source ./bin/activate
    deactivate
    source /usr/local/bin/virtualenvwrapper.sh
    mkvirtualenv test1 # 创建
    deactivate # 离开
    workon test1 # 返回
    rmvirtualenv test1 # 删除
    /usr/local/myenv/vnev/lib/python2.7/site-packages
    该虚拟环境的库都放在这里
    import scrapy