Ruby script which prints all happy numbers <= 100

happy.rb

#!/usr/bin/env ruby

# prints all happy numbers <= 100
# https://en.wikipedia.org/wiki/Happy_number

# returns true, if the number is happy
def happy?(n)
   n = n.digits.sum { |x| x * x } while n > 6
   n == 1
end

# filter all numbers <= 100 for happiness and print the list
puts (1..100).select { |x| happy? x }