1.先查看当前系统的版本号，ubuntu的每个大版本所对应的代号（Codename的值后面会用到）是不一样的，需要使用如下命令查看：
root@ubuntu-xenial:/etc/apt# lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.6 LTS
Release: 16.04
Codename: xenial
1.1.各个版本对应的代号（Codename）
| 序号 | 版本号 | 代号（Codename） |
| 1 |
Ubuntu 12.04 (LTS) |
precise |
| 2 |
Ubuntu 14.04 (LTS) |
trusty |
| 3 |
Ubuntu 15.04 |
vivid |
| 4 |
Ubuntu 15.10 |
wily |
| 5 |
Ubuntu 16.04 (LTS) |
xenial |
| 6 |
Ubuntu 18.04 (LTS) |
bionic |
| 7 | Ubuntu 19.10 | eoan |
2.找切换到源配置文件的目录，对源文件进行备份，出错时可回滚。如果没有配置文件，则需要创建：
root@ubuntu-xenial:/# cd /etc/apt root@ubuntu-xenial:/etc/apt# sudo mv sources.list sources.list.bak root@ubuntu-xenial:/etc/apt#
3.使用“sudo vi sources.list”指令，将如下阿里的源镜像地址写入到源配置文件中，我目前所有的版本代号为“xenial”所以源地址配置中会带代号标识符，其他版本的可对应替换标识符即可：
deb http://mirrors.aliyun.com/ubuntu/ xenial main multiverse restricted universe deb http://mirrors.aliyun.com/ubuntu/ xenial-backports main multiverse restricted universe deb http://mirrors.aliyun.com/ubuntu/ xenial-proposed main multiverse restricted universe deb http://mirrors.aliyun.com/ubuntu/ xenial-security main multiverse restricted universe deb http://mirrors.aliyun.com/ubuntu/ xenial-updates main multiverse restricted universe deb-src http://mirrors.aliyun.com/ubuntu/ xenial main multiverse restricted universe deb-src http://mirrors.aliyun.com/ubuntu/ xenial-backports main multiverse restricted universe deb-src http://mirrors.aliyun.com/ubuntu/ xenial-proposed main multiverse restricted universe deb-src http://mirrors.aliyun.com/ubuntu/ xenial-security main multiverse restricted universe deb-src http://mirrors.aliyun.com/ubuntu/ xenial-updates main multiverse restricted universe
4.更新apt的源配置：
sudo apt-get update