Randomize the digits, uniq for each line of each run.

randomize_digits.rb

#!/usr/bin/env ruby

s = gets
while s
  map_old_to_new = {}
  available_digits = %w(0 1 2 3 4 5 6 7 8 9)
  (0..9).each do |old|
    new = available_digits.sample
    available_digits -= [new]
    map_old_to_new["#{old}"] = new
  end

  puts s.gsub(/\d/) { |old| map_old_to_new[old] }
  s = gets
end