There's also Math::Pari which can do this sort of calculation extremely fast and with huge numbers: 
use strict;
use Math::Pari qw(:int PARI nextprime);
 
print "Find primes from: ";
chomp(my $o = <>);
print "to: ";
chomp(my $e = <>);
 
$o = PARI $o;
$e = PARI $e;
 
if ($o > $e) {
  ($o,$e) = ($e,$o);
}
 
my $p = nextprime($o);
while ($p <= $e) {
   print "$p is prime\n";
   $p = nextprime($p + 1);
}

[download]

Update: Fixed the code so that numbers not representable as integers can be converted to PARI objects.

In reply to Re: Prime Number Finder by tall_man
in thread Prime Number Finder by munchie

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