首先，使用su - root切换至超级用户权限；然后，vim /etc/apt/sources.list，打开源列表文件，这里没有进行备份，如果需要，也可以用cp命令进行下备份；将以下所示的源列表之一全部复制到sources.list文件中，替换原有内容；最后，保存并关闭已经打开的source.list文件，在终端输入sudo apt-get update命令，网易源 速度很快。
·deb http://mirrors.163.com/ubuntu/ precise main universe restricted multiverse
·deb-src http://mirrors.163.com/ubuntu/ precise main universe restricted multiverse
·deb http://mirrors.163.com/ubuntu/ precise-security universe main multiverse restricted
·deb-src http://mirrors.163.com/ubuntu/ precise-security universe main multiverse restricted
·deb http://mirrors.163.com/ubuntu/ precise-updates universe main multiverse restricted
·deb http://mirrors.163.com/ubuntu/ precise-proposed universe main multiverse restricted
·deb-src http://mirrors.163.com/ubuntu/ precise-proposed universe main multiverse restricted
·deb http://mirrors.163.com/ubuntu/ precise-backports universe main multiverse restricted
·deb-src http://mirrors.163.com/ubuntu/ precise-backports universe main multiverse restricted
·deb-src http://mirrors.163.com/ubuntu/ precise-updates universe main multiverse restricted
