通常官方自带的软件源都是官方的，下载速度比较慢，而且有些资源不一定能找到，所以这是我们就会相应的去更新软件源来提高apt命令下载安装软件的速度。
这是linaro系统中的自带软件源：
deb http://ports.ubuntu.com/ubuntu-ports/ trusty main universe
deb-src http://ports.ubuntu.com/ubuntu-ports/ trusty main universe
为防止操作失误，在修改之前我们先备份下软件源# cp /etc/apt/sources.list /etc/apt/sources.list_backup（普通用户前面加上sudo）
查看下你的系统信息，看看该换哪个版本的软件源，使用命令# lsb_release -a （Linaro查看版本当前操作系统信息）
No LSB modules are available.
Distributor ID: Linaro
Description: Linaro 14.04
Release: 14.04
Codename: trusty
接下来我们就可以来更改linaro的软件源了，使用命令 vi /etc/apt/sources.list即可进入文件编辑窗口，这里我想要使用ubuntu的软件源。我找了一些ubuntu140.4的软件源，有大型网站的，也有教育网的，可以根据自己的情况添加两三个即可。
##Ubuntu 官方更新服务器（欧洲，此为官方源，国内较慢，但无同步延迟问题，电信、移动/铁通、联通等公网用户可以使用)：
deb http://archive.ubuntu.com/ubuntu/ trusty main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ trusty-security main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ trusty-updates main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ trusty main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ trusty-security main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ trusty-updates main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ trusty-backports main restricted universe multiverse
##Ubuntu官方提供的其他软件（第三方闭源软件等）：
deb http://archive.canonical.com/ubuntu/ trusty partner
deb http://extras.ubuntu.com/ubuntu/ trusty main
##骨头兄亲自搭建并维护的 Ubuntu 源（该源位于浙江杭州百兆共享宽带的电信机房)，包含 Deepin 等镜像：
deb http://ubuntu.srt.cn/ubuntu/ trusty main restricted universe multiverse
deb http://ubuntu.srt.cn/ubuntu/ trusty-security main restricted universe multiverse
deb http://ubuntu.srt.cn/ubuntu/ trusty-updates main restricted universe multiverse
deb http://ubuntu.srt.cn/ubuntu/ trusty-proposed main restricted universe multiverse
deb http://ubuntu.srt.cn/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://ubuntu.srt.cn/ubuntu/ trusty main restricted universe multiverse
deb-src http://ubuntu.srt.cn/ubuntu/ trusty-security main restricted universe multiverse
deb-src http://ubuntu.srt.cn/ubuntu/ trusty-updates main restricted universe multiverse
deb-src http://ubuntu.srt.cn/ubuntu/ trusty-proposed main restricted universe multiverse
deb-src http://ubuntu.srt.cn/ubuntu/ trusty-backports main restricted universe multiverse
##网易163更新服务器（广东广州电信/联通千兆双线接入），包含其他开源镜像：
deb http://mirrors.163.com/ubuntu/ trusty main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ trusty-security main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ trusty-updates main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ trusty main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ trusty-security main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ trusty-updates main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ trusty-backports main restricted universe multiverse
##搜狐更新服务器（山东联通千兆接入，官方中国大陆地区镜像跳转至此） ，包含其他开源镜像：
deb http://mirrors.sohu.com/ubuntu/ trusty main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ trusty-security main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ trusty-updates main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ trusty main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ trusty-security main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ trusty-updates main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ trusty-backports main restricted universe multiverse
##LupaWorld 更新服务器（浙江杭州电信/联通双线服务器），包含其他开源镜像：
