$ git diff -U0 HEAD~22.. | ./contrib/devtools/clang-format-diff.py -p1 -i -v
Formatting src/test/gen/script_gen.h
Traceback (most recent call last):
  File "./contrib/devtools/clang-format-diff.py", line 164, in <module>
    main()
  File "./contrib/devtools/clang-format-diff.py", line 147, in main
    stderr=None, stdin=subprocess.PIPE)
  File "/usr/lib/python2.7/subprocess.py", line 711, in __init__
    errread, errwrite)
  File "/usr/lib/python2.7/subprocess.py", line 1343, in _execute_child
    raise child_exception
OSError: [Errno 2] No such file or directory