cat /etc/apt/sources.list deb http://mirrors.aliyun.com/ubuntu-ports/ xenial main deb-src http://mirrors.aliyun.com/ubuntu-ports/ xenial main deb http://mirrors.aliyun.com/ubuntu-ports/ xenial-updates main deb-src http://mirrors.aliyun.com/ubuntu-ports/ xenial-updates main deb http://mirrors.aliyun.com/ubuntu-ports/ xenial universe deb-src http://mirrors.aliyun.com/ubuntu-ports/ xenial universe deb http://mirrors.aliyun.com/ubuntu-ports/ xenial-updates universe deb-src http://mirrors.aliyun.com/ubuntu-ports/ xenial-updates universe deb http://mirrors.aliyun.com/ubuntu-ports/ xenial-security main deb-src http://mirrors.aliyun.com/ubuntu-ports/ xenial-security main deb http://mirrors.aliyun.com/ubuntu-ports/ xenial-security universe deb-src http://mirrors.aliyun.com/ubuntu-ports/ xenial-security universe
1604版本：
deb http://mirrors.aliyun.com/ubuntu-ports/ xenial main restricted universe multiverse
1804版本：
deb http://mirrors.aliyun.com/ubuntu-ports/ cosmic main restricted universe multiverse
网易源：http://ubuntu.cn99.com/ubuntu
ubuntu 网易开源镜像站：http://mirrors.163.com
ubuntu ISO 下载地址：http://mirrors.163.com/ubuntu-releases/