EdgeOS is the custom operating system that runs on Ubiquiti routing and switching devices. It was forked from VyOS. A complete guide to the commands is maintained by Ubiquiti and is available free for download.
show interfaces: display information about the network interfaces.
show firewall: display information about the firewall.
show service: display information about all services.
show dns: display DNS information.
Commit active configuration:commit
Remove a key:delete
delete service dns forwarding listen-on eth2.2: delete a DNS forwarding listen on eth2.2.
Discard configuration changes:discard
Enter Configuration Mode:configure
Exit to Operational Mode:exit
Save active configuration to default:save
Problem: DNS forwarding seems to use incorrect servers.
Solution: Log into the CLI and issue show dns forwarding nameservers. This will show a list of the servers as they are actually being used.