1.備份原來的源
sudo cp /etc/apt/sources.list /etc/apt/sources_init.list
將以前的源備份一下，以防以后可以用的。
2.更換源
/etc/apt/sources.list
使用gedit或者vim打開文檔，將下邊的阿里源復制進去，然后點擊保存關閉。
阿里源
deb http://mirrors.aliyun.com/ubuntu/ trusty main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ trusty-security main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ trusty-updates main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ trusty main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ trusty-security main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ trusty-updates main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ trusty-backports main restricted universe multiverse
3.更新
更新源
sudo apt-get update
更新軟件
sudo apt-get upgrade
可以看到速度嗖嗖嗖~ 很給力啊，大家果斷都換了吧！！！