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GROFF(7) GROFF(7)
NAME
groff - a short reference for the GNU roff language
DESCRIPTION
The name groff stands for GNU roff and is the free implementation of the roff type-setting system.
See roff(7) for a survey and the background of the groff system.
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.
Historically, the roff language was called troff. groff is compatible with the classical system and
provides proper extensions. So in GNU, the terms roff, troff, and groff language could be used as
synonyms. However troff slightly tends to refer more to the classical aspects, whereas groff empha-sizes emphasizes
sizes the GNU extensions, and roff is the general term for the language.
This file is only a short version of the complete documentation that is found in the groff info(1)
file, which contains more detailed, actual, and concise information.
The general syntax for writing groff documents is relatively easy, but writing extensions to the roff
language can be a bit harder.
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 "." or a single quote "'"; all
other lines are text lines.
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,
.command_name arg1 arg2
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.
Text lines represent the parts that will be printed. They can be modified by escape sequences, which
are recognized by a leading backslash `\'. These are in-line or even in-word formatting elements or
functions. Some of these take arguments separated by single quotes "'", others are regulated by a
length encoding introduced by an open parenthesis `(' or enclosed in brackets `[' and `]'.
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 copy
mode.
The copy mode behavior can be quite tricky, but there are some rules that ensure a safe usage.
1. Printable backslashes must be denoted as \e. To be more precise, \e represents the current
escape character. To get a backslash glyph, use \(rs or \[rs].
2. Double all backslashes.
3. Begin all text lines with the special non-spacing character \&.
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 groff_tmac(5).
Reading roff source files is easier, just reduce all double backslashes to a single one in all macro
definitions.
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.
There are two kinds of roff commands, possibly with arguments. Requests are written on a line of
their own starting with a dot `.' or a "'", whereas Escape sequences are in-line functions and in-word inword
word formatting elements starting with a backslash `\'.
The user can define her own formatting commands using the de request. These commands are called
macros, but they are used exactly like requests. Macro packages are pre-defined sets of macros writ-ten written
ten in the groff language. A user's possibilities to create escape sequences herself is very lim-ited, limited,
ited, only special characters can be mapped.
The groff language provides several kinds of variables with different interfaces. There are pre-defined predefined
defined variables, but the user can define her own variables as well.
String variables store character sequences. They are set with the ds request and retrieved by the \*
escape sequences. Strings can have variables.
Register variables can store numerical values, numbers with a scale unit, and occasionally string-like stringlike
like objects. They are set with the nr request and retrieved by the \n escape sequences.
Environments allow the user to temporarily store global formatting parameters like line length, font
size, etc. for later reuse. This is done by the ev request.
Fonts are identified either by a name or by an internal number. The current font is chosen by the ft
request or by the \f escape sequences. Each device has special fonts, but the following fonts are
available for all devices. R is the standard font Roman. B is its bold counterpart. The italic
font is called I and is available everywhere, 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,
CR, CI, and CB. On text devices, all characters have a constant width anyway.
Moreover, there are some advanced roff elements. A diversion stores information into a macro for
later usage. A 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.
More detailed information and examples can be found in the groff info file.
CONTROL CHARACTERS
There is a small set of characters that have a special controlling task in certain conditions.
. A dot is only special at the beginning of a line or after the condition in the requests if,
ie, el, and while. There it is the control character that introduces a request (or macro).
The special behavior can be delayed by using the \. escape. By using the cc request, the
control character can be set to a different character, making the dot `.' a non-special char-acter. character.
acter.
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.
' 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 c2 request, the non-break control character can be set to a different character.
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 posi-tions, positions,
tions, it denotes the single quote or apostrophe character. Groff provides a printable repre-sentation representation
sentation with the \(cq escape sequence.
" The double quote is used to enclose arguments in requests, macros, and strings. In the ds and
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 \" introduces a comment. Otherwise, it is not special. Groff provides a printable rep-resentation representation
resentation with the \(dq escape sequence.
\ The backslash usually introduces an escape sequence (this can be changed with the ec request).
A printed version of the escape character is the \e escape; a backslash glyph can be obtained
by \(rs.
( 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
[] construct.
[ 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.
] 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.
space Space characters are only functional characters. They separate the arguments in requests,
macros, and strings, and the words in text lines. They are subject to groff's horizontal
spacing calculations. To get a defined space width, escape sequences like `\ ' (this is the
escape character followed by a space), \|, \^, or \h should be used.
newline
In text paragraphs, newlines mostly behave like space characters. Continuation lines can be
specified by an escaped newline, i.e., by specifying a backslash `\' as the last character of
a line.
tab If a tab character occurs during text the interpreter makes a horizontal jump to the next pre-defined predefined
defined tab position. There is a sophisticated interface for handling tab positions.
