ubuntu系统与网络关系密切，往往在完成系统安装之后需要进行必需软件的安装及更新。方法网上都可以找得到，这里再重述一下。
首先，使用su root切换至超级用户权限；
然后，gedit /etc/apt/sources.list，打开源列表文件，这里没有进行备份，如果需要，也可以用cp命令进行下备份；
将以下所示的源列表之一全部复制到sources.list文件中，替换原有内容；
最后，保存并关闭已经打开的source.list文件，在终端输入 apt-get update命令。
以上三步即完成源列表的更新。
#台湾源
deb http://tw.archive.ubuntu.com/ubuntu/ precise main universe restricted multiverse
deb-src http://tw.archive.ubuntu.com/ubuntu/ precise main universe restricted multiverse
deb http://tw.archive.ubuntu.com/ubuntu/ precise-security universe main multiverse restricted
deb-src http://tw.archive.ubuntu.com/ubuntu/ precise-security universe main multiverse restricted
deb http://tw.archive.ubuntu.com/ubuntu/ precise-updates universe main multiverse restricted
deb-src http://tw.archive.ubuntu.com/ubuntu/ precise-updates universe main multiverse restricted
#网易 Ubuntu 源（速度很快）
deb http://mirrors.163.com/ubuntu/ precise main universe restricted multiverse
deb-src http://mirrors.163.com/ubuntu/ precise main universe restricted multiverse
deb http://mirrors.163.com/ubuntu/ precise-security universe main multiverse restricted
deb-src http://mirrors.163.com/ubuntu/ precise-security universe main multiverse restricted
deb http://mirrors.163.com/ubuntu/ precise-updates universe main multiverse restricted
deb http://mirrors.163.com/ubuntu/ precise-proposed universe main multiverse restricted
deb-src http://mirrors.163.com/ubuntu/ precise-proposed universe main multiverse restricted
deb http://mirrors.163.com/ubuntu/ precise-backports universe main multiverse restricted
deb-src http://mirrors.163.com/ubuntu/ precise-backports universe main multiverse restricted
deb-src http://mirrors.163.com/ubuntu/ precise-updates universe main multiverse restricted
#骨头源，骨头源是bones7456架设的一个Ubuntu源 ，提供ubuntu,deepin
deb http://ubuntu.srt.cn/ubuntu/ precise main universe restricted multiverse
deb-src http://ubuntu.srt.cn/ubuntu/ precise main universe restricted multiverse
deb http://ubuntu.srt.cn/ubuntu/ precise-security universe main multiverse restricted
deb-src http://ubuntu.srt.cn/ubuntu/ precise-security universe main multiverse restricted
deb http://ubuntu.srt.cn/ubuntu/ precise-updates universe main multiverse restricted
deb http://ubuntu.srt.cn/ubuntu/ precise-proposed universe main multiverse restricted
deb-src http://ubuntu.srt.cn/ubuntu/ precise-proposed universe main multiverse restricted
deb http://ubuntu.srt.cn/ubuntu/ precise-backports universe main multiverse restricted
deb-src http://ubuntu.srt.cn/ubuntu/ precise-backports universe main multiverse restricted
deb-src http://ubuntu.srt.cn/ubuntu/ precise-updates universe main multiverse restricted
#mirror.lupaworld.com的源，速度很快
deb http://mirror.lupaworld.com/ubuntu/archive/ precise main restricted universe multiverse
deb http://mirror.lupaworld.com/ubuntu/archive/ precise-security main restricted universe multiverse
deb http://mirror.lupaworld.com/ubuntu/archive/ precise-updates main restricted universe multiverse
deb http://mirror.lupaworld.com/ubuntu/archive/ precise-backports main restricted universe multiverse
deb http://mirror.lupaworld.com/ubuntu/ubuntu-cn/ precise main restricted universe multiverse
#ubuntu.cn99.com源（推荐）:
deb http://ubuntu.cn99.com/ubuntu/ precise main restricted universe multiverse
deb http://ubuntu.cn99.com/ubuntu/ precise-updates main restricted universe multiverse
deb http://ubuntu.cn99.com/ubuntu/ precise-security main restricted universe multiverse
deb http://ubuntu.cn99.com/ubuntu/ precise-backports main restricted universe multiverse
deb http://ubuntu.cn99.com/ubuntu-cn/ precise main restricted universe multiverse
#电子科技大学
deb http://ubuntu.uestc.edu.cn/ubuntu/ precise main restricted universe multiverse
deb http://ubuntu.uestc.edu.cn/ubuntu/ precise-backports main restricted universe multiverse
deb http://ubuntu.uestc.edu.cn/ubuntu/ precise-proposed main restricted universe multiverse
deb http://ubuntu.uestc.edu.cn/ubuntu/ precise-security main restricted universe multiverse
deb http://ubuntu.uestc.edu.cn/ubuntu/ precise-updates main restricted universe multiverse
deb-src http://ubuntu.uestc.edu.cn/ubuntu/ precise main restricted universe multiverse
deb-src http://ubuntu.uestc.edu.cn/ubuntu/ precise-backports main restricted universe multiverse
deb-src http://ubuntu.uestc.edu.cn/ubuntu/ precise-proposed main restricted universe multiverse
deb-src http://ubuntu.uestc.edu.cn/ubuntu/ precise-security main restricted universe multiverse
deb-src http://ubuntu.uestc.edu.cn/ubuntu/ precise-updates main restricted universe multiverse
#中国科技大学
deb http://debian.ustc.edu.cn/ubuntu/ precise main restricted universe multiverse
deb http://debian.ustc.edu.cn/ubuntu/ precise-backports restricted universe multiverse
deb http://debian.ustc.edu.cn/ubuntu/ precise-proposed main restricted universe multiverse
deb http://debian.ustc.edu.cn/ubuntu/ precise-security main restricted universe multiverse
deb http://debian.ustc.edu.cn/ubuntu/ precise-updates main restricted universe multiverse
deb-src http://debian.ustc.edu.cn/ubuntu/ precise main restricted universe multiverse
deb-src http://debian.ustc.edu.cn/ubuntu/ precise-backports main restricted universe multiverse
deb-src http://debian.ustc.edu.cn/ubuntu/ precise-proposed main restricted universe multiverse
deb-src http://debian.ustc.edu.cn/ubuntu/ precise-security main restricted universe multiverse
deb-src http://debian.ustc.edu.cn/ubuntu/ precise-updates main restricted universe multiverse
#北京理工大学
deb http://mirror.bjtu.edu.cn/ubuntu/ precise main multiverse restricted universe
deb http://mirror.bjtu.edu.cn/ubuntu/ precise-backports main multiverse restricted universe
deb http://mirror.bjtu.edu.cn/ubuntu/ precise-proposed main multiverse restricted universe
