os.system（cmd），其回傳值是shell指令運行後傳回的狀態碼，
int類型，
0--表示shell指令成功執行，
256--表示shell找不到，
此方法適用於shell指令不需要輸出內容的場景。
該方法以檔案的形式傳回shell指令執行後的結果，
需要取得內容時可使用read()或readlines（）方法，舉例如下：
（1）commands.getstatusoutput(cmd)，其以字串的形式傳回的是輸出結果和狀態碼，即（status,output）。
（2）commands.getoutput(cmd)，傳回cmd的輸出結果。
（3）commands.getstatus(file)，傳回ls -l file的執行結果字串，呼叫了getoutput，不建議使用此方法
允許創建很多子進程，創建的時候能指定子進程和子進程的輸入、輸出、錯誤輸出管道，執行後可以獲取輸出結果和執行狀態。
（1）subprocess.run()：python3.5新增的函數， 執行指定的指令， 等待指令執行完成後傳回一個包含執行結果的CompletedProcess類別的實例。
（2）subprocess.call()：執行指定的指令，傳回指令執行狀態， 功能類似os.system（cmd）。
（3）subprocess.check_call()：python2.5中新增的函數, 執行指定的指令, 如果執行成功則傳回狀態碼， 否則拋出例外。
說明：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，若以字串形式給予shell指令，如"ls -l "則需要使shell = Ture 。否則預設已數組形式表示shell變量，如"ls","-l"。
當使用比較複雜的shell語句時，可以先使用shlex模組的shlex.split()方法來幫助格式化指令，然後在傳遞給run()方法或Popen。
附上python2.7中的subprocess模組原始碼供理解（pycharm檢視方法原始碼，ctrl 左鍵）。
# 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以上是python巡檢腳本怎麼寫的詳細內容。更多資訊請關注PHP中文網其他相關文章！
