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Date: Mon, 16 Jun 2014 21:09:01 +1000
Subject: Re: line to argv transformation
From: Chris Angelico <rosuav@gmail.com>
Cc: "python-list@python.org" <python-list@python.org>
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On Mon, Jun 16, 2014 at 8:51 PM, Tim Chase
<python.list@tim.thechases.com> wrote:
> On 2014-06-16 20:41, Chris Angelico wrote:
>> Oops! I made the cardinal error of trying in one and assuming it'd
>> work in both. Just needs a b prefix on the split string:
>>
>> def shell_split(cmd):
>>     return subprocess.check_output("""python -c 'import sys;
>> print("\\0".join(sys.argv[1:]))'
>> """+cmd,shell=True)[:-1].split(b"\0")
>>
>> You'll get back a list of byte strings, in any case. Feel free to
>> pass them through a decode operation, or to incorporate a .decode()
>> into the above stream, as you wish.
>
> Tested on Win32?  The behavior of "shell expansion" on Windows
> cmd.exe differs from most *nix shells (i.e., it *doesn't* expand, so
> you have to do it yourself), so Antoon would need to describe the
> desired behavior on Win32.

Well, his example commands began "ls", which is a common Unix command,
but isn't present on most Windows systems. If he'd started out with
something that looked more Windowsish, I'd totally understand - you
start with a single line, and you need to do what the cmd.exe shell
hasn't done for you. (Although splitting is done, so it still wouldn't
be quite as clear.) But he said "treated as a command line". So that's
exactly what I did. :) He didn't ask about globbing, he asked about
doing what the shell does... maybe he wants variable expansion too?

>>> shell_split("echo $DISPLAY")
[b'echo', b'localhost:10.0']

(This is running over SSH, so my $DISPLAY is a perhaps unusual value.)

ChrisA