Question

>>> import subprocess
>>> f = open('txt', 'w+')
>>> p = subprocess.Popen(['dir'],stdout=f,stderr=f, shell=True)
>>> p.communicate()
(None, None) # stdout, stderr are empty. Same happens if I open a win32 gui app instead of python (don't think win32 gui apps set a stdout/stderr)

我想检索subprocess的stdout或stderr来测试它们的一些特征（不是当前的sys.__stdout__）。我怎么能从python解释器那里做到这一点？

Answer 1

我认为您正在寻找subprocess.PIPE

示例

>>> from subprocess import Popen, PIPE >>> process = subprocess.Popen(['ls'], stdout = PIPE, stderr = PIPE, shell = True ) >>> process.communicate() ('file\nfile1\nfile2, '')

可以看出，

process.communicate()[0]

是命令的标准输出和

process.communicate()[1]

是stderr

Answer 2

您可以使用check_output并捕获CalledProcessError：

from subprocess import check_output, CalledProcessError

try:
    out = check_output(["dir"]) # windows  out = check_output(["cmd", "/c", "dir"])
except CalledProcessError as e:
    out = e.output

print(out)

我如何在Windows上的python中测试子进程的stdout，stderr

2 个答案: