8.2 Marking Conflicts

diff3 can mark conflicts in the merged output by bracketing them with special marker lines. A conflict that comes from two files A and B is marked as follows:

<<<<<<< A lines from A ======= lines from B >>>>>>> B

A conflict that comes from three files A, B and C is marked as follows:

<<<<<<< A lines from A ||||||| B lines from B ======= lines from C >>>>>>> C

The `-A' or `--show-all' option acts like the `-e' option, except that it brackets conflicts, and it outputs all changes from older to yours, not just the unmerged changes. Thus, given the sample input files (see section 7.1 A Third Sample Input File), `diff3 -A lao tzu tao' puts brackets around the conflict where only `tzu' differs:

<<<<<<< tzu ======= The Way that can be told of is not the eternal Way; The name that can be named is not the eternal name. >>>>>>> tao

And it outputs the three-way conflict as follows:

<<<<<<< lao ||||||| tzu They both may be called deep and profound. Deeper and more profound, The door of all subtleties! ======= -- The Way of Lao-Tzu, tr. Wing-tsit Chan >>>>>>> tao

The `-E' or `--show-overlap' option outputs less information than the `-A' or `--show-all' option, because it outputs only unmerged changes, and it never outputs the contents of the second file. Thus the `-E' option acts like the `-e' option, except that it brackets the first and third files from three-way overlapping changes. Similarly, `-X' acts like `-x', except it brackets all its (necessarily overlapping) changes. For example, for the three-way overlapping change above, the `-E' and `-X' options output the following:

<<<<<<< lao ======= -- The Way of Lao-Tzu, tr. Wing-tsit Chan >>>>>>> tao

If you are comparing files that have meaningless or uninformative names, you can use the `-L label' or `--label=label' option to show alternate names in the `<<<<<<<', `|||||||' and `>>>>>>>' brackets. This option can be given up to three times, once for each input file. Thus `diff3 -A -L X -L Y -L Z A B C' acts like `diff3 -A A B C', except that the output looks like it came from files named `X', `Y' and `Z' rather than from files named `A', `B' and `C'.