メールユーザー追加用スクリプト python2

createNewMailUser.py

# -*- coding: utf-8 -*-
import os
import random
username = raw_input("user name? >>")
cmd = "useradd -s /sbin/nologin " + username
os.system(cmd)
length = random.randint(8, 12)
chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890%/'
newpass = ""
for i in range(1, length):
    newpass = newpass + random.choice(chars)
print "youcan use this string to new password."
print newpass
cmd = "passwd " + username
os.system(cmd)