'\" t .ig groff.man Last update: 6 Jan 2002 This file is part of groff, the GNU roff type-setting system. Copyright (C) 2000, 2001, 2002 Free Software Foundation, Inc. written by Bernd Warken maintained by Werner Lemberg Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with the Invariant Sections being this .ig-section and AUTHORS, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the Free Documentation License is included as a file called FDL in the main directory of the groff source package. .. . .\" -------------------------------------------------------------------- .\" Setup .\" -------------------------------------------------------------------- . .mso www.tmac . .if n \{\ . mso tty-char.tmac . ftr CR R . ftr CI I . ftr CB B .\} . .if '\*[.T]'dvi' \{\ . ftr CB CW .\} . . .\" -------------------------------------------------------------------- .\" start of macro definitions .eo . .de c .. . .de TPx . TP 10n .. .c --------------------------------------------------------------------- .c .Text anything ... .c .c All arguments are printed as text. .c .de Text . nop \)\$* .. .c --------------------------------------------------------------------- .c .ExecFF macro font1 font2 text1 text2 text1 text2 ... .c .c Concat text arguments using alternating fonts and feed into macro. .c For a trailing punctuation, terminate the call with \c. .c .de ExecFF . if (\n[.$] < 4) \ . return . ds @a\" . ds @m \$1\" . ds @f1 \$2\" . ds @f2 \$3\" . shift 3 . ds @s\" . while 1 \{\ . if (\n[.$] = 0) \ . break . ds @a \$1\" . as @s \f[\*[@f1]]\*[@a]\f[P]\" . shift . if (\n[.$] = 0) \ . break . ds @a \$1\" . as @s \f[\*[@f2]]\*[@a]\f[P]\" . shift . \} . \*[@m] \*[@s]\f[R] . ft P \" to make \c happy . rm @m . rm @s . rm @a . rm @f1 . rm @f2 .. . .c --------- command line option --------- . .de option . Text \f[CB]\$* . ft P .. . .c --------- characters --------- . .de character . ExecFF Text CB R \$* .. .de squoted_char . ds @1 \$1\" . shift . ExecFF Text R CB \[oq] \*[@1] "\[cq]\$*" . rm @1 .. .de dquoted_char . ds @1 \$1\" . shift . ExecFF Text R CB \[lq] \*[@1] "\[rq]\$*" . rm @1 .. .c --------- requests --------- . .c synopsis of a request .de REQ . if (\n[.$] = 0) \ . return . ds @1 \$1\" . shift 1 . ie (\n[.$] = 0) \{\ . TP 10n . Text \f[CB]\*[@1]\f[P] . \} . el \{\ . TP 10n . Text \f[CB]\*[@1]\~\f[P]\f[I]\$*\f[P] . \} . rm @1 .. .c reference of a request .de request . BR \$* .. . .c --------- numerical elements --------- . .c number with a trailing unit .de scalednumber . Text \$1\^\f[CB]\$2\f[P]\$3\f[R] . ft P .. . .c representation of units within the text .de scaleindicator . Text \f[CB]\$1\f[P]\$2\f[R] . ft P .. . .c representation of mathematical operators within the text .de operator . squoted_char \$@ .. . . .c --------- escape sequences --------- . .c --------------------------------------------------------------------- .c .ESC name [arg] .c .c Synopsis of an escape sequence, optionally with argument .c Args : 1 or 2; `name' obligatory, `arg' optional .c name : suitable name for an escape sequence (c, (xy, [long]) .c arg : arbitrary word .c Result : prints \namearg, where `name' is in CB, `arg' in I .c .de ESC . if (\n[.$] < 1) . ab .ESC needs 1 or 2 arguments. . ExecFF IP CB I "\[rs]\$1" "\,\$2\/" .. .c --------------------------------------------------------------------- .c .ESC[] name arg .c .c Synopsis for escape sequence with a bracketed long argument .c Args : 2 obligatory .c name : suitable name for an escape sequence (c, (xy, [long]) .c arg : arbitrary text .c Result : prints \name[arg], where `name' is in CB, `arg' in I .c .de ESC[] . if !(\n[.$] = 2) \ . ab .ESC[] needs exactly 2 arguments. . ExecFF IP CB I "\[rs]\$1\[lB]" "\h'-0.2m'\$2\h'-0.15m'" \[rB] .. .c --------------------------------------------------------------------- .c .ESCq name arg .c .c Synopsis for escape sequence with a bracketed long argument .c Args : 2 obligatory .c name : suitable name for an escape sequence (c, (xy, [long]) .c arg : arbitrary text .c Result : prints \name'arg', where `name' is in CB, `arg' in I .c .de ESCq . if !(\n[.$] = 2) \ . ab .ESCq needs exactly 2 argument. . ExecFF IP CB I "\[rs]\$1\[cq]" "\h'-0.3m'\$2" \[cq] .. .c --------------------------------------------------------------------- .c .ESC? arg .c .c Synopsis for escape sequence with a bracketed long argument .c Args : 1 obligatory .c arg : arbitrary text .c Result : prints `\?arg?', where the `?' are in CB, `arg' in I .c .de ESC? . if !(\n[.$] = 1) \ . ab .ESC? needs exactly 1 arguments. . ExecFF IP CB I \[rs]? "\$1" ? .. .c --------------------------------------------------------------------- .c .esc name [punct] .c .c Reference of an escape sequence (no args), possibly punctuation .c Args : 1 obligatory .c name : suitable name for an escape sequence (c, (xy, [long]) .c punct : arbitrary .c Result : prints \name, where `name' is in B, `punct' in R .c .de esc . if (\n[.$] < 1) \ . ab .esc needs 1 or 2 arguments. . BR "\[rs]\$1" \$2 .. .c --------------------------------------------------------------------- .c .escarg name arg [punct] .c .c Reference of an escape sequence (no args) .c Args : 1 obligatory, 1 optional .c name : suitable name for an escape sequence (c, (xy, [long]) .c arg : arbitrary word .c Result : prints \namearg, where .c `name' is in B, `arg' in I .c .de escarg . if (\n[.$] < 2) \ . ab .esc needs 2 or 3 arguments. . Text \f[B]\[rs]\$1\f[P]\f[I]\$2\f[P]\$3 .. .c --------------------------------------------------------------------- .c .esc[] name arg [punct] .c .c Reference for escape sequence with a bracketed long argument .c Args : 2 obligatory .c name : suitable name for an escape sequence (c, (xy, [long]) .c arg : arbitrary text .c Result : prints \name[arg], where `name' is in CB, `arg' in CI .c .de esc[] . if (\n[.$] < 2) \ . ab .esc[] needs 2 or 3 arguments. . Text \f[B]\[rs]\$1\[lB]\f[P]\f[I]\$2\f[P]\f[B]\[rB]\f[P]\$3 .. . .c --------------------------------------------------------------------- .c .escq name arg .c .c Reference for escape sequence with a bracketed long argument .c Args : 2 obligatory .c name : suitable name for an escape sequence (c, (xy, [long]) .c arg : arbitrary text .c Result : prints \name'arg', where `name' is in CB, `arg' in CI .c .de escq . if (\n[.