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diff --git a/man/groff_differences.man b/man/groff_differences.man new file mode 100755 index 00000000..960cd44d --- /dev/null +++ b/man/groff_differences.man @@ -0,0 +1,2426 @@ +.ig +groff_differences.7 + +Last update : 14 Nov 2001 + +This file is part of groff, the GNU roff type-setting system. + +Copyright (C) 2000, 2001 Free Software Foundation, Inc. +written by James Clark + +modified by Werner Lemberg <wl@gnu.org> + Bernd Warken <bwarken@mayn.de> + +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 AUTHOR, 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 +. +.\" define a string tx for the TeX logo +.ie t .ds tx T\h'-.1667m'\v'.224m'E\v'-.224m'\h'-.125m'X +.el .ds tx TeX +. +.de TQ +.br +.ns +.TP \\$1 +.. +. +.\" Like TP, but if specified indent is more than half +.\" the current line-length - indent, use the default indent. +.de Tp +.ie \\n(.$=0:((0\\$1)*2u>(\\n(.lu-\\n(.iu)) .TP +.el .TP "\\$1" +.. +. +.\" Don't use .ne for TTY devices +.de NE +.if t .ne \\$1 +.. +. +. +.\" -------------------------------------------------------------------- +.\" Title +.\" -------------------------------------------------------------------- +. +.TH GROFF_DIFFERENCES @MAN7EXT@ "@MDATE@" "Groff Version @VERSION@" +.SH NAME +groff_differences \- differences between GNU troff and classical troff +. +. +.\" -------------------------------------------------------------------- +.SH DESCRIPTION +.\" -------------------------------------------------------------------- +. +This manual page describes the language differences between +.IR groff , +the GNU +.I roff +text processing system and the classical +.I roff +formatter of the free Unix\~7 of the 1970s, documented in the +.I Troff User's Manual +by +.I Osanna +and +.IR Kernighan . +. +.P +The section +.I SEE ALSO +gives pointers to both the classical +.I roff +and the modern +.I groff +documentation. +. +.P +At the moment, this document is the place of the most actual documentation +with the +.I groff +system. +All novelties are first described here and will pervade into the other +documents only at a later stage. +This might be changed in the future. +. +. +.\" -------------------------------------------------------------------- +.SH "NEW FEATURES" +.\" -------------------------------------------------------------------- +. +In this section, all additional features of +.I groff +compared to the classical Unix\~7 +.I troff +are described in detail. +. +. +.\" -------------------------------------------------------------------- +.SS Long names +.\" -------------------------------------------------------------------- +. +The names of number registers, fonts, strings/\:macros/\:diversions, +special characters, and colors can be of any length. +In escape sequences, additionally to the classical +.BI ( xx +construction for a two character name, you can use +.BI [ xxx ] +for a name of arbitrary length, for example in +. +.TP \w'\ef[xxx]'u+3n +.BI \e[ xxx ] +Print the special character called +.IR xxx . +. +.TP +.BI \ef[ xxx ] +Set font +.IR xxx . +. +.TP +.BI \e*[ xxx ] +Interpolate string +.IR xxx . +. +.TP +.BI \en[ xxx ] +Interpolate number register +.IR xxx . +. +. +.\" -------------------------------------------------------------------- +.SS Fractional pointsizes +.\" -------------------------------------------------------------------- +. +A +.I scaled point +is equal to +.B 1/sizescale +points, where +.B sizescale +is specified in the +.B DESC +file (1 by default). +There is a new scale indicator +.B z +that has the effect of multiplying by sizescale. +Requests and escape sequences in troff interpret arguments that represent a +pointsize as being in units of scaled points, but they evaluate each such +argument using a default scale indicator of +.BR z . +Arguments treated in this way are the argument to the +.B ps +request, the third argument to the +.B cs +request, the second and fourth arguments to the +.B tkf +request, the argument to the +.B \eH +escape sequence, and those variants of the +.B \es +escape sequence that take a numeric expression as their argument. +. +.P +For example, suppose sizescale is 1000; then a scaled point will be +equivalent to a millipoint; the request +.B .ps\~10.25 +is equivalent to +.B .ps\~10.25z +and so sets the pointsize to 10250 scaled points, which is equal to +10.25 points. +. +.P +The number register +.B \en[.s] +returns the pointsize in points as decimal fraction. +There is also a new number register +.B \en[.ps] +that returns the pointsize in scaled points. +. +.P +It would make no sense to use the +.B z +scale indicator in a numeric expression whose default scale indicator was +neither +.B u +nor +.BR z , +and so +.B troff +disallows this. +Similarly it would make no sense to use a scaling indicator other than +.B z +or +.B u +in a numeric expression whose default scale indicator was +.BR z , +and so +.B troff +disallows this as well. +. +.P +There is also new scale indicator +.B s +which multiplies by the number of units in a scaled point. +So, for example, +.B \en[.ps]s +is equal to +.BR 1m . +Be sure not to confuse the +.B s +and +.B z +scale indicators. +. +. +.\" -------------------------------------------------------------------- +.SS Numeric expressions +.\" -------------------------------------------------------------------- +. +Spaces are permitted in a number expression within parentheses. +. +.P +.B M +indicates a scale of 100ths of an em. +.B f +indicates a scale of 65536 units, providing fractions for color +definitions with +.B defcolor +request. +For example, 0.5f = 32768u. +. +.TP +.IB e1 >? e2 +The maximum of +.I e1 +and +.IR e2 . +. +.TP +.IB e1 <? e2 +The minimum of +.I e1 +and +.IR e2 . +. +.TP +.BI ( c ; e ) +Evaluate +.I e +using +.I c +as the default scaling indicator. +If +.I c +is missing, ignore scaling indicators in the evaluation of +.IR e . +. +. +.\" -------------------------------------------------------------------- +.SS New escape sequences +.