ced4568andClaude Sonnet 5
15b616274b
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]>
1.1 KiB
Demonstration: Watching a Process Actually Terminate
OBSERVE
Start a long-running background process and note its PID:
$ sleep 300 &
[1] 1421
1421 is the PID (yours will differ every time).
HYPOTHESIS
Predict: will kill -0 1421 print anything if the process is still running?
INSPECT
$ kill -0 1421 && echo "still running"
still running
kill -0 sends no real signal — silence (or, here, our own echo) means the process exists.
CHANGE
Now actually terminate it:
$ kill 1421
VERIFY
$ kill -0 1421 2>/dev/null && echo "still running" || echo "gone"
gone
The exact same check now reports the opposite result — real, observable proof the process is gone, not an assumption.
Instructor Notes
Demo goal: Make "checking before and after" a visible habit, not just narrated — students should see the SAME command return a different real answer once state actually changed.
Approximate timing: 8 minutes live.
Common mistake to watch for: reaching for kill -9 by default "to be safe" — reinforce that
plain kill (SIGTERM) is the correct first attempt almost always.