Linux更改镜像源

https://mirrors.tuna.tsinghua.edu.cn/ # 清华大学镜像源
# 1、搜索Ubuntu
# 2、点击Ubuntu旁边的'？' 注意Ubuntu的版本
# 3、cd /etc/apt
# 4、sudo cp sources.list sources.listcp
# 5、sudo chmod 667 sources.list
# 6、vim sources.list
# 7、V + ↓ dd
# 8、按i 把清华源粘贴进去 :x按Enter
# 9、sudo apt update

# vim 打开sources.list之后 在命令模式按shift+v 之后按↓箭头全选 按俩下dd

**删除之后按i**把镜像写里面
# 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/ focal main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-updates main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-updates main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-backports main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-backports main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-security main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ 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/ focal-proposed main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-proposed main restricted universe multiverse

sudo apt update