So we've already got an open work item tracking "display the parse error (if any) in commandline mode", #7284. What if, when we determine that the commandline is valid, we then display what commands are about to be executed, instead of the parse error?

So if you type in

nt ssh user@server.com

We'll parse that, and that won't generate an error message, it'll instead successfully turn into a newTab(commandline="ssh user@server.com") action. We'll then take that action, and call GenerateName on it, and we'll get "Open a new tab, commandline: ssh user@server.com". We'll then display that text to the user, as a preview of what they're about to run.