改变源

　　推荐网易的开源镜像站  mirrors.163.com

　　如何使用参见 mirrors.163.com/.help/ubuntu.html

　　以我现在 ubuntu14.04为例 ，则把以下的红色部分换成 trusty (这是该版本的代号), 然后修改source.list就好了

　　deb http://mirrors.163.com/ubuntu/ karmic main restricted universe multiverse

　　deb http://mirrors.163.com/ubuntu/ karmic-security main restricted universe multiverse

　　deb http://mirrors.163.com/ubuntu/ karmic-updates main restricted universe multiverse

　　deb http://mirrors.163.com/ubuntu/ karmic-proposed main restricted universe multiverse

　　deb http://mirrors.163.com/ubuntu/ karmic-backports main restricted universe multiverse

　　deb-src http://mirrors.163.com/ubuntu/ karmic main restricted universe multiverse

　　deb-src http://mirrors.163.com/ubuntu/ karmic-security main restricted universe multiverse

　　deb-src http://mirrors.163.com/ubuntu/ karmic-updates main restricted universe multiverse

　　deb-src http://mirrors.163.com/ubuntu/ karmic-proposed main restricted universe multiverse

　　deb-src http://mirrors.163.com/ubuntu/ karmic-backports main restricted universe multiverse

　　修改完成后执行 sudo apt-get update 更新软件包列表

apt-get的用法

　　百度百科，简单详细 :

　　http://baike.baidu.com/view/1580236.htm

dbkg的用法

　　百度百科:

　　http://baike.baidu.com/view/1314054.htm

Ubuntu 软件管理