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
#might require more voodoo to see if
#the user itself can exec it
raise
except:
raise ValueError, "phc not found"
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