在virtualBox安裝完系統(tǒng)，登錄后提示系統(tǒng)可以升級(jí)：
Welcome to Ubuntu 14.04.3 LTS (GNU/Linux 3.19.0-25-generic x86_64)
* Documentation: https://help.ubuntu.com/
424 packages can be updated.
247 updates are security updates.
New release '16.04.2 LTS' available.
Run 'do-release-upgrade' to upgrade to it.
Last login: Sun Mar 19 16:57:40 2017 from 192.168.88.105
按照提示輸入do-release-upgrade锁摔，一會(huì)蹦出來一個(gè)提示：
The required dependency 'apt (>= 1.0.1ubuntu2.13)' is not installed.
所以要把a(bǔ)pt和dpkg（更新完apt后還會(huì)檢查dpkg版本）升級(jí)到最新版：
$ sudo apt-get download apt dpkg
$ sudo dpkg -i *.deb
繼續(xù)輸入do-release-upgrade巡验，接來下一路按y际插，經(jīng)過1～2小時(shí)的下載和更新后，就可以享受16.04了显设！
