;;; 10-ssh-service-lesson.el --- ssh-service-lesson

(defun ssh-service-lesson ()
  "Hands-on Linux+ lesson for managing the SSH service with systemctl."
  (interactive)
  (delete-other-windows)
  (let ((lesson-buffer (get-buffer-create "*SSH Service Lesson*"))
        (shell (or shell-file-name (getenv "SHELL") "/bin/sh")))
    (switch-to-buffer lesson-buffer)
    (read-only-mode -1)
    (erase-buffer)
    (insert
     "Linux+ Lesson: SSH Service Management\n"
     "====================================\n\n"
     "Concept:\n"
     "Learn the difference between starting/stopping a service now and\n"
     "enabling/disabling it for boot.\n\n"
     "VM requirement:\n"
     "- Use a systemd-based Linux VM.\n"
     "- Debian/Ubuntu usually use service name: ssh\n"
     "- Fedora/Rocky/Alma/RHEL usually use service name: sshd\n\n"
     "In the terminal below, determine whether your VM uses ssh or sshd:\n"
     "  systemctl status ssh\n"
     "  systemctl status sshd\n\n"
     "Use the correct service name for the rest of the lesson.\n\n"
     "Hands-on tasks:\n"
     "A. Check status:\n"
     "     sudo systemctl status <service>\n\n"
     "B. Stop the service:\n"
     "     sudo systemctl stop <service>\n"
     "   Then check status again.\n\n"
     "C. Start the service:\n"
     "     sudo systemctl start <service>\n"
     "   Then check status again.\n\n"
     "D. Disable the service:\n"
     "     sudo systemctl disable <service>\n\n"
     "E. Re-enable the service:\n"
     "     sudo systemctl enable <service>\n\n"
     "What to notice:\n"
     "- start   = runs now\n"
     "- stop    = stops now\n"
     "- enable  = starts at boot\n"
     "- disable = does not start at boot\n\n"
     "Important Linux+ trap:\n"
     "A service can be enabled but not currently running.\n"
     "If so, use:\n"
     "  systemctl start <service>\n\n"
     "When you finish the hands-on portion, run:\n"
     "  M-x ssh-service-quiz\n")
    (goto-char (point-min))
    (view-mode 1)
    (split-window-below)
    (other-window 1)
    (let ((term-buffer (get-buffer "*term*")))
      (if (buffer-live-p term-buffer)
          (switch-to-buffer term-buffer)
        (ansi-term shell "term")))
    (other-window -1)))

;;; 10-ssh-service-lesson.el ends here