best way of testing a program exists before using it?

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    Nick> Tim Golden <tim.golden at viacom-outdoor.co.uk> wrote:
    >> [Nick Craig-Wood]
    >> 
    >> | Tim Golden <tim.golden at viacom-outdoor.co.uk> wrote:
    >> | >          if os.path.isfile (filepath):
    >> | >            print filepath
    >> | 
    >> | You might get a more accurate result using
    >> | 
    >> |   os.access(filepath, os.X_OK)
    >> | 
    >> | instead of
    >> | 
    >> |   os.path.isfile(filepath)
    >> | 
    >> | Which checks the file is executable

Just picking up this thread late.  Note that access() doesn't do what you
want unless your real and effective user ids are the same.  Granted, that's
the case most of the time, but not always...

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