Installation fails on system-wide install on os.x

From the debug log:

Cleaning up...
  Removing temporary dir /private/tmp/pip_build_root...
Exception:
Traceback (most recent call last):
  File "/Library/Python/2.7/site-packages/pip-1.5.6-py2.7.egg/pip/basecommand.py", line 122, in main
    status = self.run(options, args)
  File "/Library/Python/2.7/site-packages/pip-1.5.6-py2.7.egg/pip/commands/install.py", line 283, in run
    requirement_set.install(install_options, global_options, root=options.root_path)
  File "/Library/Python/2.7/site-packages/pip-1.5.6-py2.7.egg/pip/req.py", line 1431, in install
    requirement.uninstall(auto_confirm=True)
  File "/Library/Python/2.7/site-packages/pip-1.5.6-py2.7.egg/pip/req.py", line 598, in uninstall
    paths_to_remove.remove(auto_confirm)
  File "/Library/Python/2.7/site-packages/pip-1.5.6-py2.7.egg/pip/req.py", line 1836, in remove
    renames(path, new_path)
  File "/Library/Python/2.7/site-packages/pip-1.5.6-py2.7.egg/pip/util.py", line 295, 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-ZBkEd1-uninstall/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/six-1.4.1-py2.7.egg-info'

[jamyouss]

I had the same issue. The solution of @mikeecb worked for me 👍

[georules]

sudo pip install http-prompt --ignore-installed six

worked for me. I assume the --user option would work in combination with the ignore-installed as well.