I'm on El Capitan OSX. Got following error:

Installing collected packages: six, python-dateutil, docutils, botocore, pyasn1, rsa, awscli
Found existing installation: six 1.4.1
DEPRECATION: Uninstalling a distutils installed project (six) has been deprecated and will be removed in a future version. This is due to the fact that uninstalling a distutils project will only partially uninstall the project.
Uninstalling six-1.4.1:
Exception:
Traceback (most recent call last):
File "/Library/Python/2.7/site-packages/pip/basecommand.py", line 211, in main
status = self.run(options, args)
File "/Library/Python/2.7/site-packages/pip/commands/install.py", line 311, in run
root=options.root_path,
File "/Library/Python/2.7/site-packages/pip/req/req_set.py", line 640, in install
requirement.uninstall(auto_confirm=True)
File "/Library/Python/2.7/site-packages/pip/req/req_install.py", line 716, in uninstall
paths_to_remove.remove(auto_confirm)
File "/Library/Python/2.7/site-packages/pip/req/req_uninstall.py", line 125, in remove
renames(path, new_path)
File "/Library/Python/2.7/site-packages/pip/utils/init.py", line 315, in renames
shutil.move(old, new)
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/shutil.py", line 302, in move
copy2(src, real_dst)
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/shutil.py", line 131, in copy2
copystat(src, dst)
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/shutil.py", line 103, in copystat
os.chflags(dst, st.st_flags)
OSError: [Errno 1] Operation not permitted: '/tmp/pip-ion1Bt-uninstall/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/six-1.4.1-py2.7.egg-info'
Bournes-MacBook-Pro:~ BourneWang$