What happens if you put a print statement into the sort? Use a small @vfs dataset and look what happens. 
my @sorted_vfs = sort {print "a: ",$a->start(),
                            " b: ",$b->start(),"\n";
                       $a->start() <=> $b->start() 
                      } @vfs;

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In reply to Re: why doesn't this sort work? by Marshall
in thread why doesn't this sort work? by Anonymous Monk

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