troff(1) — Linux manual page

Name | Synopsis | Description | Options | Warnings | Environment | Files | Authors | See also | COLOPHON

troff(1)                 General Commands Manual                troff(1)

Name         top

       troff - GNU troff document formatter

Synopsis         top

       troff [-abcizCERU] [-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 ...]

       troff --help

       troff -v
       troff --version

Description         top

       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         top

       -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

              •      Page breaks are marked by a phrase in angle
                     brackets; for example, “<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

       -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; also disable SGR escape output to
              grotty(1) devices.

       -C     Enable compatibility mode; implies -c.

              Define c or name to be a string s; c must be a one letter

       -E     Inhibit troff error messages; implies -Ww.  Note that this
              doesn't suppress messages sent to the standard error
              stream by documents or macro packages using .tm or related

       -ffam  Use fam as the default font family.

       -Fdir  Search in directory dir for the selected output device's
              directory 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 after all the named input files
              have been processed.

       -I dir Search dir for input files (those on the command line,
              those named in .psbb, .so, and .soquiet requests, and
              those named in “\X'ps: import'”, “\X'ps: file'”, and
              “\X'pdf: pdfpic'” escapes).  This option may be specified
              more than once; the directories are then searched in the
              order specified.  If you want to search the current
              directory before others, add “-I .” at the appropriate
              place.  The current working directory is otherwise
              searched last.  -I works similarly to, and is named for,
              the “include” option of Unix C compilers.  No directory
              search is performed for files specified using an absolute
              file name.

       -mname Process name.tmac before any input files.  If name.tmac is
              not found, 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.

       -Mdir  Search directory dir for macro files.  See the description
              of GROFF_TMAC_PATH in section “Environment” below for the
              default search locations and ordering.

       -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.

              Set number register c or name to n; c must be a one
              character name; n can be any roff 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     Operate in unsafe mode, which enables the .open, .opena,
              .pi, .pso, and .sy requests.  These requests are disabled
              by default because they allow an untrusted input document
              to write to arbitrary file names and run arbitrary
              commands.  This option also adds the current directory to
              the macro search path; see the -m option above.

       -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         top

       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   When filling is enabled, a line could not be
                           broken such that its length was less than the
                           output line length \n[.l].  This is enabled
                           by default.

       char            1   Non-existent characters.  This is enabled by

       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

       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

       ig         262144   Invalid escapes in text ignored with the ig
                           request.  These are conditions that are
                           errors when they do not occur in ignored

       input       16384   Invalid input characters.

       mac           512   An undefined string, macro, diversion, or box
                           was used.  When such an object is
                           dereferenced, an empty object of that name is
                           automatically created.  So, in most cases, at
                           most one warning is given for each name.

                           This warning is also emitted upon an attempt
                           to move an unplanted trap.  In such cases,
                           the unplanted macro is not dereferenced, so
                           it is not created if it does not exist.

       missing      8192   Requests that are missing non-optional

       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

       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   Invalid syntax.

       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

       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         top

       GROFF_FONT_PATH and GROFF_TMAC_PATH each accept a search path of
       directories; 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 (;).

              A list of directories in which to seek the selected output
              device's directory of device and font description files.
              troff will scan directories given as arguments to any
              specified -F options before these, then in a site-specific
              directory (/usr/local/share/groff/site-font), a standard
              location (/usr/local/share/groff/1.23.0/font), and a
              compatibility directory (/usr/lib/font) after them.

              A list of directories in which to search for macro files.
              troff will scan directories given as arguments to any
              specified -M options before these, then the current
              directory (only if in unsafe mode), the user's home
              directory, a platform-specific directory (/usr/local/lib/
              groff/site-tmac), a site-specific directory (/usr/local/
              share/groff/site-tmac), and a standard location (/usr/
              local/share/groff/1.23.0/tmac) after them.

              Default output device.

              A timestamp (expressed as seconds since the Unix epoch) to
              use as the creation timestamp in place of the current
              time.  The time is converted to human-readable form using
              ctime(3) when the formatter starts up and stored in
              registers usable by documents and macro packages.

       TZ     The timezone to use when converting the current time (or
              value of SOURCE_DATE_EPOCH) to human-readable form; see

Files         top

              Initialization file (called before any other macro

              Initialization file (called after any other macro

              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 necessary.

Authors         top

       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

See also         top

              The main program of the groff system, a wrapper around

              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”.

COLOPHON         top

       This page is part of the groff (GNU troff) project.  Information
       about the project can be found at 
       ⟨⟩.  If you have a bug report
       for this manual page, see ⟨⟩.
       This page was obtained from the project's upstream Git repository
       ⟨⟩ on 2021-06-20.  (At
       that time, the date of the most recent commit that was found in
       the repository was 2021-06-17.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to

groff 1.23.0.rc1.654-4e1db-dirt1y6 June 2021                      troff(1)

Pages that refer to this page: colcrt(1)groffer(1)grops(1)man(1)zsoelim(1)groff_out(5)groff_char(7)groff_trace(7)roff(7)