the troff processor of the groff text formatting system
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groff - info
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page describes the GNU version of troff. It is part
of the groff document formatting system. It is functionally
compatible with UNIX troff, but has many extensions, see
groff_diff(7). Usually it should be invoked using the
groff(1) command which will also run preprocessors
and postprocessors in the appropriate order and with the
It is possible
to have whitespace between a command line option and its
Generate an ASCII approximation of the
Print a backtrace with each warning or error message.
This backtrace should help track down the cause of the
error. The line numbers given in the backtrace may not
always be correct, for troff’s idea of line
numbers gets confused by as or am
Disable color output (always disabled in compatibility
Enable compatibility mode.
Define c or name to be a string s;
c must be a one letter name.
Inhibit all error messages of troff. Note that
this doesn’t affect messages output to standard error
by macro packages using the tm or tm1
Use fam as the default font family.
Search in directory (or directory path) dir for
subdirectories devname (name is the
name of the device) and there for the DESC file and
font files. dir is scanned before all other font
Read the standard input after all the named input files
have been processed.
This option may be used to add a directory to the search
path for files (both those on the command line and those
named in .psbb requests). The search path is
initialized with the current directory. This option may be
specified more than once; the directories are then searched
in the order specified (but before the current directory).
If you want to make the current directory be read before
other directories, add -I. at the appropriate
search is performed for files with an absolute file
Read in the file
name.tmac. If it isn’t found, try
tmac.name instead. It will be first searched
for in directories given with the -M command
line option, then in directories given in the
GROFF_TMAC_PATH environment variable, then in the
current directory (only if in unsafe mode), the home
Search directory (or directory path) dir for
macro files. This is scanned before all other macro
Number the first page num.
Output only pages in list, which is a
comma-separated list of page ranges; n means print
page n, m-n means print
every page between m and n,
-n means print every page up to
n, n- means print every page from
n. troff will exit after printing the last
page in the list.
Set number register c or name to n;
c must be a one character name; n can be any
troff numeric expression.
Don’t load troffrc and
Prepare output for device name, rather than the
default ps; see groff(1) for a more detailed
Unsafe mode. This will enable the following requests:
open, opena, pso, sy, and
pi. For security reasons, these potentially dangerous
requests are disabled otherwise. It will also add the
current directory to the macro search path.
Print the version number.
Enable warning name. Available warnings are
described in the section WARNINGS below. For example,
to enable all warnings, use -w all. Multiple
-w options are allowed.
Inhibit warning name. Multiple -W
options are allowed.
Suppress formatted output.
A colon separated list of directories in which to search for
macro files. troff will scan directories given in the
-M option before these, and in standard directories
(current directory if in unsafe mode, home directory,
/usr/share/groff/1.22.1/tmac) after these.
A colon separated list of directories in which to search for the
devname directory. troff will scan
directories given in the -F option before these, and in
standard directories (/usr/share/groff/site-font,
/usr/share/groff/1.22.1/font, /usr/lib/font) after
Initialization file (called before any other macro package).
Initialization file (called after any other macro package).
Device description file for device name.
Font file for font F of device name.
Note that troffrc and troffrc-end are neither
searched in the current nor in the home directory by default for
security reasons (even if the -U option is given). Use the
-M command line option or the GROFF_TMAC_PATH
environment variable to add these directories to the search path
The warnings that can be given by troff are divided into
the following categories. The name associated with each warning
is used by the -w and -W options; the number is
used by the warn request, and by the .warn
register; it is always a power of 2 to allow bitwise composition.
In fill mode, lines which could not be broken so that their
length was less than the line length. This is enabled by default.
Non-existent characters. This is enabled by default.
Color related warnings.
Missing or mismatched closing delimiters.
Use of di or da without an argument when there is
no current diversion.
Use of the el request with no matching ie request.
Unrecognized escape sequences. When an unrecognized escape
sequence is encountered, the escape character is ignored.
Indicates a missing file for the mso request. Enabled by
Non-existent fonts. This is enabled by default.
Invalid escapes in text ignored with the ig request. These
are conditions that are errors when they do not occur in ignored
Invalid input characters.
Use of undefined strings, macros and diversions. When an
undefined string, macro or diversion is used, that string is
automatically defined as empty. So, in most cases, at most one
warning will be given for each name.
Requests that are missing non-optional arguments.
Invalid numeric expressions. This is enabled by default.
Out of range arguments.
Use of undefined number registers. When an undefined number
register is used, that register is automatically defined to have
a value of 0. So, in most cases, at most one warning will be
given for use of a particular name.
Use of \} where a number was expected.
Meaningless scaling indicators.
Missing space between a request or macro and its argument. This
warning will be given when an undefined name longer than two
characters is encountered, and the first two characters of the
name make a defined name. The request or macro will not be
invoked. When this warning is given, no macro is automatically
defined. This is enabled by default. This warning will never
occur in compatibility mode.
Dubious syntax in numeric expressions.
Inappropriate use of a tab character. Either use of a tab
character where a number was expected, or use of tab character in
an unquoted macro argument.
There are also names that can be used to refer to groups of
All warnings except di, mac, and reg. It is
intended that this covers all warnings that are useful with
traditional macro packages.
The main program of the
groff system, a wrapper around troff.
A description of the
groff language, including a short but complete
reference of all predefined requests, registers, and escapes
of plain groff. From the command line, this is called
The differences of the
groff language and the classical troff
language. Currently, this is the most actual document of the
An overview over groff
and other roff systems, including pointers to further
info file, cf. info, presents all groff
documentation within a single document.
1989, 2001, 2002, 2003, 2007, 2008, 2009 Free Software
is distributed under the terms of the FDL (GNU Free
Documentation License) version 1.3 or later. You should have
received a copy of the FDL on your system, it is also
available on-line at the
site (http://www.gnu.org/copyleft/fdl.html). This document was written by James Clark, with
modifications from Werner
Lemberg (mailto:wl[:at:]gnu[:dot:]org) and Bernd
is part of groff, the GNU roff distribution.