Provided by: groff-base_1.22.4-10_amd64 bug


       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

       -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 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 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.

              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

                          │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

       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

       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.


              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 necessary.


       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”.