troff(1) General Commands Manual troff(1)
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 ]8;;man:groff(7)\groff(7)]8;;\ language input into the device-independent
output format described in ]8;;man:groff_out(5)\groff_out(5)]8;;\; 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 ]8;;man:groff(1)\groff(1)]8;;\
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 ver-
sion 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 exam-
ple, “<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, be-
cause 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
]8;;man:groff_diff(7)\groff_diff(7)]8;;\.
-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 hap-
pen before any macro file is loaded, including the startup file.
Due to ]8;;man:getopt_long(3)\getopt_long(3)]8;;\ 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 direc-
tory 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 se-
quences). -I may be specified more than once; each dir is
searched in the given order. To search the current working di-
rectory 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 in-
clusive page ranges; n means page n, m-n means every page be-
tween m and n, -n means every page up to n, and n- means every
page from n on. troff stops processing and exits after format-
ting 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 ]8;;man:getopt_long(3)\getopt_long(3)]8;;\ 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 ]8;;man:groff(1)\groff(1)]8;;\.
-U Operate in unsafe mode, enabling the open, opena, pi, pso, and sy
requests, which are disabled by default because they allow an un-
trusted 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 sec-
tion “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 fol-
lowing 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 corre-
sponding ie request.
escape 32768 An unsupported escape sequence was encountered.
file 1048576 An attempt was made to load a file that does not ex-
ist. 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 diag-
noses 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 un-
planted macro is not dereferenced, so it is not cre-
ated if it does not exist.
missing 8192 A request was invoked with a mandatory argument ab-
sent.
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 con-
text.
reg 1024 An undefined register was used. When an undefined
register is dereferenced, it is automatically de-
fined 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 un-
defined name longer than two characters is encoun-
tered and the first two characters of the name con-
stitute 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 oc-
curs in compatibility mode.
syntax 128 A self-contradictory hyphenation mode was requested;
an empty or incomplete numeric expression was en-
countered; 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 descen-
dants, 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 direc-
tories; 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 de-
vice's directory of device and font description files. troff
will scan directories given as arguments to any specified -F op-
tions 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 op-
tions 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 ]8;;man:gmtime(3)\gmtime(3)]8;;\ and
]8;;man:asctime(3)\asctime(3)]8;;\ 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 ]8;;man:tzset(3)\tzset(3)]8;;\. 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 envi-
ronment variable to add these directories to the search path if neces-
sary.
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 ]8;;mailto:wl@gnu.org\Werner
Lemberg]8;;\, ]8;;mailto:groff-bernd.warken-72@web.de\Bernd Warken]8;;\, and ]8;;mailto:g.branden.robinson@gmail.com\G. Branden Robinson]8;;\.
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”.
]8;;man:groff(1)\groff(1)]8;;\
offers an overview of the GNU roff system and describes its front
end executable.
]8;;man:groff(7)\groff(7)]8;;\
details the groff language, including a short but complete refer-
ence of all predefined requests, registers, and escape sequences.
]8;;man:groff_char(7)\groff_char(7)]8;;\
explains the syntax of groff special character escape sequences,
and lists all special characters predefined by the language.
]8;;man:groff_diff(7)\groff_diff(7)]8;;\
enumerates the differences between AT&T device-independent troff
and groff.
]8;;man:groff_font(5)\groff_font(5)]8;;\
covers the format of groff device and font description files.
]8;;man:groff_out(5)\groff_out(5)]8;;\
describes the format of troff's output.
]8;;man:groff_tmac(5)\groff_tmac(5)]8;;\
includes information about macro files that ship with groff.
]8;;man:roff(7)\roff(7)]8;;\
supplies background on roff systems in general, including point-
ers to further related documentation.
groff 1.23.0 3 June 2025 troff(1)
Generated by dwww version 1.16 on Tue Dec 16 04:02:30 CET 2025.