1DITROFF(7)             Miscellaneous Information Manual             DITROFF(7)
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NAME

6       ditroff - classical device-independent roff
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DESCRIPTION

9       The  name  ditroff  refers  to  a  historical  development stage of the
10       roff(7) text processing system.  In roff systems extant today, the name
11       troff is a synonym for ditroff.
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13       Early  versions  of roff by Joe Ossanna generated two programs from the
14       same sources, using conditional compilation to distinguish them.  nroff
15       produced text-oriented TTY output, while troff generated graphical out‐
16       put for exactly one output device, the Wang Graphic Systems CAT  photo‐
17       typesetter.
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19       In  1979, Brian Kernighan rewrote troff to support more devices by cre‐
20       ating an intermediate output format for troff that could  be  fed  into
21       postprocessor  programs  which  actually do the printout on the device.
22       Kernighan's version marks what is known as “classical troff” today.  In
23       order  to distinguish it from Ossanna's original version, it was called
24       ditroff (device independent troff) on some systems, though this  naming
25       isn't mentioned in the classical documentation.
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27       Today,  all existing roff systems are based on Kernighan's multi-device
28       troff.  The distinction between troff and ditroff is no  longer  neces‐
29       sary; each modern troff provides the complete functionality of ditroff.
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31       The  easiest way to use ditroff is via the GNU roff system, groff.  The
32       groff(1) program is a wrapper around (di)troff that automatically  han‐
33       dles device postprocessing.
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AUTHORS

36       This  document  was  written  by  Bernd  Warken ⟨groff-bernd.warken-72@
37       web.de⟩.
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SEE ALSO

40       CSTR #54
41              refers to the 1992 revision of the Nroff/Troff User's Manual  by
42              J. F. Ossanna and Brian Kernighan.
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44       CSTR #97
45              refers to A Typesetter-independent TROFF, by Brian Kernighan and
46              is the original documentation of the  first  multi-device  troff
47              (ditroff).
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49       roff(7)
50              provides a history and conceptual overview of roff systems.
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52       troff(1)
53              describes the GNU implementation of (di)troff.
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55       groff(1)
56              documents  the GNU roff program and includes pointers to further
57              documentation about groff.
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59       groff_out(5)
60              describes the groff version of the intermediate output language,
61              the basis for multi-device output.
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65groff 1.22.4                     17 March 2021                      DITROFF(7)