归并排序归并排序05-11 14:48

Python调用shell命令常用方法(4种)

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表示未找到,该方法适用于shell命令不需要输出内容的场景。

举例说明:

1. 列举当前目录下的所有文件。

import os
val = os.system('ls -al')
print val

没有找到时,sh返回的状态码是1,而适用python调用,返回的是:256

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)。

# 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

shell脚本使用python脚本的参数

写一个hello.sh脚本,需要传入两个参数:

执行结果如下:

在python脚本中调用shell脚本,并传入参数,注意参数前后要有空格

执行python脚本

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