\" -------------------------------------------------------------------- +. +.TP +.BI \eA' anything ' +This expands to +.B 1 +or +.B 0 +resp., depending on whether +.I anything +is or is not acceptable as the name of a string, macro, diversion, number +register, environment, font, or color. +It will return\~\c +.B 0 +if +.I anything +is empty. +This is useful if you want to lookup user input in some sort of associative +table. +. +.TP +.BI \eB' anything ' +This expands to +.B 1 +or +.B 0 +resp., depending on whether +.I anything +is or is not a valid numeric expression. +It will return\~\c +.B 0 +if +.I anything +is empty. +. +.TP +.BI \eC' xxx ' +Typeset character named +.IR xxx . +Normally it is more convenient to use +.BI \e[ xxx ]\fR. +But +.B \eC +has the advantage that it is compatible with recent versions of +.SM UNIX +and is available in compatibility mode. +. +.TP +.B \eE +This is equivalent to an escape character, but it is not interpreted in +copy-mode. +For example, strings to start and end superscripting could be defined like +this +. +.RS +.IP +\&.ds { \ev'\-.3m'\es'\eEn[.s]*6u/10u' +.br +\&.ds } \es0\ev'.3m' +. +.P +The use of +.B \eE +ensures that these definitions will work even if +.B \e*{ +gets interpreted in copy-mode (for example, by being used in a macro +argument). +.RE +. +.TP +.BI \em x +.TQ +.BI \em( xx +.TQ +.BI \em[ xxx ] +Set drawing color. +.B \emP +switches back to the previous color. +. +.TP +.BI \eM x +.TQ +.BI \eM( xx +.TQ +.BI \eM[ xxx ] +Set background color for filled objects drawn with the +.BI \eD' .\|.\|. ' +commands. +.B \eMP +switches back to the previous color. +. +.TP +.BI \eN' n ' +Typeset the character with code +.I n +in the current font. +.I n +can be any integer. +Most devices only have characters with codes between 0 and 255. +If the current font does not contain a character with that code, special +fonts will +.I not +be searched. +The +.B \eN +escape sequence can be conveniently used in conjunction with the +.B char +request, for example +. +.RS +.IP +.B +\&.char \e[phone] \ef(ZD\eN'37' +.RE +. +.IP +The code of each character is given in the fourth column in the font +description file after the +.B charset +command. +It is possible to include unnamed characters in the font description file by +using a name of +.BR \-\-\- ; +the +.B \eN +escape sequence is the only way to use these. +. +.TP +.BI \eR' name\ \(+-n ' +This has the same effect as +. +.RS +.IP +.BI .nr\ name\ \(+-n +.RE +. +.TP +.BI \es( nn +.TQ +.BI \es\(+-( nn +Set the point size to +.I nn +points; +.I nn +must be exactly two digits. +. +.TP +.BI \es[\(+- n ] +.TQ +.BI \es\(+-[ n ] +.TQ +.BI \es'\(+- n ' +.TQ +.BI \es\(+-' n ' +Set the point size to +.I n +scaled points; +.I n +is a numeric expression with a default scale indicator of\~\c +.BR z . +. +.TP +.BI \eV x +.TQ +.BI \eV( xx +.TQ +.BI \eV[ xxx ] +Interpolate the contents of the environment variable +.IR xxx , +as returned by +.BR getenv (3). +.B \eV +is interpreted in copy-mode. +. +.TP +.BI \eY x +.TQ +.BI \eY( xx +.TQ +.BI \eY[ xxx ] +This is approximately equivalent to +.BI \eX'\e*[ xxx ]'\fR. +However the contents of the string or macro +.I xxx +are not interpreted; also it is permitted for +.I xxx +to have been defined as a macro and thus contain newlines (it is not +permitted for the argument to +.B \eX +to contain newlines). +The inclusion of newlines requires an extension to the UNIX troff output +format, and will confuse drivers that do not know about this extension. +. +.TP +.BI \eZ' anything ' +Print anything and then restore the horizontal and vertical position; +.I anything +may not contain tabs or leaders. +. +.TP +.B \e$0 +The name by which the current macro was invoked. +. +The +.B als +request can make a macro have more than one name. +. +.TP +.B \e$* +In a macro, the concatenation of all the arguments separated by spaces. +. +.TP +.B \e$@ +In a macro, the concatenation of all the arguments with each surrounded by +double quotes, and separated by spaces. +. +.TP +.BI \e$( nn +.TQ +.BI \e$[ nnn ] +In a macro, this gives the +.IR nn -th +or +.IR nnn -th +argument. +Macros can have an unlimited number of arguments. +. +.TP +.BI \e? anything \e? +When used in a diversion, this will transparently embed +.I anything +in the diversion. +.I anything +is read in copy mode. +When the diversion is reread, +.I anything +will be interpreted. +.I anything +may not contain newlines; use +.B \e!\& +if you want to embed newlines in a diversion. +The escape sequence +.B \e?\& +is also recognised in copy mode and turned into a single internal code; it +is this code that terminates +.IR anything . +Thus +. +.RS +.IP +.NE 14v+\n(.Vu +.ft B +.nf +\&.nr x 1 +\&.nf +\&.di d +\e?\e\e?\e\e\e\e?\e\e\e\e\e\e\e\enx\e\e\e\e?\e\e?\e? +\&.di +\&.nr x 2 +\&.di e +\&.d +\&.di +\&.nr x 3 +\&.di f +\&.e +\&.di +\&.nr x 4 +\&.f +.fi +.ft +.RE +. +.IP +will print\~\c +.BR 4 . +. +.TP +.B \e/ +This 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. +.if t \{\ +. nop For example, if an italic f is immediately followed by a roman right +. nop parenthesis, then in many fonts the top right portion of the f will +. nop overlap the top left of the right parenthesis producing \fIf\fR)\fR, +. nop which is ugly. +. nop Inserting +. B \e/ +. nop produces +. ie \n(.g \fIf\/\fR)\fR +. el \fIf\|\fR)\fR +. nop and avoids this problem. +.\} +It is a good idea to use this escape sequence whenever an italic character +is immediately followed by a roman character without any intervening space. +. +.TP +.B \e, +This 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. +.if t \{\ +. nop For example, inserting +. B \e, +. nop between the parenthesis and the f changes +. nop \fR(\fIf\fR to +. ie \n(.g \fR(\,\fIf\fR. +. el \fR(\^\fIf\fR. +.\} +It is a good idea to use this escape sequence whenever a roman +character is immediately followed by an italic character without any +intervening space. +. +.TP +.B \e) +Like +.B \e& +except that it behaves like a character declared with the +.B cflags +request to be transparent for the purposes of end-of-sentence recognition. +. +.TP +.B \e~ +This produces an unbreakable space that stretches like a normal inter-word +space when a line is adjusted. +. +.TP +.B \e: +This causes the insertion of a zero-width break point. +It is equal to +.B \e% +but without insertion of a soft hyphen character. +. +.TP +.B \e# +Everything up to and including the next newline is ignored. +This is interpreted in copy mode. +It is like +.B \e" +except that +.B \e" +does not ignore the terminating newline. +. +. +.\" -------------------------------------------------------------------- +.SS New requests +.