1、备份原文件 mv /etc/apt/sources.list /etc/apt/sources.list.old

2、写入新源，以下是 Debian 11 的：

cat > /etc/apt/sources.list << EOF
deb https://mirrors.tuna.tsinghua.edu.cn/debian/ bullseye main contrib non-free
deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ bullseye main contrib non-free
 
deb https://mirrors.tuna.tsinghua.edu.cn/debian/ bullseye-updates main contrib non-free
deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ bullseye-updates main contrib non-free
 
deb https://mirrors.tuna.tsinghua.edu.cn/debian/ bullseye-backports main contrib non-free
deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ bullseye-backports main contrib non-free
 
deb https://mirrors.tuna.tsinghua.edu.cn/debian-security/ bullseye-security main contrib non-free
deb-src https://mirrors.tuna.tsinghua.edu.cn/debian-security/ bullseye-security main contrib non-free
EOF

如果是 Debian 12：

cat > /etc/apt/sources.list << EOF
deb https://mirrors.tuna.tsinghua.edu.cn/debian/ bookworm main contrib non-free non-free-firmware
deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ bookworm main contrib non-free non-free-firmware

deb https://mirrors.tuna.tsinghua.edu.cn/debian/ bookworm-updates main contrib non-free non-free-firmware
deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ bookworm-updates main contrib non-free non-free-firmware

deb https://mirrors.tuna.tsinghua.edu.cn/debian/ bookworm-backports main contrib non-free non-free-firmware
deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ bookworm-backports main contrib non-free non-free-firmware

deb https://mirrors.tuna.tsinghua.edu.cn/debian-security bookworm-security main contrib non-free non-free-firmware
deb-src https://mirrors.tuna.tsinghua.edu.cn/debian-security bookworm-security main contrib non-free non-free-firmware
EOF

注：

deb 指向的是编译好的二进制软件包。
deb-src 指向的是软件的源代码包，可以使用apt source命令下载软件的源代码并自行编译。

注：本文始发于我的博客园 https://www.cnblogs.com/art ，之后重新发于本站。