$] < 2) \ . ab .escq needs 2 arguments. . Text \f[B]\[rs]\$1\[cq]\f[P]\f[I]\$2\f[P]\f[B]\[cq]\f[P]\$3 .. . .c --------- strings --------- . .c synopsis for string, with \*[] .de STRING . ds @1 \$1\" . shift 1 . TP 10n . ExecFF Text R CB \[rs]*[ \*[@1]\f[P]\f[R]] \$* . rm @1 .. .c synopsis for a long string .de string . if (\n[.$] = 0) \ . return . Text \f[CB]\[rs]*\[lB]\$1\[rB]\f[P]\$2 .. . . .c --------- registers --------- . .c synopsis for registers, with \n[] .de REG . ds @1 \$1\" . shift 1 . TP 10n . ExecFF Text R CB \[rs]n[ \*[@1]\f[P]\f[R]] \$* . rm @1 .. .c reference of a register, without decoration .de register . Text register . BR \$* .. . .ec .\" end of macro definitions . . .\" -------------------------------------------------------------------- .\" Title .\" -------------------------------------------------------------------- . .TH GROFF @MAN7EXT@ "@MDATE@" "Groff Version @VERSION@" .SH NAME groff \- a short reference for the GNU roff language . . .\" -------------------------------------------------------------------- .SH DESCRIPTION .\" -------------------------------------------------------------------- . The name .I groff stands for .I GNU roff and is the free implementation of the roff type-setting system. . See .BR roff (@MAN7EXT@) for a survey and the background of the groff system. . .P This document gives only short descriptions of the predefined roff language elements as used in groff. . Both the classical features and the groff extensions are provided. . .P Historically, the .I roff language was called .IR troff . .I groff is compatible with the classical system and provides proper extensions. . So in GNU, the terms .IR roff , .IR troff , and .I groff language could be used as synonyms. . However .I troff slightly tends to refer more to the classical aspects, whereas .I groff emphasizes the GNU extensions, and .I roff is the general term for the language. . .P This file is only a short version of the complete documentation that is found in the .I groff .BR info (1) file, which contains more detailed, actual, and concise information. . .P The general syntax for writing groff documents is relatively easy, but writing extensions to the roff language can be a bit harder. . .P The roff language is line-oriented. . There are only two kinds of lines, control lines and text lines. . The control lines start with a control character, by default a period .dquoted_char . or a single quote .dquoted_char ' ; all other lines are text lines. . .P .B Control lines represent commands, optionally with arguments. . They have the following syntax. . The leading control character can be followed by a command name; arguments, if any, are separated by blanks from the command name and among themselves, for example, .RS . .P .Text .command_name arg1 arg2 .RE . .P For indentation, any number of space or tab characters can be inserted between the leading control character and the command name, but the control character must be on the first position of the line. . .P .B Text lines represent the parts that will be printed. They can be modified by escape sequences, which are recognized by a leading backslash .squoted_char \[rs] . These are in-line or even in-word formatting elements or functions. . Some of these take arguments separated by single quotes .dquoted_char ' , others are regulated by a length encoding introduced by an open parenthesis .squoted_char ( or enclosed in brackets .squoted_char [ and .squoted_char ] . . .P The roff language provides flexible instruments for writing language extension, such as macros. . When interpreting macro definitions, the roff system enters a special operating mode, called the .BR "copy mode" . . .P The copy mode behavior can be quite tricky, but there are some rules that ensure a safe usage. . .IP 1. Printable backslashes must be denoted as .esc e . To be more precise, .esc e represents the current escape character. . To get a backslash glyph, use .esc (rs or .esc [rs] . .IP 2. Double all backslashes. .IP 3. Begin all text lines with the special non-spacing character .esc & . . .P This does not produce the most efficient code, but it should work as a first measure. . For better strategies, see the groff info file and .BR groff_tmac (@MAN5EXT@). . .P Reading roff source files is easier, just reduce all double backslashes to a single one in all macro definitions. . . .\" -------------------------------------------------------------------- .SH "GROFF ELEMENTS" .\" -------------------------------------------------------------------- . The roff language elements add formatting information to a text file. . The fundamental elements are predefined commands and variables that make roff a full-blown programming language. . .P There are two kinds of roff commands, possibly with arguments. .B Requests are written on a line of their own starting with a dot .squoted_char . or a .dquoted_char ' , whereas .B Escape sequences are in-line functions and in-word formatting elements starting with a backslash .squoted_char \[rs] . . .P The user can define her own formatting commands using the .request .de request. . These commands are called .BR macros , but they are used exactly like requests. . Macro packages are pre-defined sets of macros written in the groff language. . A user's possibilities to create escape sequences herself is very limited, only special characters can be mapped. . .P The groff language provides several kinds of variables with different interfaces. . There are pre-defined variables, but the user can define her own variables as well. . .P .B String variables store character sequences. . They are set with the .request .ds request and retrieved by the .esc * escape sequences. . .P .B Register variables can store numerical values, numbers with a scale unit, and occasionally string-like objects. . They are set with the .request .nr request and retrieved by the .esc n escape sequences. . .P .B Environments allow the user to temporarily store global formatting parameters like line length, font size, etc.