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]>
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Linux and the Shell
What "Linux" actually means
Linux is a kernel — the core piece of software from Module 1 that manages CPU, memory, and storage. What most people call "a Linux system" (Ubuntu, Debian, Fedora, Alpine...) is a distribution: the Linux kernel plus a chosen set of standard tools, package manager, and configuration conventions layered on top. Different distributions, same kernel underneath — which is why a command you learn on Ubuntu mostly still works on Alpine.
Shell vs. terminal
These get used interchangeably but are different things:
- The terminal is the window/program that displays text and sends your keystrokes somewhere.
- The shell is the program actually interpreting what you type as commands —
bashis the shell this Lab uses. The terminal is just the display; the shell is the brain.
Command structure
Every command follows roughly the same shape:
command [options] [arguments]
ls -la /var/log — ls is the command, -la are options (flags) that change its behavior,
/var/log is the argument (what to act on). Options can usually be combined (-l -a = -la).
Exit codes: how a command reports success or failure
Every command returns a number when it finishes: 0 means success, anything else (1-255) means
some kind of failure. This isn't a Linux quirk — it's the exact mechanism scripts, CI pipelines,
and (much later) Kubernetes health checks all rely on to know whether something worked. You can
read the last command's exit code with the special variable $?.
Getting help without leaving the terminal
- Tab completion — press Tab while typing a command or path; the shell completes it for you or shows you the options. This is a genuine time-saver, not just a convenience.
- Command history — press the Up arrow to recall previous commands;
historylists them. man <command>— the manual page for almost any command, with every option explained.man ls,man grep,man chmodare all real, useful references — reaching formanbefore a search engine is a habit worth building now.
Instructor Notes
Lesson goal: Establish shell fluency vocabulary (shell vs. terminal, exit codes, options vs. arguments) that every later module assumes without re-explaining.
Approximate timing: 15 minutes read; 10 minutes live with a short live demo of tab
completion and man.
Common misconception to watch for: students often think "Linux" and "the terminal" are the same thing — clarify the kernel/distribution/shell/terminal layering explicitly.
Demo idea: live-type a command that fails (e.g. ls /nonexistent), then run echo $?
immediately after to show the exit code in real time — more convincing than describing it.