diffmk(1)							     diffmk(1)

NAME
       diffmk - mark changes between two different versions of a file

SYNOPSIS
       prevfile currfile markfile

DESCRIPTION
       compares	 the  previous	version of a file with the current version and
       creates a file that includes ``change mark'' commands.  prevfile is the
       name  of	 the  previous version of the file and currfile is the name of
       the current version of the file.	 generates markfile which contains all
       the  lines  of  the  currfile  plus  inserted formatter ``change mark''
       requests.  When markfile is formatted,  changed	or  inserted  text  is
       shown by a character at the right margin of each line.  The position of
       deleted text is shown by a single

       If the characters and are inappropriate, a copy of  can	be  edited  to
       change them because is a shell script.

EXTERNAL INFLUENCES
   International Code Set Support
       Single- and multi-byte character code sets are supported.

EXAMPLES
       A typical command line for comparing two versions of an file and gener‐
       ating a file with the changes marked is:

       can also be used to produce listings of	C  (or	other)	programs  with
       changes marked.	A typical command line for such use is:

       where the file contains:

       The  request  can  specify  a  different	 line length, depending on the
       nature of the program being printed.  The request  is  probably	needed
       only for C programs.

WARNINGS
       Aesthetic considerations may dictate manual adjustment of some output.

       does not differentiate between changes in text and changes in formatter
       request coding.	 Thus,	file  differences  involving  only  formatting
       changes	(such  as replacing with in a text source file) with no change
       in actual text can produce change marks.

       Although unlikely, certain  combinations	 of  formatting	 requests  can
       cause  change  marks  to	 either disappear or to mark too much.	Manual
       intervention may be required because the subtleties of various  format‐
       ting  macro  packages  and  preprocessors is beyond the scope of cannot
       tolerate commands in its input (see tbl(1)), so any request that	 would
       appear  inside  a range is silently deleted.  The script can be changed
       if this action is inappropriate, or can be run on two files  that  have
       both been run through the preprocessor before any comparisons are made.

       uses  and  thus	has  the same limitations on file size and performance
       that may impose	(see diff(1)).	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.

       also  uses  the	ed(1) editor.  If the file is too large for error mes‐
       sages may be embedded in the  file.   Again,  breaking  the  file  into
       smaller pieces may be advisable.

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

								     diffmk(1)

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