pip install virtualenv

[idingwu]

I tried to run
pip install virtualenv

in the directory
/System/Library/Frameworks/Python.framework/Versions

and get below error

Downloading/unpacking virtualenv
Exception:
Traceback (most recent call last):
File "/usr/local/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip-1.1-py2.7.egg/pip/basecommand.py", line 104, in main
status = self.run(options, args)
File "/usr/local/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip-1.1-py2.7.egg/pip/commands/install.py", line 245, in run
requirement_set.prepare_files(finder, force_root_egg_info=self.bundle, bundle=self.bundle)
File "/usr/local/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip-1.1-py2.7.egg/pip/req.py", line 971, in prepare_files
location = req_to_install.build_location(self.build_dir, not self.is_download)
File "/usr/local/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip-1.1-py2.7.egg/pip/req.py", line 153, in build_location
_make_build_dir(build_dir)
File "/usr/local/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip-1.1-py2.7.egg/pip/req.py", line 1225, in _make_build_dir
os.makedirs(build_dir)
File "/usr/local/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/os.py", line 157, in makedirs
mkdir(name, mode)
OSError: [Errno 13] Permission denied: '/System/Library/Frameworks/Python.framework/Versions/build'

however, in /System/Library/Frameworks/Python.framework/Versions
there is no "build"

please advise where goes wrong?

[takluyver]

N.B. This is the IPython bug tracker - it doesn't look like IPython is involved in your problem at all.

Try sudo pip install virtualenv.