Thanks for idea #2. So I've got my {key, offset} pair nicely sorted - no problem there. I can also seek to each offset in the unsorted file without a problem. My problem is this: once I'm in the correct starting position for my next record in the unsorted file (i.e after calling seek), how can I extract *just* the next record and not the rest of the file from that point on:

for my $zip(sort{ $a <=> $b }(keys(%zips))) {
   seek FILE, $zips{$zip}, 0;
   print NEW <FILE>;
}
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Obviously, <FILE> contains the rest of the file following OFFSET (i.e $zips{$zip}) and not just the next record. Any ideas as to what I'm doing wrong?