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 out-
put for exactly one output device, the Wang Graphic Systems CAT photo-
typesetter.
In 1979, Brian Kernighan rewrote troff to support more devices by cre-
ating 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 neces-
sary; 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 han-
dles 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.
groff_out(5)
describes the groff version of the intermediate output language,
the basis for multi-device output.
groff 1.22.4 7 March 2023 DITROFF(7)
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