#coding=utf-8
import subprocess

# 如果使用了stdout=subprocess.PIPE，则要自己打印输出，否则控制台不会打印
#
result=subprocess.Popen('dir',shell=True,stderr=subprocess.PIPE,stdout=subprocess.PIPE)

result.wait()
outs,errs=result.communicate()  #返回元组，标准输出以及err
#执行成功则打印输出的信息
if result.returncode==0:
    for i in outs.splitlines():
        print(i.decode('GBK')) #UTF-8

只想获取失败信息，忽略成功信息

result=subprocess.Popen('ddd',shell=True,stderr=subprocess.PIPE,stdout=subprocess.PIPE)

result.wait()
outs,errs=result.communicate()
#执行成功则打印输出的信息
if not result.returncode==0:
    for i in errs.splitlines():
        print(i.decode('GBK')) #UTF-8

有时调用稍微复杂的命令，该命令又会调用其他命令，虽然返回时0，但err却不为空，因此再加层判断

result=subprocess.Popen('ddd',shell=True,stderr=subprocess.PIPE,stdout=subprocess.PIPE)

result.wait()
outs,errs=result.communicate()
#执行成功则打印输出的信息 注意b''即使为不为None，因此不能用not None来判断
if not result.returncode==0 or not len(errs)==0:
    for i in errs.splitlines():
        print(i.decode('GBK')) #返回为字节，需要转成str
    for i in outs.splitlines():
        print(i.decode('GBK'))  # UTF-8