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

  -e  --ed  Output unmerged changes from OLDFILE to YOURFILE into MYFILE.
  -E  --show-overlap  Output unmerged changes, bracketing conflicts.
  -A  --show-all  Output all changes, bracketing conflicts.
  -x  --overlap-only  Output overlapping changes.
  -X  Output overlapping changes, bracketing them.
  -3  --easy-only  Output unmerged nonoverlapping changes.

  -m  --merge  Output merged file instead of ed script (default -A).
  -L LABEL  --label=LABEL  Use LABEL instead of file name.
  -i  Append `w' and `q' commands to ed scripts.
  -a  --text  Treat all files as text.
  -T  --initial-tab  Make tabs line up by prepending a tab.
  --diff-program=PROGRAM  Use PROGRAM to compare files.

  -v  --version  Output version info.
  --help  Output this help.

If a FILE is `-', read standard input.

Report bugs to <bug-gnu-utils@gnu.org>.