[ python-Bugs-1714451 ] subprocess.py problems errors when calling cmd.exe

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Bugs item #1714451, was opened at 2007-05-07 14:13
Message generated for change (Comment added) made by gagenellina
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Category: Windows
Group: Python 2.5
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: tzellman (tzellman)
Assigned to: Nobody/Anonymous (nobody)
Summary: subprocess.py problems errors when calling cmd.exe

Initial Comment:
An example:

>>> import subprocess
>>> proc = subprocess.Popen('"c:\Windows\system\ping.exe" "localhost"', shell=1, stdout=subprocess.PIPE, stderr=subprocess.PIPE)

'c:\Windows\system32\ping.exe" "localhost' is not recognized as an internal or external command, operable program or batch file.

This normally works from the cmd.exe prompt, so the command line is being passed incorrectly in the subprocess module.

My ACTUAL use case arises when I want to call the Microsoft compiler (CL.exe), and add include directories that have spaces in the name. For example:

"C:\Program Files\Microsoft Visual Studio 8\VC\BIN\CL.exe" /TC /O2 /DNDEBUG /W3
/nologo /c /EHsc /errorReport:prompt /Idefault\ /I.. /I. /Idefault /I"C:\Program Files\GnuWin32" /DWIN32 ..\pcreposix.c /Fodefault\pcreposix.obj

The fix for this problem is to modify line 765 in subprocess.py, replacing it with:


args = comspec + " /s /c \"%s\"" % args.replace('""', '"')


The /s tells cmd.exe not to re-format the command line. We then encase the entire command line in double quotes. I also replace occurrences of "" with " in the arg string, in case the user already encased the command in double quotes.

With this fix, the commands execute correctly.

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Comment By: Gabriel Genellina (gagenellina)
Date: 2007-05-07 18:06

Message:
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Use a list of arguments instead, and please remember to use raw strings or
double backslashes:

proc = subprocess.Popen([r"c:\Windows\system\ping.exe","localhost"],
shell=1, stdout=subprocess.PIPE, stderr=subprocess.PIPE)


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Comment By: tzellman (tzellman)
Date: 2007-05-07 14:20

Message:
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This could likely be rejected.

I realize a solution to this w/o modifying the Python source is to encase
the expression yourself in double quotes. So, the example given would look
like:
>>> import subprocess
>>> proc = subprocess.Popen('""c:\Windows\system\ping.exe" "localhost""',
shell=1, stdout=subprocess.PIPE, stderr=subprocess.PIPE)

And that will work.

Sorry for any confusion.


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