ubuntu14安装python3后，打开命令行界面总会提示：
/usr/bin/python: Error while finding module specification for 'virtualenvwrapper.hook_loader' (ModuleNotFoundError: No module named 'virtualenvwrapper')
virtualenvwrapper.sh: There was a problem running the initialization hooks.
If Python could not import the module virtualenvwrapper.hook_loader,
check that virtualenvwrapper has been installed for
VIRTUALENVWRAPPER_PYTHON=/usr/bin/python and that PATH is
set properly.
有的文章说修改.bashrc中的VIRTUALENVWRAPPER_PYTHON，之后执行source .bashrc。这个方法对我本机没有起作用
之后查询：
http://www.itkeyword.com/doc/1445534594720488x414/usr-bin-python3-error-while-finding-spec-for-virtualenvwrapper-hook-loader
$ sudo pip3 install virtualenv virtualenvwrapper
$ source .bashrc
然后就没有提示了