Prime Number Calculator in Ruby

prime.rb

#!/usr/bin/env ruby

puts "limit number:"
max = Integer(gets)
primes = []
puts "going from 2 to #{max}"
(2..max).select do |current|
   # if current is divisible by any number in the array (that is not itself) it is not prime
   isPrime = true
   primes.each do |prime|
      md = current % prime
      if md == 0 then isPrime = false end
   end
   if isPrime then primes << current end
end

primes.each do |prime|
   puts prime
end