\" -------------------------------------------------------------------- +. +.TP +.BI .aln\ xx\ yy +Create an alias +.I xx +for number register object named +.IR yy . +The new name and the old name will be exactly equivalent. +If +.I yy +is undefined, a warning of type +.B reg +will be generated, and the request will be ignored. +. +.TP +.BI .als\ xx\ yy +Create an alias +.I xx +for request, string, macro, or diversion object named +.IR yy . +The new name and the old name will be exactly equivalent (it is similar to a +hard rather than a soft link). +If +.I yy +is undefined, a warning of type +.B mac +will be generated, and the request will be ignored. +The +.BR de , +.BR am , +.BR di , +.BR da , +.BR ds , +and +.B as +requests only create a new object if the name of the macro, diversion or +string diversion is currently undefined or if it is defined to be a request; +normally they modify the value of an existing object. +. +.TP +.BI .am1\ xx\ yy +Similar to +.BR .am , +but compatibility mode is switched off during execution. +On entry, the current compatibility mode is saved and restored at exit. +. +.TP +.BI .asciify\ xx +This request `unformats' the diversion +.I xx +in such a way that +.SM ASCII +and space characters (and some escape sequences) that were formatted and +diverted into +.I xx +will be treated like ordinary input characters when +.I xx +is reread. +Useful for diversions in conjunction with the +.B .writem +request. +It can be also used for gross hacks; for example, this +. +.RS +.IP +.NE 7v+\n(.Vu +.ft B +.nf +\&.tr @. +\&.di x +\&@nr n 1 +\&.br +\&.di +\&.tr @@ +\&.asciify x +\&.x +.fi +.RE +. +.IP +will set register\~\c +.B n +to\~1. +Note that glyph information (font, font size, etc.) is not preserved; use +.B .unformat +instead. +. +.TP +.B .backtrace +Print a backtrace of the input stack on stderr. +. +.TP +.BI .blm\ xx +Set the blank line macro to +.IR xx . +If there is a blank line macro, it will be invoked when a blank line +is encountered instead of the usual troff behaviour. +. +.TP +.BI .box\ xx +.TQ +.BI .boxa\ xx +These requests are similar to the +.B di +and +.B da +requests with the exception that a partially filled line will not become +part of the diversion (i.e., the diversion always starts with a new line) +but restored after ending the diversion, discarding the partially filled +line which possibly comes from the diversion. +. +.TP +.B .break +Break out of a while loop. +See also the +.B while +and +.B continue +requests. +Be sure not to confuse this with the +.B br +request. +. +.TP +.B .brp +This is the same as +.BR \ep . +. +.TP +.BI .cflags\ n\ c1\ c2\|.\|.\|. +Characters +.IR c1 , +.IR c2 ,\|.\|.\|. +have properties determined by +.IR n , +which is ORed from the following: +. +.RS +.IP 1 +The character ends sentences (initially characters +.B .?!\& +have this property). +. +.IP 2 +Lines can be broken before the character (initially no characters have this +property); a line will not be broken at a character with this property +unless the characters on each side both have non-zero hyphenation codes. +. +.IP 4 +Lines can be broken after the character (initially characters +.B \-\e(hy\e(em +have this property); a line will not be broken at a character with this +property unless the characters on each side both have non-zero hyphenation +codes. +. +.IP 8 +The character overlaps horizontally (initially characters +.B \e(ul\e(rn\e(ru +have this property); +. +.IP 16 +The character overlaps vertically (initially character +.B \e(br +has this property); +. +.IP 32 +An end-of-sentence character followed by any number of characters with +this property will be treated as the end of a sentence if followed by +a newline or two spaces; in other words the character is transparent +for the purposes of end-of-sentence recognition; this is the same as +having a zero space factor in \*(tx (initially characters +.B \(dq')]*\e(dg\e(rq +have this property). +.RE +. +.TP +.BI .char\ c\ string +Define character +.I c +to be +.IR string . +Every time character +.I c +needs to be printed, +.I string +will be processed in a temporary environment and the result will be wrapped +up into a single object. +Compatibility mode will be turned off and the escape character will be set +to +.B \e +while +.I string +is being processed. +Any emboldening, constant spacing or track kerning will be applied to this +object rather than to individual characters in +.IR string . +A character defined by this request can be used just like a normal character +provided by the output device. +In particular other characters can be translated to it with the +.B tr +request; it can be made the leader character by the +.B lc +request; repeated patterns can be drawn with the character using the +.B \el +and +.B \eL +escape sequences; words containing the character can be hyphenated +correctly, if the +.B hcode +request is used to give the character a hyphenation code. +There is a special anti-recursion feature: use of character within the +character's definition will be handled like normal characters not defined +with +.BR char . +A character definition can be removed with the +.B rchar +request. +. +.TP +.BI .chop\ xx +Chop the last character off macro, string, or diversion +.IR xx . +This is useful for removing the newline from the end of diversions that are +to be interpolated as strings. +. +.TP +.BI .close\ stream +Close the stream named +.IR stream ; +.I stream +will no longer be an acceptable argument to the +.B write +request. +See the +.B open +request. +. +.TP +.B .continue +Finish the current iteration of a while loop. +See also the +.B while +and +.B break +requests. +. +.TP +.BI .cp\ n +If +.I n +is non-zero or missing, enable compatibility mode, otherwise disable it. +In compatibility mode, long names are not recognised, and the +incompatibilities caused by long names do not arise. +. +.TP +.BI .defcolor\ xxx\ scheme\ color_components +Define color. +.I scheme +can be one of the following values: +.B rgb +(three components), +.B cym +(three components), +.B cmyk +(four components), and +.B gray +or +.B grey +(one component). +. +Color components can be given either as a hexadecimal string or as positive +decimal integers in the range 0-65535. +A hexadecimal string contains all color components concatenated; it must +start with either +.B # +or +.BR ## . +The former specifies hex values in the range 0-255 (which are internally +multiplied by\~257), the latter in the range 0-65535. +Examples: #FFC0CB (pink), ##ffff0000ffff (magenta). +A new scaling indicator\~\c +.B f +has been introduced which multiplies its value by 65536; this makes it +convenient to specify color components as fractions in the range 0 to\~1. +Example: +. +.RS +.IP +.B +\&.defcolor darkgreen rgb 0.1f 0.5f 0.2f +.RE +. +.IP +Note that +.B f +is the default scaling indicator for the +.B defcolor +request, thus the above statement