Extracting main domain from url having subdomain (works with <any number of subdomain>.maindomain.<com|org|co>.<in|uk|ng|dl>)

domain-from-subdomain.php

<?php

echo "Running Domain extraction script at ".date('Y-m-d H:i:s')."\n\n";

if(empty($argv[1])){
	echo "please enter in below format \n php domain-from-subdomain.php http://<subdomain/domain name>/xyz/mypath/to/some/image/folder\n";
	exit;
}else{
	if(explode(":",$argv[1])[0] == "http" || explode(":",$argv[1])[0] == "https"){
		print get_domain($argv[1]);
	}else{
		echo "Please pass a valid url:\neg.\n1. https://<subdomain-if-any>.example.org \n2. https://<subdomain-if-any>.example.com\n";
	}
}

function get_domain($url)
{
	$infoArr = parse_url($url);
	$domain = isset($infoArr['host']) ? $infoArr['host'] : '';
	if (preg_match('/(?P<domain>[a-z0-9][a-z0-9\-]{1,63}\.[a-z\.]{1,6})$/i', $domain, $dataInRegex)) {
		return $dataInRegex['domain'];
	}
	return false;
}

?>