CentOS 安装 pip
$ sudo yum install python-pip
$ sudo pip install --upgrade pip
虚拟环境
http://virtualenvwrapper.readthedocs.io/en/latest/install.html
$ sudo pip install virtualenvwrapper
$ vim .bashrc
export WORKON_HOME=$HOME/.virtualenvs
export PROJECT_HOME=$HOME/Project
source /usr/bin/virtualenvwrapper.sh
export VIRTUALENVWRAPPER_VIRTUALENV_ARGS='--no-site-packages'
$ mkvirtualenv venv # venv 是新建虚拟环境的名称
$ mkvirtualenv venv --python=python2.7 # 创建python2.7的虚拟环境
$ workon venv # 进入虚拟环境
$ deactivate # 退出虚拟环境