NUMERICAL EXPRESSIONS
A numerical value is a signed or unsigned integer or float with or without an appended scaling indi-cator. indicator.
cator. A scaling indicator is a one-character abbreviation for a unit of measurement. A number fol-lowed followed
lowed by a scaling indicator signifies a size value. By default, numerical values do not have a
scaling indicator, i.e., they are normal numbers.
The roff language defines the following scaling indicators.
c Centimeter
i Inch
P Pica = 1/6 inch
p Point = 1/72 inch
m Em = the font size in points (width of letter `m')
M 100th of an Em
n En = Em/2
u Basic unit for actual output device
v Vertical line space in basic units scaled point = 1/sizescale of a point (defined in
font DESC file)
f Scale by 65536.
Numerical expressions are combinations of the numerical values defined above with the following
arithmetical operators already defined in classical troff.
+ Addition
- Subtraction
* Multiplication
/ Division
% Modulo
= Equals
== Equals
< Less than
> Greater than
<= Less or equal
>= Greater or equal
& Logical and
: Logical or
! Logical not
( Grouping of expressions
) Close current grouping
Moreover, groff added the following operators for numerical expressions:
e1>?e2 The maximum of e1 and e2.
e1<?e2 The minimum of e1 and e2.
(c;e) Evaluate e using c as the default scaling indicator.
For details see the groff info file.
CONDITIONS
Conditions occur in tests raised by the if, ie, and the while requests. The following table charac-
terizes the different types of conditions.
N A numerical expression N yields true if its value is greater than 0.
!N True if the value of I is 0.
's1's2' True if string s1 is identical to string s2.
!'s1's2' True if string s1 is not identical to string s2.
cch True if there is a character ch available.
dname True if there is a string, macro, diversion, or request called name.
e Current page number is even.
o Current page number is odd.
mname True if there is a color called name.
n Formatter is nroff.
rreg True if there is a register named reg.
t Formatter is troff.
Ffont True if there exists a font named font.
Sstyle True if a style named style has been registered.
REQUESTS
This section provides a short reference for the predefined requests. In groff, request and macro
names can be arbitrarily long. No bracketing or marking of long names is needed.
Most requests take one or more arguments. The arguments are separated by space characters (no
tabs!); there is no inherent limit for their length or number. An argument can be enclosed by a pair
of double quotes. This is very handy if an argument contains space characters, e.g., "arg with
space" denotes a single argument.
Some requests have optional arguments with a different behaviour. Not all of these details are out-lined outlined
lined here. Refer to the groff info file and groff_diff(7) for all details.
In the following request specifications, most argument names were chosen to be descriptive. Only the
following denotations need clarification.
c denotes a single character.
font a font either specified as a font name or a font number.
anything all characters up to the end of the line or within \{ and \}.
n is a numerical expression that evaluates to an integer value.
N is an arbitrary numerical expression, signed or unsigned.
+-N has three meanings depending on its sign, described below.
If an expression defined as +-N starts with a `+' sign the resulting value of the expression will be
added to an already existing value inherent to the related request, e.g. adding to a number register.
If the expression starts with a `-' the value of the expression will be subtracted from the request
value.
Without a sign, N replaces the existing value directly. To assign a negative number either prepend 0
or enclose the negative number in parentheses.
Request Short Reference
. Empty line, ignored. Useful for structuring documents.
.\" anything
Complete line is a comment.
.ab string
Print string on standard error, exit program.
.ad Begin line adjustment for output lines in current adjust mode.
.ad c Start line adjustment in mode c (c=l,r,b,n).
.af register c
Assign format c to register (c=l,i,I,a,A).
.aln alias register
Create alias name for register.
.als alias object
Create alias name for request, string, macro, or diversion object.
.am macro Append to macro until .. is encountered.
.am macro end
Append to macro until .end is called.
.am1 macro
Same as .am but with compatibility mode switched off during macro expansion.
.am1 macro end
Same as .am but with compatibility mode switched off during macro expansion.
.ami macro
Append to a macro whose name is contained in the string register macro until .. is encoun-tered. encountered.
tered.
.ami macro end
Append to a macro indirectly. macro and end are string registers whose contents are inter-polated interpolated
polated for the macro name and the end macro, respectively.
.ami1 macro
Same as .ami but with compatibility mode switched off during macro expansion.
.ami1 macro end
Same as .ami but with compatibility mode switched off during macro expansion.
.as stringvar anything
Append anything to stringvar.
.as1 stringvar anything
Same as .as but with compatibility mode switched off during string expansion.
.asciify diversion
Unformat ASCII characters, spaces, and some escape sequences in diversion.
.backtrace
Print a backtrace of the input on stderr.
.bd font N
Embolden font by N-1 units.
.bd S font N
Embolden Special Font S when current font is font.
.blm Unset the blank line macro.
.blm macro
Set the blank line macro to macro.
.box End current diversion.
.box macro
Divert to macro, omitting a partially filled line.
