[Python-Dev] subprocess shell=True on Windows doesn't escape ^ character (original) (raw)

Akira Li 4kir4.1i at gmail.com
Fri Jun 13 18🔞45 CEST 2014

Florian Bruhin <me at the-compiler.org> writes:

* Nikolaus Rath <Nikolaus at rath.org> [2014-06-12 19:11:07 -0700]:

"R. David Murray" <rdmurray at bitdance.com> writes: > Also notice that using a list with shell=True is using the API > incorrectly. It wouldn't even work on Linux, so that torpedoes > the cross-platform concern already :) > > This kind of confusion is why I opened http://bugs.python.org/issue7839.

Can someone describe an use case where shell=True actually makes sense at all? It seems to me that whenever you need a shell, the argument's that you pass to it will be shell specific. So instead of e.g. Popen('for i in seq 42; do echo $i; done', shell=True) you almost certainly want to do Popen(['/bin/sh', 'for i in seq 42; do echo $i; done'], shell=False) because if your shell happens to be tcsh or cmd.exe, things are going to break. My usecase is a spawn-command in a GUI application, which the user can use to spawn an executable. I want the user to be able to use the usual shell features from there. However, I also pass an argument to that command, and that should be escaped.

You should pass the command as a string and use cmd.exe quote rules 1 (note: they are different from the one provided by subprocess.list2cmdline() 2 that follows Microsoft C/C++ startup code rules 3 e.g., ^ is not special unlike in cmd.exe case).

-- akira

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