やっぱりsys.pathが違う．
$ python -c "import sys;arr=sys.path;ans=[a for a in arr if a.find('usr') > 0];print ans;print len(ans)" # ['/usr/local/Cellar/python/2.7.8_2/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg', '/usr/local/Cellar/python/2.7.8_2/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/setuptools-5.4.2-py2.7.egg', '/usr/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg', '/usr/local/lib/python2.7/site-packages/setuptools-5.4.2-py2.7.egg', '/usr/local/lib/wxPython-3.0.0.0/lib/python2.7/site-packages', '/usr/local/lib/wxPython-3.0.0.0/lib/python2.7/site-packages/wx-3.0-osx_cocoa', '/usr/local/Cellar/python/2.7.8_2/Frameworks/Python.framework/Versions/2.7/lib/python27.zip', '/usr/local/Cellar/python/2.7.8_2/Frameworks/Python.framework/Versions/2.7/lib/python2.7', '/usr/local/Cellar/python/2.7.8_2/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-darwin', '/usr/local/Cellar/python/2.7.8_2/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac', '/usr/local/Cellar/python/2.7.8_2/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac/lib-scriptpackages', '/usr/local/Cellar/python/2.7.8_2/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-tk', '/usr/local/Cellar/python/2.7.8_2/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-old', '/usr/local/Cellar/python/2.7.8_2/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-dynload', '/usr/local/Cellar/python/2.7.8_2/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/gtk-2.0', '/usr/local/lib/wxPython-3.0.0.0/lib/python2.7', '/usr/local/lib/python2.7/site-packages', '/usr/local/lib/python2.7/site-packages/gtk-2.0'] # 18 $ /usr/bin/python -c "import sys;arr=sys.path;ans=[a for a in arr if a.find('usr') > 0];print ans;print len(ans)" # ['/usr/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg', '/usr/local/lib/python2.7/site-packages/setuptools-5.4.2-py2.7.egg', '/usr/local/lib/wxPython-3.0.0.0/lib/python2.7/site-packages', '/usr/local/lib/wxPython-3.0.0.0/lib/python2.7/site-packages/wx-3.0-osx_cocoa', '/usr/local/lib/python2.7/site-packages', '/usr/local/lib/wxPython-3.0.0.0/lib/python2.7', '/usr/local/lib/python2.7/site-packages/gtk-2.0'] # 7
