Ubuntu系统自带的源都是国外的网址，国内用户在使用的时候网速比较慢。一个软件的下载是十分痛苦的，这里讲解一下如何将国外源更换为国内源，让你的网速Biu.Biu.Biu
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
deb http://mirrors.aliyun.com/ubuntu/ xenial main deb-src http://mirrors.aliyun.com/ubuntu/ xenial main deb http://mirrors.aliyun.com/ubuntu/ xenial-updates main deb-src http://mirrors.aliyun.com/ubuntu/ xenial-updates main deb http://mirrors.aliyun.com/ubuntu/ xenial universe deb-src http://mirrors.aliyun.com/ubuntu/ xenial universe deb http://mirrors.aliyun.com/ubuntu/ xenial-updates universe deb-src http://mirrors.aliyun.com/ubuntu/ xenial-updates universe deb http://mirrors.aliyun.com/ubuntu/ xenial-security main deb-src http://mirrors.aliyun.com/ubuntu/ xenial-security main deb http://mirrors.aliyun.com/ubuntu/ xenial-security universe deb-src http://mirrors.aliyun.com/ubuntu/ xenial-security universe
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
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
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