Here is an example for starting a dedicated Urban Terror server:
/usr/local/games/ioquake3/ioq3ded.i386 +set fs_game q3ut4 +set dedicated 2 +set net_IP <IP> +set net_port 27960 +set com_hunkmegs 256 +set sv_maxclients 12 +exec server.cfg
Don't forget to replace <IP> with the machine's IP. You will also have to configure your server.cfg file (more details in the official documentation, here). Once everything is in place the server should be listed in the in-game Internet server browser.