tests/readlink.py

help: improve merge-tools topic, describe --tool and clarify details

This doesn't make it simpler, but it makes it more correct.

With help from erikz, mg and abuehl.

#!/usr/bin/env python

import errno, os, sys

for f in sys.argv[1:]:
    try:
        print f, '->', os.readlink(f)
    except OSError, err:
        if err.errno != errno.EINVAL:
            raise
        print f, 'not a symlink'

sys.exit(0)