<?php phpinfo(); ?>
Now, save the file as "phpinfo.php", upload it to your server, and access it via your browser.
DreamHost users far more than just one server. You can view a (somewhat accurate) representation of your uptime at Status/System Status in your DH Control Panel.
You can take it with you, but it won't be free after you leave DH.
I don't work here. I'm just your typical support forum volunteer.