usage: diff_py [-h] [-c | -C NUM | -u | -U NUM | -n | -H OUTPUT_FILE] [-v]
               FILES FILES

The simple diff tool which is written by Python.

positional arguments:
  FILES                 can be "FILE1 FILE2", "DIR1 DIR2", "FILE DIR", or "DIR
                        FILE"

optional arguments:
  -h, --help            show this help message and exit
  -c, --context         output 3 lines of copied context
  -C NUM                output NUM lines of copied context
  -u, --unified         output 3 lines of unified context
  -U NUM                output NUM lines of unified context
  -n, --ndiff           output Python Differ-style context
  -H OUTPUT_FILE, --html OUTPUT_FILE
                        output HTML format context
  -v, --version         show program's version number and exit