.boxa End current diversion.
.boxa macro
Divert and append to macro, omitting a partially filled line.
.bp Eject current page and begin new page.
.bp +-N Eject current page; next page number +-N.
.br Line break.
.brp Break and spread output line. Same as \p.
.break Break out of a while loop.
.c2 Reset no-break control character to "'".
.c2 c Set no-break control character to c.
.cc Reset control character to `.'.
.cc c Set control character to c.
.ce Center the next input line.
.ce N Center following N input lines.
.cf filename
Copy contents of file filename unprocessed to stdout or to the diversion.
.cflags mode c1 c2 ...
Treat characters c1, c2, ... according to mode number.
.ch trap N
Change trap location to N .
.char c anything
Define character c as string anything.
.chop object
Chop the last character off macro, string, or diversion object.
.close stream
Close the stream.
.color Enable colors.
.color N If N is zero disable colors, otherwise enable them.
.composite from to
Map glyph name from to glyph name to while constructing a composite glyph name.
.continue Finish the current iteration of a while loop.
.cp Enable compatibility mode.
.cp N If N is zero disable compatibility mode, otherwise enable it.
.cs font N M
Set constant character width mode for font to N/36 ems with em M.
.cu N Continuous underline in nroff, like .ul in troff.
.da End current diversion.
.da macro Divert and append to macro.
.de macro Define or redefine macro until .. is encountered.
.de macro end
Define or redefine macro until .end is called.
.de1 macro
Same as .de but with compatibility mode switched off during macro expansion.
.de1 macro end
Same as .de but with compatibility mode switched off during macro expansion.
.defcolor color scheme component
Define or redefine a color with name color. scheme can be rgb, cym, cymk, gray, or grey.
component can be single components specified as fractions in the range 0 to 1 (default
scaling indicator f), as a string of two-digit hexadecimal color components with a leading
#, or as a string of four-digit hexadecimal components with two leading #. The color
default can't be redefined.
.dei macro
Define or redefine a macro whose name is contained in the string register macro until .. is
encountered.
.dei macro end
Define or redefine a macro indirectly. macro and end are string registers whose contents
are interpolated for the macro name and the end macro, respectively.
.dei1 macro
Same as .dei but with compatibility mode switched off during macro expansion.
.dei1 macro end
Same as .dei but with compatibility mode switched off during macro expansion.
.di End current diversion.
.di macro Divert to macro .
.do name Interpret .name with compatibility mode disabled.
.ds stringvar anything
Set stringvar to anything.
.ds1 stringvar anything
Same as .ds but with compatibility mode switched off during string expansion.
.dt N trap
Set diversion trap to position N (default scaling indicator v).
.ec Reset escape character to `\'.
.ec c Set escape character to c.
.ecr Restore escape character saved with .ecs.
.ecs Save current escape character.
.el anything
Else part for if-else (ie) request.
.em macro The macro will be run after the end of input.
.eo Turn off escape character mechanism.
.ev Switch to previous environment.
.ev env Push down environment number or name env and switch to it.
.evc env Copy the contents of environment env to the current environment. No pushing or popping.
.ex Exit from roff processing.
.fam Return to previous font family.
.fam name Set the current font family to name.
.fc Disable field mechanism.
.fc a Set field delimiter to a and pad character to space.
.fc a b Set field delimiter to a and pad character to b.
.fchar c anything
Define fallback character c as string anything.
.fcolor Set fill color to previous fill color.
.fcolor c Set fill color to c.
.fi Fill output lines.
.fl Flush output buffer.
.fp n font
Mount font on position n.
.fp n internal external
Mount font with long external name to short internal name on position n.
.fschar f c anything
Define fallback character c for font f as string anything.
.fspecial font
Reset list of special fonts for font to be empty.
.fspecial font s1 s2 ...
When the current font is font, then the fonts s1, s2, ... will be special.
.ft Return to previous font. Same as \f[] or \fP.
.ft font Change to font name or number font; same as \f[font] escape sequence.
.ftr font1 font2
Translate font1 to font2.
.gcolor Set glyph color to previous glyph color.
.gcolor c Set glyph color to c.
.hc Remove additional hyphenation indicator character.
.hc c Set up additional hyphenation indicator character c.
.hcode c1 code1 c2 code2 ...
Set the hyphenation code of character c1 to code1, that of c2 to code2, etc.
.hla lang Set the current hyphenation language to lang.
.hlm n Set the maximum number of consecutive hyphenated lines to n.
.hpf file Read hyphenation patterns from file.
.hpfa file
Append hyphenation patterns from file.
.hpfcode file
Set input mapping for .hpf.
.hw words List of words with exceptional hyphenation.
.hy N Switch to hyphenation mode N.
.hym n Set the hyphenation margin to n (default scaling indicator m).
.hys n Set the hyphenation space to n.
