[TOC] ## 概述 ### 修改源 ``` > mv /etc/apt/sources.list /etc/apt/sources.list.bak > echo "deb https://mirror.tuna.tsinghua.edu.cn/ubuntu-ports/ focal main restricted universe multiverse deb https://mirror.tuna.tsinghua.edu.cn/ubuntu-ports/ focal-updates main restricted universe multiverse deb https://mirror.tuna.tsinghua.edu.cn/ubuntu-ports/ focal-backports main restricted universe multiverse deb https://mirror.tuna.tsinghua.edu.cn/ubuntu-ports/ focal-security main restricted universe multiverse deb https://mirror.tuna.tsinghua.edu.cn/ubuntu-ports/ focal-proposed main restricted universe multiverse">/etc/apt/sources.list > apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 3B4FE6ACC0B21F32 > apt update ```