diffmk

PURPOSE

     Marks differences between files.

SYNOPSIS
     diffmk [ -b ] [ -ab"req" ] [ -ae"req" ] [ -cb"req" ] [ -ce"req" ]
     [ -db"req" ] [ -de"req" ] old.version new.version [ marked.file ]


DESCRIPTION

     The diffmk command compares file1 and file2 and creates a
     third  file that  includes change  mark commands  for the
     nroff and  troff commands.  file1  and file2 are  the old
     and new  versions of the  file.  diffmk writes  the newly
     created  file  to file3,  if  specified,  or to  standard
     output.  This file contains the  lines of file2 with for-
     matter  change mark  (.mc)  requests  inserted as  appro-
     priate.  When file3 is formatted, the changed or inserted
     text is marked by a |  (vertical bar) at the right margin
     of each line.  An "*"  (asterisk) in the margin indicates
     that a line was deleted.

     If  the environment  parameter  DIFFMARK  is defined,  it
     names a  command string that  diffmk uses to  compare the
     files.  (Normally,  diffmk uses  the diff  command.)  For
     example, you might set DIFFMARK  to "diff -h" in order to
     better handle extremely large files.

FLAGS

     -abX   Uses X to mark where added lines begin.
     -aeX   Uses X to mark where added lines end.
     -b     Ignores differences that are  only changes in tabs
            or spaces on a line.
     -cbX   Uses X to mark where changed lines begin.
     -ceX   Uses X to mark where changed lines end.
     -dbX   Uses X to mark where deleted lines begin.
     -deX   Uses X to mark where deleted lines end.

EXAMPLES

     1.  To  mark the  differences between  two versions  of a
         text file:

           diffmk  chap1.old  chap1  > chap1.nroff

         This   produces   a   copy  of   "chap1"   containing
         nroff/troff  change mark  commands  to identify  text
         that has been  added to, changed in,  or deleted from

         "chap1.old".   This   copy  is  saved  in   the  file
         "chap1.nroff".
     2.  To mark differences with non-nroff/troff messages:

           diffmk -ab'>>New:' -ae'<<End New' chap1.old  chap1  >chap1.nroff

         This  causes diffmk  to  write ">>New:"  on the  line
         before a section of new lines that have been added to
         "chap1" and  to write  "<<End New"  on the  line fol-
         lowing the added lines.   Changes and deletions still
         generate nroff/troff  commands to put  a | or  "*" in
         the margin.
     3.  To  use different  nroff/troff  marking commands  and
         ignore changes in white space:

           diffmk  -b  -cb'.mc  %'  chap1.old  chap1  > chap1.nroff

         This  imbeds commands  that  mark  changes with  "%",
         additions with  |, and  deletions with "*".   It does
         not mark changes that only involve a different number
         of spaces or tabs between words ("-b").

RELATED INFORMATION

     The  following commands:   "diff,"   "nroff, troff,"  and
     "troff."