Ubuntu 14.04 升级到16.04

Ubuntu 16.04 升级到18.04

1、以上两种的升级方法如下：

1. sudo apt-get update
2. sudo apt-get upgrade -y
3. sudo apt-get dist-upgrade
4. sudo do-release-upgrade

2、常见问题

Checking for a new Ubuntu release

Please install all available updates for your release before upgrading.

解决方法，只要运行1中的指令即可。