diffmk(1)               (BSD Compatibility Package)               diffmk(1)


   NAME
         diffmk - mark differences between versions of a troff input file

   SYNOPSIS
         /usr/ucb/diffmk oldfile newfile markedfile

   DESCRIPTION
         The diffmk command compares two versions of a file and creates a
         third version that includes ``change mark'' (.mc) commands for nroff
         and troff.  oldfile and newfile are the old and new versions of the
         file.  diffmk generates markedfile, which, contains the text from
         newfile with troff(1) ``change mark'' requests (.mc) inserted where
         newfile differs from oldfile.  When markedfile is formatted, changed
         or inserted text is shown by a | at the right margin of each line.
         The position of deleted text is shown by a single *.

         diffmk can also be used in conjunction with the proper troff requests
         to produce program listings with marked changes.  In the following
         command line:

               diffmk old.c new.c marked.c ; nroff reqs marked.c | pr

         the file reqs contains the following troff requests:
               .pl 1
               .ll 77
               .nf
               .eo
               .nh

         which eliminate page breaks, adjust the line length, set no-fill
         mode, ignore escape characters, and turn off hyphenation,
         respectively.

         If the characters | and * are inappropriate, you might run markedfile
         through sed to globally change them.

   SEE ALSO
         nroff(1), troff(1)

         diff(1), sed(1) in the User's Reference Manual.

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






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