deb http://mirror.lupaworld.com/ubuntu trusty main restricted universe multiverse
deb http://mirror.lupaworld.com/ubuntu trusty-security main restricted universe multiverse
deb http://mirror.lupaworld.com/ubuntu trusty-updates main restricted universe multiverse
deb http://mirror.lupaworld.com/ubuntu trusty-backports main restricted universe multiverse
deb http://mirror.lupaworld.com/ubuntu trusty-proposed main restricted universe multiverse
deb-src http://mirror.lupaworld.com/ubuntu trusty main restricted universe multiverse
deb-src http://mirror.lupaworld.com/ubuntu trusty-security main restricted universe multiverse
deb-src http://mirror.lupaworld.com/ubuntu trusty-updates main restricted universe multiverse
deb-src http://mirror.lupaworld.com/ubuntu trusty-backports main restricted universe multiverse
deb-src http://mirror.lupaworld.com/ubuntu trusty-proposed main restricted universe multiverse
##常州贝特康姆软件技术有限公司 更新服务器（江苏常州电信服务器），包含其他开源镜像。
##( CN99域名 系 “常州市亚科技术有限公司” 所注册，但此公司与常州贝特康姆的法人代表和营业地址相同。所以本镜像实际即原 CN99。但现在 CN99镜像的域名已改为跳转至网易镜像）:
deb http://centos.bitcomm.cn/ubuntu trusty main restricted universe multiverse
deb http://centos.bitcomm.cn/ubuntu trusty-security main restricted universe multiverse
deb http://centos.bitcomm.cn/ubuntu trusty-updates main restricted universe multiverse
deb http://centos.bitcomm.cn/ubuntu trusty-backports main restricted universe multiverse
deb http://centos.bitcomm.cn/ubuntu trusty-proposed main restricted universe multiverse
deb-src http://centos.bitcomm.cn/ubuntu trusty main restricted universe multiverse
deb-src http://centos.bitcomm.cn/ubuntu trusty-security main restricted universe multiverse
deb-src http://centos.bitcomm.cn/ubuntu trusty-updates main restricted universe multiverse
deb-src http://centos.bitcomm.cn/ubuntu trusty-backports main restricted universe multiverse
deb-src http://centos.bitcomm.cn/ubuntu trusty-proposed main restricted universe multiverse
##以下为有教育网接入的服务器（推荐教育网用户使用，部分非教育网用户也有可观的速度。教育网用户请优先使用IPv6地址。
##中国科学技术大学更新服务器（位于合肥，千兆教育网接入，百兆电信/联通线路智能路由），由中科大Linux 用户协会和中科大学网络信息中心维护，包含其他开源镜像，Deepin 官方服##务器 实际亦指向此处：
deb http://debian.ustc.edu.cn/ubuntu/ trusty main multiverse restricted universe
deb http://debian.ustc.edu.cn/ubuntu/ trusty-backports main multiverse restricted universe
deb http://debian.ustc.edu.cn/ubuntu/ trusty-proposed main multiverse restricted universe
deb http://debian.ustc.edu.cn/ubuntu/ trusty-security main multiverse restricted universe
deb http://debian.ustc.edu.cn/ubuntu/ trusty-updates main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ trusty main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ trusty-backports main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ trusty-proposed main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ trusty-security main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ trusty-updates main multiverse restricted universe
##IPv6-Only 地址
deb http://mirrors6.ustc.edu.cn/ubuntu/ trusty main multiverse restricted universe
deb http://mirrors6.ustc.edu.cn/ubuntu/ trusty-backports main multiverse restricted universe
deb http://mirrors6.ustc.edu.cn/ubuntu/ trusty-proposed main multiverse restricted universe
deb http://mirrors6.ustc.edu.cn/ubuntu/ trusty-security main multiverse restricted universe
deb http://mirrors6.ustc.edu.cn/ubuntu/ trusty-updates main multiverse restricted universe
deb-src http://mirrors6.ustc.edu.cn/ubuntu/ trusty main multiverse restricted universe
