Is there a Python equivalent to the ‘which’ command [duplicate]

Question

Python 3.3 added shutil.which() to provide a cross-platform means of discovering executables:

http://docs.python.org/3.3/library/shutil.html#shutil.which

Return the path to an executable which would be run if the given cmd was called. If no cmd would be called, return None.

Sample calls:

>>> shutil.which("python")
'/usr/local/bin/python'

>>> shutil.which("python")
'C:\\Python33\\python.EXE'

Unfortunately, this has not been backported to 2.7.x.