python 带参数执行命令并得到输出结果

import os
import sys

argv_0 = sys.argv[0]
argv_1 = sys.argv[1]

print argv_0
print argv_1

def execCmd(cmd):
    r = os.popen(argv_1)
    text = r.read()
    r.close()
    return text

result = execCmd("dir")
print result