PHP script (/root/scripts/set_free_shipping.sh)
<?php
$URL="https://raw.githubusercontent.com/panticz/magento/master/scripts/set_free_shipping.sh";

echo "<div><pre>";
</pre></div>

$c = curl_init();
curl_setopt($c, CURLOPT_URL, $URL);
curl_setopt($c, CURLOPT_RETURNTRANSFER, 1);

echo htmlspecialchars(curl_exec($c));

curl_close($c);

echo "";

?>

Cronjob (/etc/cron.d/newyear)
0 0 1 1 * root /root/scripts/set_free_shipping.sh 0