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DITROFF(7)							    DITROFF(7)

       ditroff - classical device independent roff

       The name	ditroff	once marked a development level	of the troff text pro-
       cessing system.	In actual roff(7) systems, the name troff is used as a
       synonym for ditroff.

       The  first  roff	system was written by Joe Osanna around	1973.  It sup-
       ported only two output devices, the nroff program  produced  text  ori-
       ented  tty  output,  while the troff program generated graphical	output
       for exactly one output device, the Wang Graphic Systems CAT typesetter.

       In  1979, Brian Kernighan rewrote troff to support more devices by cre-
       ating an	intermediate output format for troff  that  can	 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 Osanna's original mono-device version, it
       was called ditroff (device independent troff) on	some  systems,	though
       this naming isn't mentioned in the classical documentation.

       Today,  any  existing  roff system is based on Kernighan's multi-device
       troff.  The distinction between troff and ditroff isn't	necessary  any
       longer, for each	modern troff provides already the complete functional-
       ity of ditroff.	On most	systems, the name  troff  is  used  to	denote

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

       [CSTR #54]
	      The  1992	 revision  of  the  Nroff/Troff	User's Manual by J. F.
	      Osanna and Brian Kernighan, see
	      Bell Labs	CSTR #54 <>.

       [CSTR #97]
	      A	 Typesetter-independent	TROFF by Brian Kernighan is the	origi-
	      nal documentation	of the first multi-device troff	(ditroff), see
	      Bell Labs	CSTR #97 <>.

	      This document gives details on the history and concepts of roff.

	      The actual implementation	of ditroff.

	      The  GNU	roff  program and pointers to all documentation	around

	      The groff	version	of the intermediate output language, the basis
	      for multi-devicing.

       Copyright (C) 2001, 2002, 2004 Free Software Foundation,	Inc.

       This document is	distributed under the terms of the FDL (GNU Free Docu-
       mentation License) version 1.1 or later.	 You should  have  received  a
       copy of the FDL on your system, it is also available on-line at the GNU
       copyleft	site <>.

       This document is	part of	groff, the  GNU	 roff  distribution.   It  was
       written	by  Bernd Warken <> and is maintained by	Werner
       Lemberg <>.

Groff Version 1.19.2	       27 September 2013		    DITROFF(7)


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