is equivalent to +. +.RS +.IP +.B +\&.defcolor darkgreen rgb 0.1 0.5 0.2 +.RE +. +.TP +.BI .dei\ xx\ yy +Define macro indirectly. +. +The following example +. +.RS +.IP +.NE 2v+\n(.Vu +.ft B +.nf +\&.ds xx aa +\&.ds yy bb +\&.dei xx yy +.fi +.RE +. +.IP +is equivalent to +. +.RS +.IP +.B +\&.de aa bb +.RE +. +.TP +.BI .de1\ xx\ yy +Similar to +.BR .de , +but compatibility mode is switched off during execution. +On entry, the current compatibility mode is saved and restored at exit. +. +.TP +.BI .do\ xxx +Interpret +.I .xxx +with compatibility mode disabled. +For example, +. +.RS +.IP +.B +\&.do fam T +.P +would have the same effect as +. +.IP +.B +\&.fam T +.P +except that it would work even if compatibility mode had been enabled. +Note that the previous compatibility mode is restored before any files +sourced by +.I xxx +are interpreted. +.RE +. +.TP +.B .ecs +Save current escape character. +. +.TP +.B .ecr +Restore escape character saved with +.BR ecs . +Without a previous call to +.BR ecs , +.RB ` \e ' +will be the new escape character. +. +.TP +.BI .evc\ xx +Copy the contents of environment +.I xx +to the current environment. +No pushing or popping of environments will be done. +. +.TP +.BI .fam\ xx +Set the current font family to +.IR xx . +The current font family is part of the current environment. +If +.I xx +is missing, switch back to previous font family. +See the description of the +.B sty +request for more information on font families. +. +.TP +.BI .fspecial\ f\ s1\ s2\|.\|.\|. +When the current font is +.IR f , +fonts +.IR s1 , +.IR s2 ,\|.\|.\|. +will be special, that is, they will searched for characters not in the +current font. +Any fonts specified in the +.B special +request will be searched after fonts specified in the +.B fspecial +request. +. +.TP +.BI .ftr\ f\ g +Translate font +.I f +to +.IR g . +Whenever a font named +.I f +is referred to in an +.B \ef +escape sequence, or in the +.BR ft , +.BR ul , +.BR bd , +.BR cs , +.BR tkf , +.BR special , +.BR fspecial , +.BR fp , +or +.BR sty +requests, font +.I g +will be used. +If +.I g +is missing, or equal to +.I f +then font +.I f +will not be translated. +. +.TP +.BI .hcode \ c1\ code1\ c2\ code2\|.\|.\|. +Set the hyphenation code of character +.I c1 +to +.I code1 +and that of +.I c2 +to +.IR code2 . +A hyphenation code must be a single input character (not a special +character) other than a digit or a space. +Initially each lower-case letter has a hyphenation code, which is itself, +and each upper-case letter has a hyphenation code which is the lower case +version of itself. +See also the +.B hpf +request. +. +.TP +.BI .hla\ lang +Set the current hyphenation language to +.IR lang . +Hyphenation exceptions specified with the +.B hw +request and hyphenation patterns specified with the +.B hpf +request are both associated with the current hyphenation language. +The +.B hla +request is usually invoked by the +.B troffrc +file. +. +.TP +.BI .hlm\ n +Set the maximum number of consecutive hyphenated lines to\~\c +.IR n . +If +.I n +is negative, there is no maximum. +The default value is\~\-1. +This value is associated with the current environment. +Only lines output from an environment count towards the maximum associated +with that environment. +Hyphens resulting from +.B \e% +are counted; explicit hyphens are not. +. +.TP +.BI .hpf\ file +Read hyphenation patterns from +.IR file ; +this will be searched for in the same way that +.IB name .tmac +is searched for when the +.BI \-m name +option is specified. +It should have the same format as the argument to the \epatterns primitive +in \*(tx; the letters appearing in this file are interpreted as hyphenation +codes. +A +.BR % \~\c +character in the patterns file introduces a comment that continues to the +end of the line. +The set of hyphenation patterns is associated with the current language set +by the +.B hla +request. +The +.B hpf +request is usually invoked by the +.B troffrc +file. +. +.TP +.BI .hym\ n +Set the +.I hyphenation margin +to\~\c +.IR n : +when the current adjustment mode is not\~\c +.BR b , +the line will not be hyphenated if the line is no more than +.I n +short. +The default hyphenation margin is\~0. +The default scaling indicator for this request is\~\c +.IR m . +The hyphenation margin is associated with the current environment. +The current hyphenation margin is available in the +.B \en[.hym] +register. +. +.TP +.BI .hys\ n +Set the +.I hyphenation space +to\~\c +.IR n : +when the current adjustment mode is\~\c +.B b +don't hyphenate the line if the line can be justified by adding no more than +.I n +extra space to each word space. +The default hyphenation space is\~0. +The default scaling indicator for this request is\~\c +.BR m . +The hyphenation space is associated with the current environment. +The current hyphenation space is available in the +.B \en[.hys] +register. +. +.TP +.BI .kern\ n +If +.I n +is non-zero or missing, enable pairwise kerning, otherwise disable it. +. +.TP +.BI .length\ xx\ string +Compute the length of +.I string +and return it in the number register +.I xx +(which is not necessarily defined before). +. +.TP +.BI .linetabs\ n +If +.I n +is non-zero or missing, enable line-tabs mode, otherwise disable it +(which is the default). +In line-tabs mode, tab distances are computed relative to the (current) +output line. +Otherwise they are taken relative to the input line. +For example, the following +. +.RS +.IP +.NE 6v+\n(.Vu +.ft B +.nf +\&.ds x a\et\ec +\&.ds y b\et\ec +\&.ds z c +\&.ta 1i 3i +\e*x +\e*y +\e*z +.fi +.RE +. +.IP +yields +. +.RS +.IP +a b c +.RE +. +.IP +In line-tabs mode, the same code gives +. +.RS +.IP +a b c +.RE +. +.IP +Line-tabs mode is associated with the current environment; the read-only +number register +.B \\en[.linetabs] +is set to\~1 if in line-tabs mode, and 0 otherwise. +. +.TP +.BI .mso\ file +The same as the +.B so +request except that +.I file +is searched for in the same directories as macro files for the the +.B \-m +command line option. +If the file name to be included has the form +.IB name .tmac +and it isn't found, +.B mso +tries to include +.BI tmac. name +instead and vice versa. +. +.TP +.BI .nop \ anything +Execute +.IR anything . +This is similar to `.if\ 1'. +. +.TP +.B .nroff +Make the +.B n +built-in condition true and the +.B t +built-in condition false. +This can be reversed using the +.B troff +request. +. +.TP +.BI .open\ stream\ filename +Open +.I filename +for writing and associate the stream named +.I stream +with it. +See also the +.B close +and +.B write +requests. +. +.TP +.BI .opena\ stream\ filename +Like +.BR open , +but if +.I filename +exists, append to it instead of truncating it. +. +.TP +.B .pnr +Print the names and contents of all currently defined number registers on +stderr. +. +.TP +.BI .psbb \ filename +Get the bounding box of a PostScript image +.IR filename . +This file must conform to Adobe's Document Structuring Conventions; the +command looks for a +.B \%%%BoundingBox +comment to extract the bounding box values. +After a successful call, the coordinates (in PostScript units) of the lower +left and upper right corner can be found in the registers +.BR \en[llx] , +.BR \en[lly] , +.BR \en[urx] , +and +.BR \en[ury] , +respectively. +If some error has occurred, the four registers are set to zero. +. +.TP +.BI .pso \ command +This behaves like the +.B so +request except that input comes from the standard output of +.IR command . +. +.TP +.B .ptr +Print the names and positions of all traps (not including input line +traps and diversion traps) on stderr. +. +Empty slots in the page trap list are printed as well, because they +can affect the priority of subsequently planted traps. +. +.TP +.BI .rchar\ c1\ c2\|.\|.\|. +Remove the definitions of characters +.IR c1 , +.IR c2 ,\|.\|.\|. +This undoes the effect of a +.B char +request. +. +.TP +.B .return +Within a macro, return immediately. +No effect otherwise. +. +.TP +.B .rj +.TQ +.BI .rj\ n +Right justify the next +.IR n \~\c +input lines. +Without an argument right justify the next input line. +The number of lines to be right justified is available in the +.B \en[.rj] +register. +This implicitly does +.BR .ce \~0 . +The +.B ce +request implicitly does +.BR .rj \~0 . +. +.TP +.BI .rnn \ xx\ yy +Rename number register +.I xx +to +.IR yy . +. +.TP +.BI .shc\ c +Set the soft hyphen character to +.IR c . +If +.I c +is omitted, the soft hyphen character will be set to the default +.BR \e(hy . +The soft hyphen character is the character which will be inserted when a +word is hyphenated at a line break. +If the soft hyphen character does not exist in the font of the character +immediately preceding a potential break point, then the line will not be +broken at that point. +Neither definitions (specified with the +.B char +request) nor translations (specified with the +.B tr +request) are considered when finding the soft hyphen character. +. +.TP +.BI .shift\ n +In a macro, shift the arguments by +.I n +positions: argument\~\c +.I i +becomes argument +.IR i \- n ; +arguments 1 to\~\c +.I n +will no longer be available. +If +.I n +is missing, arguments will be shifted by\~1. +Shifting by negative amounts is currently undefined. +. +.TP +.BI .special\ s1\ s2\|.\|.\|. +Fonts +.IR s1 , +.IR s2 , +are special and will be searched for characters not in the current +font. +. +.TP +.BI .sty\ n\ f +Associate style\~\c +.I f +with font position\~\c +.IR n . +A font position can be associated either with a font or with a style. +The current font is the index of a font position and so is also either a +font or a style. +When it is a style, the font that is actually used is the font the name of +which is the concatenation of the name of the current family and the name of +the current style. +For example, if the current font is\~1 and font position\~1 is associated +with style +.B R +and the current font family is\~\c +.BR T , +then font +.BR TR +will be used. +If the current font is not a style, then the current family is ignored. +When the requests +.BR cs , +.BR bd , +.BR tkf , +.BR uf , +or +.B fspecial +are applied to a style, then they will instead be applied to the member of +the current family corresponding to that style. +The default family can be set with the +.B \-f +option. +The styles command in the +.SM DESC +file controls which font positions (if any) are initially associated +with styles rather than fonts. +. +.TP +.BI .substring\ xx\ n1\ [ n2 ] +Replace the string in register +.I xx +with the substring defined by the indices +.I n1 +and +.IR n2 . +The first character in the string has index one. +If +.I n2 +is omitted, it is taken to be equal to the string's length. +If the index value +.I n1 +or +.I n2 +is negative or zero, it will be counted from the end of the string, going +backwards: +The last character has index\~0, the character before the last character has +index\~-1, etc. +. +.TP +.BI .tkf\ f\ s1\ n1\ s2\ n2 +Enable track kerning for font +.IR f . +When the current font is +.I f +the width of every character will be increased by an amount between +.I n1 +and +.IR n2 ; +when the current point size is less than or equal to +.I s1 +the width will be increased by +.IR n1 ; +when it is greater than or equal to +.I s2 +the width will be increased by +.IR n2 ; +when the point size is greater than or equal to +.I s1 +and less than or equal to +.I s2 +the increase in width is a linear function of the point size. +. +.TP +.BI .tm1\ string +Similar to the +.B tm +request, +.I string +is read in copy mode and written on the standard error, but an initial +double quote in +.I string +is stripped off to allow initial blanks. +. +.TP +.BI .tmc\ string +Similar to +.BR tm1 +but without writing a final newline. +. +.TP +.BI .trf\ filename +Transparently output the contents of file +.IR filename . +Each line is output as it would be preceded by +.BR \e! ; +however, the lines are not subject to copy-mode interpretation. +If the file does not end with a newline, then a newline will be added. +For example, you can define a macro\~\c +.I x +containing the contents of file\~\c +.IR f , +using +. +.RS +.IP +.NE 2v+\n(.Vu +.ft B +.nf +\&.di x +\&.trf f +\&.di +.fi +.RE +. +.IP +Unlike with the +.B cf +request, the file cannot contain characters such as +.SM NUL +that are not legal troff input characters. +. +.TP +.B .trnt abcd +This is the same as the +.B tr +request except that the translations do not apply to text that is +transparently throughput into a diversion with +.BR \e! . +For example, +. +.RS +.IP +.nf +.ft B +\&.tr ab +\&.di x +\e!.tm a +\&.di +\&.x +.fi +.ft +.RE +. +.IP +will print\~\c +.BR b ; +if +.B trnt +is used instead of +.B tr +it will print\~\c +.BR a . +. +.TP +.B .troff +Make the +.B n +built-in condition false, and the +.B t +built-in condition true. +This undoes the effect of the +.B nroff +request. +. +.TP +.BI .unformat\ xx +This request `unformats' the diversion +.IR xx . +Contrary to the +.B .asciify +request, which tries to convert formatted elements