Ubuntu换源解决下载安装软件速度太慢问题

由于国内的网络环境，在Ubuntu上用apt-get install安装软件时，官方的源下载速度太慢，而且容易安装出错，只需换成国内的源然后update一下即可解决此问题。

步骤一：换成163的源

编辑/etc/apt/sources.list文件，换成163的源（以Wily(15.10)为例）：

deb http://mirrors.163.com/ubuntu/ wily main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ wily-security main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ wily-updates main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ wily-proposed main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ wily-backports main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ wily main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ wily-security main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ wily-updates main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ wily-proposed main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ wily-backports main restricted universe multiverse

Ubuntu其他版本的对应163源，查看地址：mirrors.163.com

步骤二：执行update命令

update更新刚改过的下载源：

sudo apt-get update