Ubuntu全版本通用换源教程：
打开终端：按下
Ctrl + Alt + T组合键，打开终端。备份源列表文件：在终端中执行以下命令备份原有的源列表文件：
sudo cp /etc/apt/sources.list /etc/apt/sources.list.backup修改源列表文件：使用文本编辑器（例如nano或gedit）打开源列表文件：
sudo nano /etc/apt/sources.list替换默认源：用下面提供的新源地址替换文件中的内容（根据你所在的地理位置选择一个可用的镜像源）：
# 默认官方源 deb http://archive.ubuntu.com/ubuntu/ focal main restricted universe multiverse deb-src http://archive.ubuntu.com/ubuntu/ focal main restricted universe multiverse deb http://archive.ubuntu.com/ubuntu/ focal-updates main restricted universe multiverse deb-src http://archive.ubuntu.com/ubuntu/ focal-updates main restricted universe multiverse deb http://archive.ubuntu.com/ubuntu/ focal-security main restricted universe multiverse deb-src http://archive.ubuntu.com/ubuntu/ focal-security main restricted universe multiverse deb http://archive.ubuntu.com/ubuntu/ focal-backports main restricted universe multiverse deb-src http://archive.ubuntu.com/ubuntu/ focal-backports main restricted universe multiverse # 阿里云源 deb http://mirrors.aliyun.com/ubuntu/ focal main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ focal main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ focal-updates main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ focal-updates main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ focal-security main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ focal-security main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ focal-backports main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ focal-backports main restricted universe multiverse将
focal替换为你使用的Ubuntu版本代号，例如bionic、xenial等。保存并关闭文件：按下
Ctrl + X，然后按Y确认保存，最后按Enter键退出编辑器。更新软件源：执行以下命令更新软件源列表：
sudo apt-get update现在，你已经成功地更换了Ubuntu系统的软件源。新的源地址将提供更快的下载速度和更稳定的软件包更新。