of the diversion back to +input tokens as much as possible, +.B .unformat +will only handle tabs and spaces between words (usually caused by spaces or +newlines in the input) specially. +The former are treated as if they were input tokens, and the latter are +stretchable again. +Note that the vertical size of lines is not preserved. +Glyph information (font, font size, space width, etc.) is retained. +Useful in conjunction with the +.B .box +and +.B .boxa +requests. +. +.TP +.BI .vpt\ n +Enable vertical position traps if +.I n +is non-zero, disable them otherwise. +Vertical position traps are traps set by the +.B wh +or +.B dt +requests. +Traps set by the +.B it +request are not vertical position traps. +The parameter that controls whether vertical position traps are enabled is +global. +Initially vertical position traps are enabled. +. +.TP +.BI .warn\ n +Control warnings. +.I n +is the sum of the numbers associated with each warning that is to be +enabled; all other warnings will be disabled. +The number associated with each warning is listed in the `Warnings' section. +For example, +.B .warn\~0 +will disable all warnings, and +.B .warn\~1 +will disable all warnings except that about missing characters. +If +.I n +is not given, all warnings will be enabled. +. +.TP +.BI .while \ c\ anything +While condition\~\c +.I c +is true, accept +.I anything +as input; +.IR c \~\c +can be any condition acceptable to an +.B if +request; +.I anything +can comprise multiple lines if the first line starts with +.B \e{ +and the last line ends with +.BR \e} . +See also the +.B break +and +.B continue +requests. +. +.TP +.BI .write\ stream\ anything +Write +.I anything +to the stream named +.IR stream . +.I stream +must previously have been the subject of an +.B open +request. +.I anything +is read in copy mode; +a leading\~\c +.B \(dq +will be stripped. +. +.TP +.BI .writem\ stream\ xx +Write the contents of the macro or string +.I xx +to the stream named +.IR stream . +.I stream +must previously have been the subject of an +.B open +request. +.I xx +is read in copy mode. +. +. +.\" -------------------------------------------------------------------- +.SS Extended requests +.\" -------------------------------------------------------------------- +. +.TP +.BI .cf\ filename +When used in a diversion, this will embed in the diversion an object which, +when reread, will cause the contents of +.I filename +to be transparently copied through to the output. +. +In UNIX troff, the contents of +.I filename +is immediately copied through to the output regardless of whether there is a +current diversion; this behaviour is so anomalous that it must be considered +a bug. +. +.TP +.BI .ev\ xx +If +.I xx +is not a number, this will switch to a named environment called +.IR xx . +The environment should be popped with a matching +.B ev +request without any arguments, just as for numbered environments. +There is no limit on the number of named environments; they will be created +the first time that they are referenced. +. +.TP +.BI .fp\ n\ f1\ f2 +The +.B fp +request has an optional third argument. +This argument gives the external name of the font, which is used for finding +the font description file. +The second argument gives the internal name of the font which is used to +refer to the font in troff after it has been mounted. +If there is no third argument then the internal name will be used as the +external name. +This feature allows you to use fonts with long names in compatibility mode. +. +.TP +.BI .ss\ m\ n +When two arguments are given to the +.B ss +request, the second argument gives the +.IR "sentence space size" . +If the second argument is not given, the sentence space size will be the +same as the word space size. +Like the word space size, the sentence space is in units of one twelfth of +the spacewidth parameter for the current font. +Initially both the word space size and the sentence space size are\~12. +Contrary to UNIX troff, GNU troff handles this request in nroff mode also; a +given value is then rounded down to the nearest multiple of\~12. +The sentence space size is used in two circumstances: +If the end of a sentence occurs at the end of a line in fill mode, then both +an inter-word space and a sentence space will be added; if two spaces follow +the end of a sentence in the middle of a line, then the second space will be +a sentence space. +Note that the behaviour of UNIX troff will be exactly that exhibited by GNU +troff if a second argument is never given to the +.B ss +request. +In GNU troff, as in UNIX troff, you should always follow a sentence with +either a newline or two spaces. +. +.TP +.BI .ta\ n1\ n2\|.\|.\|.nn \ T\ r1\ r2\|.\|.\|.\|rn +Set tabs at positions +.IR n1 , +.IR n2 ,\|.\|.\|.\|, +.I nn +and then set tabs at +.IR nn + r1 , +.IR nn + r2 ,\|.\|.\|.\|.\|, +.IR nn + rn +and then at +.IR nn + rn + r1 , +.IR nn + rn + r2 ,\|.\|.\|.\|, +.IR nn + rn + rn , +and so on. +For example, +. +.RS +.IP +.B +\&.ta T .5i +.P +will set tabs every half an inch. +.RE +. +. +.\" -------------------------------------------------------------------- +.SS New number registers +.\" -------------------------------------------------------------------- +. +The following read-only registers are available: +. +.TP +.B \en[.C] +1\~if compatibility mode is in effect, 0\~otherwise. +. +.TP +.B \en[.cdp] +The depth of the last character added to the current environment. +It is positive if the character extends below the baseline. +. +.TP +.B \en[.ce] +The number of lines remaining to be centered, as set by the +.B ce +request. +. +.TP +.B \en[.cht] +The height of the last character added to the current environment. +It is positive if the character extends above the baseline. +. +.TP +.B \en[.csk] +The skew of the last character added to the current environment. +The +.I 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. +. +.TP +.B \en[.ev] +The name or number of the current environment. +This is a string-valued register. +. +.TP +.B \en[.fam] +The current font family. +This is a string-valued register. +. +.TP +.B \en[.fp] +The number of the next free font position. +. +.TP +.B \en[.g] +Always\~1. +Macros should use this to determine whether they are running under GNU +troff. +. +.TP +.B \en[.hla] +The current hyphenation language as set by the +.B hla +request. +. +.TP +.B \en[.hlc] +The number of immediately preceding consecutive hyphenated lines. +. +.TP +.B \en[.hlm] +The maximum allowed number of consecutive hyphenated lines, as set