Colored string output with ANSI escape sequences - http://ascii-table.com/ansi-escape-sequences.php

colored_strings.rb

class String
  
  def colorize(color_code)
    "\e[#{color_code}m#{self}\e[0m"
  end

  color_escapes = {"black" => 30, "red" => 31, "green" => 32, "yellow" => 33, "blue" => 34, "magenta" => 35, "cyan" => 36, "white" => 37}

  color_escapes.each do |key, value|
    define_method(key) { colorize(value) }
  end

  color_escapes.each do |key, value|
    define_method("bg_" + key) { colorize(value + 10) }
  end

end

puts "Hello, World!".red
puts "Hello, World!".black.bg_white