Provided by: groff-base_1.23.0-2_amd64 
Name
troff - GNU roff typesetter and document formatter
Synopsis
troff [-abcCEiRUz] [-d ctext] [-d string=text] [-f font-family] [-F font-directory]
[-I inclusion-directory] [-m macro-package] [-M macro-directory] [-n page-number]
[-o page-list] [-r cnumeric-expression] [-r register=numeric-expression] [-T output-
device] [-w warning-category] [-W warning-category] [file ...]
troff --help
troff -v
troff --version
Description
GNU troff transforms groff(7) language input into the device-independent output format
described in groff_out(5); troff is thus the heart of the GNU roff document formatting
system. If no file operands are given on the command line, or if file is “-”, the
standard input stream is read.
GNU troff is functionally compatible with the AT&T troff typesetter and features numerous
extensions. Many people prefer to use the groff(1) command, a front end which also runs
preprocessors and output drivers in the appropriate order and with appropriate options.
Options
-h and --help display a usage message, while -v and --version show version information;
all exit afterward.
-a Generate a plain text approximation of the typeset output. The read-only register
.A is set to 1. This option produces a sort of abstract preview of the formatted
output.
• Page breaks are marked by a phrase in angle brackets; for example, “<beginning of
page>”.
• Lines are broken where they would be in the formatted output.
• A horizontal motion of any size is represented as one space. Adjacent horizontal
motions are not combined. Inter-sentence space nodes (those arising from the
second argument to the .ss request) are not represented.
• Vertical motions are not represented.
• Special characters are rendered in angle brackets; for example, the default soft
hyphen character appears as “<hy>”.
The above description should not be considered a specification; the details of -a
output are subject to change.
-b Write a backtrace reporting the state of troff's input parser to the standard error
stream with each diagnostic message. The line numbers given in the backtrace might
not always be correct, because troff's idea of line numbers can be confused by
requests that append to macros.
-c Start with color output disabled.
-C Enable AT&T troff compatibility mode; implies -c. See groff_diff(7).
-d ctext
-d string=text
Define roff string c or string as text. c must be one character; string can be of
arbitrary length. Such string assignments happen before any macro file is loaded,
including the startup file. Due to getopt_long(3) limitations, c cannot be, and
string cannot contain, an equals sign, even though that is a valid character in a
roff identifier.
-E Inhibit troff error messages; implies -Ww. This option does not suppress messages
sent to the standard error stream by documents or macro packages using tm or
related requests.
-f fam Use fam as the default font family.
-F dir Search in directory dir for the selected output device's directory of device and
font description files. See the description of GROFF_FONT_PATH in section
“Environment” below for the default search locations and ordering.
-i Read the standard input stream after all named input files have been processed.
-I dir Search the directory dir for files (those named on the command line; in psbb, so,
and soquiet requests; and in “\X'ps: import'”, “\X'ps: file'”, and “\X'pdf:
pdfpic'” device control escape sequences). -I may be specified more than once;
each dir is searched in the given order. To search the current working directory
before others, add “-I .” at the desired place; it is otherwise searched last. -I
works similarly to, and is named for, the “include” option of Unix C compilers.
-m name
Process the file name.tmac prior to any input files. If not found, tmac.name is
attempted. name (in both arrangements) is presumed to be a macro file; see the
description of GROFF_TMAC_PATH in section “Environment” below for the default
search locations and ordering.
-M dir Search directory dir for macro files. See the description of GROFF_TMAC_PATH in
section “Environment” below for the default search locations and ordering.
-n num Begin numbering pages at num. The default is 1.
-o list
Output only pages in list, which is a comma-separated list of inclusive page
ranges; n means page n, m-n means every page between m and n, -n means every page
up to n, and n- means every page from n on. troff stops processing and exits after
formatting the last page enumerated in list.
