为什么我的python子流程代码无法正常工作? [英] Why won't my python subprocess code work?

问题描述

from subprocess import *

test = subprocess.Popen('ls')
print test

当我尝试运行此简单代码时，出现一个错误窗口，提示:

When i try to run this simple code, I get an error window saying:

WindowsError: [Error 2] The system cannot find the file specified

我不知道为什么我无法使这个简单的代码正常工作并且令人沮丧，任何帮助将不胜感激！

I have no clue why I can't get this simple code to work and it's frustrating, any help would be greatly appreciated!

推荐答案

您似乎想存储来自subprocess.Popen()调用的输出.
有关更多信息，请参见子进程-Popen.communicate(input=None) .

It looks like you want to store the output from a subprocess.Popen() call.
For more information see Subprocess - Popen.communicate(input=None).

>>> import subprocess
>>> test = subprocess.Popen('ls', stdout=subprocess.PIPE)
>>> out, err = test.communicate()
>>> print out
fizzbuzz.py
foo.py
[..]

但是Windows shell(cmd.exe)没有ls命令，但是还有其他两种选择:

However Windows shell (cmd.exe) doesn't have a ls command, but there's two other alternatives:

使用os.listdir() -这应该是首选方法，因为使用起来更容易:

Use os.listdir() - This should be the preffered method since it's much easier to work with:

>>> import os
>>> os.listdir("C:\Python27")
['DLLs', 'Doc', 'include', 'Lib', 'libs', 'LICENSE.txt', 'NEWS.txt', 'python.exe
', 'pythonw.exe', 'README.txt', 'tcl', 'Tools', 'w9xpopen.exe']

使用Powershell -默认安装在较新版本的Windows(> = Windows 7)上:

Use Powershell - Installed by default on newer versions of Windows (>= Windows 7):

>>> import subprocess
>>> test = subprocess.Popen(['powershell', '/C', 'ls'], stdout=subprocess.PIPE)
>>> out, err = test.communicate()
>>> print out


    Directory: C:\Python27


Mode                LastWriteTime     Length Name
----                -------------     ------ ----
d----        14.05.2013     16:00            DLLs
d----        14.05.2013     16:01            Doc
[..]

使用cmd.exe的Shell命令将如下所示:

Shell commands using cmd.exe would be something like this:

test = subprocess.Popen(['cmd', '/C', 'ipconfig'], stdout=subprocess.PIPE)

有关更多信息，请参见:
永远有用且整洁的子流程模块-在终端模拟器-Windows

For more information see:
The ever useful and neat subprocess module - Launch commands in a terminal emulator - Windows

注释:

• 请勿使用shell=True，因为这会带来安全风险.
  有关更多信息，请参见为什么不只是使用在subprocess.Popen中使用Python?
• 请勿使用from module import *.在您不应该使用的语言构造中查看原因br> 当您使用subprocess.Popen()时，它甚至在这里都没有用.

• Do not use shell=True as it is a security risk.
  For more information see Why not just use shell=True in subprocess.Popen in Python?
• Do not use from module import *. See why in Language Constructs You Should Not Use
  It doesn't even serve a purpose here, when you use subprocess.Popen().

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