deb-src http://mirrors6.ustc.edu.cn/ubuntu/ trusty-backports main multiverse restricted universe
deb-src http://mirrors6.ustc.edu.cn/ubuntu/ trusty-proposed main multiverse restricted universe
deb-src http://mirrors6.ustc.edu.cn/ubuntu/ trusty-security main multiverse restricted universe
deb-src http://mirrors6.ustc.edu.cn/ubuntu/ trusty-updates main multiverse restricted universe
##清华大学更新服务器，（教育网核心节点百兆接入，已计划提高到千兆）由清华大学学生网管会维护。包含其他开源镜像：
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ trusty main restricted universe multiverse
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ trusty-security main restricted universe multiverse
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ trusty-updates main restricted universe multiverse
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ trusty-backports main restricted universe multiverse
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ trusty-proposed main restricted universe multiverse
deb-src http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ trusty main restricted universe multiverse
deb-src http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ trusty-security main restricted universe multiverse
deb-src http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ trusty-updates main restricted universe multiverse
deb-src http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ trusty-proposed main restricted universe multiverse
##IPv4-Only 地址
deb http://mirrors.4.tuna.tsinghua.edu.cn/ubuntu/ trusty main restricted universe multiverse
deb http://mirrors.4.tuna.tsinghua.edu.cn/ubuntu/ trusty-security main restricted universe multiverse
deb http://mirrors.4.tuna.tsinghua.edu.cn/ubuntu/ trusty-updates main restricted universe multiverse
deb http://mirrors.4.tuna.tsinghua.edu.cn/ubuntu/ trusty-backports main restricted universe multiverse
deb http://mirrors.4.tuna.tsinghua.edu.cn/ubuntu/ trusty-proposed main restricted universe multiverse
deb-src http://mirrors.4.tuna.tsinghua.edu.cn/ubuntu/ trusty main restricted universe multiverse
deb-src http://mirrors.4.tuna.tsinghua.edu.cn/ubuntu/ trusty-security main restricted universe multiverse
deb-src http://mirrors.4.tuna.tsinghua.edu.cn/ubuntu/ trusty-updates main restricted universe multiverse
deb-src http://mirrors.4.tuna.tsinghua.edu.cn/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://mirrors.4.tuna.tsinghua.edu.cn/ubuntu/ trusty-proposed main restricted universe multiverse
##IPv6-Only 地址
deb http://mirrors.6.tuna.tsinghua.edu.cn/ubuntu/ trusty main multiverse restricted universe
deb http://mirrors.6.tuna.tsinghua.edu.cn/ubuntu/ trusty-backports main multiverse restricted universe
deb http://mirrors.6.tuna.tsinghua.edu.cn/ubuntu/ trusty-proposed main multiverse restricted universe
deb http://mirrors.6.tuna.tsinghua.edu.cn//ubuntu/ trusty-security main multiverse restricted universe
deb http://mirrors.6.tuna.tsinghua.edu.cn/ubuntu/ trusty-updates main multiverse restricted universe
deb-src http://mirrors.6.tuna.tsinghua.edu.cn/ubuntu/ trusty main multiverse restricted universe
deb-src http://mirrors.6.tuna.tsinghua.edu.cn/ubuntu/ trusty-backports main multiverse restricted universe
deb-src http://mirrors.6.tuna.tsinghua.edu.cn/ubuntu/ trusty-proposed main multiverse restricted universe
deb-src http://mirrors.6.tuna.tsinghua.edu.cn/ubuntu/ trusty-security main multiverse restricted universe
deb-src http://mirrors.6.tuna.tsinghua.edu.cn/ubuntu/ trusty-updates main multiverse restricted universe
