Ubuntu更新源设置
在编辑之前做个备份
sudo cp /etc/apt/source.list /etc/apt/sources.list_backup
编辑源地址
sudo gedit /etc/apt/sources.list
更新命令
sudo apt-get update
sudo apt-get dist-upgrade
教育网可用更新源：
编辑软件源列表，添加如下语句：
deb ftp://openware.byr.edu.cn/pub/mirror/ubuntu/ jaunty main multiverse restricted universe
deb ftp://openware.byr.edu.cn/pub/mirror/ubuntu/ jaunty-backports main multiverse restricted universe
deb ftp://openware.byr.edu.cn/pub/mirror/ubuntu/ jaunty-proposed main multiverse restricted universe
deb ftp://openware.byr.edu.cn/pub/mirror/ubuntu/ jaunty-security main multiverse restricted universe
deb ftp://openware.byr.edu.cn/pub/mirror/ubuntu/ jaunty-updates main multiverse restricted universe
注意：将其中的jaunty替换成你现在使用的ubuntu版本名。版本名和版本号对照表：
dapper = 6.06
edgy = 6.10
feisty = 7.04
gutsy = 7.10
hardy =8.04
intrepid = 8.10
jaunty = 9.04
karmic = 9.10
lucid = 10.04
maverick = 10.10
以上为BYR源，如果源有问题（比如提示failed to open file），请更换下列教育网源（挑选一个就可以了）：
#中科大
deb http://debian.ustc.edu.cn/ubuntu/ jaunty main restricted universe multiverse
deb http://debian.ustc.edu.cn/ubuntu/ jaunty-backports restricted universe multiverse
deb http://debian.ustc.edu.cn/ubuntu/ jaunty-proposed main restricted universe multiverse
deb http://debian.ustc.edu.cn/ubuntu/ jaunty-security main restricted universe multiverse
deb http://debian.ustc.edu.cn/ubuntu/ jaunty-updates main restricted universe multiverse
#上海交大
deb http://ftp.sjtu.edu.cn/ubuntu/ jaunty main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ jaunty-backports main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ jaunty-proposed main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ jaunty-security main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ jaunty-updates main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu-cn/ jaunty bleeding main multiverse restricted universe
# 台湾交大
deb http://ubuntu.csie.nctu.edu.tw/ubuntu/ jaunty main multiverse restricted universe
deb http://ubuntu.csie.nctu.edu.tw/ubuntu/ jaunty-backports main multiverse restricted universe
deb http://ubuntu.csie.nctu.edu.tw/ubuntu/ jaunty-proposed main multiverse restricted universe
deb http://ubuntu.csie.nctu.edu.tw/ubuntu/ jaunty-security main multiverse restricted universe
deb http://ubuntu.csie.nctu.edu.tw/ubuntu/ jaunty-updates main multiverse restricted universe
外网源：
#163
deb http://mirrors.163.com/ubuntu/ intrepid main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ intrepid-security main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ intrepid-updates main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ intrepid-proposed main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ intrepid-backports main restricted universe multiverse
#sohu
deb http://mirrors.sohu.com/ubuntu/ intrepid main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ intrepid-security main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ intrepid-updates main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ intrepid-proposed main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ intrepid-backports main restricted universe multiverse
参考文档：
http://blog.sina.com.cn/s/blog_4b8de29f0100mkhw.html
