On Nov 2, 5:32 pm, Ronan Paixão <[EMAIL PROTECTED]> wrote:
> Em Dom, 2008-11-02 às 16:26 -0800, William Stein escreveu:
>
>
>
> > On Sun, Nov 2, 2008 at 4:15 PM, Ronan Paixão <[EMAIL PROTECTED]> wrote:
>
> > > don't know if this is "the right"(tm) way to do it, but it seems more
> > > pythonic:
>
> > > import os
> > > [p for p in os.environ['PATH'].split(':') if os.path.exists('%s/%s' %
> > > (p,'phc'))]
>
> > > which should return a list with the paths in which the file 'phc'
> > > exists, or an empty list if it doesn't
>
> > > Ronan Paixão
>
> > That is unfortunately not equivalent to the unix which command.
> > For example, if the file phc appears anywhere in the path it will
> > get included. The which command instead will tell you whether
> > or not there is an *executable* called phc that is in the path.
> > So that's a subtle difference.
>
> > -- William
>
> Sure, there some subtle difference
> that can be overcome with some changes:
>
> import os
> try:
> filename = [p for p in os.environ['PATH'].split(':') if
> os.path.exists('%s/%s' % (p,'phc'))] + "/phc"
> s = os.stat(filename)[0]
> if not s & 0x49: #sees if at least one exec bit is set
It is not sufficient that at least one exec bit is set, it has to be
the right one depending on ownership. I really don't see any benefit
over using "which" - aside from the fact that some versions of which
do not return an error code unequal zero when no binary is found.
> #might require more voodoo to see if
> #the user itself can exec it
> raise
> except:
> raise ValueError, "phc not found"
Cheers,
Michael
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