ubuntu18安装python3后或者升级到18.0版本，打开终端总会提示：

/usr/bin/python3: 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 forVIRTUALENVWRAPPER_PYTHON=/usr/bin/python3 and that PATH is
/usr/bin/python3:查找’virtualenvwrapper的模块规范时出错。hook_loader’ (ModuleNotFoundError:没有名为’virtualenvwrapper’的模块)
virtualenvwrapper。sh:在运行初始化钩子时出现了问题。
如果Python不能导入模块virtualenvwrapper.hook_loader，
检查virtualenvwrapper是否已经安装
VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3，路径是

解决办法

$:sudo pip3 install virtualenv virtualenvwrapper

$:source .bashrc

如果上面的不行，试下下面这个命令：