1. sudo vim /etc/apt/sources.list

在文件开始处插入：

deb quantal main restricted universe multiverse

deb quantal-security main restricted universe multiverse

deb quantal-updates main restricted universe multiverse

deb quantal-proposed main restricted universe multiverse

deb quantal-backports main restricted universe multiverse

deb-src quantal main restricted universe multiverse

deb-src quantal-security main restricted universe multiverse

deb-src quantal-updates main restricted universe multiverse

deb-src quantal-proposed main restricted universe multiverse

deb-src 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)