PHP: how to remove the last line break from the text file?

In a school work, I built a site for a fictional space museum in my city using PHP. It has a Data Inclusion and Data Consultation systems, but I have a problem with the consultation that I want to know how to solve: how to delete the last line break from the file?

Data Inclusion

In the restricted area of the site, I have a HTML5 form with 5 fields (name, addres, telephone number, sex and visited exhibitions) that sends the data by the method POST to a function in PHP that writes it on a given txt file by using the fwrite command:

fwrite ($pointer, "$name | $addres | $telephone | $sex | $exhibitions " .PHP_EOL);

As you can see, it writes in a txt file the data entered on the form, plus a line break. The pointer is the variable used by fopen to open the file that I need to work. Example of output:

Márcio Aguiar | Belmiro Braga Street | 1234-5678 | M | Planets of Solar System
Joana Tobias | Santos Dummont Avenue | 8765-4321 | F | Black Holes, Satellites

Data Consultation

Then there is a consultation system. It has a loop that runs until the file ends. Inside this loop there is a variable named $buffer that gets one line of the txt file each time. It is then exploded to create a array named $lines[$counter]. To print it nicely, I use a array_combine where I join the names of the fields on another array ($keys) to the values written in $lines[$counter], and attibutes that to $combined[$counter]. Then the loop ends and I use a print_r inside <pre></pre> to see the data written in $combined, while mantaining the spaces and breaks that HTML would otherwise ignore. Here is the code:

$keys = array ("Name", "Address", "Telephone", "Sex", "Visited exhibition");
for ($counter=0;!feof($reader);$counter++){
    $buffer = fgets($reader);
    $lines[$counter] = explode(" | ", $buffer);
    $combined[$counter] = array_combine($keys, $lines[counter]
}
echo "<pre>";
print_r($combined);
echo "</pre>";

Example of output:

    Array
    (
    [0] => Array
        (
            [Name] => Márcio Aguiar
            [Address] => Belmiro Braga Street
            [Telephone] => 1234-5678
            [Sex] => M
            [Visited exhibitions] => Planets of Solar System 

        )

    [1] => Array
        (
            [Name] => Joana Tobias
            [Address] => Santos Dummont Avenue
            [Telephone] => 8765-4321
            [Sex] => F
            [Visited exhibitions] => Black Holes, Satellites 

        )

    [2] => 
    )

Here you can see that a 2 Array was created blank. It's caused by the last line, that contains only a line break inserted by the form above. I need to remove this last line break, and only that one, but don't know how. I want to know! Not knowing causes the exhibition of an error when the execution arrive at the array_combine, because it's needed that the two arrays have the same number of elements, and 2 is blank. Here the error:

Warning: array_combine(): Both parameters should have an equal number of elements in E:\Aluno\Documents\Wamp\www\trab_1\area_restrita\consulta.php on line 60