Вы хотите модуль sys
:
>>> print sys.executable
/usr/bin/python
>>> print sys.path
['', '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python26.zip',
'/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6',
'/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/plat-darwin',
'/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/plat-mac',
'/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/plat-mac/lib-scriptpackages',
'/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python',
'/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/lib-tk',
'/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/lib-old',
'/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/lib-dynload',
'/Library/Python/2.6/site-packages',
'/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/PyObjC',
'/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/wx-2.8-mac-unicode']