sudo cp /etc/apt/sources.list /etc/apt/sources.list_backup 备份现有更新源
sudo gedit /etc/apt/sources.list 编辑更新源列表
从下面各服务器列表内容中选择一段替换文件中的所有内容
保存编辑好的文件，执行以下命令更新。
sudo apt-get update (修改sources.list后必须运行！)
sudo apt-get dist-upgrade （更新所有软件）
# Shanghai Jiaotong Unverisity. APT source for Ubuntu 8.04 (hardy heron)
deb http://ftp.sjtu.edu.cn/ubuntu/ hardy main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ hardy-backports main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ hardy-proposed main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ hardy-security main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ hardy-updates main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ hardy main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ hardy-backports main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ hardy-proposed main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ hardy-security main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ hardy-updates main multiverse restricted universe
# University of Science and Technology of China. APT source for Ubuntu 8.04 (hardy heron)
deb http://debian.ustc.edu.cn/ubuntu/ hardy main multiverse restricted universe
deb http://debian.ustc.edu.cn/ubuntu/ hardy-backports main multiverse restricted universe
deb http://debian.ustc.edu.cn/ubuntu/ hardy-proposed main multiverse restricted universe
deb http://debian.ustc.edu.cn/ubuntu/ hardy-security main multiverse restricted universe
deb http://debian.ustc.edu.cn/ubuntu/ hardy-updates main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ hardy main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ hardy-backports main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ hardy-proposed main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ hardy-security main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ hardy-updates main multiverse restricted universe