def report (a)
  puts
  a.each {|hexword| puts "%6s  %8d  %d" % hexword}
  puts "Total count of these words: #{a.size}"
end

hexwords = File.read_lines("unixdict.txt").reject{|w| w.size < 4 || w.matches?(/[^abcdef]/) }
res = hexwords.map {|hw| {hw, hw.to_i(16), 1 + (hw.to_i(16) - 1) % 9} }.sort_by(&.last)
report res
report res.reject {|hw| hw[0].chars.uniq.size < 4}.sort_by {|w| -w[1] }