[Tutor] subprocess.call list vs. str argument

[Albert-Jan Roskam]

Hi,

In the code below, cmd1 and cmd2 are equivalent, as in: " ".join(cmd1) == cmd2.
But the first example returns a code 2, whereas the second runs successfully.
What is the difference? I prefer using a list as it looks a little cleaner.
Btw, shell=True is needed here.


# Python 2.7.3 (default, Jan  2 2013, 13:56:14) [GCC 4.7.2] on linux2

import subprocess

#1# returns retcode 2 (whatever error that maybe)
title, author, version = "title", "author", "1.0.0"
output_dir, input_dir = '/tmp/input', '/tmp/output'
cmd1 = [r'sphinx-apidoc',
       r'-f -F',
       r'-H', '"%s"' % title,
       r'-A', '"%s"' % author,
       r'-V', '"%s"' % version,
       r'-o', output_dir, input_dir]
retcode = subprocess.call(cmd1, shell=True)
assert not retcode, retcode

#2# returns retcode 0 (succes)
cmd2 = (r'sphinx-apidoc '
       r'-f -F '
       r'-H "%(title)s" '
       r'-A "%(author)s" '
       r'-V "%(version)s" '
       r'-o %(output_dir)s %(input_dir)s') % locals()

retcode = subprocess.call(cmd2, shell=True)
assert not retcode, retcode

# no AssertionError
assert " ".join(cmd1) == cmd2



Thanks in advance!
 
Regards,

Albert-Jan




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