1. 备份
sudo cp /etc/apt/sources.list /etc/apt/sources.list.bak
2.修改
sudo vim /etc/apt/sources.list
将source.list文件内容替换成下面的
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
sudo apt-get update