ubuntu修改源

一、先备份原始源（必做！防止出错）
打开终端，执行这条命令备份默认源文件：

sudo cp /etc/apt/sources.list /etc/apt/sources.list.bak

二、一键替换为国内高速源
直接用命令覆盖源文件，任选一个源复制执行即可：

1. 阿里云源（推荐，速度快、稳定）
   sudo tee /etc/apt/sources.list <<-'EOF'
   deb http://mirrors.aliyun.com/ubuntu/ noble main restricted universe multiverse
   deb http://mirrors.aliyun.com/ubuntu/ noble-security main restricted universe multiverse
   deb http://mirrors.aliyun.com/ubuntu/ noble-updates main restricted universe multiverse
   deb http://mirrors.aliyun.com/ubuntu/ noble-backports main restricted universe multiverse
   deb-src http://mirrors.aliyun.com/ubuntu/ noble main restricted universe multiverse
   deb-src http://mirrors.aliyun.com/ubuntu/ noble-security main restricted universe multiverse
   deb-src http://mirrors.aliyun.com/ubuntu/ noble-updates main restricted universe multiverse
   deb-src http://mirrors.aliyun.com/ubuntu/ noble-backports main restricted universe multiverse
   EOF

2. 清华大学源（高校镜像，极速）
   sudo tee /etc/apt/sources.list <<-'EOF'
   deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ noble main restricted universe multiverse
   deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ noble-security main restricted universe multiverse
   deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ noble-updates main restricted universe multiverse
   deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ noble-backports main restricted universe multiverse
   deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ noble main restricted universe multiverse
   deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ noble-security main restricted universe multiverse
   deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ noble-updates main restricted universe multiverse
   deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ noble-backports main restricted universe multiverse
   EOF

3. 中科大源
   sudo tee /etc/apt/sources.list <<-'EOF'
   deb https://mirrors.ustc.edu.cn/ubuntu/ noble main restricted universe multiverse
   deb https://mirrors.ustc.edu.cn/ubuntu/ noble-security main restricted universe multiverse
   deb https://mirrors.ustc.edu.cn/ubuntu/ noble-updates main restricted universe multiverse
   deb https://mirrors.ustc.edu.cn/ubuntu/ noble-backports main restricted universe multiverse
   deb-src https://mirrors.ustc.edu.cn/ubuntu/ noble main restricted universe multiverse
   deb-src https://mirrors.ustc.edu.cn/ubuntu/ noble-security main restricted universe multiverse
   deb-src https://mirrors.ustc.edu.cn/ubuntu/ noble-updates main restricted universe multiverse
   deb-src https://mirrors.ustc.edu.cn/ubuntu/ noble-backports main restricted universe multiverse
   EOF
   三、更新源配置（最后一步）
   替换完成后，必须执行更新命令生效：

sudo apt update