问题1：-bash: curl: command not found

解决方法：

apt-get --allow-releaseinfo-change update
apt-get dist-upgrade
apt install -y curl

问题2：-bash: sudo: command not found

apt install -y sudo

问题3：-bash: wget: command not found

apt install -y wget

问题4：-bash: ufw: command not found

apt install -y ufw

问题5：Debian首次SSH连接,提示 Type `help' to learn how to use Xshell prompt.

sudo nano /etc/ssh/sshd_config

关键参数：

Port 22                  # 确认端口未被注释
ListenAddress 0.0.0.0    # 监听所有IP
PermitRootLogin yes      # 临时允许root登录（测试后建议关闭）
PasswordAuthentication yes # 允许密码登录

我是一键修复命令

curl -sSL https://down.9930.top:4466/shell/xiufussh.sh  -o xiufussh.sh 
sudo bash xiufussh.sh 

问题6：运行apt install -y curl   

报错：E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?

  解决方法：  更新本地 apt 源或替换源

apt update