-- main::(gcd.pl:18)
die sprintf "Need two integer arguments, got %d", scalar(@ARGV) unless 
    @ARGV == 2;
Breakpoint 1 set in gcd.pl at line 21
-- main::(gcd.pl:20)
my ($a, $b) = @ARGV[0,1];
xx main::(gcd.pl:21)
printf "The GCD of %d and %d is %d\n", $a, $b, gcd($a, $b);
-- main::(gcd.pl:9)
    my ($a, $b) = @_;
<- main::(gcd.pl:21) main::gcd
printf "The GCD of %d and %d is %d\n", $a, $b, gcd($a, $b);
Return array value for main::gcd is:
1

trepan.pl: That's all, folks...