#备份当前源

cd /etc/apt/

sudo cp sources.list sources.list.bak

#修改为ali的源

/etc/apt$ cat sources.list

deb http://mirrors.aliyun.com/ubuntu/ utopic main restricted universe multiverse

deb http://mirrors.aliyun.com/ubuntu/ utopic-security main restricted universe multiverse

deb http://mirrors.aliyun.com/ubuntu/ utopic-updates main restricted universe multiverse

deb http://mirrors.aliyun.com/ubuntu/ utopic-proposed main restricted universe multiverse

deb http://mirrors.aliyun.com/ubuntu/ utopic-backports main restricted universe multiverse

deb-src http://mirrors.aliyun.com/ubuntu/ utopic main restricted universe multiverse

deb-src http://mirrors.aliyun.com/ubuntu/ utopic-security main restricted universe multiverse

deb-src http://mirrors.aliyun.com/ubuntu/ utopic-updates main restricted universe multiverse

deb-src http://mirrors.aliyun.com/ubuntu/ utopic-proposed main restricted universe multiverse

deb-src http://mirrors.aliyun.com/ubuntu/ utopic-backports main restricted universe multiverse

#更新

sudo apt-get update