gistfile1.py

import sys

def perms(s):
    num_perms = 2**len(s)

    for perm in xrange(num_perms):
        yield ''.join(
            c.swapcase() if (1 << i & perm) else c
            for i, c in enumerate(s)
        )

for perm in perms(sys.argv[1]):
    print perm