First off, the regular expression you have my $code=$_ if /^CODE/ will never match anything because the caret (^) means if what follows is at the very beginning of the line, so it is looking for a line which starts with the word "CODE", not "[CODE]" (remember [ and ] are used in regular expressions so they need to be escaped like another poster suggested: m/^\[CODE\]/

Secondly, is the number of users of variable length? You might be better off storing users as a hashref in an array, so you can access user 0 as $array[0] (or $array->[0] if you're using an array reference)

Third, why don't you have the following at the top of your script:

use warnings;
use strict;
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