##北京交通大学更新服务器（教育网/电信百兆接入），由北京交通大学信息中心赞助，包含其他开源镜像。
##（域名中的 bjtu 可以替换为 njtu ，即北交旧名“北方交通大学”对应域名） ：
deb http://mirror.bjtu.edu.cn/ubuntu/ trusty main multiverse restricted universe
deb http://mirror.bjtu.edu.cn/ubuntu/ trusty-backports main multiverse restricted universe
deb http://mirror.bjtu.edu.cn/ubuntu/ trusty-proposed main multiverse restricted universe
deb http://mirror.bjtu.edu.cn/ubuntu/ trusty-security main multiverse restricted universe
deb http://mirror.bjtu.edu.cn/ubuntu/ trusty-updates main multiverse restricted universe
deb-src http://mirror.bjtu.edu.cn/ubuntu/ trusty main multiverse restricted universe
deb-src http://mirror.bjtu.edu.cn/ubuntu/ trusty-backports main multiverse restricted universe
deb-src http://mirror.bjtu.edu.cn/ubuntu/ trusty-proposed main multiverse restricted universe
deb-src http://mirror.bjtu.edu.cn/ubuntu/ trusty-security main multiverse restricted universe
deb-src http://mirror.bjtu.edu.cn/ubuntu/ trusty-updates main multiverse restricted universe
##IPv6-Only 地址
deb http://mirror6.bjtu.edu.cn/ubuntu/ trusty main multiverse restricted universe
deb http://mirror6.bjtu.edu.cn/ubuntu/ trusty-backports main multiverse restricted universe
deb http://mirror6.bjtu.edu.cn/ubuntu/ trusty-proposed main multiverse restricted universe
deb http://mirror6.bjtu.edu.cn/ubuntu/ trusty-security main multiverse restricted universe
deb http://mirror6.bjtu.edu.cn/ubuntu/ trusty-updates main multiverse restricted universe
deb-src http://mirror6.bjtu.edu.cn/ubuntu/ trusty main multiverse restricted universe
deb-src http://mirror6.bjtu.edu.cn/ubuntu/ trusty-backports main multiverse restricted universe
deb-src http://mirror6.bjtu.edu.cn/ubuntu/ trusty-proposed main multiverse restricted universe
deb-src http://mirror6.bjtu.edu.cn/ubuntu/ trusty-security main multiverse restricted universe
deb-src http://mirror6.bjtu.edu.cn/ubuntu/ trusty-updates main multiverse restricted universe
##北京理工大学更新服务器（仅教育网可以访问），包含其他开源镜像：
deb http://mirror.bit.edu.cn/ubuntu/ trusty main restricted universe multiverse
deb http://mirror.bit.edu.cn/ubuntu/ trusty-security main restricted universe multiverse
deb http://mirror.bit.edu.cn/ubuntu/ trusty-updates main restricted universe multiverse
deb http://mirror.bit.edu.cn/ubuntu/ trusty-backports main restricted universe multiverse
deb http://mirror.bit.edu.cn/ubuntu/ trusty-proposed main restricted universe multiverse
deb-src http://mirror.bit.edu.cn/ubuntu/ trusty main restricted universe multiverse
deb-src http://mirror.bit.edu.cn/ubuntu/ trusty-security main restricted universe multiverse
deb-src http://mirror.bit.edu.cn/ubuntu/ trusty-updates main restricted universe multiverse
deb-src http://mirror.bit.edu.cn/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://mirror.bit.edu.cn/ubuntu/ trusty-proposed main restricted universe multiverse
##IPv6-Only 地址
deb http://mirror.bit6.edu.cn/ubuntu/ trusty main restricted universe multiverse
deb http://mirror.bit6.edu.cn/ubuntu/ trusty-security main restricted universe multiverse
deb http://mirror.bit6.edu.cn/ubuntu/ trusty-updates main restricted universe multiverse
deb http://mirror.bit6.edu.cn/ubuntu/ trusty-backports main restricted universe multiverse
deb http://mirror.bit6.edu.cn/ubuntu/ trusty-proposed main restricted universe multiverse
deb-src http://mirror.bit6.edu.cn/ubuntu/ trusty main restricted universe multiverse
