Nice to see that my topic gains that interest :)
And I see that I should have gone more into detail about what I'm actually
trying to point out.
Chris Angelico wrote:
> Hmm... hm... Ha! Found the difference. I had an explicit shebang on my
> script; yours just starts out with shell commands. That means that
> your shell script wasn't truly executable, and thus requires a shell
> to execute it. Try adding "#!/bin/sh" to the top and rerun that - at
> that point, it becomes kernel-executable instead of just
> shell-executable.
That's the big advantage of Unix. You can write an kernel-executable script
without any file extension, just by putting a shebang to the beginning of that
file. And for the caller it makes no difference if 'command' is a binary or a
script and Popen('command') works in both cases, without the shell=True
overhead.
Steven D'Aprano wrote:
> Apart from any other number of problems, surely having "foo" alone run
> foo.exe, foo.bat etc. is at best confusing and at worst a security risk?
> What if you have *both* foo.exe and foo.bat in the same directory?
On Unix you can shadow any binary with a wrapper script of the same name
located in a path appearing earlier in $PATH. Any caller will automatically run
your script instead of the original binary. An that's usually seen as a big
advantage on Unix.
On Windows executability depends on the file extension and if you want to wrap
some command.exe you usually write a command.bat in a path with higher
precedence. And in Windows it's standard that .exe, .com, .bat and .cmd files
should be callable without writing the file extension.
And as already mentioned, there is a defined precedence order if they are in
the same directory.
That's not more or less security risky as shadowing binaries with scripts on
Unix.
My point is that compared to Unix it's just a big disadvantage on Windows that
the subprocess.Popen(['command']) can only call command.exe implicitly, which
makes it impossible to work with custom wrapper .bat or .cmd scripts without
the shell=True overhead.
And this is acutally confusing for a Windows user.
You write a wrapper .bat for some .exe and are wondering why your Python script
doesn't use it.
And the FindExecutable() function from the win32 API would just be the perfect
solution for implementing this.
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