\& for later reuse. . This is done by the .request .ev request. . .P .B Fonts are identified either by a name or by an internal number. . The current font is chosen by the .request .ft request or by the .esc f escape sequences. . Each device has special fonts, but the following fonts are available for all devices. .B R is the standard font Roman. .B B is its .B bold counterpart. . The .I italic font is called .B I is everywhere available, but on text devices, it is displayed as an underlined Roman font. . For the graphical output devices, there exist constant-width pendants of these fonts, .BR CR , .BR CI , and .BR CB . On text devices, all characters have a constant width anyway. . .P Moreover, there are some advanced roff elements. . A .B diversion stores information into a macro for later usage. . A .B trap is a positional condition like a certain number of lines from page top or in a diversion or in the input. . Some action can be prescribed to be run automatically when the condition is met. . .P More detailed information and examples can be found in the groff info file. . . .\" -------------------------------------------------------------------- .SH "CONTROL CHARACTERS" .\" -------------------------------------------------------------------- . There is a small set of characters that have a special controlling task in certain conditions. . .TP .character . A dot is only special at the beginning of a line or after the condition in the requests .request .if , .request .ie , .request .el , and .request .while . There it is the control character that introduces a request (or macro). . The special behavior can be delayed by using the .esc . escape. . By using the .request .cc request, the control character can be set to a different character, making the dot .squoted_char . a non-special character. .IP "" In all other positions, it just means a dot character. . In text paragraphs, it is advantageous to start each sentence at a line of its own. . .TP .character ' The single quote has two controlling tasks. . At the beginning of a line and in the conditional requests it is the non-breaking control character. . That means that it introduces a request like the dot, but with the additional property that this request doesn't cause a linebreak. . By using the .request .c2 request, the non-break control character can be set to a different character. . .IP "" As a second task, it is the most commonly used argument separator in some functional escape sequences (but any pair of characters not part of the argument will work). . In all other positions, it denotes the single quote or apostrophe character. . Groff provides a printable representation with the .esc (cq escape sequence. . .TP .character \[dq] The double quote is used to enclose arguments in requests and macros. In the .request .ds and .request .as requests, a leading double quote in the argument will be stripped off, making everything else afterwards the string to be defined (enabling leading whitespace). . The escaped double quote .esc \[dq] introduces a comment. . Otherwise, it is not special. . Groff provides a printable representation with the .esc (dq escape sequence. . .TP .character \[rs] The backslash usually introduces an escape sequence (this can be changed with the .request ec request). . A printed version of the escape character is the .esc e escape; a backslash glyph can be obtained by .esc (rs . .TP .character ( The open parenthesis is only special in escape sequences when introducing an escape name or argument consisting of exactly two characters. . In groff, this behavior can be replaced by the \f[CB][]\f[P] construct. .TP .character [ The opening bracket is only special in groff escape sequences; there it is used to introduce a long escape name or long escape argument. . Otherwise, it is non-special, e.g.\& in macro calls. .TP .character ] The closing bracket is only special in groff escape sequences; there it terminates a long escape name or long escape argument. . Otherwise, it is non-special. .TP \f[CI]space\f[P] Space characters are only functional characters. . They separate the arguments in requests or macros, and the words in text lines. . They are subject to groff's horizontal spacing calculations. . To get a defined space width, escape sequences like .squoted_char "\[rs]\ " (this is the escape character followed by a space), .esc | , .esc ^ , or .esc h should be used. . .IP \f[CI]newline\f[P] In text paragraphs, newlines mostly behave like space characters. . Continuation lines can be specified by an escaped newline, i.e., by specifying a backslash .squoted_char \[rs] as the last character of a line. .IP \f[CI]tab\f[P] If a tab character occurs during text the interpreter makes a horizontal jump to the next pre-defined tab position. . There is a sophisticated interface for handling tab positions. . . .\" -------------------------------------------------------------------- .SH "NUMERICAL EXPRESSIONS" .\" -------------------------------------------------------------------- . A .B numerical value is a signed or unsigned integer or float with or without an appended scale indicator. . A .B scale indicator is a one-character abbreviation for a unit of measurement. . A number followed by a scale indicator signifies a size value. . By default, numerical values do not have a scale indicator, i.e., they are normal numbers. . .P The .I roff language defines the following scale indicators. . . .P .PD 0 .RS . .TPx .B c Centimeter . .TPx .B i Inch . .TPx .B P Pica\ \[eq]\ 1/6\ inch . .TPx .B p Point\ \[eq]\ 1/72\ inch . .TPx .B m Em\ \[eq]\ \f[R]the font size in points (width of letter `\f[CR]m\f[R]') . .TPx .B M 100\^th \f[R]of an \f[CR]Em . .TPx .B n En\ \[eq]\ Em/2 . .TPx .B u Basic unit for actual output device . .TPx .B v Vertical line space in basic units scaled point\ \[eq]\ 1/\f[CI]sizescale\f[R] of a point (defined in font \f[I]DESC\f[P] file) . .TPx .B f Scale by 65536. .RE .PD . .P .B Numerical expressions are combinations of the numerical values defined above with the following arithmetical operators already defined in classical troff. . .P .PD 0 .RS . .TPx .B + Addition . .TPx .B \- Subtraction . .TPx .B * Multiplication . .TPx .B / Division . .TPx .B % Modulo . .TPx .B = Equals . .TPx .B == Equals . .TPx .B < Less than . .TPx .B > Greater than . .TPx .B <= Less or equal . .TPx .B >= Greater or equal . .TPx .B & Logical and . .TPx .B : Logical or . .TPx .B ! Logical not . .TPx .B ( Grouping of expressions . .TPx .B ) Close current grouping . .RE .PD . .P Moreover, .I groff added the following operators for numerical expressions: . .P .PD 0 .RS . .TPx .ExecFF Text I CB e1 >? e2 The maximum of .I e1 and .IR e2 . . .TPx .ExecFF Text I CB e1 0. . .REQ .ll Change to previous line length. . .REQ .ll \[+-]N Set line length according to .I \[+-]N (default size .scalednumber 6.5 i , default scale indicator\~\c .scaleindicator m ). . .REQ .ls Change to the previous value of additional intra-line skip. . .REQ .ls N Set additional intra-line skip value to .IR N , i.e., .IR N -1 blank lines are inserted after each text output line. . .REQ .lt \[+-]N Length of title (default scale indicator\~\c .scaleindicator m ). . .REQ .mc Margin character off. . .REQ .mc c Print character .I c after each text line at actual distance from right margin. . .REQ .mc c N Set margin character to .I c and distance to .I N from right margin (default scale indicator\~\c .scaleindicator m ). . .REQ .mk register Mark current vertical position in .IR register . . .REQ .mso file The same as the .so request except that .I file is searched in the tmac directories. . .REQ .na No output-line adjusting. . .REQ .ne Need a one-line vertical space. . .REQ .ne N Need .I N vertical space (default scale indicator\~\c .scaleindicator v ). . .REQ .nf No filling or adjusting of output-lines. . .REQ .nh No hyphenation. . .REQ .nm Number mode off. . .REQ .nm \[+-]N M S I In line number mode, set number, multiple, spacing, and indent. . .REQ .nn Do not number next line. . .REQ .nn N Do not number next .I N lines. . .REQ .nop anything Always execute .IR anything . . .REQ .nr register \[+-]N M Define or modify .I register using .I \[+-]N with auto-increment .IR M . . .REQ .nroff Make the built-in condition .B n true and .B t false. . .REQ .ns Turn no-space mode on. . .REQ .nx filename Next file. . .REQ .open stream filename Open .register filename for writing and associate the stream named .register stream with it. . .REQ .opena stream filename Like .request .open but append to it. . .REQ .os Output vertical distance that was saved by the .request .sv request. . .REQ .pc Reset page number character to\~\c .squoted_char % . . .REQ .pc c Page number character. . .REQ .pi program Pipe output to .I program (nroff only). . .REQ .pl Set page length to default .scalednumber 11 i . The current page length is stored in .register .p . . .REQ .pl \[+-]N Change page length to .I \[+-]N (default scale indicator\~\c .scaleindicator v ). . .REQ .pm Print macro names and sizes (number of blocks of 128 bytes). . .REQ ".pm t" Print only total of sizes of macros (number of 128 bytes blocks). . .REQ .pn \[+-]N Next page number .IR N . . .REQ .pnr Print the names and contents of all currently defined number registers on stderr. . .REQ .po Change to previous page offset. . The current page offset is available in .register .o . . .REQ .po \[+-]N Page offset .IR N . . .REQ .ps Return to previous point-size. .REQ .ps \[+-]N Point size; same as .esc[] s \[+-]N . . .REQ .psbb filename Get the bounding box of a PostScript image .IR filename . . .REQ .pso command This behaves like the .request .so request except that input comes from the standard output of .IR command . . .REQ .ptr Print the names and positions of all traps (not including input line traps and diversion traps) on stderr. . .REQ .rchar c1 c2 .\|.\|.\& Remove the definitions of characters .IR c1 , .IR c2 , .I .\|.\|.\& . .REQ .rd prompt Read insertion. . .REQ .return Return from a macro. . .REQ .rj n Right justify the next .I n input lines. . .REQ .rm name Remove request, macro, or string .IR name . . .REQ .rn old new Rename request, macro, or string .I old to .IR new . . .REQ .rnn reg1 reg2 Rename register .I reg1 to .IR reg2 . . .REQ .rr register Remove .IR register . . .REQ .rs Restore spacing; turn no-space mode off. . .REQ .rt \[+-]N Return .I (upward only) to marked vertical place (default scale indicator\~\c .scaleindicator v ). . .REQ .shc Reset soft hyphen character to .esc (hy . . .REQ .shc c Set the soft hyphen character to .IR c . . .REQ .shift n In a macro, shift the arguments by .IR n \~\c positions. . .REQ .so filename Include source file. . .REQ .sp Skip one line vertically. . .REQ .sp N Space vertical distance .I N up or down according to sign of .I N (default scaling indicator\~\c .scaleindicator v ). . .REQ .special s1 s2 .\|.\|.\& Fonts .IR s1 , .IR s2 , etc.\& are special and will be searched for characters not in the current font. . .REQ .ss N Space-character size set to .IR N /12 of the spacewidth in the current font. . .REQ .ss N M Space-character size set to .IR N /12 and sentence space size set to .IR M /12 of the spacewidth in the current font (\f[CR]\[eq]1/3 em\f[P]). . .REQ .sty n style Associate .I style with font position .IR n . . .REQ .substring register n1 n2 Replace the string in .I register with the substring defined by the indices .I n1 and .IR n2 . . .REQ .sv Save .scalednumber 1 v of vertical space. . .REQ .sv N Save the vertical distance .I N for later output with .request .os request. . .REQ .sy command-line Execute program .IR command-line . . .REQ ".ta T" N Set tabs after every position that is a multiple of .I N (default scaling indicator\~\c .scaleindicator m ). .REQ .ta n1 n2 .\|.\|.\& nn \f[CB]T\f[P] r1 r2 .\|.\|.\& rn Set tabs at positions .IR n1 , .IR n2 , .Text .\|.\|., .IR nn , then set tabs at .IR nn + r1 , .IR nn + r2 , .Text .\|.\|., .IR nn + rn , then at .IR nn + rn + r1 , .IR nn + rn + r2 , .Text .\|.\|., .IR nn + rn + rn , and so on. . .\".REQ .tar .\"Restore internally saved tab positions. .\". .\".REQ .tas .