linuxplus/RECOVERY.md

Recovery Instructions

This file explains how to recover the working context for this Linux+ Emacs study project.

Use this file when ChatGPT or another assistant has lost context, when starting a new chat, or when restoring the workflow from the repository alone.

Project Summary

This is a GNU Emacs-based CompTIA Linux+ study system.

The user studies Linux+ topics through Emacs Lisp lesson files and corresponding quiz files. Lessons display instructional text in an Emacs buffer and open an ansi-term buffer for hands-on Linux commands. Quizzes use a custom quiz engine to test the lesson material and reinforce weak areas.

The repository is the source of truth for the project.

Read These Files First

Read files in this order:

1. README.md
2. RECOVERY.md
3. dotemacs
4. linuxplus-load-all.el
5. 06-linuxplus-quiz-mode.el
6. The highest-numbered lesson file
7. The highest-numbered quiz file
8. STUDY.md

The highest-numbered lesson and quiz files are usually the best examples of the current project style. Older files may not reflect the latest conventions.

Important Workflow Facts

The user’s .emacs setup already loads the Linux+ system.

The repository may contain a copy of that file named:

dotemacs

The relevant startup code is:

;; Load custom Elisp
(let ((dir "~/.emacs.d/lisp/linuxplus/"))
  (add-to-list 'load-path dir)
  (load (concat dir "linuxplus-load-all.el"))
  (linuxplus-load-all))

Therefore, after saving new lesson or quiz files into:

~/.emacs.d/lisp/linuxplus/

the correct refresh step is:

M-x linuxplus-load-all

Do not tell the user to manually add the directory to load-path, manually load linuxplus-load-all.el, or manually require individual lesson/quiz files unless specifically troubleshooting the loader.

Loader Behavior

The loader file is:

linuxplus-load-all.el

The function:

linuxplus-load-all

loads the numbered Linux+ Emacs Lisp files.

Future generated files should fit the existing loader behavior rather than requiring special manual loading.

Numbering Scheme

Lesson and quiz files are separate.

The current convention uses consecutive numbers for each lesson/quiz pair.

Example:

102-user-management-lesson.el
103-user-management-quiz.el

The next topic should use the next unused lesson number and the next unused quiz number.

Example:

104-storage-lvm-quotas-lesson.el
105-storage-lvm-quotas-quiz.el

Do not use the same number for both lesson and quiz files unless the repository later changes its convention.

Lesson File Expectations

A lesson file should:

• use the established numbered filename format
• define one interactive lesson function
• create a named lesson buffer
• insert the lesson content into that buffer
• use a split-window layout
• open or reuse an ansi-term terminal buffer
• return focus to the lesson buffer
• avoid fragile or undefined variables

Avoid this problem:

explicit-shell-file-name

Use a safer shell fallback pattern based on current repository style, such as:

(or shell-file-name (getenv "SHELL") "/bin/sh")

The exact buffer names and formatting should follow the highest-numbered current lesson files.

Quiz File Expectations

A quiz file should:

• use the established numbered filename format

• define one interactive quiz function

• call linuxplus-start-quiz

• pass exactly three arguments:

  1. the lesson function symbol
  2. the question list
  3. the quiz buffer name

The expected call shape is:

(linuxplus-start-quiz
 'linuxplus-NNN-topic-name-lesson
 '((:type true-false
    :prompt "..."
    :answer true))
 "*Linux+ Topic Quiz*")

Supported question types include:

true-false
yes-no
multiple

For multiple-choice questions, inspect 06-linuxplus-quiz-mode.el and the highest-numbered quiz files to confirm the current format.

Study Target File

The user will maintain:

STUDY.md

This file contains study priorities, weak areas, missed concepts, and notes from Linux+ book or practice work.

Use STUDY.md to decide what future lessons and quizzes should reinforce.

Prefer paraphrased concepts over exact copyrighted question text.

Good format:

Missed area: LVM volume groups
Correct concept: vgcreate creates a volume group.
Exam trap: lvcreate creates a logical volume, not a volume group.

