default values, but these can be modified for
3219 customizing a document.
3224 Current page number.
3227 Current input line number.
3230 Character type (set by width function
3234 Maximal width of last completed diversion.
3237 Height of last completed diversion.
3240 Current day of week (1-7).
3243 Current day of month (1-31).
3246 The number of hours past midnight.
3248 Initialized at start-up.
3251 Current horizontal position at input line.
3254 Lower left x-coordinate (in PostScript units) of a given PostScript
3259 Lower left y-coordinate (in PostScript units) of a given PostScript
3267 The number of minutes after the hour.
3269 Initialized at start-up.
3272 Current month (1-12).
3275 Vertical position of last printed text base-line.
3280 but takes account of the heights and depths of characters.
3285 but takes account of the heights and depths of characters.
3288 Depth of string below base line (generated by width function
3292 The number of seconds after the minute.
3294 Initialized at start-up.
3297 Right skip width from the center of the last character in the
3302 If greater than 0, the maximum number of objects on the input stack.
3304 If \[<=]0 there is no limit, i.e., recursion can continue until virtual
3305 memory is exhausted.
3308 The amount of horizontal space (possibly negative) that should be
3309 added to the last character before a subscript (generated by width
3314 Height of string above base line (generated by width function
3318 The return value of the
3320 function executed by the last
3325 Upper right x-coordinate (in PostScript units) of a given PostScript
3330 Upper right y-coordinate (in PostScript units) of a given PostScript
3335 The current year (year 2000 compliant).
3338 Current year minus 1900.
3340 For Y2K compliance use register
3347 .\" --------------------------------------------------------------------
3349 .\" --------------------------------------------------------------------
3351 The differences of the groff language in comparison to classical troff
3355 .BR groff_diff (@MAN7EXT@).
3358 The groff system provides a compatibility mode, see
3359 .BR groff (@MAN1EXT@)
3360 on how to invoke this.
3363 .\" --------------------------------------------------------------------
3365 .\" --------------------------------------------------------------------
3368 .MTO bug-groff@gnu.org "groff bug mailing list" .
3369 Include a complete, self-contained example that will allow the bug to
3370 be reproduced, and say which version of groff you are using.
3373 .\" --------------------------------------------------------------------
3375 .\" --------------------------------------------------------------------
3377 Copyright (C) 2000, 2001, 2002 Free Software Foundation, Inc.
3380 This document is distributed under the terms of the FDL (GNU Free
3381 Documentation License) version 1.1 or later.
3383 You should have received a copy of the FDL on your system, it is also
3384 available on-line at the
3385 .URL http://\:www.gnu.org/\:copyleft/\:fdl.html "GNU copyleft site" .
3388 This document is part of
3390 the GNU roff distribution.
3393 .MTO bwarken@mayn.de "Bernd Warken" ;
3395 .MTO wl@gnu.org "Werner Lemberg" .
3398 .\" --------------------------------------------------------------------
3400 .\" --------------------------------------------------------------------
3403 The main source of information for the groff language is the
3408 Besides the gory details, it contains many examples.
3411 .BR groff (@MAN1EXT@)
3412 the usage of the groff program and pointers to the documentation and
3413 availability of the groff system.
3416 .BR groff_diff (@MAN7EXT@)
3417 the differences of the groff language as compared to classical roff.
3419 This is the authoritative document for the predefined language
3420 elements that are specific to groff.
3423 .BR groff_char (@MAN7EXT@)
3424 the predefined groff characters (glyphs).
3427 .BR groff_font (@MAN5EXT@)
3428 the specification of fonts and the DESC file.
3431 .BR roff (@MAN7EXT@)
3432 the history of roff, the common parts shared by all roff systems, and
3433 pointers to further documentation.
3437 .URL http://\:cm.bell-labs.com/\:cm/\:cs/\:54.ps \
3438 "Nroff/\:Troff User's Manual by Osanna & Kernighan"
3439 \[em] the bible for classical troff.
3442 .\" --------------------------------------------------------------------
3444 .\" --------------------------------------------------------------------
3446 .\" Local Variables: