term_colours.rb

#!/usr/bin/env ruby
# this script can be used to find out what colours will look like on your terminal all in one go

module TermColours
  @attributes  = [0,1,4,5,7]
  @foregrounds = 30..37
  @backgrounds = 40..47
  
  def self.print_all_attribute_foreground_background_combinations
    @attributes.each do |attr|
      print_attr_listing(attr)
    end
  end
  
  def self.print_attr_listing(attr)
    print_attr_header(attr)
    @foregrounds.each do |fg|
      print_for_foreground_set(attr, fg)
    end
  end
  
  def self.print_attr_header(attr)
    puts '----------------------------------------------------------------'
    puts "ESC[#{attr};Foreground;Background"
  end
  
  def self.print_for_foreground_set(attr, fg)
    @backgrounds.each do |bg|
      print_color_entry(attr, fg, bg)
    end
    puts
  end
  
  def self.print_color_entry(attr, fg, bg)
    print "\033[#{attr};#{fg};#{bg}m #{fg};#{bg}\033[0m"
  end
end

TermColours.print_all_attribute_foreground_background_combinations