rotX with ruby

gistfile1.rb

# when you guessed a letter
# rotate("ammi://zbmanu.vhf/tulmktdmhk", "h".ord - "a".ord)

def rotate(str, num)
  str.chars.map{|c| (c.ord<97) ? c: ((c.ord+num - 97)%26 + 97).chr}.join("")
end

string.rb

# when working with encryptions prior ruby 1.9, you might want *ord* anyway
class String
  def ord
    unpack("C")[0]
  end
end

Example wont work with Ruby < 1.9 since String has no ord() there, maybe use unpack("C")[0] instead of ord().