.ie cond anything
If cond then anything else goto .el.
.if cond anything
If cond then anything; otherwise do nothing.
.ig Ignore text until .. is encountered.
.ig end Ignore text until .end.
.in Change to previous indent value.
.in +-N Change indent according to +-N (default scaling indicator m).
.it N trap
Set an input-line count trap for the next N lines.
.itc N trap
Same as .it but count lines interrupted with \c as one line.
.kern Enable pairwise kerning.
.kern n If n is zero, disable pairwise kerning, otherwise enable it.
.lc Remove leader repetition character.
.lc c Set leader repetition character to c.
.length register anything
Write the length of the string anything in register.
.linetabs Enable line-tabs mode (i.e., calculate tab positions relative to output line).
.linetabs n
If n is zero, disable line-tabs mode, otherwise enable it.
.lf N Set input line number to N.
.lf N file
Set input line number to N and filename to file.
.lg N Ligature mode on if N>0.
.ll Change to previous line length.
.ll +-N Set line length according to +-N (default size 6.5i, default scaling indicator m).
.ls Change to the previous value of additional intra-line skip.
.ls N Set additional intra-line skip value to N, i.e., N-1 blank lines are inserted after each
text output line.
.lt +-N Length of title (default scaling indicator m).
.mc Margin character off.
.mc c Print character c after each text line at actual distance from right margin.
.mc c N Set margin character to c and distance to N from right margin (default scaling indica-tor indicator
tor m).
.mk register
Mark current vertical position in register.
.mso file The same as the .so request except that file is searched in the tmac directories.
.na No output-line adjusting.
.ne Need a one-line vertical space.
.ne N Need N vertical space (default scaling indicator v).
.nf No filling or adjusting of output-lines.
.nh No hyphenation.
.nm Number mode off.
.nm +-N [M [S [I]]]
In line number mode, set number, multiple, spacing, and indent.
.nn Do not number next line.
.nn N Do not number next N lines.
.nop anything
Always execute anything.
.nr register +-N M
Define or modify register using +-N with auto-increment M.
.nroff Make the built-in condition n true and t false.
.ns Turn no-space mode on.
.nx Immediately jump to end of current file.
.nx filename
Next file.
.open stream filename
Open register filename for writing and associate the stream named register stream with it.
.opena stream filename
Like .open but append to it.
.os Output vertical distance that was saved by the sv request.
.output string
Emit string directly to intermediate output, allowing leading whitespace if string starts
with " (which will be stripped off).
.pc Reset page number character to `%'.
.pc c Page number character.
.pi program
Pipe output to program (nroff only).
.pl Set page length to default 11i. The current page length is stored in register .p.
.pl +-N Change page length to +-N (default scaling indicator v).
.pm Print macro names and sizes (number of blocks of 128 bytes).
.pm t Print only total of sizes of macros (number of 128 bytes blocks).
.pn +-N Next page number N.
.pnr Print the names and contents of all currently defined number registers on stderr.
.po Change to previous page offset. The current page offset is available in register .o.
.po +-N Page offset N.
.ps Return to previous point-size.
.ps +-N Point size; same as \s[+-N].
.psbb filename
Get the bounding box of a PostScript image filename.
.pso command
This behaves like the so request except that input comes from the standard output of com-mand. command.
mand.
.ptr Print the names and positions of all traps (not including input line traps and diversion
traps) on stderr.
.pvs Change to previous post-vertical line spacing.
.pvs +-N Change post-vertical line spacing according to +-N (default scaling indicator p).
.rchar c1 c2 ...
Remove the definitions of characters c1, c2, ...
.rd prompt
Read insertion.
.return Return from a macro.
.return anything
Return twice, namely from the macro at the current level and from the macro one level
higher.
.rfschar f c1 c2 ...
Remove the definitions of characters c1, c2, ... for font f.
.rj n Right justify the next n input lines.
.rm name Remove request, macro, or string name.
.rn old new
Rename request, macro, or string old to new.
.rnn reg1 reg2
Rename register reg1 to reg2.
.rr register
Remove register.
.rs Restore spacing; turn no-space mode off.
.rt +-N Return (upward only) to marked vertical place (default scaling indicator v).
.schar c anything
Define global fallback character c as string anything.
.shc Reset soft hyphen character to \(hy.
.shc c Set the soft hyphen character to c.
.shift n In a macro, shift the arguments by n positions.
.sizes s1 s2 ... sn [0]
Set available font sizes similar to the sizes command in a DESC file.
.so filename
Include source file.
.sp Skip one line vertically.
.sp N Space vertical distance N up or down according to sign of N (default scaling indicator v).
.special Reset global list of special fonts to be empty.
.special s1 s2 ...
Fonts s1, s2, etc. are special and will be searched for characters not in the current font.
.spreadwarn
Toggle the spread warning on and off without changing its value.
