The only problem with that is the threshold is not exact, for example, if the threshold is instead .5, and the length of the query is three characters, I still come up with all the matches that have at least (1/3). I have tried fixing this to no avail, here is my attempt:

foreach my $key (keys %o) {
my $keydisplay=1;
my $target = $o{$key};
#my $threshold = 0.79;
my $searchlength = length $search;
my $truethreshold = int($searchlength * $threshold*100) /100; #(page46
+)

    if ($searchlength - $truethreshold >= .005) {
$truethreshold += .01;
}
$searchlength = $truethreshold;


for my $position (0 .. (length ($target) - $searchlength)) {
    my $test = substr $target, $position, $searchlength;
    my $matched = ($test ^ $search) =~ tr/\x00//;

next if $matched < $truethreshold;
    print "\t\tFound <$test> at position $position which matches in $m
+atched of $searchlength places\n";
  }
}
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