On 05/06/2015 06:11 PM, Stefan Zimmermann wrote:
Hi.
I don't like that subprocess.Popen(['command']) only works on Windows if there
is a command.exe in %PATH%.
As a Windows user you would normally expect that also command.bat and
command.cmd can be run that way.
and command.com.
If it's really unfortunate that you picked "command" for your sample
program name. Since command.com was the shell in MSDOS, I was about to
point you to COMSPEC to address your problem.
There's nothing Windows-specific about that behaviour. In Linux, there
are bash commands that can only be run by using shell=True. Fortunately
Popen didn't make the mistake of pretending it's a shell.
There is lots more to running a batch file than launching it. The whole
syntax of the rest of the commandline differs when you're doing that.
There are simple workarounds like Popen(..., shell=True) but that is a heavy
overhead for .exe files.
And the reason there's such an overhead is because you're requesting the
services of the shell. If you don't need those services, use shell=False.
Currently I use pywin32 and call Popen([win32api.FindExecutable('command')[1]])
as a workaround. This has zero overhead.
It should be default for Popen to call FindExecutable internally.
Was this discussed before?
Is it worth a PEP?
Or at least an issue?
Cheers,
Stefan
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DaveA
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