.spreadwarn limit
Emit a warning if each space in an output line is widened by limit or more (default scaling
indicator m).
.ss N Space-character size set to N/12 of the spacewidth in the current font.
.ss N M Space-character size set to N/12 and sentence space size set to M/12 of the spacewidth in
the current font (=1/3 em).
.sty n style
Associate style with font position n.
.substring xx n1 n2
Replace the string named xx with the substring defined by the indices n1 and n2.
.sv Save 1v of vertical space.
.sv N Save the vertical distance N for later output with os request.
.sy command-line
Execute program command-line.
.ta T N Set tabs after every position that is a multiple of N (default scaling indicator m).
.ta n1 n2 ... nn T r1 r2 ... rn
Set tabs at positions n1, n2, ..., nn, then set tabs at nn+r1, nn+r2, ..., nn+rn, then at
nn+rn+r1, nn+rn+r2, ..., nn+rn+rn, and so on.
.tc Remove tab repition character.
.tc c Set tab repetition character to c.
.ti +-N Temporary indent next line (default scaling indicator m).
.tkf font s1 n1 s2 n2
Enable track kerning for font.
.tl 'left'center'right'
Three-part title.
.tm anything
Print anything on terminal (UNIX standard message output).
.tm1 anything
Print anything on terminal (UNIX standard message output), allowing leading whitespace if
anything starts with " (which will be stripped off).
.tmc anything
Similar to .tm1 without emitting a final newline.
.tr abcd...
Translate a to b, c to d, etc. on output.
.trf filename
Transparently output the contents of file filename.
.trin abcd...
This is the same as the tr request except that the asciify request will use the character
code (if any) before the character translation.
.trnt abcd...
This is the same as the tr request except that the translations do not apply to text that
is transparently throughput into a diversion with \!.
.troff Make the built-in condition t true and n false.
.uf font Underline font set to font (to be switched to by .ul).
.ul N Underline (italicize in troff) N input lines.
.unformat diversion
Unformat space characters and tabs, preserving font information in diversion.
.vpt n Enable vertical position traps if n is non-zero, disable them otherwise.
.vs Change to previous vertical base line spacing.
.vs +-N Set vertical base line spacing according to +-N (default scaling indicator p). Default
value is 12p.
.warn n Set warnings code to n.
.warnscale si
Set scaling indicator used in warnings to si.
.wh N Remove (first) trap at position N.
.wh N trap
Set location trap; negative means from page bottom.
.while cond anything
While condition cond is true, accept anything as input.
.write stream anything
Write anything to the stream named stream.
.writec stream anything
Similar to .write without emitting a final newline.
.writem stream xx
Write contents of macro or string xx to the stream named stream.
Besides these standard groff requests, there might be further macro calls. They can originate from a
macro package (see roff(7) for an overview) or from a preprocessor.
Preprocessor macros are easy to be recognized. They enclose their code into a pair of characteristic
macros.
+-------------+-------------+------------+
|preprocessor | start macro | end macro |
+-------------+-------------+------------+
| eqn | .PS | .PE |
| grap | .G1 | .G2 |
| grn | .GS | .GE |
| pic | .PS | .PE |
| refer | .R1 | .R2 |
| soelim | none | none |
| tbl | .TS | .TE |
+-------------+-------------+------------+
ESCAPE SEQUENCES
Escape sequences are in-line language elements usually introduced by a backslash `\' 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.
This is done by enclosing names (escape name and arguments consisting of a variable name) by a pair
of brackets [name] and constant arguments (number expressions and characters) by apostrophes (ASCII
0x27) like 'constant'.
There are abbreviations for short names. Two character escape names can be specified by an opening
parenthesis like \(xy without a closing counterpart. And all one-character names different from the
special characters `[' and `(' can even be specified without a marker in the form \c.
Constant arguments of length 1 can omit the marker apostrophes, too, but there is no two-character
analogue.
While 1-character escape sequences are mainly used for in-line functions and system related tasks,
the 2-letter names following the \( construct are used for special characters predefined by the roff
system. Escapes sequences with names of more than two characters \[name] denote user defined named
characters (see the char request).
Single Character Escapes
\" Beginning of a comment. Everything up to the end of the line is ignored.
\# Everything up to and including the next newline is ignored. This is interpreted in copy mode.
This is like \" except that the terminating newline is ignored as well.
\*s The string stored in the string variable with 1-character name s.
\*(st The string stored in the string variable with 2-character name st.
\*[stringvar arg1 arg2 ...]
The string stored in the string variable with arbitrary length name stringvar, taking arg1,
arg2, ... as arguments.
\$0 The name by which the current macro was invoked. The als request can make a macro have more
than one name.
\$x Macro or string argument with 1-place number x, where x is a digit between 1 and 9.
\$(xy Macro or string argument with 2-digit number xy.
