1. 备份原来的更新源
cp /etc/apt/sources.list /etc/apt/sources.list.backup
如果提示权限不够就输入下面两行，先进入到超级用户，再备份
sudo -s cp /etc/apt/sources.list /etc/apt/sources.list.backup
2. 修改更新源
打开sources.list：
vim /etc/apt/sources.list
阿里云：
# deb cdrom:[Ubuntu 16.04 LTS _Xenial Xerus_ - Release amd64 (20160420.1)]/ xenial main restricted deb-src http://archive.ubuntu.com/ubuntu xenial main restricted #Added by software-properties deb http://mirrors.aliyun.com/ubuntu/ xenial main restricted deb-src http://mirrors.aliyun.com/ubuntu/ xenial main restricted multiverse universe #Added by software-properties deb http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted deb-src http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted multiverse universe #Added by software-properties deb http://mirrors.aliyun.com/ubuntu/ xenial universe deb http://mirrors.aliyun.com/ubuntu/ xenial-updates universe deb http://mirrors.aliyun.com/ubuntu/ xenial multiverse deb http://mirrors.aliyun.com/ubuntu/ xenial-updates multiverse deb http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse #Added by software-properties deb http://archive.canonical.com/ubuntu xenial partner deb-src http://archive.canonical.com/ubuntu xenial partner deb http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted deb-src http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted multiverse universe #Added by software-properties deb http://mirrors.aliyun.com/ubuntu/ xenial-security universe deb http://mirrors.aliyun.com/ubuntu/ xenial-security multiverse
错误：
Could not resolve 'mirrors.aliyun.com'
1.vim /etc/resolv.conf在文件后面添加：
nameserver 8.8.8.8 nameserver 8.8.4.4
2.重启网络：
sudo /etc/init.d/networking restart
3.再次执行
sudo apt-get update
执行完成,然后:
sudo apt-get upgrade
这小玩意还挺有意思？！是吧！