...
    chomp;
    $hash{$_}= $pbxex-1 if (not exists $hash{$_});
    $hash {$_} ++;
...

##</code><code>##

...
    chomp;
    $hash {$_} ++;
}

foreach (keys %hash) {
    $hash{$_}+= $pbxex-1;
    print PBXNUM1 "$_$hash{$_}\n";
}