Python模块---subprocess系统指令交互

# subprocess系统指令交互 `subprocess`通过子进程来执行外部指令，并通过`input/output/error`管道，获取子进程的执行的返回信息。其他类似的如`os.system`、`os.spawn*`、`os.popen*`、`commands.*`等 导入模块 ```python import subprocess ``` ## subprocess.call() 执行命令，并返回执行状态，其中shell参数为`False`时，命令需要通过列表的方式传入，当shell为`True`时，可直接传入命令，执行成功返回0，失败返回1 ```bash root@StarMeow-Svr:~# df -hT Filesystem Type Size Used Avail Use% Mounted on udev devtmpfs 424M 0 424M 0% /dev tmpfs tmpfs 87M 2.2M 85M 3% /run /dev/vda1 ext3 50G 7.5G 40G 17% / ``` ```python >>> a = subprocess.call(['df','-hT'],shell=False) Filesystem Type Size Used Avail Use% Mounted on udev devtmpfs 424M 0 424M 0% /dev tmpfs tmpfs 87M 2.2M 85M 3% /run /dev/vda1 ext3 50G 7.5G 40G 17% / >>> a 0 >>> a = subprocess.call('df -hT',shell=True) Filesystem Type Size Used Avail Use% Mounted on udev devtmpfs 424M 0 424M 0% /dev tmpfs tmpfs 87M 2.2M 85M 3% /run /dev/vda1 ext3 50G 7.5G 40G 17% / >>> a 0 >>> a = subprocess.call('test',shell=True) >>> a 1 ``` ## subprocess.check_call() 用法与`subprocess.call()`类似，区别是，当返回值不为0时，直接抛出异常 ```python >>> a = subprocess.check_call('df -hT',shell=True) Filesystem Type Size Used Avail Use% Mounted on udev devtmpfs 424M 0 424M 0% /dev tmpfs tmpfs 87M 2.2M 85M 3% /run /dev/vda1 ext3 50G 7.5G 40G 17% / >>> a 0 >>> a = subprocess.check_call('test',shell=True) Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/root/.pyenv/versions/3.6.6/lib/python3.6/subprocess.py", line 291, in check_call raise CalledProcessError(retcode, cmd) subprocess.CalledProcessError: Command 'test' returned non-zero exit status 1. ``` ## subprocess.check_output() 用法与上面两个方法类似，区别是，如果当返回值为0时，直接返回输出结果，如果返回值不为0，直接抛出异常。该方法在python3.x中才有。 ```python >>> a = subprocess.check_output('test',shell=True) Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/root/.pyenv/versions/3.6.6/lib/python3.6/subprocess.py", line 336, in check_output **kwargs).stdout File "/root/.pyenv/versions/3.6.6/lib/python3.6/subprocess.py", line 418, in run output=stdout, stderr=stderr) subprocess.CalledProcessError: Command 'test' returned non-zero exit status 1. >>> a = subprocess.check_output('pwd',shell=True) >>> a b'/root\n' ``` ## subprocess.Popen() - 将一个进程的执行输出作为另一个进程的输入 - 先进入到某个输入环境，然后再执行一系列的指令 有以下参数： - `args`：shell命令，可以是字符串，或者序列类型，如`list`,`tuple`。 - `bufsize`：缓冲区大小，可不用关心 - `stdin,stdout,stderr`：分别表示程序的标准输入，标准输出及标准错误 - `shell`：与上面方法中用法相同 - `cwd`：用于设置子进程的当前目录 - `env`：用于指定子进程的环境变量。如果`env=None`，则默认从父进程继承环境变量 - `universal_newlines`：不同系统的的换行符不同，当该参数设定为`true`时，则表示使用`\n`作为换行符 在`/root`下创建一个test的目录，然后删除该目录： ```python >>> a = subprocess.Popen('ls',shell=True,cwd='/root') >>> coolq-data django-web DockerCoolQ.sh software-download >>> a <subprocess.Popen object at 0x7f0741afba58> >>> subprocess.Popen('mkdir test', shell=True, cwd='/root') <subprocess.Popen object at 0x7f0741afbb00> >>> subprocess.Popen('ls',shell=True, cwd='/root') <subprocess.Popen object at 0x7f0741afb9e8> >>> coolq-data django-web DockerCoolQ.sh software-download test >>> subprocess.Popen('rm -rf test', shell=True, cwd='/root') <subprocess.Popen object at 0x7f0741afb940> >>> subprocess.Popen('ls',shell=True, cwd='/root') <subprocess.Popen object at 0x7f0741afb9e8> >>> coolq-data django-web DockerCoolQ.sh software-download ``` 将一个子进程的输出，作为另一个子进程的输入： ```python import subprocess child1 = subprocess.Popen(["cat","/etc/passwd"], stdout=subprocess.PIPE) child2 = subprocess.Popen(["grep","0:0"],stdin=child1.stdout, stdout=subprocess.PIPE) out = child2.communicate() ``` 执行shell脚本，获取脚本中输出的内容 ```python try: sub = subprocess.Popen("/root/django-web/AutoUwsgi.sh", shell=True, stdout=subprocess.PIPE, cwd="/root/django-web/") text = sub.stdout.read().decode('utf8') print(text) except NotADirectoryError as e: print(e) ``` http://www.cnblogs.com/breezey/p/6673901.html

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