deb http://mirror.bjtu.edu.cn/ubuntu/ precise-security main multiverse restricted universe
deb http://mirror.bjtu.edu.cn/ubuntu/ precise-updates main multiverse restricted universe
deb-src http://mirror.bjtu.edu.cn/ubuntu/ precise main multiverse restricted universe
deb-src http://mirror.bjtu.edu.cn/ubuntu/ precise-backports main multiverse restricted universe
deb-src http://mirror.bjtu.edu.cn/ubuntu/ precise-proposed main multiverse restricted universe
deb-src http://mirror.bjtu.edu.cn/ubuntu/ precise-security main multiverse restricted universe
deb-src http://mirror.bjtu.edu.cn/ubuntu/ precise-updates main multiverse restricted universe
#兰州大学
deb ftp://mirror.lzu.edu.cn/ubuntu/ precise main multiverse restricted universe
deb ftp://mirror.lzu.edu.cn/ubuntu/ precise-backports main multiverse restricted universe
deb ftp://mirror.lzu.edu.cn/ubuntu/ precise-proposed main multiverse restricted universe
deb ftp://mirror.lzu.edu.cn/ubuntu/ precise-security main multiverse restricted universe
deb ftp://mirror.lzu.edu.cn/ubuntu/ precise-updates main multiverse restricted universe
deb ftp://mirror.lzu.edu.cn/ubuntu-cn/ precise main multiverse restricted universe
#上海交通大学
deb http://ftp.sjtu.edu.cn/ubuntu/ precise main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ precise-backports main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ precise-proposed main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ precise-security main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ precise-updates main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu-cn/ precise main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ precise main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ precise-backports main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ precise-proposed main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ precise-security main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ precise-updates main multiverse restricted universe
我的资源：
deb http://mirrors.163.com/ubuntu/ oneiric main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ oneiric-security main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ oneiric-updates main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ oneiric-proposed main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ oneiric-backports main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ oneiric main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ oneiric-security main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ oneiric-updates main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ oneiric-proposed main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ oneiric-backports main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ oneiric main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ oneiric-security main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ oneiric-updates main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ oneiric-proposed main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ oneiric-backports main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ oneiric main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ oneiric-security main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ oneiric-updates main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ oneiric-proposed main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ oneiric-backports main restricted universe multiverse
官网更新源：
# deb cdrom:[Ubuntu 12.04.2 LTS _Precise Pangolin_ - Release i386 (20130213)]/ precise main restricted
# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://archive.ubuntu.com/ubuntu precise main restricted
deb-src http://archive.ubuntu.com/ubuntu precise main restricted
## Major bug fix updates produced after the final release of the
## distribution.
deb http://archive.ubuntu.com/ubuntu precise-updates main restricted
deb-src http://archive.ubuntu.com/ubuntu precise-updates main restricted
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://archive.ubuntu.com/ubuntu precise universe
deb-src http://archive.ubuntu.com/ubuntu precise universe
deb http://archive.ubuntu.com/ubuntu precise-updates universe
deb-src http://archive.ubuntu.com/ubuntu precise-updates universe
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://archive.ubuntu.com/ubuntu precise multiverse
deb-src http://archive.ubuntu.com/ubuntu precise multiverse
deb http://archive.ubuntu.com/ubuntu precise-updates multiverse
deb-src http://archive.ubuntu.com/ubuntu precise-updates multiverse
## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb http://archive.ubuntu.com/ubuntu precise-backports main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu precise-backports main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu precise-security main restricted
deb-src http://archive.ubuntu.com/ubuntu precise-security main restricted
deb http://archive.ubuntu.com/ubuntu precise-security universe
deb-src http://archive.ubuntu.com/ubuntu precise-security universe
deb http://archive.ubuntu.com/ubuntu precise-security multiverse
deb-src http://archive.ubuntu.com/ubuntu precise-security multiverse
## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
deb http://archive.canonical.com/ubuntu precise partner
deb-src http://archive.canonical.com/ubuntu precise partner
## This software is not part of Ubuntu, but is offered by third-party
## developers who want to ship their latest software.
deb http://extras.ubuntu.com/ubuntu precise main
deb http://archive.ubuntu.com/ubuntu precise-proposed restricted main multiverse universe
deb-src http://extras.ubuntu.com/ubuntu precise main