- array_map: documentation ( source)
- implode: documentation ( source)
- explode: documentation ( source)
<?php
$string = 'ZWxpZWVsYW1AeWFob28uY29t
ZWxpZXJvbWVyQGhvdG1haWwuY29t
ZWxsaXNjdXN0b21AZ21haWwuY29t
ZWxsYWxvMTAuZ3ZAZ21haWwuY29t
ZWxsZW5ib2x0OTFAb3V0bG9vay5jb20';
echo implode("<br>\n", array_map('base64_decode', explode(PHP_EOL, $string)));