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ced4568andClaude Sonnet 5 15b616274b feat(root01): author Computing & Linux Foundations, and the real 01->05 prerequisite chain

Adds all 6 ROOT 01 modules (how computers run software, the shell, filesystem navigation,
files & text, processes, users & permissions foundations), each with a real lesson,
demonstration/guided exercise, knowledge check where warranted, a hands-on Lab, and a
reflection — 35 activities, 29 new content files.

Adds 6 new hands-on Linux scenarios (linux-inspect-hardware, linux-shell-basics,
linux-filesystem-navigation, linux-files-and-text, linux-process-management,
linux-permissions-foundations) plus 2 MCQ scenarios, using the existing generic scenario/
validation engine (docs/ROOT_FOUNDATIONS_LAB_STRATEGY.md §1) — every one tested end-to-end via
the real scenario setup/validate API, including negative tests confirming they correctly FAIL
when not actually solved (e.g. the process-management scenario fails while the target process
is still running; the permissions scenario is tested against a real `su - labuser` denial).

Wires rootnode-linux-foundations-assessment (2 required + 4 random-draw scenarios) using the
existing Phase 3B assessment engine.

Adds a real, server-side ROOT 01->02->03->04->05 course prerequisite chain
(courses.prerequisites) — verified live on two students: one who completed ROOT 01 sees ROOT 02
unlock; a fresh student sees ROOT 02 correctly locked while 03/04/05 stay vacuously satisfied
(their own prerequisite courses are still empty). ROOT 06+ and the Capstone are unaffected.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

2026-08-26 12:59:52 -05:00

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Demonstration: Watching Exit Codes in Real Time

OBSERVE

Run a command you know will succeed, then immediately check its exit code:

$ true
$ echo $?
0

HYPOTHESIS

Now predict: what will the exit code be if the command fails instead?

INSPECT

Run a command that fails, and check immediately:

$ ls /this-does-not-exist
ls: cannot access '/this-does-not-exist': No such file or directory
$ echo $?
2

CHANGE

Try a few other failing commands and note their codes: grep nomatch /etc/hostname (exit 1 — "no matches found," a different kind of failure than "file not found").

VERIFY

Notice: exit codes aren't just "0 or 1" — different failures often get different non-zero codes. 0 always means success; the exact non-zero value's MEANING varies by command, but ANY non-zero value reliably means "something went wrong," which is the part every script actually relies on (if command; then ... else ...).

Instructor Notes

Demo goal: Make the abstract "exit code" concept concrete by actually watching $? change in real time, immediately after each command — this is far more convincing live than described in prose.

Approximate timing: 8 minutes live.

Common mistake to watch for: running echo $? after ANY other command in between (even ls) silently checks the WRONG command's exit code — emphasize "check it immediately."

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