8.1 Selecting Which Changes to Incorporate

You can select all unmerged changes from older to yours for merging into mine with the `-e' or `--ed' option. You can select only the nonoverlapping unmerged changes with `-3' or `--easy-only', and you can select only the overlapping changes with `-x' or `--overlap-only'.

The `-e', `-3' and `-x' options select only unmerged changes, i.e. changes where mine and yours differ; they ignore changes from older to yours where mine and yours are identical, because they assume that such changes have already been merged. If this assumption is not a safe one, you can use the `-A' or `--show-all' option (see section 8.2 Marking Conflicts).

Here is the output of the command diff3 with each of these three options (see section 7.1 A Third Sample Input File, for the complete contents of the files). Notice that `-e' outputs the union of the disjoint sets of changes output by `-3' and `-x'.

Output of `diff3 -e lao tzu tao':

11a -- The Way of Lao-Tzu, tr. Wing-tsit Chan . 8c so we may see their result. .

Output of `diff3 -3 lao tzu tao':

8c so we may see their result. .

Output of `diff3 -x lao tzu tao':

11a -- The Way of Lao-Tzu, tr. Wing-tsit Chan .