Inspect $PATH environment variable for duplicates and invalid paths. Prints cleaned version afterwards.

cleanpath.py

#!/usr/bin/env python
import os
paths = os.getenv('PATH').split(os.pathsep)
cleaned_paths = []
for path in paths:
    if path in cleaned_paths:
        print 'Duplicated:', path
        continue
    if not os.path.exists(path):
        print 'Doesn\'t exist: ', path
        continue
    cleaned_paths.append(path)
print 'Cleaned PATH:', os.pathsep.join(cleaned_paths)