DITROFF(7)         FreeBSD Miscellaneous Information Manual         DITROFF(7)

NAME
       ditroff - classical device-independent roff

DESCRIPTION
       The name ditroff refers to a historical development stage of the
       roff(7) text processing system.  In roff systems extant today, the name
       troff is a synonym for ditroff.

       Early versions of roff by Joe Ossanna generated two programs from the
       same sources, using conditional compilation to distinguish them.  nroff
       produced text-oriented TTY output, while troff generated graphical
       output for exactly one output device, the Wang Graphic Systems CAT
       phototypesetter.

       In 1979, Brian Kernighan rewrote troff to support more devices by
       creating an intermediate output format for troff that could be fed into
       postprocessor programs which actually do the printout on the device.
       Kernighan's version marks what is known as "classical troff" today.  In
       order to distinguish it from Ossanna's original version, it was called
       ditroff (device independent troff) on some systems, though this naming
       isn't mentioned in the classical documentation.

       Today, all existing roff systems are based on Kernighan's multi-device
       troff.  The distinction between troff and ditroff is no longer
       necessary; each modern troff provides the complete functionality of
       ditroff.

       The easiest way to use ditroff is via the GNU roff system, groff.  The
       groff(1) program is a wrapper around (di)troff that automatically
       handles device postprocessing.

AUTHORS
       This document was written by Bernd Warken <groff-bernd.warken-72@
       web.de>.

SEE ALSO
       CSTR #54
              refers to the 1992 revision of the Nroff/Troff User's Manual by
              J. F. Ossanna and Brian Kernighan.

       CSTR #97
              refers to A Typesetter-independent TROFF, by Brian Kernighan and
              is the original documentation of the first multi-device troff
              (ditroff).

       roff(7)
              provides a history and conceptual overview of roff systems.

       troff(1)
              describes the GNU implementation of (di)troff.

       groff(1)
              documents the GNU roff program and includes pointers to further
              documentation about groff.

       _out&section=5">groff_out(5)
              describes the groff version of the intermediate output language,
              the basis for multi-device output.

groff 1.22.4                   18 November 2018                     DITROFF(7)