Ubuntu不能联网 Networking disabled 的解决办法
Ubuntu不能联网，提示Networking disabled, 这时需要重启一下network-manager,具体方法如下：

b456@b456:~$ sudo service network-manager stop
[sudo] password for b456:
network-manager stop/waiting

b456@b456:~$ sudo rm /var/lib/NetworkManager/NetworkManager.state

b456@b456:~$ sudo service network-manager start
network-manager start/running, process 2433