ubuntu18 软件源替换成清华源 啊没错，这又是一个转载 能用就好 ubuntu18替换软件源 sudo cp /etc/apt/sources.list /etc/apt/sources.list.backup
![sudo apt-get update 出错 Updating from such a repository can‘t be done securely, and is therefore[图]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)