\"Save tab positions internally. . .REQ .tc Remove tab repition character. .REQ .tc c Set tab repetition character to\~\c .IR c . . .REQ .ti \[+-]N Temporary indent next line (default scaling indicator\~\c .scaleindicator m ). . .REQ .tkf font s1 n1 s2 n2 Enable track kerning for .IR font . . .REQ .tl \f[CB]\[cq]\f[P]left\f[CB]\[cq]\f[P]center\f[CB]\[cq]\f[P]right\f[CB]\[cq]\f[P] Three-part title. . .REQ .tm anything Print .I anything on terminal (UNIX standard message output). . .REQ .tm1 anything Print .I anything on terminal (UNIX standard message output), allowing leading whitespace if .I anything starts with .character \[dq] (which will be stripped off). . .REQ .tmc anything Similar to .request .tm1 without emitting a final newline. . .REQ .tr abcd.\|.\|.\& Translate .I a to .IR b , .I c to .IR d , etc.\& on output. . .REQ .trf filename Transparently output the contents of file .IR filename . . .REQ .trnt abcd.\|.\|.\& This is the same as the .request .tr request except that the translations do not apply to text that is transparently throughput into a diversion with .esc ! . . .REQ .troff Make the built-in condition .B t true and .B n false. . .REQ .uf font Underline font set to .I font (to be switched to by .request .ul ). . .REQ .ul N Underline (italicize in troff) .I N input lines. . .REQ .unformat diversion Unformat space characters and tabs, preserving font information in .IR diversion . .REQ .vpt n Enable vertical position traps if .I n is non-zero, disable them otherwise. . .REQ .vs Change to previous vertical base line spacing. . .REQ .vs N Set vertical base line spacing to .IR N . Default value is .scalednumber 12 p . . .REQ .warn n Set warnings code to .IR n . . .REQ .wh N trap Set location trap; negative means from page bottom. . .REQ .while cond anything While condition .I cond is true, accept .I anything as input. . .REQ .write stream anything Write .I anything to the stream named .IR stream . . .PD . .P Besides these standard groff requests, there might be further macro calls. They can originate from a macro package (see .BR roff (@MAN7EXT@) for an overview) or from a preprocessor. . .P Preprocessor macros are easy to be recognized. . They enclose their code into a pair of characteristic macros. . .P .TS box, center, tab (@); c | c | c CfCB | CfCB | CfCB. preprocessor@start macro@ end macro = eqn@.PS@.PE grap@.G1@.G2 grn@.GS@.GE pic@.PS@.PE refer@.R1@.R2 soelim@\f[I]none@\f[I]none tbl@.TS@.TE .TE .P . . .\" -------------------------------------------------------------------- .SH "ESCAPE SEQUENCES" .\" -------------------------------------------------------------------- . Escape sequences are in-line language elements usually introduced by a backslash .squoted_char \[rs] and followed by an escape name and sometimes by a required argument. . Input processing is continued directly after the escaped character or the argument resp.\& without an intervening separation character. . So there must be a way to determine the end of the escape name and the end of the argument. . .P This is done by enclosing names (escape name and arguments consisting of a variable name) by a pair of brackets .BI \[lB] name \[rB] and constant arguments (number expressions and characters) by apostrophes (ASCII 0x27) like .BI \[cq] constant \[cq] \f[R]. . .P There are abbreviations for short names. . Two character escape names can be specified by an opening parenthesis like .esc ( xy without a closing counterpart. . And all one-character names different from the special characters .squoted_char [ and .squoted_char ( can even be specified without a marker in the form .esc c . . .P Constant arguments of length\~1 can omit the marker apostrophes, too, but there is no two-character analogue. . .P While 1-character escape sequences are mainly used for in-line functions and system related tasks, the 2-letter names following the .esc ( construct are used for special characters predefined by the roff system. . Escapes sequences with names of more than two characters .esc[] "" name denote user defined named characters (see the .request .char request). . . .\" -------------------------------------------------------------------- .SS "Single Character Escapes" .\" -------------------------------------------------------------------- . .PD 0 . .\" --------- comments --------- . .ESC \[dq] Beginning of a comment. . Everything up to the end of the line is ignored. . .ESC # Everything up to and including the next newline is ignored. . This is interpreted in copy mode. . This is like .esc \[dq] except that the terminating newline is ignored as well. . .\" --------- strings --------- . .ESC *\f[I]s\f[P] The string stored in the string variable with 1-character name .IR s . . .ESC *(\f[I]st\f[P] The string stored in the string variable with 2-character name .IR st . . .ESC[] * stringvar The string stored in the string variable with arbitrary length name .IR stringvar . . .\" --------- macro arguments --------- . .ESC $0 The name by which the current macro was invoked. . The .request .als request can make a macro have more than one name. . .ESC $ x Macro argument with 1-place number .IR x , where .I x is a digit between 1 and 9. . .ESC $( xy Macro argument with 2-digit number .IR xy . . .ESC[] $ nexp Macro argument with number .IR nexp , where .I nexp is a numerical expression evaluating to an integer \[>=]1. . .ESC $* In a macro, the concatenation of all the arguments separated by spaces. . .ESC $@ In a macro, the concatenation of all the arguments with each surrounded by double quotes, and separated by spaces. . .\" --------- escaped characters --------- . .ESC \[rs] reduces to a single backslash; useful to delay its interpretation as escape character in copy mode. . For a printable backslash, use .esc e , or even better .esc [rs] , to be independent from the current escape character. . .ESC \[cq] The acute accent \[aa]; same as .esc (aa . Unescaped: apostrophe, right quotation mark, single quote (ASCII 0x27). . .ESC ` The grave accent \[ga]; same as .esc (ga . Unescaped: left quote, backquote (ASCII 0x60). . .ESC \- The \- sign in the current font. . .ESC . An uninterpreted dot (period), even at start of line. . .ESC % Default optional hyphenation character. . .ESC ! Transparent line indicator. . .ESC? anything In a diversion, this will transparently embed .I anything in the diversion. .I anything is read in copy mode. . See also the escape sequences .esc ! and .esc ? . . . .