升级到最新的 osx 版本 Maverick 之后，打开 iTerm2 就报错：
Traceback (most recent call last):
File "<string>", line 1, in <module>
ImportError: No module named virtualenvwrapper.hook_loader
virtualenvwrapper.sh: There was a problem running the initialization hooks.
If Python could not import the module virtualenvwrapper.hook_loader,
check that virtualenv has been installed for
VIRTUALENVWRAPPER_PYTHON=/usr/bin/python and that PATH is
set properly.
敲 pip 之后也报错：
Traceback (most recent call last):
File "/usr/local/bin/pip", line 5, in <module>
from pkg_resources import load_entry_point
File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources.py", line 2603, in <module>
working_set.require(__requires__)
File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources.py", line 666, in require
needed = self.resolve(parse_requirements(requirements))
File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources.py", line 565, in resolve
raise DistributionNotFound(req) # XXX put more info here
pkg_resources.DistributionNotFound: pip==1.3.1
这坨pkg_resources.DistributionNotFound的错正好前两天装 CentOS 的机器看到过。
运行下面的命令更新了setuptools之后重装了pip和virtualenv、virtualenvwrapper就好了：
wget https://bitbucket.org/pypa/setuptools/raw/bootstrap/ez_setup.py
sudo python ez_setup.py
sudo easy_install -U pip