升级前版本

升级步骤
首先在终端中先把软件源和软件升级成最新的
root@localhost:~# apt-get update
root@localhost:~# apt-get upgrade //需要按Y的时候直接按Y确认
root@localhost:~# apt-get dist-upgrade 一路按y和回车,更新完后重启下系统
更新16.04到18.04
root@localhost:~# do-release-upgrade 一路按y和回车
To finish the upgrade, a restart is required. If you select 'y' the system will be restarted. 按Y重启

root@localhost:~# cat /etc/issue


