Provided by: groff-base_1.22.4-10_amd64 
NAME
troff - the troff processor of the groff text formatting system
SYNOPSIS
troff [-abcivzCERU] [-d cs] [-f fam] [-F dir] [-I dir] [-m name] [-M dir] [-n num]
[-o list] [-r cn] [-T name] [-w name] [-W name] [file ...]
DESCRIPTION
This manual 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
appropriate options.
OPTIONS
Whitespace is permitted between a command-line option and its argument.
-a Generate an ASCII approximation of the typeset output.
-b 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
requests.
-c Disable color output (always disabled in compatibility mode).
-C Enable compatibility mode.
-dcs
-dname=s
Define c or name to be a string s; c must be a one letter name.
-E 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 requests.
-ffam Use fam as the default font family.
-Fdir 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 directories.
-i Read the standard input after all the named input files have been processed.
-Idir 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 place.
No directory search is performed for files with an absolute file name.
-mname 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 directory, /usr/lib/groff/site-tmac,
/usr/share/groff/site-tmac, and /usr/share/groff/1.22.4/tmac.
-Mdir Search directory (or directory path) dir for macro files. This is scanned before
all other macro directories.
-nnum Number the first page num.
-olist 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.
-rcn
-rname=n
Set number register c or name to n; c must be a one character name; n can be any
troff numeric expression.
-R Don't load troffrc and troffrc-end.
-Tname Prepare output for device name, rather than the default ps; see groff(1) for a more
detailed description.
-U 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.
-v Print the version number.
-wname Enable warning name. Available warnings are described in section “Warnings” below.
To enable most useful warnings use -w all. To enable absolutely all warnings use
-w w instead. Multiple -w options are allowed.
-Wname Inhibit warning name. Multiple -W options are allowed.
-z Suppress formatted output.
WARNINGS
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.
┌─────────────────────┬─────────────────────────────┐
│Bit Code Warning │ Bit Code Warning │
├─────────────────────┼─────────────────────────────┤
│ 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 In fill mode, lines which could not be broken so that their length was
less than the line length. This is enabled by default.
char 1 Non-existent characters. This is enabled by default.
color 524288 Color-related warnings.
delim 8 Missing or mismatched closing delimiters.
di 256 Use of di or da without an argument when there is no current
diversion.
el 16 Use of the el request with no matching ie request.
escape 32768 Unrecognized escape sequences. When an unrecognized escape sequence
is encountered, the escape character is ignored.
file 1048576 Indicates a missing file for the mso request. Enabled by default.
font 131072 Non-existent fonts. This is enabled by default.
ig 262144 Invalid escapes in text ignored with the ig request. These are
conditions that are errors when they do not occur in ignored text.
input 16384 Invalid input characters.
mac 512 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.
missing 8192 Requests that are missing non-optional arguments.
number 2 Invalid numeric expressions. This is enabled by default.
range 64 Out of range arguments.
reg 1024 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.
right-brace 4096 Use of \} where a number was expected.
scale 32 Meaningless scaling indicators.
space 65536 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.
syntax 128 Dubious syntax in numeric expressions.
tab 2048 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 warnings:
all All warnings except di, mac, and reg. It is intended that this covers all warnings
that are useful with traditional macro packages.
w All warnings.
ENVIRONMENT
GROFF_TMAC_PATH
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/lib/groff/
site-tmac, /usr/share/groff/site-tmac, /usr/share/groff/1.22.4/tmac) after these.
GROFF_TYPESETTER
Default device.
GROFF_FONT_PATH
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/1.22.4/font, /usr/lib/
font) after these.
FILES
/usr/share/groff/1.22.4/tmac/troffrc
Initialization file (called before any other macro package).
/usr/share/groff/1.22.4/tmac/troffrc-end
Initialization file (called after any other macro package).
/usr/share/groff/1.22.4/tmac/name.tmac
/usr/share/groff/1.22.4/tmac/tmac.name
Macro files
/usr/share/groff/1.22.4/font/devname/DESC
Device description file for device name.
/usr/share/groff/1.22.4/font/devname/F
Font file for font F of device name.
Note that troffrc and troffrc-end are searched for neither in the current nor 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 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 modified by Werner Lemberg ⟨wl@gnu.org⟩ and Bernd
Warken ⟨groff-bernd.warken-72@web.de⟩.
SEE ALSO
groff(1)
The main program of the groff system, a wrapper around troff.
groff(7)
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 by
man 7 groff
groff_diff(7)
The differences of the groff language and the classical troff language. Currently,
this is the most actual document of the groff system.
roff(7)
An overview over groff and other roff systems, including pointers to further
related documentation.
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”.