Remove narration to reduce file size. Update to questions to improve applicability.

Updates to quiz questions and UI improvements.

Master Linux from your phone - through narrated terminal animations and adaptive practice. Textbook of Linux teaches the command line the way it's actually used. Each topic opens with a short, narrated walkthrough of a real terminal session, then immediately rolls into a quiz so the concepts stick. The 63-topic curriculum starts with the absolute basics - what a shell is, listing files, navigating paths - and builds up through pipes and redirection, then system administration (users, permissions, packages, networking, systemd), then scripting and editors (bash, vi, git), and finally modern Linux (containers, Docker, Kubernetes, observability, eBPF, security). Adaptive practice uses spaced repetition plus Bayesian Knowledge Tracing to focus your reviews on the topics you're shakiest on. Earn XP, build a streak, level up, and unlock achievements as you go. The Command Line domain is free. Subscribe to unlock the full curriculum. Built by Dr Chris Paton. Tux artwork by Larry Ewing, used with permission.

This update brings real progression and a smoother reading flow: • Finishing a lesson now records your progress and unlocks the next topic • Reading lessons jumps straight into the quiz — and the quiz finishes with a one-tap path to the next topic • Lesson slides are now text-only; tap Watch Demo from the topic page for the narrated terminal walkthrough • Watch Demo button only appears when a demo is ready — no more dead ends • Behind-the-scenes fixes for stability and diagnostics