python 万能脚本，到哪里搞巡检都不怕，反正有我就是老大

方法一、使用os模块的system方法：os.system（cmd），
其返回值是shell指令运行后返回的状态码，
int类型，
0--表示shell指令成功执行，
256--表示shell未找到，
该方法适用于shell命令不需要输出内容的场景。

方法二、使用os.popen()，
该方法以文件的形式返回shell指令运行后的结果，
需要获取内容时可使用read()或readlines（）方法，举例如下：

方法三、使用commands模块，有三个方法可以使用：

（1）commands.getstatusoutput(cmd)，其以字符串的形式返回的是输出结果和状态码，即（status,output）。

（2）commands.getoutput(cmd)，返回cmd的输出结果。

（3）commands.getstatus(file)，返回ls -l file的执行结果字符串，调用了getoutput，不建议使用此方法

方法四、subprocess模块，允许创建很多子进程，创建的时候能指定子进程和子进程的输入、输出、错误输出管道，执行后能获取输出结果和执行状态。

（1）subprocess.run()：python3.5中新增的函数， 执行指定的命令， 等待命令执行完成后返回一个包含执行结果的CompletedProcess类的实例。

（2）subprocess.call()：执行指定的命令， 返回命令执行状态， 功能类似os.system（cmd）。

（3）subprocess.check_call()：python2.5中新增的函数, 执行指定的命令, 如果执行成功则返回状态码， 否则抛出异常。

说明：subprocess.run(args, *, stdin=None, input=None, stdout=None, stderr=None, shell=False, timeout=None, check=False, universal_newlines=False)

　　 subprocess.call(args, *, stdin=None, stdout=None, stderr=None, shell=False, timeout=None)

　　 subprocess.check_call(args, *, stdin=None, stdout=None, stderr=None, shell=False, timeout=None)

　　 args：表示shell指令，若以字符串形式给出shell指令，如"ls -l "则需要使shell = Ture。否则默认已数组形式表示shell变量，如"ls","-l"。

　　 当使用比较复杂的shell语句时，可以先使用shlex模块的shlex.split()方法来帮助格式化命令，然后在传递给run()方法或Popen。

附上python2.7中的subprocess模块源码供理解（pycharm查看方法源码，ctrl+左键）。

附上python2.7中的subprocess模块源码供理解（pycharm查看方法源码，ctrl+左键）。

# Stubs for subprocess

# Based on http://docs.python.org/2/library/subprocess.html and Python 3 stub

from typing import Sequence, Any, Mapping, Callable, Tuple, IO, Union, Optional, List, Text

_FILE = Union[None, int, IO[Any]]
_TXT = Union[bytes, Text]
_CMD = Union[_TXT, Sequence[_TXT]]
_ENV = Union[Mapping[bytes, _TXT], Mapping[Text, _TXT]]

# Same args as Popen.__init__
def call(args: _CMD,
         bufsize: int = ...,
         executable: _TXT = ...,
         stdin: _FILE = ...,
         stdout: _FILE = ...,
         stderr: _FILE = ...,
         preexec_fn: Callable[[], Any] = ...,
         close_fds: bool = ...,
         shell: bool = ...,
         cwd: _TXT = ...,
         env: _ENV = ...,
         universal_newlines: bool = ...,
         startupinfo: Any = ...,
         creationflags: int = ...) -> int: ...

def check_call(args: _CMD,
               bufsize: int = ...,
               executable: _TXT = ...,
               stdin: _FILE = ...,
               stdout: _FILE = ...,
               stderr: _FILE = ...,
               preexec_fn: Callable[[], Any] = ...,
               close_fds: bool = ...,
               shell: bool = ...,
               cwd: _TXT = ...,
               env: _ENV = ...,
               universal_newlines: bool = ...,
               startupinfo: Any = ...,
               creationflags: int = ...) -> int: ...

# Same args as Popen.__init__ except for stdout
def check_output(args: _CMD,
                 bufsize: int = ...,
                 executable: _TXT = ...,
                 stdin: _FILE = ...,
                 stderr: _FILE = ...,
                 preexec_fn: Callable[[], Any] = ...,
                 close_fds: bool = ...,
                 shell: bool = ...,
                 cwd: _TXT = ...,
                 env: _ENV = ...,
                 universal_newlines: bool = ...,
                 startupinfo: Any = ...,
                 creationflags: int = ...) -> bytes: ...

PIPE = ...  # type: int
STDOUT = ...  # type: int

class CalledProcessError(Exception):
    returncode = 0
    # morally: _CMD
    cmd = ...  # type: Any
    # morally: Optional[bytes]
    output = ...  # type: Any

    def __init__(self,
                 returncode: int,
                 cmd: _CMD,
                 output: Optional[bytes] = ...) -> None: ...

class Popen:
    stdin = ...  # type: Optional[IO[Any]]
    stdout = ...  # type: Optional[IO[Any]]
    stderr = ...  # type: Optional[IO[Any]]
    pid = 0
    returncode = 0

    def __init__(self,
                 args: _CMD,
                 bufsize: int = ...,
                 executable: Optional[_TXT] = ...,
                 stdin: Optional[_FILE] = ...,
                 stdout: Optional[_FILE] = ...,
                 stderr: Optional[_FILE] = ...,
                 preexec_fn: Optional[Callable[[], Any]] = ...,
                 close_fds: bool = ...,
                 shell: bool = ...,
                 cwd: Optional[_TXT] = ...,
                 env: Optional[_ENV] = ...,
                 universal_newlines: bool = ...,
                 startupinfo: Optional[Any] = ...,
                 creationflags: int = ...) -> None: ...

    def poll(self) -> int: ...
    def wait(self) -> int: ...
    # morally: -> Tuple[Optional[bytes], Optional[bytes]]
    def communicate(self, input: Optional[_TXT] = ...) -> Tuple[Any, Any]: ...
    def send_signal(self, signal: int) -> None: ...
    def terminate(self) -> None: ...
    def kill(self) -> None: ...
    def __enter__(self) -> 'Popen': ...
    def __exit__(self, type, value, traceback) -> bool: ...

# Windows-only: STARTUPINFO etc.

STD_INPUT_HANDLE = ...  # type: Any
STD_OUTPUT_HANDLE = ...  # type: Any
STD_ERROR_HANDLE = ...  # type: Any
SW_HIDE = ...  # type: Any
STARTF_USESTDHANDLES = ...  # type: Any
STARTF_USESHOWWINDOW = ...  # type: Any
CREATE_NEW_CONSOLE = ...  # type: Any
CREATE_NEW_PROCESS_GROUP = ...  # type: Any