每当我尝试使用pip时，都会出现错误。例如：

$ sudo pip install gevent-websocket

Traceback (most recent call last):  
File "/usr/local/bin/pip", line 5, in <module>
from pkg_resources import load_entry_point
File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 2675, in <module>
parse_requirements(__requires__), Environment()
File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 552, in resolve
raise DistributionNotFound(req)
pkg_resources.DistributionNotFound: pip==0.8.1

我很想将pip的值更改为pip == 0.8.2 ..，但是我没有处理“黑客入侵”安装的后果…我正在运行python 2.7，pip的版本为0.8.2。