1.备份原来的源
sudo cp /etc/apt/sources.list /etc/apt/sources_init.list
将以前的源备份一下，以防以后可以用的。
2.更换源
sudo gedit /etc/apt/sources.list
使用gedit打开文档，将下边的阿里源复制进去，然后点击保存关闭。
阿里源 （Ubuntu 18.04）
deb http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
3.更新
更新源
sudo apt-get update
复损坏的软件包，尝试卸载出错的包，重新安装正确版本的。
sudo apt-get -f install
更新软件
sudo apt-get upgrade
4.其他常用源
西电源（只有校内网网线使用，但是不限制流量，还是十分靠谱的）
deb http://linux.xidian.edu.cn/mirrors/ubuntu/ xenial main restricted universe multiverse
#deb-src http://linux.xidian.edu.cn/mirrors/ubuntu/ xenial main restricted universe multiverse
deb http://linux.xidian.edu.cn/mirrors/ubuntu/ xenial-security main restricted universe multiverse
#deb-src http://linux.xidian.edu.cn/mirrors/ubuntu/ xenial-security main restricted universe multiverse
deb http://linux.xidian.edu.cn/mirrors/ubuntu/ xenial-updates main restricted universe multiverse
#deb-src http://linux.xidian.edu.cn/mirrors/ubuntu/ xenial-updates main restricted universe multiverse
#deb http://linux.xidian.edu.cn/mirrors/ubuntu/ xenial-backports main restricted universe multiverse
#deb-src http://linux.xidian.edu.cn/mirrors/ubuntu/ xenial-backports main restricted universe multiverse
#deb http://linux.xidian.edu.cn/mirrors/ubuntu/ xenial-proposed main restricted universe multiverse
#deb-src http://linux.xidian.edu.cn/mirrors/ubuntu/ xenial-proposed main restricted universe multiverse
清华源
# 默认注释了源码镜像以提高 apt update 速度，如有需要可自行取消注释
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-security main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-security main restricted universe multiverse
# 预发布软件源，不建议启用
# deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse
网易源
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
