convert text into 256 colors

256_cat.rb

# ref.
# http://www.frexx.de/xterm-256-notes/

$stdin.sync = true

filename = ARGV.shift
open(filename || '/dev/stdin') do |f|
  f.each do |line|
    line.unpack('U*') do |c|
      print "\033[38;5;%im" % c
      print "\033[48;5;%im" % c
      print [c].pack('U')
    end
  end
end