deb-src http://mirror.bit6.edu.cn/ubuntu/ trusty-security main restricted universe multiverse
deb-src http://mirror.bit6.edu.cn/ubuntu/ trusty-updates main restricted universe multiverse
deb-src http://mirror.bit6.edu.cn/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://mirror.bit6.edu.cn/ubuntu/ trusty-proposed main restricted universe multiverse
##天津大学更新服务器，由天津大学信息与网络协会和天津大学自由软件联盟维护，包含其他开源镜像 (校外限 IPv6 访问)
##（域名可以替换为 jx.tju.zyrj.org 或 jx6.tju.zyrj.org）
deb http://mirror.tju.edu.cn/ubuntu/ trusty main restricted universe multiverse
deb http://mirror.tju.edu.cn/ubuntu/ trusty-security main restricted universe multiverse
deb http://mirror.tju.edu.cn/ubuntu/ trusty-updates main restricted universe multiverse
deb http://mirror.tju.edu.cn/ubuntu/ trusty-backports main restricted universe multiverse
deb http://mirror.tju.edu.cn/ubuntu/ trusty-proposed main restricted universe multiverse
deb-src http://mirror.tju.edu.cn/ubuntu/ trusty main restricted universe multiverse
deb-src http://mirror.tju.edu.cn/ubuntu/ trusty-security main restricted universe multiverse
deb-src http://mirror.tju.edu.cn/ubuntu/ trusty-updates main restricted universe multiverse
deb-src http://mirror.tju.edu.cn/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://mirror.tju.edu.cn/ubuntu/ trusty-proposed main restricted universe multiverse
##青岛大学更新服务器（教育网/山东青岛移动专线双线服务器），由 OSQDU维护，位于青岛大学。包含开源镜像和Opera、马克思主义文库等其他镜像。：
deb http://mirror.qdu.edu.cn/ubuntu trusty main restricted universe multiverse
deb http://mirror.qdu.edu.cn/ubuntu trusty-security main restricted universe multiverse
deb http://mirror.qdu.edu.cn/ubuntu trusty-updates main restricted universe multiverse
deb http://mirror.qdu.edu.cn/ubuntu trusty-backports main restricted universe multiverse
deb http://mirror.qdu.edu.cn/ubuntu trusty-proposed main restricted universe multiverse
deb-src http://mirror.qdu.edu.cn/ubuntu trusty main restricted universe multiverse
deb-src http://mirror.qdu.edu.cn/ubuntu trusty-security main restricted universe multiverse
deb-src http://mirror.qdu.edu.cn/ubuntu trusty-updates main restricted universe multiverse
deb-src http://mirror.qdu.edu.cn/ubuntu trusty-backports main restricted universe multiverse
deb-src http://mirror.qdu.edu.cn/ubuntu trusty-proposed main restricted universe multiverse
##东北大学更新服务器，包含其他开源镜像：
deb http://ftp.neu.edu.cn/mirrors/ubuntu/ trusty main multiverse restricted universe
deb http://ftp.neu.edu.cn/mirrors/ubuntu/ trusty-backports main multiverse restricted universe
deb http://ftp.neu.edu.cn/mirrors/ubuntu/ trusty-proposed main multiverse restricted universe
deb http://ftp.neu.edu.cn/mirrors/ubuntu/ trusty-security main multiverse restricted universe
deb http://ftp.neu.edu.cn/mirrors/ubuntu/ trusty-updates main multiverse restricted universe
deb-src http://ftp.neu.edu.cn/mirrors/ubuntu/ trusty main multiverse restricted universe
deb-src http://ftp.neu.edu.cn/mirrors/ubuntu/ trusty-backports main multiverse restricted universe
deb-src http://ftp.neu.edu.cn/mirrors/ubuntu/ trusty-proposed main multiverse restricted universe
deb-src http://ftp.neu.edu.cn/mirrors/ubuntu/ trusty-security main multiverse restricted universe
deb-src http://ftp.neu.edu.cn/mirrors/ubuntu/ trusty-updates main multiverse restricted universe
##IPv6-Only 地址
deb http://ftp.neu6.edu.cn/mirrors/ trusty main multiverse restricted universe
deb http://ftp.neu6.edu.cn/mirrors/ trusty-backports main multiverse restricted universe
