cribbed from http://www.ioncannon.net/ruby/101/fun-with-ansi-escape-codes/

ansi_sample.rb

#!/usr/bin/ruby
printf "\033[0mAll attributes off\033[0m\n"
printf "\033[1mBold\033[0m\n"
printf "\033[4mUnderline\033[0m\n"
printf "\033[5mBlink\033[0m\n"
printf "\033[8mHide\033[0m\n"
printf "\033[30mBlack\033[0m\n"
printf "\033[31mRed\033[0m\n"
printf "\033[32mGreen\033[0m\n"
printf "\033[33mYellow\033[0m\n"
printf "\033[34mBlue\033[0m\n"
printf "\033[35mMagenta\033[0m\n"
printf "\033[36mCyan\033[0m\n"
printf "\033[37mWhite\033[0m\n"
printf "\033[40m\033[37mBlack Background\033[0m\n"
printf "\033[41mRead Background\033[0m\n"
printf "\033[42mGreen Background\033[0m\n"
printf "\033[43mYellow Background\033[0m\n"
printf "\033[44mBlue Background\033[0m\n"
printf "\033[45mMagenta Background\033[0m\n"
printf "\033[46mCyan Background\033[0m\n"
printf "\033[47mWhite Background\033[0m\n"