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]>
1.3 KiB
Demonstration: A Real Permission Denial, and the Real Fix
OBSERVE
A file is owned by root with permissions 600 (owner read/write only):
$ stat -c '%a %U' data.txt
600 root
HYPOTHESIS
Predict: can a different, non-root user read this file?
INSPECT
$ su - labuser -c "cat data.txt"
cat: data.txt: Permission denied
Confirmed — 600 grants nothing to group or other, so labuser (neither the owner nor root)
is correctly denied.
CHANGE
Grant read access to everyone, while keeping write access limited to the owner:
$ chmod 644 data.txt
$ stat -c '%a' data.txt
644
VERIFY
$ su - labuser -c "cat data.txt"
sensitive
The exact same command that failed before now succeeds — the permission bits, not the file's actual content, were the only thing that changed.
Instructor Notes
Demo goal: Show a permission denial as a real, reproducible fact (not just a described
error message) and the exact minimal fix, not an overcorrection like chmod 777.
Approximate timing: 8 minutes live.
Common mistake to watch for: students reaching for chmod 777 "to make the error go away"
— explicitly name why that's wrong (it also grants WRITE to everyone, not just the read access
actually needed) and connect it back to least privilege.