#!/usr/bin/ruby

class String ### Open standard class String
  def puts_uppercase ## Add a method
    puts upcase
  end
end

"asdasd".puts_uppercase

class String
  alias :old_puts_uppercase :puts_uppercase # save original puts_uppercase method

  def puts_uppercase # and override it
    "HELLO #{self}".old_puts_uppercase
  end
end

"asdasdas".puts_uppercase