Introduction to Ruby

Ruby is a dynamic, open-source programming language with a focus on simplicity and productivity. Created by Yukihiro Matsumoto ("Matz") in 1995, Ruby has an elegant syntax that is natural to read and easy to write.

Philosophy

Ruby follows the principle of "least surprise" - the language should behave in a way that minimizes confusion for experienced users. Matz designed Ruby to make programmers happy and productive.

Key Features

• Everything is an Object: In Ruby, everything is an object, including primitive data types
• Dynamic Typing: Variables don't have types, values do
• Duck Typing: If it walks like a duck and quacks like a duck, it's a duck
• Blocks and Iterators: Powerful constructs for functional programming
• Metaprogramming: Code that writes code
• Garbage Collection: Automatic memory management
• Rich Standard Library: Extensive built-in functionality
• Cross-platform: Runs on Windows, macOS, Linux, and more
• Great for Web Development: Powers Ruby on Rails framework
• Expressive Syntax: Reads almost like natural language
• Open Source: Free to use, modify, and distribute

Installation

macOS

Ruby comes pre-installed on macOS, but you can install a newer version:

# Using Homebrew
brew install ruby

# Using rbenv (recommended for managing multiple versions)
brew install rbenv ruby-build
rbenv install 3.2.0
rbenv global 3.2.0

Windows

1. Download RubyInstaller from rubyinstaller.org
2. Run the installer and follow the setup wizard
3. Make sure to check "Add Ruby executables to PATH"
4. Install MSYS2 development toolchain when prompted

Linux

# Ubuntu/Debian
sudo apt-get update
sudo apt-get install ruby-full

# CentOS/RHEL/Fedora
sudo yum install ruby

# Using rbenv (recommended)
git clone https://github.com/rbenv/rbenv.git ~/.rbenv
echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc
echo 'eval "$(rbenv init -)"' >> ~/.bashrc
source ~/.bashrc

Verify Installation

ruby -v
# Output: ruby 3.2.0 (or your version)

irb
# Opens Interactive Ruby console

Using OneCompiler

For quick testing without installation:

1. Visit OneCompiler Ruby
2. Write your code and run instantly
3. Perfect for learning and experimentation

Your First Ruby Program

# hello.rb
puts "Hello, World!"

# Run with: ruby hello.rb

Basic Syntax Elements

# Single line comment

=begin
Multi-line
comment
=end

# Variables (no declaration needed)
name = "Ruby"
version = 3.2
is_awesome = true

# String interpolation
puts "Welcome to #{name} version #{version}"

# Methods
def greet(name)
  "Hello, #{name}!"
end

puts greet("World")

# Classes
class Person
  def initialize(name)
    @name = name  # Instance variable
  end
  
  def say_hello
    puts "Hi, I'm #{@name}"
  end
end

person = Person.new("Alice")
person.say_hello

Ruby vs Other Languages

Feature	Ruby	Python	Java
Typing	Dynamic	Dynamic	Static
Syntax	Very flexible	Clean, strict	Verbose
OOP	Everything is object	Multi-paradigm	Class-based
Performance	Moderate	Moderate	Fast
Use Case	Web, Scripts	AI/ML, Web	Enterprise

Common Use Cases

1. Web Development: Ruby on Rails, Sinatra
2. DevOps: Chef, Puppet, Vagrant
3. Testing: RSpec, Cucumber
4. Static Sites: Jekyll, Middleman
5. Game Development: Gosu, Ruby2D
6. Data Processing: Scripts and automation

Next Steps

Now that you have Ruby installed and understand the basics, you're ready to explore:

• Data types and variables
• Control structures
• Object-oriented programming
• The Ruby ecosystem and gems