-r cnumeric-expression
-r register=numeric-expression
Define roff register c or register as numeric-expression. c must be a one-
character name; register can be of arbitrary length. Such register assignments
happen before any macro file is loaded, including the startup file. Due to
getopt_long(3) limitations, c cannot be, and register cannot contain, an equals
sign, even though that is a valid character in a roff identifier.
-R Don't load troffrc and troffrc-end.
-T dev Prepare output for device dev. The default is ps; see groff(1).
-U Operate in unsafe mode, enabling the open, opena, pi, pso, and sy requests, which
are disabled by default because they allow an untrusted input document to write to
arbitrary file names and run arbitrary commands. This option also adds the current
directory to the macro package search path; see the -m and -M options above.
-w name
-W name
Enable (-w) or inhibit (-W) warnings in category name. See section “Warnings”
below.
-z Suppress formatted output.
Warnings
Warning diagnostics emitted by troff are divided into named, numbered categories. The
name associated with each warning category is used by the -w and -W options. Each
category is also assigned a power of two; the sum of enabled category codes is used by the
warn request and the .warn register. Warnings of each category are produced under the
following circumstances.
┌──────────────────────┬─────────────────────────────┐
│Bit Code Category │ Bit Code Category │
├──────────────────────┼─────────────────────────────┤
│ 0 1 char │ 10 1024 reg │
│ 1 2 number │ 11 2048 tab │
│ 2 4 break │ 12 4096 right-brace │
│ 3 8 delim │ 13 8192 missing │
│ 4 16 el │ 14 16384 input │
│ 5 32 scale │ 15 32768 escape │
│ 6 64 range │ 16 65536 space │
│ 7 128 syntax │ 17 131072 font │
│ 8 256 di │ 18 262144 ig │
│ 9 512 mac │ 19 524288 color │
│ │ 20 1048576 file │
└──────────────────────┴─────────────────────────────┘
break 4 A filled output line could not be broken such that its length was less
than the output line length \n[.l]. This category is enabled by
default.
char 1 No mounted font defines a glyph for the requested character. This
category is enabled by default.
color 524288 An undefined color name was selected, an attempt was made to define a
color using an unrecognized color space, an invalid component in a
color definition was encountered, or an attempt was made to redefine a
default color.
delim 8 The closing delimiter in an escape sequence was missing or mismatched.
di 256 A di, da, box, or boxa request was invoked without an argument when
there was no current diversion.
el 16 The el request was encountered with no prior corresponding ie request.
escape 32768 An unsupported escape sequence was encountered.
file 1048576 An attempt was made to load a file that does not exist. This category
is enabled by default.
font 131072 A non-existent font was selected, or the selection was ignored because
a font selection escape sequence was used after the output line
continuation escape sequence on an input line. This category is
enabled by default.
ig 262144 An invalid escape sequence occurred in input ignored using the ig
request. This warning category diagnoses a condition that is an error
when it occurs in non-ignored input.
input 16384 An invalid character occurred on the input stream.
mac 512 An undefined string, macro, or diversion was used. When such an
object is dereferenced, an empty one of that name is automatically
created. So, unless it is later deleted, at most one warning is given
for each.
This warning is also emitted upon an attempt to move an unplanted trap
macro. In such cases, the unplanted macro is not dereferenced, so it
is not created if it does not exist.
missing 8192 A request was invoked with a mandatory argument absent.
number 2 An invalid numeric expression was encountered. This category is
enabled by default.
range 64 A numeric expression was out of range for its context.
reg 1024 An undefined register was used. When an undefined register is
dereferenced, it is automatically defined with a value of 0. So,
unless it is later deleted, at most one warning is given for each.
right-brace 4096 A right brace escape sequence \} was encountered where a number was
expected.
scale 32 A scaling unit inappropriate to its context was used in a numeric
expression.
space 65536 A space was missing between a request or macro and its argument. This
warning is produced when an undefined name longer than two characters
is encountered and the first two characters of the name constitute a
defined name. No request is invoked, no macro called, and an empty
macro is not defined. This category is enabled by default. It never
occurs in compatibility mode.
syntax 128 A self-contradictory hyphenation mode was requested; an empty or
incomplete numeric expression was encountered; an operand to a numeric
operator was missing; an attempt was made to define a recursive,
empty, or nonsensical character class; or a groff extension
conditional expression operator was used while in compatibility mode.
tab 2048 A tab character was encountered where a number was expected, or
appeared in an unquoted macro argument.
