ubuntu18.04没有网络开关，没网问题

如下操作：

sudo service network-manager stop
sudo rm /var/lib/NetworkManager/NetworkManager.state
sudo service network-manager start

sudo gedit /etc/NetworkManager/NetworkManager.conf

把false改成true

sudo service network-manager restart

原文链接：https://blog.csdn.net/lj695242104/article/details/80922108