几个比较常用和速度不错的ubuntu更新源

默认的中国源速度非常不错，为了保证源内软件的齐全，建议电信用户添加cn99或台湾大学的源，建议网通用户添加UBNTU官方或台湾大学的源。
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在终端输入并运行
sudo cp /etc/apt/sources.list /etc/apt/sources.list.backup （备份当前的源列表，以便日後需要时恢复）
sudo gedit /etc/apt/sources.list （修改sources.list文件中源的列表）
弹出文本后在sources.list文件中尾部添加下列内容：

台湾
代码:
deb http://tw.archive.ubuntu.com/ubuntu/ karmic main universe restricted multiverse
deb http://tw.archive.ubuntu.com/ubuntu/ karmic-updates universe main multiverse restricted
deb http://tw.archive.ubuntu.com/ubuntu/ karmic-proposed universe main multiverse restricted
deb http://tw.archive.ubuntu.com/ubuntu/ karmic-security universe main multiverse restricted
deb http://tw.archive.ubuntu.com/ubuntu/ karmic-backports main multiverse restricted universe
deb-src http://tw.archive.ubuntu.com/ubuntu/ karmic main universe restricted multiverse
deb-src http://tw.archive.ubuntu.com/ubuntu/ karmic-security universe main multiverse restricted
deb-src http://tw.archive.ubuntu.com/ubuntu/ karmic-updates universe main multiverse restricted
deb-src http://tw.archive.ubuntu.com/ubuntu/ karmic-proposed universe main multiverse restricted
deb-src http://tw.archive.ubuntu.com/ubuntu/ karmic-backports universe main multiverse restricted
SRT Sources
代码:
deb http://ubuntu.srt.cn/ubuntu/ karmic main restricted universe multiverse
deb http://ubuntu.srt.cn/ubuntu/ karmic-security main restricted universe multiverse
deb http://ubuntu.srt.cn/ubuntu/ karmic-updates main restricted universe multiverse
deb http://ubuntu.srt.cn/ubuntu/ karmic-proposed main restricted universe multiverse
deb http://ubuntu.srt.cn/ubuntu/ karmic-backports main restricted universe multiverse
deb-src http://ubuntu.srt.cn/ubuntu/ karmic main restricted universe multiverse
deb-src http://ubuntu.srt.cn/ubuntu/ karmic-security main restricted universe multiverse
deb-src http://ubuntu.srt.cn/ubuntu/ karmic-updates main restricted universe multiverse
deb-src http://ubuntu.srt.cn/ubuntu/ karmic-proposed main restricted universe multiverse
deb-src http://ubuntu.srt.cn/ubuntu/ karmic-backports main restricted universe multiverse
搜狐（速度很快，稍微不完整）
代码:
deb http://mirrors.sohu.com/ubuntu/ karmic main restricted
deb-src http://mirrors.sohu.com/ubuntu/ karmic main restricted
deb http://mirrors.sohu.com/ubuntu/ karmic-updates main restricted
deb-src http://mirrors.sohu.com/ubuntu/ karmic-updates main restricted
deb http://mirrors.sohu.com/ubuntu/ karmic universe
deb-src http://mirrors.sohu.com/ubuntu/ karmic universe
deb http://mirrors.sohu.com/ubuntu/ karmic-updates universe
deb-src http://mirrors.sohu.com/ubuntu/ karmic-updates universe
deb http://mirrors.sohu.com/ubuntu/ karmic multiverse
deb-src http://mirrors.sohu.com/ubuntu/ karmic multiverse
deb http://mirrors.sohu.com/ubuntu/ karmic-updates multiverse
deb-src http://mirrors.sohu.com/ubuntu/ karmic-updates multiverse
北京交通大学
代码:
deb http://mirror.bjtu.edu.cn/ubuntu/ karmic main multiverse restricted universe
deb http://mirror.bjtu.edu.cn/ubuntu/ karmic-backports main multiverse restricted universe
deb http://mirror.bjtu.edu.cn/ubuntu/ karmic-proposed main multiverse restricted universe
deb http://mirror.bjtu.edu.cn/ubuntu/ karmic-security main multiverse restricted universe
deb http://mirror.bjtu.edu.cn/ubuntu/ karmic-updates main multiverse restricted universe
