UTM 9.3 is built upon SUSE Linux so any CLI commands that are common to that kernel will work. Such as nslookup, top, atop, tcpdump and the ilk. The more specific commands regarding the UTM functionality can be found here (Google Cache link): webcache.googleusercontent.com/search
If the link no longer works, search for in Google "site:astaro.org useful shell commands" (without quotes) and you can click the green arrow next to a search result link for the cached page. This is because the Read-Only forum hasn't been fully re-initialised and misses out posts other than the OPs.
Please take heed: Any modification of the UTM through the CLI without Sophos' express approval/guidance can void the warranty of your UTM installation. If you're a home user, go wild :P
