-- main::(gcd.pl:18)
die sprintf "Need two integer arguments, got %d", scalar(@ARGV) unless 
basename is on.
output set to not use terminal escape sequences
-> main::(gcd.pl:8)
{ 
gcd.pl [4-13]
-------------
  4    	
  5    	# GCD. We assume positive numbers
  6    	sub gcd($$);
  7    	sub gcd($$) 
  8  ->	{ 
  9    	    my ($a, $b) = @_;
 10    	    # Make: a <= b
 11    	    ($a, $b) = ($b, $a) if ($a > $b);
 12    	
 13    	    return undef if $a <= 0;
Breakpoint 2 set in gcd.pl at line 8
gcd.pl [4-13]
-------------
  4    	
  5    	# GCD. We assume positive numbers
  6    	sub gcd($$);
  7    	sub gcd($$) 
  8  ->	{ 
  9    	    my ($a, $b) = @_;
 10    	    # Make: a <= b
 11    	    ($a, $b) = ($b, $a) if ($a > $b);
 12    	
 13    	    return undef if $a <= 0;
x1 main::(gcd.pl:9)
    my ($a, $b) = @_;
gcd.pl [5-14]
-------------
  5    	# GCD. We assume positive numbers
  6    	sub gcd($$);
  7    	sub gcd($$) 
  8    	{ 
  9  ->	    my ($a, $b) = @_;
 10    	    # Make: a <= b
 11    	    ($a, $b) = ($b, $a) if ($a > $b);
 12    	
 13    	    return undef if $a <= 0;
 14    	    return $a if ($a == 1) or ($b-$a == 0);
trepan.pl: That's all, folks...