TROFF(1)                     General Commands Manual                    TROFF(1)

       troff - the troff processor of the groff text formatting system

       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 ...]

       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.

       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.

              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

       -i     Read the standard input after all the named input files have been

       -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

              No directory search is performed for files with an absolute file

       -mname Read in the file name.tmac.  If it isn't found, try
              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/

       -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

              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.

       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

       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

       w      All warnings.

              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.

              Default device.

              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.

              Initialization file (called before any other macro package).

              Initialization file (called after any other macro package).

              Macro files

              Device description file for device name.

              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

       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 ⟨⟩ and Bernd Warken ⟨⟩.

              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 by

                     man 7 groff

              The differences of the groff language and the classical troff
              language.  Currently, this is the most actual document of the
              groff system.

              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”.

groff 1.22.4                      21 June 2021                          TROFF(1)