<?php

$str = "
Germany, Berlin
France, Paris
England, London
Spain, Madrid
";

$str = explode("\r\n", trim($str));

for ($i = 0, $l = count($str); $i < $l; $i++) {
    $str[$i] = str_replace(', ', '-', $str[$i]);
}

$str = implode(',', $str);

echo $str;

?>

Germany-Berlin,France-Paris,England-London,Spain-Madrid