deb-src http://mirror.bjtu.edu.cn/ubuntu/ karmic main multiverse restricted universe
deb-src http://mirror.bjtu.edu.cn/ubuntu/ karmic-backports main multiverse restricted universe
deb-src http://mirror.bjtu.edu.cn/ubuntu/ karmic-proposed main multiverse restricted universe
deb-src http://mirror.bjtu.edu.cn/ubuntu/ karmic-security main multiverse restricted universe
deb-src http://mirror.bjtu.edu.cn/ubuntu/ karmic-updates main multiverse restricted universe
马来西亚
代码:
deb http://archive.mmu.edu.my/ubuntu/ karmic main restricted universe multiverse
deb http://archive.mmu.edu.my/ubuntu/ karmic-security main restricted universe multiverse
deb http://archive.mmu.edu.my/ubuntu/ karmic-updates main restricted universe multiverse
deb http://archive.mmu.edu.my/ubuntu/ karmic-proposed main restricted universe multiverse
deb http://archive.mmu.edu.my/ubuntu/ karmic-backports main restricted universe multiverse
deb-src http://archive.mmu.edu.my/ubuntu/ karmic main restricted universe multiverse
deb-src http://archive.mmu.edu.my/ubuntu/ karmic-security main restricted universe multiverse
deb-src http://archive.mmu.edu.my/ubuntu/ karmic-updates main restricted universe multiverse
deb-src http://archive.mmu.edu.my/ubuntu/ karmic-proposed main restricted universe multiverse
deb-src http://archive.mmu.edu.my/ubuntu/ karmic-backports main restricted universe multiverse
江苏双线
代码:
deb http://mirror.lupaworld.com/ubuntu karmic main restricted universe multiverse
deb http://mirror.lupaworld.com/ubuntu karmic-security main restricted universe multiverse
deb http://mirror.lupaworld.com/ubuntu karmic-updates main restricted universe multiverse
deb http://mirror.lupaworld.com/ubuntu karmic-backports main restricted universe multiverse
deb http://mirror.lupaworld.com/ubuntu/ubuntu-cn karmic main restricted universe multiverse
deb http://mirror.lupaworld.com/ubuntu/ karmic-proposed main restricted universe multiverse
deb-src http://mirror.lupaworld.com/ubuntu karmic main restricted universe multiverse
deb-src http://mirror.lupaworld.com/ubuntu karmic-security main restricted universe multiverse
deb-src http://mirror.lupaworld.com/ubuntu karmic-updates main restricted universe multiverse
deb-src http://mirror.lupaworld.com/ubuntu karmic-backports main restricted universe multiverse
deb-src http://mirror.lupaworld.com/ubuntu/ karmic-proposed main restricted universe multiverse
日本
代码:
deb http://jp.archive.ubuntu.com/ubuntu/ karmic main universe restricted multiverse
deb http://security.ubuntu.com/ubuntu/ karmic-security universe main multiverse restricted
deb http://jp.archive.ubuntu.com/ubuntu/ karmic-updates universe main multiverse restricted
deb http://jp.archive.ubuntu.com/ubuntu/ karmic-proposed universe main multiverse restricted
deb-src http://jp.archive.ubuntu.com/ubuntu/ karmic main universe restricted multiverse
deb-src http://jp.archive.ubuntu.com/ubuntu/ karmic-proposed universe main multiverse restricted
deb-src http://jp.archive.ubuntu.com/ubuntu/ karmic-security universe main multiverse restricted
deb-src http://jp.archive.ubuntu.com/ubuntu/ karmic-updates universe main multiverse restricted

然后 保存编辑好的文件，执行以下命令更新。
sudo apt-get update #这一步是更新你的源列表，换源後必须执行
（如果更新速度非常慢请更换源 sudo gedit /etc/apt/sources.list ）
sudo apt-get dist-upgrade #这一步是更新软件

台湾源的测试可能会慢一些，耐心等一下，换源后一般下载速度都有几十K，上百K也很正常。～要是总是用几K的外源，Ubuntu也不可能在PRC混了 ～