\" --------- spacing --------- . .ESC \& space Unpaddable space-size space character (no line break). . .ESC 0 Digit width. . .ESC | 1/6\ em narrow space character; zero width in nroff. . .ESC ^ 1/12\ em half-narrow space character; zero width in nroff. . .ESC & Non-printable, zero width character. . .ESC ) Like .esc & except that it behaves like a character declared with the cflags request to be transparent for the purposes of end of sentence recognition. . .ESC / Increases the width of the preceding character so that the spacing between that character and the following character will be correct if the following character is a roman character. . .ESC , Modifies the spacing of the following character so that the spacing between that character and the preceding character will correct if the preceding character is a roman character. . .ESC ~ Unbreakable space that stretches like a normal inter-word space when a line is adjusted. . .ESC : Inserts a zero-width break point (similar to .esc % but without a soft hyphen character). . .ESC "" newline Ignored newline, for continuation lines. . .\" --------- structuring --------- . .ESC { Begin conditional input. . .ESC } End conditional input. . .\" --------- longer escape names --------- . .ESC ( sc The special character with 2-character name .IR sc , see section .BR "Special Characters" . . .ESC[] "" name The named character with arbitrary length name .IR name . . .\" --------- alphabetical escapes --------- . .ESC a Non-interpreted leader character. . .ESCq A anything If .I anything is acceptable as a name of a string, macro, diversion, register, environment or font it expands to\~1, and to\~0 otherwise. . .ESCq b abc.\|.\|.\& Bracket building function. . .ESCq B anything If .I anything is acceptable as a valid numeric expression it expands to\~1, and to\~0 otherwise. . .ESC c Interrupt text processing. . .ESCq C char The character called .IR char ; same as .esc[] "" char , but compatible to other roff versions. . .ESC d Forward (down) 1/2 em vertical unit (1/2 line in nroff). . .ESCq D charseq Draw a graphical element defined by the characters in .IR charseq ; see groff info file for details. . .ESC e Printable version of the current escape character. . .ESC E Equivalent to an escape character, but is not interpreted in copy-mode. . .ESC f F Change to font with 1-character name or 1-digit number .IR F . . .ESC f( fo Change to font with 2-characer name or 2-digit number .IR fo . . .ESC[] f font Change to font with arbitrary length name or number expression .IR font . . .ESC[] g reg Return format of register with name .I reg suitable for .request .af . Alternative forms .escarg g( xy and .escarg g x . . .ESCq h N Local horizontal motion; move right .I N (left if negative). . .ESCq H N Set height of current font to .IR N . . .ESC[] k reg Mark horizontal input place in register with arbitrary length name .IR reg . Alternative forms .escarg k( xy and .escarg k x . . .ESCq l Nc Horizontal line drawing function (optionally using character .IR c ). . .ESCq L Nc Vertical line drawing function (optionally using character .IR c ). . .ESC[] m color Change to color .IR color . . Alternative forms .escarg m( co and .escarg m c . . .ESC[] M color Change filling color for closed drawn objects to color .IR color . . Alternative forms .escarg M( co and .escarg M c . . .ESC n r The numerical value stored in the register variable with the 1-character name .IR r . . .ESC n( re The numerical value stored in the register variable with the 2-character name .IR re . . .ESC[] n reg The numerical value stored in the register variable with arbitrary length name .IR reg . . .ESCq N n Typeset the character with code .I n in the current font, no special fonts are searched. . Useful for adding characters to a font using the .request .char request. . .ESCq o abc.\|.\|.\& Overstrike characters .IR a , .IR b , .IR c , etc. . .ESC O 0 Disable glyph output. . Mainly for internal use. . .ESC O 1 Enable glyph output. . Mainly for internal use. . .ESC p Break and spread output line. . .ESC r Reverse 1\ em vertical motion (reverse line in nroff). . .ESCq R "name\~\[+-]n" The same as .request .nr .I name .IR \[+-]n . . .ESC[] s \[+-]N Set the point size to .I N scaled points. . Note the alternative forms .BI \[rs]s \[+-] [ N ]\c , .BI \[rs]s' \[+-]N '\c .Text , .BI \[rs]s \[+-] ' N '\c .Text , .escarg s( \[+-]xy\c .Text , .BI \[rs]s \[+-] ( xy\c .Text , .escarg s \[+-]x . Same as .request .ps request. . .ESCq S N Slant output .I N degrees. . .ESC t Non-interpreted horizontal tab. . .ESC u Reverse (up) 1/2 em vertical motion (1/2 line in nroff). . .ESCq v N Local vertical motion; move down .I N (up if negative). . .ESC[] V env The contents of the environment variable .IR env . . Alternative forms .escarg V( xy and .escarg V x . . .ESCq w string The width of the character sequence .IR string . . .ESCq x N Extra line-space function (negative before, positive after). . .ESCq X string Output .I string as device control function. . .ESC[] Y name Output string variable or macro .I name uninterpreted as device control function. . Alternative forms .escarg Y( xy and .escarg Y x . . .ESC z c Print .I c with zero width (without spacing). . .ESCq Z anything Print .I anything and then restore the horizontal and vertical position; .I anything may not contain tabs or leaders. . .PD .P The escape sequences .esc e , .esc . , .esc \[dq] , .esc $ , .esc * , .esc a , .esc n , .esc t , .esc g , and .escarg \& newline are interpreted in copy mode. . .P Escape sequences starting with .esc ( or .esc [ do not represent single character escape sequences, but introduce escape names with two or more characters. . .P If a backslash is followed by a character that does not constitute a defined escape sequence the backslash is silently ignored and the character maps to itself. . . .\" -------------------------------------------------------------------- .SS "Special Characters" .