#!/usr/bin/perl -w

sub is_prime {
  my ($num) = @_;
  my $i;

  return(0) if ($num==1);
  return(0) if ($num % 2 == 0 and $num != 2);

  for($i=3;$i < int(sqrt($num))+1;$i+=2) {
    return(0) if ($num % $i == 0);
  }
  return(1);
}

sub print_primes_to_file {
  open(F,"> primes") or die "Can't open yourfile for writing";
  for $i (1..10000) {
    print F "$i," if is_prime($i);
  }
  close(F);
}

print_primes_to_file;