Prime Sieve

primes.rb

#!/usr/bin/env ruby

def print_primes(n)
  return if (n < 2)

  primes = []

  (2..n).each do |i|
    is_prime = primes.none? { |prime| i % prime == 0}
    primes << i if is_prime
  end

  puts primes.join ","
end

filename = ARGV[0]
file = File.open(filename, "r")

file.each_line do |line|
  line.chomp!
  print_primes(line.to_i)
end