\" -------------------------------------------------------------------- . Common special characters are predefined by escape sequences of the form .BI \[rs]( xy with characters .I x and .IR y . . Some of these exist in the usual font while most of them are only available in the special font. . Below you'll find a selection of the most important glyphs; a complete list can be found in .BR groff_char (@MAN7EXT@). .RS .P .PD 0 . .ESC (bu Bullet sign .ESC (co Copyright .ESC (ct Cent .ESC (dd Double dagger .ESC (de Degree .ESC (dg Dagger .ESC (rs Printable double quote .ESC (em Em-dash .ESC (hy Hyphen .ESC (rg Registered sign .ESC (rs Printable backslash character .ESC (sc Section sign .ESC (ul Underline character .ESC (== Identical .ESC (>= Larger or equal .ESC (<= Less or equal .ESC (!= Not equal .ESC (-> Right arrow .ESC (<- Left arrow .ESC (+- Plus-minus sign .PD .RE . . .\" -------------------------------------------------------------------- .SS "Strings" .\" -------------------------------------------------------------------- . Strings are defined by the .request .ds request and can be retrieved by the .esc * escape sequence. . .P Strings share their name space with macros. . So strings and macros without arguments are roughly equivalent, though calling a string like a macro and vice-versa is not stably implemented so far. . The following strings are predefined in groff. . .STRING .T The name of the current output device as specified by the .option -T command line option. . . .\" -------------------------------------------------------------------- .SH REGISTERS .\" -------------------------------------------------------------------- . Registers are variables that store a value. In groff, most registers store numerical values (see section .B NUMERICAL EXPRESSIONS above), but some can also hold a string value. . .P Each register is given a name. Arbitrary registers can be defined and set with the request .request .nr .IR register . . .P The value stored in a register can be retrieved by the escape sequences introduced by .esc n . . .P Most useful are predefined registers. . In the following the notation .I name is used to refer to a register called .register name to make clear that we speak about registers. . Please keep in mind that the .esc[] n "" decoration is not part of the register name. . . .\" -------------------------------------------------------------------- .SS "Read-only Registers" .\" -------------------------------------------------------------------- . The following registers have predefined values that should not be modified by the user (usually, registers starting with a dot a read-only). . Mostly, they provide information on the current settings or store results from request calls. . .P .PD 0 . .REG .$ Number of arguments in the current macro. . .REG .a Post-line extra line-space most recently utilized using .escq x N . . .REG .A Set to\~1 in .B troff if option .B \-A is used; always\~1 in .BR nroff . . .REG .c Current input line number. . .REG .C 1\~if compatibility mode is in effect, 0\~otherwise. . .REG .cdp The depth of the last character added to the current environment. It is positive if the character extends below the baseline. . .REG .ce The number of lines remaining to be centered, as set by the .request .ce request. . .REG .cht The height of the last character added to the current environment. It is positive if the character extends above the baseline. . .REG .csk The skew of the last character added to the current environment. The skew of a character is how far to the right of the center of a character the center of an accent over that character should be placed. . .REG .d Current vertical place in current diversion; equal to register .register nl . . .REG .ev The name or number of the current environment (string-valued). . .REG .f Current font number. . .REG .fam The current font family (string-valued). . .REG .fn The current (internal) real font name (string-valued). . .REG .fp The number of the next free font position. . .REG .g Always 1 in GNU troff. . Macros should use it to test if running under groff. . .REG .h Text base-line high-water mark on current page or diversion. . .REG .H Available horizontal resolution in basic units. . .REG .hla The current hyphenation language as set by the .B .hla request. . .REG .hlc The number of immediately preceding consecutive hyphenated lines. . .REG .hlm The maximum allowed number of consecutive hyphenated lines, as set by the .request .hlm request. . .REG .hy The current hyphenation flags (as set by the .request .hy request). . .REG .hym The current hyphenation margin (as set by the .request .hym request). . .REG .hys The current hyphenation space (as set by the .request .hys request). . .REG .i Current ident. . .REG .in The indent that applies to the current output line. . .REG .int Positive if last output line contains .esc c . . .REG .kern 1\~if pairwise kerning is enabled, 0\~otherwise. . .REG .l Current line length. . .REG .lg The current ligature mode (as set by the .request .lg request). . .REG .linetabs The current line-tabs mode (as set by the .request .linetabs request). . .REG .ll The line length that applies to the current output line. . .REG .lt The title length (as set by the .request .lt request). . .REG .n Length of text portion on previous output line. . .REG .ne The amount of space that was needed in the last .request .ne request that caused a trap to be sprung. . Useful in conjunction with .register .trunc . . .REG .ns 1\~if in no-space mode, 0\~otherwise. . .REG .o Current page offset. . .REG .p Current page length. . .REG .pn The number of the next page: either the value set by a .request .pn request, or the number of the current page plus\ 1. . .REG .ps The current pointsize in scaled points. . .REG .psr The last-requested pointsize in scaled points. . .REG .rj The number of lines to be right-justified as set by the rj request. . .REG .s Current point size as a decimal fraction. . .REG .sr The last requested pointsize in points as a decimal fraction (string-valued). . .REG .t Distance to the next trap. . .REG .T Set to\~1 if option .B \-T is used. . .REG .tabs A string representation of the current tab settings suitable for use as an argument to the .request .ta request. . .REG .trunc The amount of vertical