在ubuntu下自帶的軟體源安裝軟體非常慢，如果想要快速下載下傳東西得更換軟體源。而更換軟體源的方法很簡單。
一 備份系統自帶的軟體源
終端輸入
sudo cp /etc/apt/sources.list /etc/apt/sources_backup.list
二 打開系統自帶的軟體源
終端輸入
sudo gedit /etc/apt/sources.list
三 替換新的軟體源
# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://ftp.sjtu.edu.cn/ubuntu/ precise main restricted
deb-src http://ftp.sjtu.edu.cn/ubuntu/ precise main restricted
deb http://cz.archive.ubuntu.com/ubuntu lucid main
## Major bug fix updates produced after the final release of the
## distribution.
deb http://ftp.sjtu.edu.cn/ubuntu/ precise-updates main restricted
deb-src http://ftp.sjtu.edu.cn/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://ftp.sjtu.edu.cn/ubuntu/ precise universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ precise universe
deb http://ftp.sjtu.edu.cn/ubuntu/ precise-updates universe
deb-src http://ftp.sjtu.edu.cn/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://ftp.sjtu.edu.cn/ubuntu/ precise multiverse
deb-src http://ftp.sjtu.edu.cn/ubuntu/ precise multiverse
deb http://ftp.sjtu.edu.cn/ubuntu/ precise-updates multiverse
deb-src http://ftp.sjtu.edu.cn/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://ftp.sjtu.edu.cn/ubuntu/ precise-backports main restricted universe multiverse
deb-src http://ftp.sjtu.edu.cn/ubuntu/ precise-backports main restricted universe multiverse
deb http://ftp.sjtu.edu.cn/ubuntu/ precise-security main restricted
deb-src http://ftp.sjtu.edu.cn/ubuntu/ precise-security main restricted
deb http://ftp.sjtu.edu.cn/ubuntu/ precise-security universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ precise-security universe
deb http://ftp.sjtu.edu.cn/ubuntu/ precise-security multiverse
deb-src http://ftp.sjtu.edu.cn/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-src http://extras.ubuntu.com/ubuntu precise main
deb http://archive.ubuntu.com/ubuntu precise multiverse main universe restricted
deb-src http://archive.ubuntu.com/ubuntu precise universe main multiverse restricted #Added by software-properties
##1 Öйú¿ÆŒŒŽóѧԎ
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
##2 ±±Ÿ©œ»ŽóÔŽ
deb http://mirror.bjtu.edu.cn/Ubuntu/ hardy main restricted universe multiverse
deb http://mirror.bjtu.edu.cn/Ubuntu/ hardy-backports restricted universe multiverse
deb http://mirror.bjtu.edu.cn/Ubuntu/ hardy-proposed main restricted universe multiverse
deb http://mirror.bjtu.edu.cn/Ubuntu/ hardy-security main restricted universe multiverse
deb http://mirror.bjtu.edu.cn/Ubuntu/ hardy-updates main restricted universe multiverse
deb-src http://mirror.bjtu.edu.cn/Ubuntu/ hardy main restricted universe multiverse
deb-src http://mirror.bjtu.edu.cn/Ubuntu/ hardy-backports main restricted universe multiverse
deb-src http://mirror.bjtu.edu.cn/Ubuntu/ hardy-proposed main restricted universe multiverse
deb-src http://mirror.bjtu.edu.cn/Ubuntu/ hardy-security main restricted universe multiverse
deb-src http://mirror.bjtu.edu.cn/Ubuntu/ hardy-updates main restricted universe multiverse
##4 CN99ÔŽ
deb http://Ubuntu.cn99.com/ubuntu/ hardy main restricted universe multiverse
deb http://Ubuntu.cn99.com/ubuntu/ hardy-security main restricted universe multiverse
deb http://Ubuntu.cn99.com/ubuntu/ hardy-updates main restricted universe multiverse
deb http://Ubuntu.cn99.com/ubuntu/ hardy-proposed main restricted universe multiverse
deb http://Ubuntu.cn99.com/ubuntu/ hardy-backports main restricted universe multiverse
deb-src http://Ubuntu.cn99.com/ubuntu/ hardy main restricted universe multiverse
deb-src http://Ubuntu.cn99.com/ubuntu/ hardy-security main restricted universe multiverse
deb-src http://Ubuntu.cn99.com/ubuntu/ hardy-updates main restricted universe multiverse
deb-src http://Ubuntu.cn99.com/ubuntu/ hardy-proposed main restricted universe multiverse
deb-src http://Ubuntu.cn99.com/ubuntu/ hardy-backports main restricted universe multiverse
三 加載軟體源，使其生效
儲存剛打開的文本檔案，在終端輸入
sudo apt-get update
等指令執行完畢，就成功更新軟體源。
PS：
1.該過程可能比較久，請耐心等待
2.可能有一些軟體源無法更新，請直接忽略
![sudo apt-get update 出錯 Updating from such a repository can‘t be done securely, and is therefore[圖]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)