When you say "doesn't work" it tells us nothing. Try telling us what your expected output and actual output were.

For starters, I would add:

use strict;
use warnings;
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to your script make coding errors more obvious. and I would hazard a guess that you are not opening the file properly. checking the return code of the open would find that:

open IN,"<","file" or die "error opening file: $!";
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