#!/usr/bin/perl

use strict;
use warnings;

my $str = "BATCATDATEFEAT";

my %hash;
while ($str =~ /([AT])/ig) {
    $hash{$1}{cnt}++;
    $hash{$1}{pos} = pos($str);
    printf "Position of $1 at: %d\n", $hash{$1}{pos};
}

my $output = "Results.txt";
open(my $results_fh, '>', $output) or do {
    die "[!] Cannot open file '$output'.\n";
};

foreach my $key (sort keys %hash) {
    print $results_fh <<"EOL";
$key=$hash{$key}{cnt} ends at $hash{$key}{pos}
EOL
}

close $results_fh;
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