python产生随机字符串
import random
import string
ran_str = ''.join(random.sample(string.ascii_letters + string.digits, 8))
print ran_str
import random
import string
ran_str = ''.join(random.sample(string.ascii_letters + string.digits, 8))
print ran_str
python -c ‘import os; print(os.urandom(16))’