Kernel Method - Illustrates how to add functionality to all objects

kernel_method.rb

# add a kernel method to make it available to all objects
# this example also serves to illustrate that everything in Ruby is an object
module Kernel

  def say_hello
    puts "hello from #{self.class.name}"
  end

end

# usage
Class.say_hello # => hello from Class
Object.say_hello # => hello from Class
Object.new.say_hello # => hello from Object
1.say_hello # => hello from Fixnum
"".say_hello # => hello from String