IRB for interactive exploration in Ruby

Introduction

IRB lets you try Ruby code right away. It helps you learn and test ideas quickly without writing a full program.

You want to check how a Ruby method works.

You need to test a small piece of code before adding it to your program.

You want to explore Ruby commands and see results immediately.

You are learning Ruby and want to practice coding interactively.

Syntax

Ruby

irb

Type irb in your terminal to start the interactive Ruby shell.

Use exit or quit to leave IRB.

Examples

This shows starting IRB, doing simple math, printing text, and exiting.

Ruby

irb
> 2 + 3
=> 5
> puts "Hello"
Hello
=> nil
> exit

Assign a variable and use it inside a string with interpolation.

Ruby

irb
> name = "Alice"
> puts "Hello, #{name}!"
Hello, Alice!
=> nil
> exit

Sample Program

This example uses IRB to print numbers from 1 to 10 using a loop.

Ruby

irb
> 10.times { |i| puts "Number: #{i + 1}" }
Number: 1
Number: 2
Number: 3
Number: 4
Number: 5
Number: 6
Number: 7
Number: 8
Number: 9
Number: 10
=> 10
> exit

Important Notes

IRB is great for quick tests but not for full programs.

You can use arrow keys to navigate your command history in IRB.

IRB shows the result of each expression automatically.

Summary

IRB is a tool to run Ruby code interactively.

It helps you learn and test code quickly.

Start it by typing irb in your terminal.