Convert Size to Human Readable String

cs.py

#!/usr/bin/env python
import sys

types = ["KB","MB","GB","TB","PB","EB","ZB","YB"]

def convert(s):
    div = 1024
    i = 0
    while i < len(types):
        s /= div
        if s < div:
            print("{:5.3f} {}".format(s, types[i]))
            return
        i += 1


if __name__ == "__main__":
    if (len(sys.argv) != 2) or (len(sys.argv) == 2 and sys.argv[1].isdigit() is False):
        print("Invalid input")
    else:
        convert(int(sys.argv[1]))