deb http://ftp.neu6.edu.cn/mirrors/ trusty-proposed main multiverse restricted universe
deb http://ftp.neu6.edu.cn/mirrors/ trusty-security main multiverse restricted universe
deb http://ftp.neu6.edu.cn/mirrors/ trusty-updates main multiverse restricted universe
deb-src http://ftp.neu6.edu.cn/mirrors/ trusty main multiverse restricted universe
deb-src http://ftp.neu6.edu.cn/mirrors/ trusty-backports main multiverse restricted universe
deb-src http://ftp.neu6.edu.cn/mirrors/ trusty-proposed main multiverse restricted universe
deb-src http://ftp.neu6.edu.cn/mirrors/ trusty-security main multiverse restricted universe
deb-src http://ftp.neu6.edu.cn/mirrors/ trusty-updates main multiverse restricted universe
##哈尔滨工业大学更新服务器，包含其他开源镜像：
deb http://run.hit.edu.cn/ubuntu/ trusty main restricted universe multiverse
deb http://run.hit.edu.cn/ubuntu/ trusty-security main restricted universe multiverse
deb http://run.hit.edu.cn/ubuntu/ trusty-updates main restricted universe multiverse
deb http://run.hit.edu.cn/ubuntu/ trusty-backports main restricted universe multiverse
deb http://run.hit.edu.cn/ubuntu/ trusty-proposed main restricted universe multiverse
deb-src http://run.hit.edu.cn/ubuntu/ trusty main restricted universe multiverse
deb-src http://run.hit.edu.cn/ubuntu/ trusty-security main restricted universe multiverse
deb-src http://run.hit.edu.cn/ubuntu/ trusty-updates main restricted universe multiverse
deb-src http://run.hit.edu.cn/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://run.hit.edu.cn/ubuntu/ trusty-proposed main restricted universe multiverse
##IPv6-Only地址
deb http://run6.hit.edu.cn/ubuntu/ trusty main restricted universe multiverse
deb http://run6.hit.edu.cn/ubuntu/ trusty-security main restricted universe multiverse
deb http://run6.hit.edu.cn/ubuntu/ trusty-updates main restricted universe multiverse
deb http://run6.hit.edu.cn/ubuntu/ trusty-backports main restricted universe multiverse
deb http://run6.hit.edu.cn/ubuntu/ trusty-proposed main restricted universe multiverse
deb-src http://run6.hit.edu.cn/ubuntu/ trusty main restricted universe multiverse
deb-src http://run6.hit.edu.cn/ubuntu/ trusty-security main restricted universe multiverse
deb-src http://run6.hit.edu.cn/ubuntu/ trusty-updates main restricted universe multiverse
deb-src http://run6.hit.edu.cn/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://run6.hit.edu.cn/ubuntu/ trusty-proposed main restricted universe multiverse
##大连理工大学更新服务器，包含其他开源镜像：
##( IPv4/v6 Both )
deb http://mirror.dlut.edu.cn/ubuntu/ trusty main restricted universe multiverse
deb http://mirror.dlut.edu.cn/ubuntu/ trusty-security main restricted universe multiverse
deb http://mirror.dlut.edu.cn/ubuntu/ trusty-updates main restricted universe multiverse
deb http://mirror.dlut.edu.cn/ubuntu/ubuntu trusty-backports main restricted universe multiverse
deb http://mirror.dlut.edu.cn/ubuntu/ trusty-proposed main restricted universe multiverse
deb-src http://mirror.dlut.edu.cn/ubuntu/ trusty main restricted universe multiverse
deb-src http://mirror.dlut.edu.cn/ubuntu/ trusty-security main restricted universe multiverse
deb-src http://mirror.dlut.edu.cn/ubuntu/ trusty-updates main restricted universe multiverse
deb-src http://mirror.dlut.edu.cn/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://mirror.dlut.edu.cn/ubuntu/ trusty-proposed main restricted universe multiverse
##上海交通大学更新服务器（教育网千兆接入，联通/电信线路情况不详），包含其他开源镜像：
