diffmk(1)          UNIX System V(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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