Two warning names group other warning categories for convenience.
all All warning categories except di, mac, and reg. This shorthand is intended to
produce all warnings that are useful with macro packages and documents written for
AT&T troff and its descendants, which have less fastidious diagnostics than GNU
troff.
w All warning categories. Authors of documents and macro packages targeting groff
are encouraged to use this setting.
Environment
GROFF_FONT_PATH and GROFF_TMAC_PATH each accept a search path of directories; that is, a
list of directory names separated by the system's path component separator character. On
Unix systems, this character is a colon (:); on Windows systems, it is a semicolon (;).
GROFF_FONT_PATH
A list of directories in which to seek the selected output device's directory of
device and font description files. troff will scan directories given as arguments
to any specified -F options before these, then in a site-specific directory (/usr/
share/groff/site-font), a standard location (/usr/share/groff/1.23.0/font), and a
compatibility directory (/usr/lib/font) after them.
GROFF_TMAC_PATH
A list of directories in which to search for macro files. troff will scan
directories given as arguments to any specified -M options before these, then the
current directory (only if in unsafe mode), the user's home directory, a site-
specific directory (/usr/share/groff/site-tmac), and a standard location (/usr/
share/groff/1.23.0/tmac) after them.
GROFF_TYPESETTER
Set the default output device. If empty or not set, ps is used. The -T option
overrides GROFF_TYPESETTER.
SOURCE_DATE_EPOCH
A timestamp (expressed as seconds since the Unix epoch) to use as the output
creation timestamp in place of the current time. The time is converted to human-
readable form using gmtime(3) and asctime(3) when the formatter starts up and
stored in registers usable by documents and macro packages.
TZ The time zone to use when converting the current time to human-readable form; see
tzset(3). If SOURCE_DATE_EPOCH is used, it is always converted to human-readable
form using UTC.
Files
/usr/share/groff/1.23.0/tmac/troffrc
is an initialization macro file loaded before any macro packages specified with -m
options.
/usr/share/groff/1.23.0/tmac/troffrc-end
is an initialization macro file loaded after all macro packages specified with -m
options.
/usr/share/groff/1.23.0/tmac/name.tmac
are macro files distributed with groff.
/usr/share/groff/1.23.0/font/devname/DESC
describes the output device name.
/usr/share/groff/1.23.0/font/devname/F
describes the font F of device name.
troffrc and troffrc-end are sought neither in the current nor the home directory by
default for security reasons, even if the -U option is specified. Use the -M command-line
option or the GROFF_TMAC_PATH environment variable to add these directories to the search
path if necessary.
Authors
The GNU version of troff was originally written by James Clark; he also wrote the original
version of this document, which was updated by Werner Lemberg ⟨wl@gnu.org⟩, Bernd Warken
⟨groff-bernd.warken-72@web.de⟩, and G. Branden Robinson ⟨g.branden.robinson@gmail.com⟩.
See also
Groff: The GNU Implementation of troff, by Trent A. Fisher and Werner Lemberg, is the
primary groff manual. You can browse it interactively with “info groff”.
groff(1)
offers an overview of the GNU roff system and describes its front end executable.
groff(7)
details the groff language, including a short but complete reference of all
predefined requests, registers, and escape sequences.
groff_char(7)
explains the syntax of groff special character escape sequences, and lists all
special characters predefined by the language.
groff_diff(7)
enumerates the differences between AT&T device-independent troff and groff.
groff_font(5)
covers the format of groff device and font description files.
groff_out(5)
describes the format of troff's output.
groff_tmac(5)
includes information about macro files that ship with groff.
roff(7)
supplies background on roff systems in general, including pointers to further
related documentation.