\$[nexp]
Macro or string argument with number nexp, where nexp is a numerical expression evaluating to
an integer >=1.
\$* In a macro or string, the concatenation of all the arguments separated by spaces.
\$@ In a macro or string, the concatenation of all the arguments with each surrounded by double
quotes, and separated by spaces.
\\ reduces to a single backslash; useful to delay its interpretation as escape character in copy
mode. For a printable backslash, use \e, or even better \[rs], to be independent from the
current escape character.
\' The acute accent '; same as \(aa. Unescaped: apostrophe, right quotation mark, single quote
(ASCII 0x27).
\` The grave accent `; same as \(ga. Unescaped: left quote, backquote (ASCII 0x60).
\- The - sign in the current font.
\. An uninterpreted dot (period), even at start of line.
\% Default optional hyphenation character.
\! Transparent line indicator.
\?anything?
In a diversion, this will transparently embed anything in the diversion. anything is read in
copy mode. See also the escape sequences \! and \?.
\space Unpaddable space-size space character (no line break).
\0 Digit width.
\| 1/6 em narrow space character; zero width in nroff.
\^ 1/12 em half-narrow space character; zero width in nroff.
\& Non-printable, zero width character.
\) Like \& except that it behaves like a character declared with the cflags request to be trans-parent transparent
parent for the purposes of end of sentence recognition.
\/ 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.
\, 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.
\~ Unbreakable space that stretches like a normal inter-word space when a line is adjusted.
\: Inserts a zero-width break point (similar to \% but without a soft hyphen character).
\newline
Ignored newline, for continuation lines.
\{ Begin conditional input.
\} End conditional input.
\(sc The special character with 2-character name sc, see section Special Characters.
\[name]
The named character (or rather glyph) with arbitrary length name name.
\[comp1 comp2 ...]
A composite glyph with components comp1, comp2, ...
\a Non-interpreted leader character.
\A'anything'
If anything is acceptable as a name of a string, macro, diversion, register, environment or
font it expands to 1, and to 0 otherwise.
\b'abc...'
Bracket building function.
\B'anything'
If anything is acceptable as a valid numeric expression it expands to 1, and to 0 otherwise.
\c Interrupt text processing.
\C'char'
The character called char; same as \[char], but compatible to other roff versions.
\d Forward (down) 1/2 em vertical unit (1/2 line in nroff).
\D'charseq'
Draw a graphical element defined by the characters in charseq; see groff info file for
details.
\e Printable version of the current escape character.
\E Equivalent to an escape character, but is not interpreted in copy-mode.
\fF Change to font with 1-character name or 1-digit number F.
\fP Switch back to previous font.
\f(fo Change to font with 2-character name or 2-digit number fo.
\f[font]
Change to font with arbitrary length name or number expression font.
\f[] Switch back to previous font.
\Ff Change to font family with 1-character name f.
\F(fm Change to font family with 2-character name fm.
\F[fam]
Change to font family with arbitrary length name fam.
\F[] Switch back to previous font family.
\g[reg]
Return format of register with name reg suitable for .af. Alternative forms \g(xy and \gx.
\h'N' Local horizontal motion; move right N (left if negative).
\H'N' Set height of current font to N.
\k[reg]
Mark horizontal input place in register with arbitrary length name reg. Alternative forms
\k(xy and \kx.
\l'Nc' Horizontal line drawing function (optionally using character c).
\L'Nc' Vertical line drawing function (optionally using character c).
\m[color]
Change to color color. Alternative forms \m(co and \mc.
\m[] Switch back to previous color.
\M[color]
Change filling color for closed drawn objects to color color. Alternative forms \M(co and
\Mc.
\M[] Switch to previous fill color.
\nr The numerical value stored in the register variable with the 1-character name r.
\n(re The numerical value stored in the register variable with the 2-character name re.
\n[reg]
The numerical value stored in the register variable with arbitrary length name reg.
\N'n' Typeset the character with code n in the current font, no special fonts are searched. Useful
for adding characters to a font using the char request.
\o'abc...'
Overstrike characters a, b, c, etc.
\O_ Disable glyph output. Mainly for internal use.
\O1 Enable glyph output. Mainly for internal use.
\p Break and spread output line.
\r Reverse 1 em vertical motion (reverse line in nroff).
\R'name +-n'
The same as .nr name +-n.
\s[+-N]
Set the point size to N scaled points. Note the alternative forms \s+-[N], \s'+-N', \s+-'N',
\s(+-xy, \s+-(xy, \s+-x. Same as ps request.
\S'N' Slant output N degrees.
\t Non-interpreted horizontal tab.
\u Reverse (up) 1/2 em vertical motion (1/2 line in nroff).
\v'N' Local vertical motion; move down N (up if negative).
\V[env]
The contents of the environment variable env. Alternative forms \V(xy and \Vx.
\w'string'
The width of the character sequence string.
