ubuntu 更换更新源

1  备份原来的更新源

cp /etc/apt/sources.list /etc/apt/sources.list.backup

如果提示权限不够就输入下面两行，先进入到超级用户，再备份
sudo -s
cp /etc/apt/sources.list /etc/apt/sources.list.backup

2  修改更新源

　　打开sources.list (这就是存放更新源的文件)

sudo vim /etc/apt/sources.list

　　　　1.阿里源     将下面所有内容复制，粘贴并覆盖sources.list文件中的所有内容

　　　　

#deb包
deb http://mirrors.aliyun.com/ubuntu/ xenial main restricted universe multiverse  
deb http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted universe multiverse  
deb http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted universe multiverse  
deb http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse  
##测试版源  
deb http://mirrors.aliyun.com/ubuntu/ xenial-proposed main restricted universe multiverse  
# 源码  
deb-src http://mirrors.aliyun.com/ubuntu/ xenial main restricted universe multiverse  
deb-src http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted universe multiverse  
deb-src http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted universe multiverse  
deb-src http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse  
##测试版源  
deb-src http://mirrors.aliyun.com/ubuntu/ xenial-proposed main restricted universe multiverse  
# Canonical 合作伙伴和附加  
deb http://archive.canonical.com/ubuntu/ xenial partner  
deb http://extras.ubuntu.com/ubuntu/ xenial main 

　　　　2.清华源

　　　　　　进入网址复制可更改系统版本：https://mirror.tuna.tsinghua.edu.cn/help/ubuntu/

3  让更新源生效

sudo apt-get update