-- main::(gcd.pl:18)
die sprintf "Need two integer arguments, got %d", scalar(@ARGV) unless 
Display 1 set
1: 3, 5
-- main::(gcd.pl:20)
my ($a, $b) = @ARGV[0,1];
*** Expecting an integer, got: a.
*** No display number 2
-- main::(gcd.pl:21)
printf "The GCD of %d and %d is %d\n", $a, $b, gcd($a, $b);
Display 2 set
2: 3 | 5
-- main::(gcd.pl:9)
    my ($a, $b) = @_;
trepan.pl: That's all, folks...