space truncated by the most recently sprung vertical position trap, or, if the trap was sprung by a .request .ne request, minus the amount of vertical motion produced by .request .ne . . In other words, at the point a trap is sprung, it represents the difference of what the vertical position would have been but for the trap, and what the vertical position actually is. . Useful in conjunction with the .register .ne register. . .REG .ss The value of the parameters set by the first argument of the .request .ss request. . .REG .sss The value of the parameters set by the second argument of the .request .ss request. . .REG .u Equal to 1 bin fill mode and 0 in nofill mode. . .REG .v Current vertical line spacing. . .REG .V Available vertical resolution in basic units. . .REG .vpt 1\~ if vertical position traps are enabled, 0\~otherwise. . .REG .w Width of previous character. . .REG .warn The sum of the number codes of the currently enabled warnings. . .REG .x The major version number. . .REG .y The minor version number. . .REG .Y The revision number of groff. . .REG .z Name of current diversion. .PD . . .\" -------------------------------------------------------------------- .SS "Writable Registers" .\" -------------------------------------------------------------------- . The following registers can be read and written by the user. They have predefined default values, but these can be modified for customizing a document. . .P .PD 0 .REG % Current page number. . .REG c. Current input line number. . .REG ct Character type (set by width function .esc w ). . .REG dl Maximal width of last completed diversion. . .REG dn Height of last completed diversion. . .REG dw Current day of week (1-7). . .REG dy Current day of month (1-31). . .REG hp Current horizontal position at input line. . .REG llx Lower left x-coordinate (in PostScript units) of a given PostScript image (set by .request .psbb ). . .REG lly Lower left y-coordinate (in PostScript units) of a given PostScript image (set by .request .psbb ). . .REG ln Output line number. . .REG mo Current month (1-12). . .REG nl Vertical position of last printed text base-line. . .REG rsb Like .register sb , but takes account of the heights and depths of characters. . .REG rst Like .register st , but takes account of the heights and depths of characters. . .REG sb Depth of string below base line (generated by width function .esc w ). . .REG skw Right skip width from the center of the last character in the .esc w argument. . .REG slimit If greater than 0, the maximum number of objects on the input stack. . If \[<=]0 there is no limit, i.e., recursion can continue until virtual memory is exhausted. . .REG ssc The amount of horizontal space (possibly negative) that should be added to the last character before a subscript (generated by width function .esc w ). . .REG st Height of string above base line (generated by width function .esc w ). . .REG systat The return value of the .I system() function executed by the last .request .sy request. . .REG urx Upper right x-coordinate (in PostScript units) of a given PostScript image (set by .request .psbb ). . .REG ury Upper right y-coordinate (in PostScript units) of a given PostScript image (set by .request .psbb ). . .REG year The current year (year 2000 compliant). . .REG yr Current year minus 1900. . For Y2K compliance use register .register year instead. . .PD . . .\" -------------------------------------------------------------------- .SH COMPATIBILITY .\" -------------------------------------------------------------------- . The differences of the groff language in comparison to classical troff as defined by .I [CSTR\~#54] are documented in .BR groff_diff (@MAN7EXT@). . .P The groff system provides a compatibility mode, see .BR groff (@MAN1EXT@) on how to invoke this. . . .\" -------------------------------------------------------------------- .SH BUGS .\" -------------------------------------------------------------------- . Report bugs to the .MTO bug-groff@gnu.org "groff bug mailing list" . Include a complete, self-contained example that will allow the bug to be reproduced, and say which version of groff you are using. . . .\" -------------------------------------------------------------------- .SH AUTHORS .\" -------------------------------------------------------------------- . Copyright (C) 2000, 2001, 2002 Free Software Foundation, Inc. . .P This document is distributed under the terms of the FDL (GNU Free Documentation License) version 1.1 or later. . You should have received a copy of the FDL on your system, it is also available on-line at the .URL http://\:www.gnu.org/\:copyleft/\:fdl.html "GNU copyleft site" . . .P This document is part of .IR groff , the GNU roff distribution. . It was written by .MTO bwarken@mayn.de "Bernd Warken" ; it is maintained by .MTO wl@gnu.org "Werner Lemberg" . . . .\" -------------------------------------------------------------------- .SH "SEE ALSO" .\" -------------------------------------------------------------------- . .P The main source of information for the groff language is the .B groff .BR info (1) file. . Besides the gory details, it contains many examples. . .TP .BR groff (@MAN1EXT@) the usage of the groff program and pointers to the documentation and availability of the groff system. . .TP .BR groff_diff (@MAN7EXT@) the differences of the groff language as compared to classical roff. . This is the authoritative document for the predefined language elements that are specific to groff. . .TP .BR groff_char (@MAN7EXT@) the predefined groff characters (glyphs). . .TP .BR groff_font (@MAN5EXT@) the specification of fonts and the DESC file. . .TP .BR roff (@MAN7EXT@) the history of roff, the common parts shared by all roff systems, and pointers to further documentation. . .TP .I [CSTR\~#54] .URL http://\:cm.bell-labs.com/\:cm/\:cs/\:54.ps \ "Nroff/\:Troff User's Manual by Osanna & Kernighan" \[em] the bible for classical troff. . . .\" -------------------------------------------------------------------- .\" Emacs Setup .\" -------------------------------------------------------------------- . .\" Local Variables: .\" mode: nroff .\" End: