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DITROFF(7) 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 dis-
tinction 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 AT 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.
groff_out(5)
describes the groff version of the intermediate output language, the basis for
multi-device output.
groff 1.22.4 23 March 2022 DITROFF(7)
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