1. sudo vim /etc/apt/sources.list
在文件开始处插入：
deb http://mirrors.163.com/ubuntu/ quantal main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ quantal-security main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ quantal-updates main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ quantal-proposed main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ quantal-backports main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ quantal main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ quantal-security main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ quantal-updates main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ quantal-proposed main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ quantal-backports main restricted universe multiverse
2. sudo apt-get update
注意，不同的Ubuntu版本要替换不同的版本号：
- hardy(8.04)
- lucid(10.04)
- maverick(10.10)
- natty(11.04)
- oneiric(11.10)
- precise(12.04)
- quantal(12.10)
