This short script displays the prime numbers found in a range given by the user.
How it works: The user inputs the range $o to $e. A for command checks every number from $o to $e. For each number that evenly goest into the tested number ( if($i % $j==0) ), the script adds the factor ($j) into an array (@prime) at the $p position. $p starts at zero, and increases by 1 with every factor placed in @prime. If the second position of @prime is equal to the tested number, the tested number is prime.

#! Perl

print "Find primes from: ";
$o = <>;
print "to: ";
$e = <>;

for($i=$o; $i<=$e; $i++){
$p=0;
    for($j=1; $j<=$i; $j++){
        if($i % $j==0){

            $prime_[$p] = "$j";
            $p++;
        }
        if ($prime_[1] == $i){
            print "$i is prime";
            print "\n";
        }
    }

}
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