Can't write to a directory made w/ os.makedirs

David Goldsmith eulergaussriemann at
Sun Jan 1 22:14:24 EST 2012

On Jan 1, 7:05 am, Tim Golden <m... at> wrote:
> On 01/01/2012 12:05, David Goldsmith wrote:
>  >> ie can the Python process creating the directories,
>  >
>  > Yes.
>  >
>  >> and a subprocess called from it create a simple file?
>  >
>  > No.
>  >
>  >> Depending on where you are in the filesystem, it may indeed
>  >> be necessary to be running as administrator. But don't try
>  >> to crack every security nut with an elevated sledgehammer.
>  >
>  > If you mean running as admin., those were my sentiments exactly.  So,
>  > there isn't something specific I should be doing to assure that my
>  > subproceses can write to directories?
> In the general case, no. By default, a subprocess will have
> the same security context as its parent. The exception is
> where the parent (the Python processing invoking
> in this example) is already impersonating a different user;
> in that case, the subprocess will inherit its grandparent's
> context.
> But unless you're doing something very deliberate here then
> I doubt if that's biting you.
> Can I ask: are you absolutely certain that the processes
> you're calling are doing what you think they are and failing
> where you think they're failing?

I'm a mathematician: the only thing I'm absolutely certain of is

Here's my script, in case that helps:

import os
import sys
import stat
import os.path as op
import subprocess as sub
from os import remove
from os import listdir as ls
from os import makedirs as mkdir

def doFlac2Mp3(arg, d, fl):
    if '.flac' in [f[-5:] for f in fl]:
        newD = d.replace('FLACS', 'MP3s')
        for f in fl:
            if f[-5:]=='.flac':
                root = f.replace('.flac', '')
                cmd = ['"C:\\Program Files (x86)\\aTunes\\win_tools\
\flac.exe" -d ' +
                       '--output-prefix=' + newD + '\\', f]
                res =, env={'PATH': os.defpath})
                if not res:
                    cmd = ['"C:\\Program Files (x86)\\aTunes\\win_tools
\\lame.exe" -h',
                            newD + root + '.wav',  newD + root +
                    res =, env={'PATH': os.defpath})
                    if not res:
                        rf = newD + root + '.wav'

op.walk(top, doFlac2Mp3, None)

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