因为ubuntu18.04默认apt源是国外的，所以在线安装软件速度非常受影响，这里列举了一些常用的国内源地址
主要修改/etc/apt/sources.list文件，我们先进行备份
sudo cp /etc/apt/sources.list /etc/apt/sources.list_bak
我们看看原来的apt源
sudo cat /etc/apt/sources.list | egrep -v "^$|#" deb http://cn.archive.ubuntu.com/ubuntu/ bionic main restricted deb http://cn.archive.ubuntu.com/ubuntu/ bionic-updates main restricted deb http://cn.archive.ubuntu.com/ubuntu/ bionic universe deb http://cn.archive.ubuntu.com/ubuntu/ bionic-updates universe deb http://cn.archive.ubuntu.com/ubuntu/ bionic multiverse deb http://cn.archive.ubuntu.com/ubuntu/ bionic-updates multiverse deb http://cn.archive.ubuntu.com/ubuntu/ bionic-backports main restricted universe multiverse deb http://security.ubuntu.com/ubuntu bionic-security main restricted deb http://security.ubuntu.com/ubuntu bionic-security universe deb http://security.ubuntu.com/ubuntu bionic-security multiverse
可以将以上全部替换为以下几个国内源地址
阿里云源
deb http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse deb 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 main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
清华源
deb 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 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 https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic main restricted universe multiverse deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-security main restricted universe multiverse deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse
中科大源
deb https://mirrors.ustc.edu.cn/ubuntu/ bionic main restricted universe multiverse deb https://mirrors.ustc.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse deb https://mirrors.ustc.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse deb https://mirrors.ustc.edu.cn/ubuntu/ bionic-security main restricted universe multiverse deb https://mirrors.ustc.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic main restricted universe multiverse deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic-security main restricted universe multiverse deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse
网易163源
deb http://mirrors.163.com/ubuntu/ bionic main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ bionic-security main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ bionic-updates main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ bionic-proposed main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ bionic-backports main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ bionic main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ bionic-security main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ bionic-updates main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ bionic-proposed main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ bionic-backports main restricted universe multiverse
然后执行更新命令刷新缓存和包
sudo apt update -y sudo apt upgrade -y