ubuntu20.04切换apt源

如果你的服务器是x86/64的，可以参考https://mirrors.tuna.tsinghua.edu.cn/help/ubuntu/

如果你的事arm的，可参考https://mirrors.tuna.tsinghua.edu.cn/help/ubuntu-ports/

由于我的是a rm的虚拟机，所以复制的是ubuntu-ports中的内容

root@lili:~# cd /etc/apt
root@lili:~# cp sources.list sources.listbak

把上述链接中的内容复制到sources.list
root@lili:/etc/apt# cat sources.list
# 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-ports/ focal main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ focal main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ focal-updates main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ focal-updates main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ focal-backports main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ focal-backports main restricted universe multiverse

# deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ focal-security main restricted universe multiverse
# # deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ focal-security main restricted universe multiverse

deb http://ports.ubuntu.com/ubuntu-ports/ focal-security main restricted universe multiverse
# deb-src http://ports.ubuntu.com/ubuntu-ports/ focal-security main restricted universe multiverse

# 预发布软件源，不建议启用
# deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ focal-proposed main restricted universe multiverse
# # deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ focal-proposed main restricted universe multiverse

更新apt源
root@lili:/etc/apt# apt-get update
root@lili:/etc/apt# apt-get upgrade