查看当前系统的版本信息

输入命令：lsb_release -a

1、备份现有配置

sudo cp /etc/apt/sources.list /etc/apt/sources.list.bak

2、修改配置信息

sudo vi /etc/apt/sources.list

deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ xenial main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ xenial-updates main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ xenial-backports main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ xenial-security main restricted universe multiverse

esc

:wq

3、执行下更新操作

sudo apt-get update
sudo apt-get upgrade