<?php
$URL="https://raw.githubusercontent.com/panticz/installit/master/install.postfix.sh";

echo "wget $URL -O - | bash -";
echo "<div><pre>";
</pre></div>

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $URL);
$result = curl_exec($ch);
curl_close($ch);
htmlspecialchars($result);

echo "";

?>

Links
http://www.gtkdb.de/index_33_727.html - SMTP Relay HowTo