\x'N' Extra line-space function (negative before, positive after).
\X'string'
Output string as device control function.
\Y[name]
Output string variable or macro name uninterpreted as device control function. Alternative
forms \Y(xy and \Yx.
\zc Print c with zero width (without spacing).
\Z'anything'
Print anything and then restore the horizontal and vertical position; anything may not contain
tabs or leaders.
The escape sequences \e, \., \", \$, \*, \a, \n, \t, \g, and \newline are interpreted in copy mode.
Escape sequences starting with \( or \[ do not represent single character escape sequences, but
introduce escape names with two or more characters.
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.
Special Characters
Common special characters are predefined by escape sequences of the form \(xy with characters x and
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
groff_char(7).
\(bu Bullet sign
\(co Copyright
\(ct Cent
\(dd Double dagger
\(de Degree
\(dg Dagger
\(rs Printable double quote
\(em Em-dash
\(hy Hyphen
\(rg Registered sign
\(rs Printable backslash character
\(sc Section sign
\(ul Underline character
\(== Identical
\(>= Larger or equal
\(<= Less or equal
\(!= Not equal
\(-> Right arrow
\(<- Left arrow
\(+- Plus-minus sign
Strings
Strings are defined by the ds request and can be retrieved by the \* escape sequence.
Strings share their name space with macros. So strings and macros without arguments are roughly
equivalent; it is possible to call a string like a macro and vice-versa, but this often leads to
unpredictable results. The following strings are predefined in groff.
\*[.T] The name of the current output device as specified by the -T command line option.
REGISTERS
Registers are variables that store a value. In groff, most registers store numerical values (see
section NUMERICAL EXPRESSIONS above), but some can also hold a string value.
Each register is given a name. Arbitrary registers can be defined and set with the request nr regis-
ter.
The value stored in a register can be retrieved by the escape sequences introduced by \n.
Most useful are predefined registers. In the following the notation name is used to refer to a reg-ister register
ister called register name to make clear that we speak about registers. Please keep in mind that the
\n[] decoration is not part of the register name.
Read-only Registers
The following registers have predefined values that should not be modified by the user (usually, reg-isters registers
isters starting with a dot a read-only). Mostly, they provide information on the current settings or
store results from request calls.
\n[.$] Number of arguments in the current macro or string.
\n[.a] Post-line extra line-space most recently utilized using \x'N'.
\n[.A] Set to 1 in troff if option -A is used; always 1 in nroff.
\n[.c] Current input line number.
\n[.C] 1 if compatibility mode is in effect, 0 otherwise.
\n[.cdp] The depth of the last character added to the current environment. It is positive if the
character extends below the baseline.
\n[.ce] The number of lines remaining to be centered, as set by the ce request.
\n[.cht] The height of the last character added to the current environment. It is positive if the
character extends above the baseline.
\n[.color]
1 if colors are enabled, 0 otherwise.
\n[.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.
\n[.d] Current vertical place in current diversion; equal to register nl.
\n[.ev] The name or number of the current environment (string-valued).
\n[.f] Current font number.
\n[.fam] The current font family (string-valued).
\n[.fn] The current (internal) real font name (string-valued).
\n[.fp] The number of the next free font position.
\n[.g] Always 1 in GNU troff. Macros should use it to test if running under groff.
\n[.h] Text base-line high-water mark on current page or diversion.
\n[.H] Available horizontal resolution in basic units.
\n[.height]
The current font height as set with \H.
\n[.hla] The current hyphenation language as set by the .hla request.
\n[.hlc] The number of immediately preceding consecutive hyphenated lines.
\n[.hlm] The maximum allowed number of consecutive hyphenated lines, as set by the hlm request.
\n[.hy] The current hyphenation flags (as set by the hy request).
\n[.hym] The current hyphenation margin (as set by the hym request).
\n[.hys] The current hyphenation space (as set by the hys request).
\n[.i] Current ident.
\n[.in] The indent that applies to the current output line.
\n[.int] Positive if last output line contains \c.
\n[.kern] 1 if pairwise kerning is enabled, 0 otherwise.
\n[.l] Current line length.
\n[.lg] The current ligature mode (as set by the lg request).
\n[.linetabs]
The current line-tabs mode (as set by the linetabs request).
\n[.ll] The line length that applies to the current output line.
\n[.lt] The title length (as set by the lt request).
\n[.m] The current drawing color (string-valued).
\n[.M] The current background color (string-valued).
\n[.n] Length of text portion on previous output line.
\n[.ne] The amount of space that was needed in the last ne request that caused a trap to be sprung.
Useful in conjunction with register .trunc.
\n[.ns] 1 if in no-space mode, 0 otherwise.
\n[.o] Current page offset.
\n[.p] Current page length.
\n[.pe] 1 during page ejection, 0 otherwise.
