how should I sort this? Then how can I take only the top 5?

my $top = 5;
foreach $w (sort { $count{$b} <=> $count{$a} } keys %count) {
   last if $top--;

   print "$count{$w} $w\n";
}
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or

my $top = 5;
foreach $w (
   (sort { $count{$b} <=> $count{$a} } keys %count)[0..$top-1]
) {
   print "$count{$w} $w\n";
}
[download]

If you need to handle ties, the following lists more than 5 if there are ties for the 5th spot:

my $top = 5;
my $last_count = -1;
foreach $w (sort { $count{$b} <=> $count{$a} } keys %count) {
   last if $top == 1 and $last_count != $count{$w};

   $top--;
   $last_count = $count{$w};

   print "$count{$w} $w\n";
}
[download]

I'll let someone else help you to extract words.