最近，我发现…Ubuntu的官方源很慢，下载速度慢到爆炸，于是决定换阿里云源
首先 sudo cp /etc/apt/sources.list /etc/apt/sources.list.bak 备份一下源文件，以防万一
在sudo vi /etc/apt/sources.list
把这个文件内容删除，改成以下(注:改成其他源也同理，还有Ubuntu好像有两个版本，一个是ubuntu一个是ubuntu-ports，不要弄错了，我就是因为弄错了apt全部不正常了)
[text] deb http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse [/text]
然后保存就好了
最后，运行 sudo apt-get update 和 sudo apt-get upgrade 更新软件列表
最后终于摆脱了Ubuntu超慢的源，换了阿里云的源，如果有错误，欢迎在留言板留言