by the +.B hlm +request. +. +.TP +.B \en[.hy] +The current hyphenation flags (as set by the +.B hy +request). +. +.TP +.B \en[.hym] +The current hyphenation margin (as set by the +.B hym +request). +. +.TP +.B \en[.hys] +The current hyphenation space (as set by the +.B hys +request). +. +.TP +.B \en[.in] +The indent that applies to the current output line. +. +.TP +.B \en[.int] +Set to a positive value if last output line is interrupted (i.e., if +it contains +.IR \ec ). +. +.TP +.B \en[.kern] +1\~if pairwise kerning is enabled, 0\~otherwise. +. +.TP +.B \en[.lg] +The current ligature mode (as set by the +.B lg +request). +. +.TP +.B \en[.linetabs] +The current line-tabs mode (as set by the +.B linetabs +request). +. +.TP +.B \en[.ll] +The line length that applies to the current output line. +. +.TP +.B \en[.lt] +The title length as set by the +.B lt +request. +. +.TP +.B \en[.ne] +The amount of space that was needed in the last +.B ne +request that caused a trap to be sprung. +Useful in conjunction with the +.B \en[.trunc] +register. +. +.TP +.B \en[.ns] +1\~if no-space mode is active, 0\~otherwise. +. +.TP +.B \en[.pn] +The number of the next page, either the value set by a +.B pn +request, or the number of the current page plus\~1. +. +.TP +.B \en[.ps] +The current pointsize in scaled points. +. +.TP +.B \en[.psr] +The last-requested pointsize in scaled points. +. +.TP +.B \en[.rj] +The number of lines to be right-justified as set by the +.B rj +request. +. +.TP +.B \en[.sr] +The last requested pointsize in points as a decimal fraction. +This is a string-valued register. +. +.TP +.B \en[.tabs] +A string representation of the current tab settings suitable for use as an +argument to the +.B ta +request. +. +.TP +.B \en[.trunc] +The amount of vertical space truncated by the most recently sprung vertical +position trap, or, if the trap was sprung by a +.B ne +request, minus the amount of vertical motion produced by the +.B ne +request. +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 +.B \en[.ne] +register. +. +.TP +.B \en[.ss] +.TQ +.B \en[.sss] +These give the values of the parameters set by the first and second +arguments of the +.B ss +request. +. +.TP +.B \en[.vpt] +1\~if vertical position traps are enabled, 0\~otherwise. +. +.TP +.B \en[.warn] +The sum of the numbers associated with each of the currently enabled +warnings. +The number associated with each warning is listed in the `Warnings' +subsection. +. +.TP +.B \en[.x] +The major version number. +For example, if the version number is 1.03, then +.B \en[.x] +will contain\~1. +. +.TP +.B \en[.y] +The minor version number. +For example, if the version number is 1.03, then +.B \en[.y] +will contain\~03. +. +.TP +.B \en[.Y] +The revision number of groff. +. +.TP +.B \en[llx] +.TQ +.B \en[lly] +.TQ +.B \en[urx] +.TQ +.B \en[ury] +These four registers are set by the +.B \&.psbb +request and contain the bounding box values (in PostScript units) of a given +PostScript image. +. +.P +The following read/write registers are set by the +.B \ew +escape sequence: +. +.TP +.B \en[rst] +.TQ +.B \en[rsb] +Like the +.B st +and +.B sb +registers, but take account of the heights and depths of characters. +. +.TP +.B \en[ssc] +The amount of horizontal space (possibly negative) that should be added to +the last character before a subscript. +. +.TP +.B \en[skw] +How far to right of the center of the last character in the +.B \ew +argument, the center of an accent from a roman font should be placed +over that character. +. +.P +Other available read/write number registers are: +. +.TP +.B \en[c.] +The current input line number. +.B \en[.c] +is a read-only alias to this register. +. +.TP +.B \en[hp] +The current horizontal position at input line. +. +.TP +.B \en[systat] +The return value of the system() function executed by the last +.B sy +request. +. +.TP +.B \en[slimit] +If greater than\~0, the maximum number of objects on the input stack. +If less than or equal to\~0, there is no limit on the number of objects on +the input stack. +With no limit, recursion can continue until virtual memory is exhausted. +. +.TP +.B \en[year] +The current year. +. +Note that the traditional +.B troff +number register +.B \en[yr] +is the current year minus 1900. +. +. +.\" -------------------------------------------------------------------- +.SS Miscellaneous +.\" -------------------------------------------------------------------- +. +.B @g@troff +predefines a single (read/write) string-based register, +.BR \e*(.T , +which contains the argument given to the +.B -T +command line option, namely the current output device (for example, +.I latin1 +or +.IR ascii ). +Note that this is not the same as the (read-only) number register +.B \en[.T] +which is defined to be\~1 if +.B troff +is called with the +.B -T +command line option, and zero otherwise. +This behaviour is different to UNIX troff. +. +.P +Fonts not listed in the +.SM DESC +file are automatically mounted on the next available font position when they +are referenced. +If a font is to be mounted explicitly with the +.B fp +request on an unused font position, it should be mounted on the first unused +font position, which can be found in the +.B \en[.fp] +register; although +.B troff +does not enforce this strictly, it will not allow a font to be mounted at a +position whose number is much greater than that of any currently used +position. +. +.P +Interpolating a string does not hide existing macro arguments. +Thus in a macro, a more efficient way of doing +. +.IP +.BI . xx\ \e\e$@ +.P +is +. +.IP +.BI \e\e*[ xx ]\e\e +. +.P +If the font description file contains pairwise kerning information, +characters from that font will be kerned. +Kerning between two characters can be inhibited by placing a +.B \e& +between them. +. +.P +In a string comparison in a condition, characters that appear at different +input levels to the first delimiter character will not be recognised as the +second or third delimiters. +This applies also to the +.B tl +request. +In a +.B \ew +escape sequence, a character that appears at a different input level to the +starting delimiter character will not be recognised as the closing delimiter +character. +When decoding a macro argument that is delimited by double quotes, a +character that appears at a different input level to the starting delimiter +character will not be recognised as the closing delimiter character. +The implementation of +.B \e$@ +ensures that the double quotes surrounding an argument will appear the same +input level, which will be different to the input level of the argument +itself. +In a long escape name +.B ] +will not be recognized as a closing delimiter except when it occurs at the +same input level as the opening +.BR ] . +In compatibility mode, no attention is paid to the input-level. +. +.P +There are some new types of condition: +. +.TP +.BI .if\ r xxx +True if there is a number register named +.IR xxx . +. +.TP +.BI .if\ d xxx +True if there is a string, macro, diversion, or request named +.IR xxx . +. +.TP +.BI .if\ m xxx +True if there is a color named +.IR xxx . +. +.TP +.BI .if\ c ch +True if there is a character +.IR ch +available; +.I ch +is either an +.SM ASCII +character or a special character +.BI \e( xx +or +.BI \e[ xxx ]\fR; +the condition will also be true if +.I ch +has been defined by the +.B char +request. +. +.P +The +.B tr +request can now map characters onto +.BR \e~ . +. +. +.