the primary question is why doesn't the following construct work: (@junk, $ads) = (split(/\s+/, $rec));

Think of the @junk array as being "greedy": it swallows up all of the list elements returned by split, leaving none for your $ads scalar.

Update: yet another way, without the temporary @junk array:

use strict;
use warnings;

my $rec = 'a b c d 96';
my $ads = (split /\s+/, $rec)[-1];
print "ads=$ads\n";

__END__
ads=96
[download]