NAME
    troff - the troff processor of the groff text formatting system

SYNOPSIS
    troff [ -abcivzCERU ] [ -dcs ] [ -ffam ] [ -Fdir ] [ -mname ] [ -Mdir ]
    [ -nnum ] [ -olist ] [ -rcn ] [ -Tname ] [ -wname ] [ -Wname ]
    [ files... ]

    It is possible to have whitespace between a command line option and its
    parameter.

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 pre-
    processors and postprocessors in the appropriate  order and with the
    appropriate options.

OPTIONS
    -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 cor-
   rect, 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 subdirecto-
   ries 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.

    -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/1.18.1/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.

    -U  Unsafe  mode. This will enable the following requests: open,
   opena, pso, sy, and pi. For security reasons,  these poten-
   tially  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 the
   section WARNINGS below. For example, to enable all warnings,
   use -w all. 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   |
   +---------------------+----------------------------+

    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 unrecog-
     nized escape sequence is encountered, the escape
     character is ignored.

    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  unde-
     fined 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 unde-
     fined name longer than two characters is encoun-
     tered, 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 compati-
     bility 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 pack-
    ages.

    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/1.18.1/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/1.18.1/font,
    /usr/lib/font) after these.

FILES
    /usr/share/groff/1.18.1/tmac/troffrc
    Initialization file (called before any other macro package).

    /usr/share/groff/1.18.1/tmac/troffrc-end
    Initialization file (called after any other macro package).

    /usr/share/groff/1.18.1/tmac/name.tmac
    /usr/share/groff/1.18.1/tmac/tmac.name
    Macro files

    /usr/share/groff/1.18.1/font/devname/DESC
    Device description file for device name.

    /usr/share/groff/1.18.1/font/devname/F
    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 if necessary.

AUTHOR
    Copyright (C) 1989, 2001, 2002 Free Software Foundation, Inc.

    This document is distributed under the terms of the FDL (GNU Free Docu-
    mentation 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
    was written by James Clark, with modifications  from Werner Lemberg
    <wl@gnu.org> and Bernd Warken <bwarken@mayn.de>

    This document is part of groff, the GNU roff distribution.

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 com-
    plete 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 point-
    ers to further related documentation.

    The groff info  file, cf.info(1), presents all groff documentation
    within a single document.