\" -------------------------------------------------------------------- +.SH Incompatibilities +.\" -------------------------------------------------------------------- +. +Long names cause some incompatibilities. +. +UNIX troff will interpret +. +.IP +.B +\&.dsabcd +. +.P +as defining a string +.B ab +with contents +.BR cd . +Normally, GNU troff will interpret this as a call of a macro named +.BR dsabcd . +Also UNIX troff will interpret +.B \e*[ +or +.B \en[ +as references to a string or number register called +.BR [ . +In GNU troff, however, this will normally be interpreted as the start of a +long name. +In +.I compatibility mode +GNU troff will interpret these things in the traditional way. +In compatibility mode, however, long names are not recognised. +Compatibility mode can be turned on with the +.B \-C +command line option, and turned on or off with the +.B cp +request. +The number register +.B \en[.C] +is\~1 if compatibility mode is on, 0\~otherwise. +. +.P +GNU troff does not allow the use of the escape sequences +.BR \e\e\e|\e^\e&\e}\e{\e (space) \e'\e`\e-\e_\e!\e%\ec +in names of strings, macros, diversions, number registers, fonts or +environments; UNIX troff does. +The +.B \eA +escape sequence may be helpful in avoiding use of these escape sequences in +names. +. +.P +Fractional pointsizes cause one noteworthy incompatibility. +In UNIX troff the +.B ps +request ignores scale indicators and so +. +.IP +.B .ps\ 10u +. +.P +will set the pointsize to 10 points, whereas in GNU troff it will set the +pointsize to 10 scaled points. +. +.P +In GNU troff there is a fundamental difference between unformatted, input +characters, and formatted, output characters. +Everything that affects how an output character will be output is stored +with the character; once an output character has been constructed it is +unaffected by any subsequent requests that are executed, including +.BR bd , +.BR cs , +.BR tkf , +.BR tr , +or +.B fp +requests. +Normally output characters are constructed from input characters at the +moment immediately before the character is added to the current output line. +Macros, diversions and strings are all, in fact, the same type of object; +they contain lists of input characters and output characters in any +combination. +An output character does not behave like an input character for the purposes +of macro processing; it does not inherit any of the special properties that +the input character from which it was constructed might have had. +For example, +. +.IP +.NE 4v+\n(.Vu +.ft B +.nf +\&.di x +\e\e\e\e +\&.br +\&.di +\&.x +.ft +.fi +. +.P +will print +.B \e\e +in GNU troff; each pair of input +.BR \e s +is turned into one output +.B \e +and the resulting output +.BR \e s +are not interpreted as escape characters when they are reread. +UNIX troff would interpret them as escape characters when they were reread +and would end up printing one +.BR \e . +The correct way to obtain a printable +.B \e +is to use the +.B \ee +escape sequence: this will always print a single instance of the current +escape character, regardless of whether or not it is used in a diversion; it +will also work in both GNU troff and UNIX troff. +If you wish for some reason to store in a diversion an escape sequence that +will be interpreted when the diversion is reread, you can either use the +traditional +.B \e!\& +transparent output facility, or, if this is unsuitable, the new +.B \e?\& +escape sequence. +. +. +.\" -------------------------------------------------------------------- +.SH AUTHOR +.\" -------------------------------------------------------------------- +. +Copyright (C) 1989, 2001 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 "GNU copyleft site" http://www.gnu.org/copyleft/fdl.html . +. +This document was written by James Clark, with modifications by +.URL "Werner Lemberg" mailto:wl@gnu.org +and +.URL "Bernd Warken" mailto:bwarken@mayn.de +. +.P +This document is part of +.IR groff , +the GNU roff distribution. +Formerly, the informations of this document were kept in the manual page +.BR troff (@MAN1EXT@). +Only the parts dealing with the language aspects of the different +.I roff +systems were carried over into this document. +The +.I troff +command line options and warnings are still available in +.BR @g@troff (@MAN1EXT@). +. +. +.\" -------------------------------------------------------------------- +.SH "SEE ALSO" +.\" -------------------------------------------------------------------- +. +.TP +.BR roff (@MAN7EXT@) +An overview over +.I groff +and other +.I roff +systems, including pointers to further related documentation. +. +.TP +.BR groff (@MAN7EXT@) +A description of the +.I groff +language, including a short, but complete reference of all predefined +requests, registers, and escapes of plain +.IR groff . +From the command line, this is called by +.BR man\~7\~groff . +. +.P +The +.I groff info +.IR file , +cf. +.BR info (@MAN1EXT@), +presents all groff documentation within a single document. +. +.P +The classical +.I troff +documentation is available on-line at +.URL "Bell Labs CSTR site" http://cm.bell-labs.com/cm/cs/cstr.html . +This includes as +.I CSTR #54 +the +.I Nroff/Troff User's Manual +by +.I J. F. Osanna +of 1976 in the revision of +.I Brian Kernighan +of 1992, being the +.URL "classical troff documentation" \ +http://cm.bell-labs.com/cm/cs/cstr/54.ps.gz . +. +. +.\" -------------------------------------------------------------------- +.\" Emacs variables +.\" -------------------------------------------------------------------- +. +.\" Local Variables: +.\" mode: nroff +.\" End: |