The GCD of 3 and 5 is 1
-- main::(gcd.pl:18)
die sprintf "Need two integer arguments, got %d", scalar(@ARGV) unless 
    @ARGV == 2;
-- main::(gcd.pl:20)
my ($a, $b) = @ARGV[0,1];
-- main::(gcd.pl:21)
printf "The GCD of %d and %d is %d\n", $a, $b, gcd($a, $b);