On a side note, I couldn't help but notice that these lines probably aren't doing what you think:

my @sorted = join("\n", sort {$b <=> $a} @array);
print foreach @sorted;
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What it looks like you want is for @sorted to be a list of your sorted values, which at the moment, it's not...

When you use join(), it returns a single scalar with your list values delimited by the characters you specify.

Try:

my @array = qw(2aa 2ba 12kf 9cn 9vn 21sg);

my @sorted = join("\n", sort {$b <=> $a} @array);
print $#sorted;    # Prints the index of the last element in the array

@sorted = sort {$b <=> $a} @array;
print $#sorted;
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And you'll see what I mean.