deb http://ftp.sjtu.edu.cn/ubuntu/ trusty main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ trusty-backports main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ trusty-proposed main multiverse restricted universe
deb http://tw.archive.ubuntu.com/ubuntu trusty-updates main restricted universe multiverse
deb http://ftp.sjtu.edu.cn/ubuntu/ trusty-security main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ trusty-updates main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ trusty main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ trusty-backports main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ trusty-proposed main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ trusty-security main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ trusty-updates main multiverse restricted universe
##IPv6-Only 地址
deb http://ftp6.sjtu.edu.cn/ubuntu/ trusty main multiverse restricted universe
deb http://ftp6.sjtu.edu.cn/ubuntu/ trusty-backports main multiverse restricted universe
deb http://ftp6.sjtu.edu.cn/ubuntu/ trusty-proposed main multiverse restricted universe
deb http://ftp6.sjtu.edu.cn/ubuntu/ trusty-security main multiverse restricted universe
deb http://ftp6.sjtu.edu.cn/ubuntu/ trusty-updates main multiverse restricted universe
deb-src http://ftp6.sjtu.edu.cn/ubuntu/ trusty main multiverse restricted universe
deb-src http://ftp6.sjtu.edu.cn/ubuntu/ trusty-backports main multiverse restricted universe
deb-src http://ftp6.sjtu.edu.cn/ubuntu/ trusty-proposed main multiverse restricted universe
deb-src http://ftp6.sjtu.edu.cn/ubuntu/ trusty-security main multiverse restricted universe
deb-src http://ftp6.sjtu.edu.cn/ubuntu/ trusty-updates main multiverse restricted universe
##厦门大学更新服务器，由厦门大学信息与网络中心维护，包含其他开源镜像：
##( IPv4/v6 Both )
deb http://mirrors.xmu.edu.cn/ubuntu/archive/ trusty main restricted universe multiverse
deb http://mirrors.xmu.edu.cn/ubuntu/archive/ trusty-backports restricted universe multiverse
deb http://mirrors.xmu.edu.cn/ubuntu/archive/ trusty-proposed main restricted universe multiverse
deb http://mirrors.xmu.edu.cn/ubuntu/archive/ trusty-security main restricted universe multiverse
deb http://mirrors.xmu.edu.cn/ubuntu/archive/ trusty-updates main restricted universe multiverse
deb-src http://mirrors.xmu.edu.cn/ubuntu/archive/ trusty main restricted universe multiverse
deb-src http://mirrors.xmu.edu.cn/ubuntu/archive/ trusty-backports main restricted universe multiverse
deb-src http://mirrors.xmu.edu.cn/ubuntu/archive/ trusty-proposed main restricted universe multiverse
deb-src http://mirrors.xmu.edu.cn/ubuntu/archive/ trusty-security main restricted universe multiverse
deb-src http://mirrors.xmu.edu.cn/ubuntu/archive/ trusty-updates main restricted universe multiverse
##成都市电子科技大学更新服务器，由电子科大学生宿舍网管会维护。仅包括 Ubuntu 镜像：
##( IPv4-Only )
##（如下列地址不通，可换用 uestc.edu.cn 域名尝试）
deb http://ubuntu.dormforce.net/ubuntu/ trusty main multiverse restricted universe
deb http://ubuntu.dormforce.net/ubuntu/ trusty-backports main multiverse restricted universe
deb http://ubuntu.dormforce.net/ubuntu/ trusty-proposed main multiverse restricted universe
deb http://ubuntu.dormforce.net/ubuntu/ trusty-security main multiverse restricted universe
deb http://ubuntu.dormforce.net/ubuntu/ trusty-updates main multiverse restricted universe
deb-src http://ubuntu.dormforce.net/ubuntu/ trusty main multiverse restricted universe
deb-src http://ubuntu.dormforce.net/ubuntu/ trusty-backports main multiverse restricted universe
deb-src http://ubuntu.dormforce.net/ubuntu/ trusty-proposed main multiverse restricted universe
deb-src http://ubuntu.dormforce.net/ubuntu/ trusty-security main multiverse restricted universe
deb-src http://ubuntu.dormforce.net/ubuntu/ trusty-updates main multiverse restricted universe
##兰州大学更新服务器，由兰大开源社区维护，包含其他开源镜像：
deb http://mirror.lzu.edu.cn/ubuntu/ trusty main multiverse restricted universe
deb http://mirror.lzu.edu.cn/ubuntu/ trusty-backports main multiverse restricted universe
deb http://mirror.lzu.edu.cn/ubuntu/ trusty-proposed main multiverse restricted universe
deb http://mirror.lzu.edu.cn/ubuntu/ trusty-security main multiverse restricted universe
deb http://mirror.lzu.edu.cn/ubuntu/ trusty-updates main multiverse restricted universe
deb-src http://mirror.lzu.edu.cn/ubuntu/ trusty main multiverse restricted universe
deb-src http://mirror.lzu.edu.cn/ubuntu/ trusty-backports main multiverse restricted universe
deb-src http://mirror.lzu.edu.cn/ubuntu/ trusty-proposed main multiverse restricted universe
deb-src http://mirror.lzu.edu.cn/ubuntu/ trusty-security main multiverse restricted universe
deb-src http://mirror.lzu.edu.cn/ubuntu/ trusty-updates main multiverse restricted universe
##以下为大陆地区外的源
##香港中文大学更新服务器，由香港中文大学资讯科技服务处维护，包含其他开源镜像：
deb http://ftp.cuhk.edu.hk/pub/Linux/ubuntu trusty main restricted universe multiverse
deb http://ftp.cuhk.edu.hk/pub/Linux/ubuntu trusty-security main restricted universe multiverse
deb http://ftp.cuhk.edu.hk/pub/Linux/ubuntu trusty-updates main restricted universe multiverse
deb http://ftp.cuhk.edu.hk/pub/Linux/ubuntu trusty-backports main restricted universe multiverse
deb http://ftp.cuhk.edu.hk/pub/Linux/ubuntu trusty-proposed main restricted universe multiverse
deb-src http://ftp.cuhk.edu.hk/pub/Linux/ubuntu trusty main restricted universe multiverse
deb-src http://ftp.cuhk.edu.hk/pub/Linux/ubuntu trusty-security main restricted universe multiverse
deb-src http://ftp.cuhk.edu.hk/pub/Linux/ubuntu trusty-updates main restricted universe multiverse
deb-src http://ftp.cuhk.edu.hk/pub/Linux/ubuntu trusty-backports main restricted universe multiverse
deb-src http://ftp.cuhk.edu.hk/pub/Linux/ubuntu trusty-proposed main restricted universe
##台湾的官方源。速度有时甚至快于内地的，包含 Debian 等其他镜像：
deb http://tw.archive.ubuntu.com/ubuntu trusty main restricted universe multiverse
deb http://tw.archive.ubuntu.com/ubuntu trusty-security main restricted universe multiverse
deb http://tw.archive.ubuntu.com/ubuntu trusty-updates main restricted universe multiverse
deb http://tw.archive.ubuntu.com/ubuntu trusty-backports main restricted universe multiverse
deb http://tw.archive.ubuntu.com/ubuntu trusty-proposed main restricted universe multiverse
deb-src http://tw.archive.ubuntu.com/ubuntu trusty main restricted universe multiverse
deb-src http://tw.archive.ubuntu.com/ubuntu trusty-updates main restricted universe multiverse
deb-src http://tw.archive.ubuntu.com/ubuntu trusty-backports main restricted universe multiverse
deb-src http://tw.archive.ubuntu.com/ubuntu trusty-proposed main restricted universe multiverse
这里我就添加了网易163的软件源。
添加好后记得保存，VI保存命令 ：按ESC键 跳到命令模式，然后：
:w 保存文件但不退出vi
:w file 将修改另外保存到file中，不退出vi
:w! 强制保存，不推出vi
:wq 保存文件并退出vi
:wq! 强制保存文件，并退出vi
q: 不保存文件，退出vi
:q! 不保存文件，强制退出vi
:e! 放弃所有修改，从上次保存文件开始再编辑
最后记得更新软件源，输入 sudo apt-get update 就可以更新软件源了。
