DIFFMK(1)			 HP-UX 5.0		     DIFFMK(1)

     NAME
	  diffmk - mark differences between files

     SYNOPSIS
	  diffmk name1 name2 name3

     HP-UX COMPATIBILITY
	  Level:    HP-UX/STANDARD

	  Origin:   System V

     DESCRIPTION
	  Diffmk compares two versions of a file and creates  a	 third
	  file	that includes ``change mark'' commands for nroff(1) or
	  troff(1).  Name1 and name2 are the old and new  versions  of
	  the  file.  Diffmk generates name3, which contains the lines
	  of name2  plus  inserted  formatter  ``change	 mark''	 (.mc)
	  requests.  When name3 is formatted, changed or inserted text
	  is shown by |	 at  the  right	 margin	 of  each  line.   The
	  position of deleted text is shown by a single *.

	  If anyone is so inclined, diffmk  can	 be  used  to  produce
	  listings  of	C  (or other) programs with changes marked.  A
	  typical command line for such use is:

	       diffmk old.c new.c tmp; nroff macs tmp | pr

	  where the file macs contains:

	       .pl 1
	       .ll 77
	       .nf
	       .eo
	       .nc

	  The .ll request  might  specify  a  different	 line  length,
	  depending  on	 the nature of the program being printed.  The
	  .eo  and  .nc	 requests  are	probably  needed  only	for  C
	  programs.

	  If the characters | and  *  are  inappropriate,  a  copy  of
	  diffmk  can  be  edited  to  change  them (diffmk is a shell
	  procedure).

     SEE ALSO
	  diff(1), nroff(1), troff(1).

     BUGS
	  Aesthetic considerations may dictate	manual	adjustment  of
	  some	output.	  File	differences  involving only formatting
	  requests may produce undesirable output, i.e., replacing .sp
	  by  .sp 2 will produce a ``change mark'' on the preceding or
	  following line of output.

	  Although  unlikely,  certain	combinations   of   formatting
	  requests  may	 cause	change marks to either disappear or to
	  mark too much.  Manual intervention may be required  as  the
	  subtleties  of all the various formatting macro packages and
	  preprocessors is beyond the scope of diffmk.	The  input  to
	  tbl(1)  cannot  tolerate  .mc	 commands.  Any .mc that would
	  appear inside a .TS range will  be  silently	deleted.   The
	  script  can  be  changed  if this action is inappropriate or
	  diffmk can be run on the output from tbl(1).

	  Diffmk uses diff(1) and thus	has  whatever  limitations  on
	  file	 size  and  performance	 that  diff  may  impose.   In
	  particular the performance is non-linear with	 the  size  of
	  the  file,  and  very large files (well over 1000 lines) may
	  take extremely long to  process.   Breaking  the  file  into
	  smaller pieces may be advisable.

	  Diffmk also uses ed(1), and if the file is too large for ed,
	  ed  error  messages  may  be	imbedded  in the file.	Again,
	  breaking the file into smaller pieces may be advisable.