每5小时更新一次
以Karmic(9.10)为例, 编辑/etc/apt/sources.list文件, 在文件最前面添加以下条目(操作前请做好相应备份)
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
或者下载相应版本的sources.list, 覆盖/etc/apt/sources.list即可(操作前请做好相应备份)