#!/usr/bin/ruby -w
# Output a list of printable non-whitespace ASCII characters that are unused
# within an text file.

unused = {}
(33..126).each{|i| unused[i] = 1}

ARGF.each_byte{|c|
   unused.delete(c)
}

unused.keys.sort.each{|i|
   print "#{i}\t#{i.chr.dump[1..-2]}\n"
}