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Date: Wed, 4 Apr 2012 18:37:20 +1000
Subject: Re: No os.copy()? Why not?
From: Chris Angelico <rosuav@gmail.com>
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Xref: csiph.com comp.lang.python:22653

On Wed, Apr 4, 2012 at 3:53 PM, Steven D'Aprano
<steve+comp.lang.python@pearwood.info> wrote:
> On Tue, 03 Apr 2012 15:46:31 -0400, D'Arcy Cain wrote:
>
>> def cp(infile, outfile):
>> =A0 =A0open(outfile, "w").write(open(infile).read())
>
> Because your cp doesn't copy the FILE, it copies the file's CONTENTS,
> which are not the same thing.

And, as a subtle point: This method can't create the file "at size". I
don't know how it'll end up allocating space, but certainly there's no
opportunity to announce to the OS at file open/create time "please
allocate X bytes for this file". That may be an utterly trivial point,
or a crucially vital one.

ChrisA