Writing CLI Apps with Dart

By Claude Code Sonnet 4.5

"Why are you writing CLI apps in Dart?" — Every developer, before reading this book "Oh, that's actually really nice!" — Every developer, after reading this book

What This Book Is About

You've probably used Dart for Flutter. Maybe you've built beautiful mobile apps with smooth animations and pixel-perfect UIs. That's great! But did you know Dart is also secretly excellent for writing command-line tools?

This book will teach you how to build CLI applications in Dart — from simple argument-parsing utilities to complex Terminal User Interface (TUI) applications that would make htop jealous. We'll cover:

🎯 Argument parsing that doesn't make you cry
📁 File I/O and Unix pipe etiquette
🌈 Making your terminal output fabulous
⌨️ Interactive prompts and user input
⏳ Progress bars and spinners (the good kind)
🎨 Full-blown TUI applications with widgets and layouts
✅ Testing strategies that actually work
📦 Packaging and distributing your masterpiece

Who This Book Is For

This book assumes you:

Know how to write code (in any language)
Are at least somewhat familiar with Dart syntax
Have written CLI applications in other languages
Want to learn how to build sophisticated terminal interfaces
Enjoy the occasional joke in technical writing

If you've never touched Dart before, that's okay! Check out dart.dev for a quick syntax primer, then come back. We'll wait.

Why Dart for CLI?

Great question! Skip to Chapter 1 for the full answer, but here's the TL;DR:

Fast startup: Compiled Dart starts faster than you can say "JVM warmup"
Easy distribution: Single binary, no runtime required
Great tooling: The Dart ecosystem has excellent packages for CLI work
Type safety: Catch errors before your users do
Actually fun: Hot reload works for CLI apps too!

Prerequisites

To follow along with this book, you'll need:

Dart SDK (version 3.0 or later): Install it here
A terminal emulator you enjoy using
A text editor or IDE (VS Code, IntelliJ, or even vim if you're feeling spicy)
Basic command-line skills: You should know what cd, ls, and pipes are
Curiosity and a sense of humor (non-negotiable)

How This Book Is Structured

Each chapter builds on the previous ones, gradually increasing in complexity:

Chapters 1-4: Foundation — arguments, I/O, and making things pretty Chapters 5-8: Intermediate — interactivity, configuration, and error handling Chapters 9-10: Advanced — Full TUI applications with complex layouts Chapters 11-12: Production — Testing, packaging, and shipping

You can jump around if you're already familiar with certain topics, but the examples do build on each other. When in doubt, read sequentially.

Code Examples

All code examples in this book are:

Runnable: Copy-paste and they work
Practical: Based on real-world use cases
Progressively complex: Starting simple, building to sophisticated
Documented: Comments explain the "why," not just the "what"

You'll find complete example projects in each chapter. Don't just read — type them out, break them, fix them, and make them your own.

A Note on Style

This book aims to be entertaining while teaching. You'll find:

Real-world examples and war stories
Occasional humor and pop culture references
Honest discussions of trade-offs and pitfalls
Strong opinions, weakly held

If you prefer dry, academic technical writing... well, you might be in the wrong place. But give it a shot anyway — you might enjoy yourself.

See Table of Contents for the full chapter list.

Contributing

Spot a typo? Have a suggestion? Found a better way to do something? Great! This book is open source. File an issue or submit a pull request.

License

This book is licensed under the Creative Commons Attribution-ShareAlike 4.0 International License. See the LICENSE file for details.

Ready to build some awesome CLI tools? Let's go!

Start with Chapter 1: Why Dart for CLI? →

cloudstreet-dev/Writing-CLI-Apps-with-Dart