python执行命令行：python中执行shell命令行read结果

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python执行shell命令
1 os.system （只有这个方法是边执行边输出，其他方法是最后一次性输出）

可以返回运行shell命令状态，同时会在终端输出运行结果

例如 ipython中运行如下命令，返回运行状态status

os.system(\'python -V\')
os.system(\'tree\')

遇到乱码问题可以采用一次性输出来解决。https://www.cnblogs.com/andy9468/p/8418649.html

或者pycharm的乱码问题：https://www.cnblogs.com/andy9468/p/12766382.html

2 os.popen()

可以返回运行结果

import os

r = os.popen(\'python -V\').read()
print(type(r))
print(r)

或者

In [20]: output = os.popen(\'cat /proc/cpuinfo\')

In [21]: lineLen = []

In [22]: for line in output.readlines():
    lineLen.append(len(line))
   ....:     

In [23]: line
line     lineLen  

In [23]: lineLen
Out[23]: 
[14,
 25,
...

3 commands.getstatusoutput(\'cat /proc/cpuinfo\')

如何同时返回结果和运行状态，commands模块:

import commands
(status, output) = commands.getstatusoutput(\'cat /proc/cpuinfo\')

In [25]: status
Out[25]: 0

In [26]: len(output)
Out[26]: 3859

4 subprocess.Popen(["ls","-l"], stdout=subprocess.PIPE)

使用模块subprocess

通常项目中经常使用方法为subporcess.Popen, 我们可以在Popen()建立子进程的时候改变标准输入、标准输出和标准错误，并可以利用subprocess.PIPE将多个子进程的输入和输出连接在一起，构成管道(pipe):

import subprocess
child1 = subprocess.Popen("tree",shell=True, stdout=subprocess.PIPE)
out = child1.stdout.read()
print(out.decode(\'gbk\'))

import subprocess
child1 = subprocess.Popen("tree /F".split(),shell=True, stdout=subprocess.PIPE)
out = child1.stdout.read()
print(out.decode(\'gbk\'))

import subprocess
child1 = subprocess.Popen([\'tree\',\'/F\'].split(),shell=True, stdout=subprocess.PIPE)
out = child1.stdout.read()
print(out.decode(\'gbk\'))

退出进程

size_str = os.popen(\'adb shell wm size\').read()
if not size_str:
　　print(\'请安装 ADB 及驱动并配置环境变量\')
　　sys.exit()

封装好的函数：Python执行shell命令

from subprocess import Popen, PIPE


def run_cmd(cmd):
    # Popen call wrapper.return (code, stdout, stderr)
    child = Popen(cmd, stdin=PIPE, stdout=PIPE, stderr=PIPE, shell=True)
    out, err = child.communicate()
    ret = child.wait()
    return (ret, out, err)

if __name__ == \'__main__\':
    r=run_cmd("dir")

    print(r[0])
    print(r[1].decode("gbk"))
    print(r[2])

python执行系统命令-小结：

# (1)os.system
# (2)os.popen
# (3)使用模块subprocess的Popen
# (4)使用模块commands模块


# (1)os.system
import os

os.system(\'start .\')

# (2)os.popen
import os

ping_list = os.popen("ping 127.0.0.1").readlines()
print(ping_list)

# (3)py3使用模块subprocess的Popen
import subprocess

# child1 = subprocess.Popen("tree".split(), shell=True, stdout=subprocess.PIPE)
# child1 = subprocess.Popen("tree /F".split(), shell=True, stdout=subprocess.PIPE)
child1 = subprocess.Popen([\'tree\', \'/F\'].split(), shell=True, stdout=subprocess.PIPE)
out = child1.stdout.read()
print(out.decode(\'gbk\'))

# (4)py2使用模块commands模块
# commands是python2版本里的，在python3.0以上已经没有commands模块了，使用subprocess代替commands
import commands

(status, output) = commands.getstatusoutput(\'cat /proc/cpuinfo\')
print(status)
print(output)