python commands 和 subprocess

在Python 2中，经常使用commands模块来执行shell的命令，尤其是常用getstatusoutput()函数。
但是Python3中已经没有commands模块了，那么在Python 3中如果要调用一个命令，如何做呢？使用subprocess模块

import commands
import subprocess

shell_commands = 'sar 1 3|grep "^平均时间:"'
status,result = commands.getstatusoutput(shell_commands)
print(status,result)
-------->(0, 'xe5xb9xb3xe5x9dx87xe6x97xb6xe9x97xb4: all 3.42 0.00 1.49 0.00 0.00 95.10')
print(type(commands.getstatusoutput(shell_commands)))
--------><type 'tuple'>
print(result.split()[2:]) # 取得cpu各个指标的值
-------->['3.19', '0.00', '0.86', '0.09', '0.00', '95.87']

result = subprocess.Popen(shell_command,shell=True,stdout=subprocess.PIPE)
print(result)
--------><subprocess.Popen object at 0x7fcd59974810>
print(result.stdout.read())
-------->平均时间: all 3.05 0.00 0.85 0.00 0.00 96.10
print(type(result.stdout.read()))
--------><type 'str'>
print(result.stdout.read().split()[2:]) # 取得cpu各个指标的值
-------->['9.54', '0.00', '1.39', '0.17', '0.00', '88.90']