<?php

$file = file_get_contents('file.txt');
$emails = explode("\n", $file);
$emailsWhitoutDuplicates = array();
$targetFile = "emails.txt";


foreach ($emails as $email=>$em) {
    $emailsWhitoutDuplicates[$em] = $em;
}


$fileOpen = fopen($targetFile, 'a');
foreach ($emailsWhitoutDuplicates as $email2=>$em2) {
    fwrite($fileOpen, $em . "\n");
}
fclose($fileOpen);
?>