Untitled

<?

$filename = 'input_file.txt';
$file = file($filename);

//if (file_exists($filename))
//    $emailsList = fopen($filename, "r") or die ("file opening not so well");

$emailList['INVALID'] = 0;

foreach ($file as $key => $emails) {

    $emailParts = explode('@', $emails);
    $domain = $emailParts[1];

    if (in_array("$domain", array_keys(&$emailList))) {
        $emailList["$domain"] += 1;
    }
    else {
        $emailList["$domain"] = 1;
    }

    //preg_match
}

var_dump($emailList);

?>