Comparing Three Different Files (diff3)

To compare three different versions of a file, use the diff3 command.

$ diff3 file1 file2 file3

diff3 compares three versions of a file and publishes the differing ranges of text that are flagged with these codes:

==== all three files differ

====1 file1 is different

====2 file2 is different

====3 file3 is different