Lesson 1 — CLI Basics

Time: ~20 minutes
Goal: Open your terminal, understand the prompt, and run your first commands.

🛠️ Before You Begin

Make sure you have the following ready before starting this lesson:

What you need Where to get it
Terminal (Mac) Built-in. Press ⌘ Space, type Terminal, press Return.
Git Bash (Windows) Download and install Git for Windows from gitforwindows.org ↗, which bundles Git Bash.
GitHub account (for later lessons) Create a free account at github.com/signup ↗.
Node.js & npm (for Lesson 3+) Download the LTS release from nodejs.org/en/download ↗.

💡 Windows users: This course uses Git Bash, not Command Prompt (cmd) or PowerShell. Make sure Git Bash is installed before continuing.

What is the CLI?

The Command Line Interface (CLI) — also called the terminal, shell, or command prompt — lets you control your computer entirely with text commands. Instead of clicking icons you type instructions and the computer responds.

Why bother?

  • It’s faster for many tasks once you’re comfortable
  • Almost all developer tools (git, npm, node, docker …) live here
  • It gives you full control that a GUI doesn’t always expose
  • It works the same way on every machine (Mac, Linux, Windows Git Bash)

Opening Your Terminal

🍎 Mac — Terminal

  1. Press ⌘ Command + Space to open Spotlight
  2. Type Terminal and press Return
  3. A dark (or light) window with a $ prompt appears — you’re in!

Alternatively: Applications → Utilities → Terminal

Recommended upgrade: Install iTerm2 for extra features (tabs, split panes, themes).

🪟 Windows — Git Bash

  1. Install Git for Windows from gitforwindows.org ↗ if you haven’t already — this installs both Git and Git Bash.
  2. Search for Git Bash in the Start menu and open it
  3. You’ll see a window with a $ prompt — identical to Mac Terminal for most commands!

Alternatively: Right-click any folder in Explorer → Git Bash Here

⚠️ Windows users: This course uses Git Bash, not Command Prompt (cmd) or PowerShell. Git Bash provides the Unix-style commands used throughout the course.

Anatomy of the Prompt

When you open your terminal you’ll see something like:

username@MacBook-Pro ~ $

or in Git Bash on Windows:

username@DESKTOP-ABC123 MINGW64 ~ $
Part Meaning
username Your computer login name
~ Your current directory (~ is shorthand for your home folder)
$ The prompt — where you type commands

Your First Commands

Type each command below and press Enter to run it.

pwd — Print Working Directory

Shows you exactly where you are in the file system.

pwd

Example output on Mac:

/Users/alex

Example output on Windows Git Bash:

/c/Users/alex

whoami — Who Am I?

Prints the name of the currently logged-in user.

whoami

Output:

alex

echo — Print Text

Prints any text to the terminal. Great for testing and simple output.

echo "Hello, CLI!"

Output:

Hello, CLI!

date — Show Date and Time

date

Output (Mac):

Sat Mar  7 07:30:00 UTC 2026

clear — Clear the Screen

When your terminal gets cluttered, clear it:

clear

Keyboard shortcut: Ctrl + L (works on both Mac and Windows Git Bash)

Getting Help

Every command has built-in documentation.

--help flag

ls --help

man (manual pages) — Mac only

man ls

Press q to quit the manual.

💡 Windows Git Bash users: man isn’t always available. Use --help instead, or search online.

Keyboard Shortcuts You’ll Use Every Day

Shortcut What it does
↑ / ↓ Arrow keys Scroll through command history
Tab Auto-complete file/folder names
Tab Tab Show all possible completions
Ctrl + C Cancel a running command
Ctrl + L Clear the screen (same as clear)
Ctrl + A Jump to beginning of line
Ctrl + E Jump to end of line
Ctrl + R Search command history

✅ Lesson 1 Checklist

  • Opened Terminal (Mac) or Git Bash (Windows)
  • Ran pwd and saw your home directory path
  • Ran whoami and saw your username
  • Used echo to print a message
  • Used clear or Ctrl + L to clear the screen
  • Tried Tab auto-complete
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