\n[.pn] The number of the next page: either the value set by a pn request, or the number of the
current page plus 1.
\n[.ps] The current pointsize in scaled points.
\n[.psr] The last-requested pointsize in scaled points.
\n[.pvs] The current post-vertical line spacing.
\n[.rj] The number of lines to be right-justified as set by the rj request.
\n[.s] Current point size as a decimal fraction.
\n[.slant]
The slant of the current font as set with \S.
\n[.sr] The last requested pointsize in points as a decimal fraction (string-valued).
\n[.ss] The value of the parameters set by the first argument of the ss request.
\n[.sss] The value of the parameters set by the second argument of the ss request.
\n[.sty] The current font style (string-valued).
\n[.t] Distance to the next trap.
\n[.T] Set to 1 if option -T is used.
\n[.tabs] A string representation of the current tab settings suitable for use as an argument to the
ta request.
\n[.trunc]
The amount of vertical space truncated by the most recently sprung vertical position trap,
or, if the trap was sprung by a ne request, minus the amount of vertical motion produced by
.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.
\n[.u] Equal to 1 in fill mode and 0 in nofill mode.
\n[.U] Equal to 1 in safer mode and 0 in unsafe mode.
\n[.v] Current vertical line spacing.
\n[.V] Available vertical resolution in basic units.
\n[.vpt] 1 if vertical position traps are enabled, 0 otherwise.
\n[.w] Width of previous character.
\n[.warn] The sum of the number codes of the currently enabled warnings.
\n[.x] The major version number.
\n[.y] The minor version number.
\n[.Y] The revision number of groff.
\n[.z] Name of current diversion.
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.
\n[%] Current page number.
\n[c.] Current input line number.
\n[ct] Character type (set by width function \w).
\n[dl] Maximal width of last completed diversion.
\n[dn] Height of last completed diversion.
\n[dw] Current day of week (1-7).
\n[dy] Current day of month (1-31).
\n[hours] The number of hours past midnight. Initialized at start-up.
\n[hp] Current horizontal position at input line.
\n[llx] Lower left x-coordinate (in PostScript units) of a given PostScript image (set by .psbb).
\n[lly] Lower left y-coordinate (in PostScript units) of a given PostScript image (set by .psbb).
\n[ln] Output line number.
\n[minutes]
The number of minutes after the hour. Initialized at start-up.
\n[mo] Current month (1-12).
\n[nl] Vertical position of last printed text base-line.
\n[rsb] Like register sb, but takes account of the heights and depths of characters.
\n[rst] Like register st, but takes account of the heights and depths of characters.
\n[sb] Depth of string below base line (generated by width function \w).
\n[seconds]
The number of seconds after the minute. Initialized at start-up.
\n[skw] Right skip width from the center of the last character in the \w argument.
\n[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.
\n[ssc] The amount of horizontal space (possibly negative) that should be added to the last charac-
ter before a subscript (generated by width function \w).
\n[st] Height of string above base line (generated by width function \w).
\n[systat]
The return value of the system() function executed by the last sy request.
\n[urx] Upper right x-coordinate (in PostScript units) of a given PostScript image (set by .psbb).
\n[ury] Upper right y-coordinate (in PostScript units) of a given PostScript image (set by .psbb).
\n[year] The current year (year 2000 compliant).
\n[yr] Current year minus 1900. For Y2K compliance use register year instead.
COMPATIBILITY
The differences of the groff language in comparison to classical troff as defined by [CSTR #54] are
documented in groff_diff(7).
The groff system provides a compatibility mode, see groff(1) on how to invoke this.
BUGS
Report bugs to the
groff bug mailing list <bug-groff@gnu.org>. Include a complete, self-contained example that will
allow the bug to be reproduced, and say which version of groff you are using.
AUTHORS
Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
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 GNU copyleft site <http://www.gnu.org/copyleft/fdl.html>.
This document is part of groff, the GNU roff distribution. It was written by
Bernd Warken <bwarken@mayn.de>; it is maintained by
Werner Lemberg <wl@gnu.org>.
SEE ALSO
The main source of information for the groff language is the groff info(1) file. Besides the gory
details, it contains many examples.
groff(1)
the usage of the groff program and pointers to the documentation and availability of the groff
system.
groff_diff(7)
the differences of the groff language as compared to classical roff. This is the authorita-tive authoritative
tive document for the predefined language elements that are specific to groff.
groff_char(7)
the predefined groff characters (glyphs).
groff_font(5)
the specification of fonts and the DESC file.
roff(7)
the history of roff, the common parts shared by all roff systems, and pointers to further doc-umentation. documentation.
umentation.
[CSTR #54]
Nroff/Troff User's Manual by Osanna & Kernighan <http://cm.bell-labs.com/cm/cs/54.ps> -- the
bible for classical troff.
Groff Version 1.19.2 16 February 2005 GROFF(7)
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