import os, subprocess

# os.system('dir')  #执行系统命令，没有获取返回值，windows下中文乱码

# result = os.popen('dir')       #执行系统命令，返回值为result
# res = result.read()
# for line in res.splitlines():
#     print(line  )

#用subprocess库获取返回值。
# p = subprocess.Popen('dir', shell=True, stdout=subprocess.PIPE)
# out, err = p.communicate()
# for line in out.splitlines():
#     print(line)