Foundations

The chapter that closes the gap between 'I use a computer' and 'I can talk about a computer.' Files, paths, hidden files, permissions, keyboard fluency, browser dev tools.

• 0.0How this course works
• 0.1What a computer actually is
• 0.2Programs vs data: what software actually is
• 0.3Installing a program — what really happens
• 0.4Files: the unit of storage
• 0.5Folders and the tree of your machine
• 0.6Paths: how to name any file
• 0.7File extensions and what they mean
• 0.8Hidden files and dotfiles
• 0.9Permissions: who is allowed to do what
• 0.10The clipboard, deeper than you think
• 0.11Keyboard shortcuts: the thirty you will use today
• 0.12Window management
• 0.13Your browser: tabs, URLs, history, bookmarks
• 0.14Browser DevTools: a first peek
• 0.assignCapture-the-flag tour of your machine

Source vs binary, compile vs interpret, runtimes, processes, memory. Why 'works on my machine' happens. The mental model every other chapter relies on.

• 1.0How this chapter works
• 1.1Source code: what it actually is
• 1.2The translation: compile vs interpret
• 1.3What a runtime actually is
• 1.4What a process really is (revisit)
• 1.5Memory while a program runs: stack vs heap
• 1.6Works on my machine: the real causes
• 1.7Why JavaScript runs in two places
• 1.8The language map (without picking favourites)
• 1.9Hands-on: same logic in three playgrounds
• 1.10Bytecode and JIT, conceptually
• 1.assignThree-language print-and-loop comparison

The shell, the prompt, and twenty commands you'll use forever. Pipes, redirection, env vars, PATH. Bash and PowerShell side by side.

• 2.0Orientation: the chapter ahead
• 2.1The shell vs the terminal vs the prompt
• 2.2Opening the right one: Terminal.app, iTerm2, PowerShell, Windows Terminal, WSL
• 2.3pwd, ls, cd — moving around
• 2.4Tab completion and history — the productivity multiplier
• 2.5mkdir, touch — creating
• 2.6cp, mv, rm — copying, moving, deleting (and why rm is dangerous)
• 2.7Reading files: cat, less, head, tail
• 2.8Pipes and redirection
• 2.9Wildcards and globbing
• 2.10Environment variables
• 2.11The PATH variable, demystified
• 2.12Configuring your shell: .zshrc, .bashrc, PowerShell $PROFILE
• 2.13Aliases that save your fingers
• 2.14The survival kit: the twenty commands you will use forever
• 2.15Assignment: Shell-only file management exercise

A packet's life from your browser to a server in another country. DNS, TCP, HTTP, HTTPS, headers, CDNs. The network tab as your first inspection tool.

• 3.0Orientation: from "the internet" to a stack of layers
• 3.1Computers talking: IP addresses and packets
• 3.2Names not numbers: DNS
• 3.3Reliable conversation: TCP (and a sentence about UDP)
• 3.4Ports: how one machine runs many servers
• 3.5The protocol of the web: HTTP
• 3.6HTTP methods (GET, POST, PUT, PATCH, DELETE)
• 3.7HTTP status codes: the families
• 3.8HTTP headers (the ones that matter to beginners)
• 3.9HTTPS and why it matters
• 3.10Caching: browser cache, CDN, server cache
• 3.11CDNs and edge locations
• 3.12Cookies and sessions, briefly
• 3.13CORS, a one-paragraph orientation
• 3.14Following a real request in DevTools, end to end
• 3.assignTrace a request and explain each step