Current Known Weak Areas

Future lessons should prioritize weak areas listed in STUDY.md.

Previously discussed weak areas included topics such as:

systemd and PID 1
GRUB2
LVM
quotas and repquota
kernel modules
SSH configuration precedence
/etc/services
netfilter
bandwidth and network tools
permissions and ACLs
cron syntax
Git
Azure Blob Storage
container orchestration
/etc/securetty
cd -
nginx as web server/load balancer
MongoDB JSON/BSON document model
mail filtering and redirection
backup and archive tools

Do not assume this list is complete. STUDY.md is the preferred source.

How to Continue the Project

To add a new topic:

1. Inspect the highest-numbered lesson and quiz files.

2. Inspect STUDY.md.

3. Choose the next unused pair of numbers.

4. Create a lesson file:

   NNN-topic-name-lesson.el

5. Create the matching quiz file:

   NNN+1-topic-name-quiz.el

6. Keep the lesson and quiz focused on one topic.

7. Save both files in:

   ~/.emacs.d/lisp/linuxplus/

8. Tell the user to run:

   M-x linuxplus-load-all

9. Then tell the user to run the new lesson and quiz functions.

Assistant Guidance

When helping with this project:

• Do not create generic Linux+ lessons.
• Use STUDY.md and the repository structure.
• Follow the current Emacs Lisp style from the highest-numbered files.
• Keep lesson and quiz files separate.
• Continue the numbering scheme.
• Do not re-explain solved setup steps unless troubleshooting.
• Do not tell the user to manually load files unless the loader is broken.
• Prefer practical study progress over redesigning the system.
• Remember that the user is trying to study for Linux+, not spend all available time maintaining infrastructure.

Goal

The goal is to help the user make steady Linux+ certification progress through targeted, topic-based, Emacs-integrated lessons and quizzes.

RECOVERY maintenance update - 2026-07-09

Corrected the firewall review lesson pair to follow the repository numbering and loader conventions.

Remove these incorrectly named files:

• linuxplus-lesson-120.el
• linuxplus-quiz-120.el

Create these replacement files:

• 104-firewall-review-lesson.el
• 105-firewall-review-quiz.el

Reason for correction:

• linuxplus-load-all.el loads numbered Emacs Lisp files.
• Lesson and quiz files use consecutive numbers.
• The lesson file should be named NNN-topic-name-lesson.el.
• The quiz file should be named NNN+1-topic-name-quiz.el.
• Quiz files should call linuxplus-start-quiz instead of using their own read-string scoring loop.

The corrected lesson function is:

• linuxplus-firewall-review-lesson

The corrected quiz function is:

• linuxplus-firewall-review-quiz

Lesson content is based on missed Linux+ firewall book questions:

• firewall ACLs
• packet inspection
• persistent configuration files
• stateful firewall review points
• firewall-cmd --runtime-to-permanent
• numbered UFW rules
• simple UFW SSH blocking
• DenyHosts
• Fail2Ban

The lesson preserves the real-world note that DenyHosts is strongly associated with /etc/hosts.deny, while Fail2Ban commonly blocks through firewall actions. For the book question, memorize the book's expected wording.

RECOVERY maintenance update - 2026-07-09

Added project-native Emacs Lisp helpers for updating existing files.

New file:

• 07-linuxplus-update-files.el

Reason:

• Hand-written patch hunks proved fragile.
• Some updates need to modify existing Markdown files safely.
• The helper file is numbered so linuxplus-load-all loads it with the rest of the project.
• Each update creates a numbered .bak.N backup before writing.

Important commands:

M-x linuxplus-update-help
M-x linuxplus-apply-firewall-score-update
M-x linuxplus-update-replace-section-with-region
M-x linuxplus-update-insert-region-before-heading

The firewall score updater modifies STUDY.md by:

• replacing the ## Weak Area: Firewall Review section
• setting its status to Solid
• inserting the 20/20 score note before ## Current Notes

Future assistants should prefer these project update helpers over hand-written shell patch hunks when updating existing project files.