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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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Files and Text

Basic file operations

touch <file> — create an empty file (or update its timestamp if it exists)
mkdir <dir> — create a directory (-p creates any missing parent directories too)
cp <src> <dst> — copy a file
mv <src> <dst> — move OR rename a file (Linux treats renaming as "moving to a new name in the same place")
rm <file> — delete a file (-r for a directory, -f to skip confirmation — dangerous combined: rm -rf deletes without asking, permanently)

Reading text

cat <file> — print the whole file at once
less <file> — page through a file interactively (press q to quit) — the right tool for anything too long to read in one screen
head <file> / tail <file> — the first/last 10 lines by default (-n 20 for a different count); tail -f follows a file live as new lines are appended — exactly how you'd watch a log file update in real time

Searching text: `grep`

grep PATTERN file prints only the lines matching PATTERN. This is one of the most-used commands in real operations work — "find the lines that matter" beats "read everything."

Pipes and redirection: composing commands

A pipe (|) sends one command's output as the next command's input: cat app.log | grep ERROR — read the file, then filter it.
Redirection (>) sends a command's output into a file instead of the screen (overwriting it): grep ERROR app.log > errors.txt. >> appends instead of overwriting.

stdout vs. stderr

A command actually has TWO separate output streams: stdout (normal output) and stderr (error messages), even though both print to your screen by default. This is why command 2>/dev/null (redirecting stream 2, stderr, to nowhere) can suppress error noise while still showing normal output — you'll use exactly this pattern in later Labs.

Instructor Notes

Lesson goal: Build real fluency composing small commands together — this is the single highest-leverage Linux skill for troubleshooting work later in ROOT_.

Approximate timing: 15 minutes read; 10 minutes live.

Common misconception to watch for: students often don't realize stdout/stderr are separate streams until they see 2>/dev/null change what's suppressed — worth demonstrating live.

Demo idea: run a command that produces both real output and an error in the same call (e.g. ls /etc /nonexistent) and show how 2>/dev/null changes what appears.

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