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 marked-
file, 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 hyphe-
nation, respectively.  If the characters | and *  are  inap-
propriate,  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.