/usr/bin/diff3

Usage: /usr/bin/diff3 [OPTION]... MYFILE OLDFILE YOURFILE
Compare three files line by line.

Mandatory arguments to long options are mandatory for short options too.
  -A, --show-all              output all changes, bracketing conflicts

  -e, --ed                    output ed script incorporating changes
                                from OLDFILE to YOURFILE into MYFILE
  -E, --show-overlap          like -e, but bracket conflicts
  -3, --easy-only             like -e, but incorporate only nonoverlapping changes
  -x, --overlap-only          like -e, but incorporate only overlapping changes
  -X                          like -x, but bracket conflicts
  -i                          append 'w' and 'q' commands to ed scripts

  -m, --merge                 output actual merged file, according to
                                -A if no other options are given

  -a, --text                  treat all files as text
      --strip-trailing-cr     strip trailing carriage return on input
  -T, --initial-tab           make tabs line up by prepending a tab
      --diff-program=PROGRAM  use PROGRAM to compare files
  -L, --label=LABEL           use LABEL instead of file name
                                (can be repeated up to three times)

      --help                  display this help and exit
  -v, --version               output version information and exit

The default output format is a somewhat human-readable representation of
the changes.

The -e, -E, -x, -X (and corresponding long) options cause an ed script
to be output instead of the default.

Finally, the -m (--merge) option causes diff3 to do the merge internally
and output the actual merged file.  For unusual input, this is more
robust than using ed.

If a FILE is '-', read standard input.
Exit status is 0 if successful, 1 if conflicts, 2 if trouble.

Report bugs to: bug-diffutils@gnu.org
GNU diffutils home page: <https://www.gnu.org/software/diffutils/>
General help using GNU software: <https://www.gnu.org/gethelp/>