Learn Enough Ruby to Be Dangerous

All You Need to Know, and Nothing You Don’t, to Create Ruby Programs, Gems, and Web Apps

Programmers love Ruby for its elegance, power, and flexibility: that’s why it was chosen for the Ruby on Rails framework that launched websites from Shopify to Coinbase. You’ll love Ruby too, but you don’t need to learn “everything” about it, just how to use it efficiently to solve real problems. In Learn Enough Ruby to Be Dangerous, renowned instructor Michael Hartl teaches the concepts, skills, and approaches you need to be professionally productive in both general-purpose programming and beginning web app development.

Even if you’re new to programming, Hartl helps you quickly build technical sophistication and master the lore you need to succeed. You’ll gain a solid understanding of object-oriented and functional programming, develop and publish a self-contained Ruby package (a gem), and use your gem to build and deploy a dynamic web app with the Sinatra framework. Focused exercises help you internalize what matters, without wasting time on details pros don’t care about. Soon, it’ll be like you were born knowing this stuff–and you’ll be suddenly, seriously dangerous.

Learn enough about . . .

• Writing real code quickly using interactive Ruby (irb)
• Working with native Ruby objects and creating your own
• Using functional techniques to write more concise and modular code
• Creating tests and improving code with test-driven development (TDD)
• Developing and publishing self-contained Ruby packages (gems)
• Writing nontrivial shell scripts to leverage Ruby’s power at the command line
• Developing and deploying a web app with routes, layouts, embedded Ruby, and forms
• Mastering modern development skills you can use with any language

Michael Hartl’s Learn Enough Series includes books and video courses that focus on the most important parts of each subject, so you don’t have to learn everything to get started–you just have to learn enough to be dangerous and solve technical problems yourself.

Table of Contents

1. Hello, World!

2. Strings

3. Arrays

4. Other Native Objects

5. Functions and Blocks

6. Functional Programming

7. Objects and Classes

8. Testing and Test-Driven Development

9. Shell Scripts

10. A Live Web Application

About the Author

Michael Hartl is a physicist and entrepreneur. He is the author of over a dozen books, including Learn Enough Python to Be Dangerous and the Ruby on Rails Tutorial, and was cofounder and principal author at Learn Enough (acquired 2022). He is also the founder of Tau Day and author of The Tau Manifesto. Previously, Michael taught theoretical and computational physics at the California Institute of Technology (Caltech), where he received a Lifetime Achievement Award for Excellence in Teaching and served as Caltech’s editor for The Feynman Lectures on Physics. He is a graduate of Harvard College, has a Ph.D. in Physics from Caltech, and is an alumnus of the Y Combinator entrepreneur program.