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This is running on Windows 7 (64 bit), Python 2.6 with Win32 Extensions for Python.

I have a simple script that just print "hello world". I can launch it with python hello.py. In this case I can redirect the output to a file. But if I run it by just typing hello.py on the command line and redirect the output, I get an exception.

C:> python hello.py hello world C:> python hello.py >output C:> type output hello world C:> hello.py hello world C:> hello.py >output close failed in file object destructor: Error in sys.excepthook: Original exception was:

I think I first get this error after upgrading to Windows 7. I remember it should work in XP. I have seen people talking about this bug python-Bugs-1012692 | Can't pipe input to a python program. But that was long time ago. And it does not mention any solution.

Have anyone experienced this? Anyone can help?

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  • 1
    Are you aware that there are TWO output streams: stdout and stderr? Commented Jun 10, 2010 at 23:04
  • Yes. And I want to redirect the stdout output. Commented Jun 11, 2010 at 5:35

4 Answers 4

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Are you asking about this?

Windows: When executing Python scripts on the command line using file type associations (i.e. starting "script.py" instead of "python script.py"), redirects may not work unless you set a specific registry key. See the Knowledge Base article STDIN/STDOUT Redirection May Not Work If Started from a File Association.

It's in the Python README. Perhaps this patch is what you're looking for.

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That's it. Just adding the InheritConsoleHandles registry value does it! Thanks a ton!!!
The link to the article is now dead. Here is an archive of the page: web.archive.org/web/20150403070207/http://support.microsoft.com/… Edit: According to the latest version of that page, the issue was fixed in a service pack for Windows XP.
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UPDATED ANSWER

A Microsoft KB issue (STDIN/STDOUT Redirection May Not Work If Started from a File Association) may be exactly this issue. The page has instructions for downloading a Win2000 hotfix, but that might not be needed on more recent Windows versions. After the hotfix (or possibly without it, depending on your Win version), a manual registry edit is needed.

You should check the link I provided; in any case, I summarize here:

  • Open Registry Editor and locate the key HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
  • Add a DWORD value named InheritConsoleHandles and set it to 1.

That's it, supposedly.

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I do have it in the PATHEXT. That's how I usually run the script. Unfortunately I got the same error with or without entering the .py extension.
@Wai: check the “new and improved” version of my answer, and let me know if this works for you.
Oops. Didn't see that S.Lott had already provided the same link. Sorry :)
Yes, that was the issue. Thanks. It helped a lot!
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If you are trying to redirect stdout and stderr from the command prompt, see http://support.microsoft.com/kb/110930

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I am not aware of the issue, but I have an idea to work around it. Have you thought about adding a command-line option (like -o) to specify an output file that will capture the output?

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Thanks for your suggestion. This will do as a last resort :) But it is not as effortless as just typing ">output" on demand. Plus I have a lot of scripts and it is not practical to change all of them.

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