修改/etc/apt/sources.list
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
或者下载
http://mirrors.163.com/.help/sources.list.trusty替换/etc/apt/sources.list
具体步骤：
默认ubuntu14.04 destktop版没有安装wget 可先安装下wget
sudo apt-get install wget
然后切换到/etc/apt目录下
cd /etc/apt
将系统默认的配置文件重命名
sudo mv /etc/apt/sources.list /etc/apt/sources.list.default
然后将下载的sources.list.trusty，放到/etc/apt/sources.list
sudo wget http://mirrors.163.com/.help/sources.list.trusty
重命名
sudo mv sources.list.trusty sources.list
更新软件源列表
sudo apt-get update
