E: The repository ‘http://ppa.launchpad.net/projectatomic/ppa/ubuntu focal Release‘ does not have a
这个是在win10上安装的Ubuntu操作系统；准备安装下其他的软件，apt-get update的时候，发现第【8】步的时候失败了。。。
root@N-20HEPF15JN1Q:/home/ubuntu# apt-get update -qq
E: The repository 'http://ppa.launchpad.net/projectatomic/ppa/ubuntu focal Release' does not have a Release file.
root@N-20HEPF15JN1Q:/home/ubuntu# add-apt-repository --remove ppa:/webupd8team/sublime-text-3
bash: /usr/bin/add-apt-repository: No such file or directory
root@N-20HEPF15JN1Q:/home/ubuntu# apt-get update
Hit:1 http://mirrors.aliyun.com/ubuntu focal InRelease
Hit:2 http://mirrors.aliyun.com/ubuntu focal-security InRelease
Hit:3 http://mirrors.aliyun.com/ubuntu focal-updates InRelease
Hit:4 http://mirrors.aliyun.com/ubuntu focal-proposed InRelease
Ign:5 http://ppa.launchpad.net/projectatomic/ppa/ubuntu focal InRelease
Hit:6 http://mirrors.aliyun.com/ubuntu focal-backports InRelease
Hit:7 https://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable/xUbuntu_20.04 InRelease
Err:8 http://ppa.launchpad.net/projectatomic/ppa/ubuntu focal Release
404 Not Found [IP: 91.189.95.83 80]
Reading package lists... Done
E: The repository 'http://ppa.launchpad.net/projectatomic/ppa/ubuntu focal Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.解决办法：在etc/apt/sources.list.d 目录中删除对应的ppa，在软件与更新其他软件中把谷歌浏览器的对勾去掉
然后执行sudo apt-get update ，问题即可解决
root@N-20HEPF15JN1Q:/home/ubuntu# cd /etc/apt/sources.list.d
root@N-20HEPF15JN1Q:/etc/apt/sources.list.d# ls
devel:kubic:libcontainers:stable.list projectatomic-ubuntu-ppa-focal.list
root@N-20HEPF15JN1Q:/etc/apt/sources.list.d# rm projectatomic-ubuntu-ppa-focal.listapt update -------------- ok
apt-get update ---------------- ok
