python - 无法使用 python 3.2 运行调用子进程方法

Question

我安装了 Python 3.2，并且正在尝试使用 subprocess 模块，但我不断收到错误。

我使用的代码是:

import subprocess
subprocess.check_output(["echo", "Hello World!"])
subprocess.check_output("exit 1", shell=True)

我不断收到 subprocess.check_output(["echo", "Hello World!"]) 的以下错误

Traceback (most recent call last):
  File "<pyshell#13>", line 1, in <module>
    subprocess.check_output(["echo", "Hello World!"])
  File "C:\Python32\lib\subprocess.py", line 514, in check_output
    process = Popen(*popenargs, stdout=PIPE, **kwargs)
  File "C:\Python32\lib\subprocess.py", line 744, in __init__
    restore_signals, start_new_session)
  File "C:\Python32\lib\subprocess.py", line 977, in _execute_child
    startupinfo)
WindowsError: [Error 2] The system cannot find the file specified

对于 subprocess.check_output("exit 1", shell=True) 行，我收到以下错误:

Traceback (most recent call last):
  File "<pyshell#14>", line 1, in <module>
    subprocess.check_output("exit 1", shell=True)
  File "C:\Python32\lib\subprocess.py", line 521, in check_output
    raise CalledProcessError(retcode, cmd, output=output)
subprocess.CalledProcessError: Command 'exit 1' returned non-zero exit status 1

Answer 1

据我所知，问题不在于subprocess——问题是没有名为echo的可执行文件路径:

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

我的猜测是echo是一个Windows Shell内部命令。尝试使用 shell=True 启动它:

subprocess.check_output(["echo", "Hello World!"], shell=True)

如果您想调用可执行程序(“.exe”)，则不需要 shell。只需传递程序的名称和可选参数:

subprocess.check_output(["notepad.exe", "file.txt"])

<小时/>

顺便说一句，你想用这条线做什么:

subprocess.check_output("exit 1", shell=True)

这只会启动一个子 shell，要求它立即退出并返回非零状态代码？!？