If I mistype a go subcommand, I get a large and mostly unhelpful list of all the legal
commands. I almost never want this and the behavior isn't very go-like. Better would be
something like:

% go installl
go: "installl" is not a valid subcommand.
% 

or perhaps

% go installl
go: "installl" is not a valid subcommand.
Run "go help" for more information.
% 

That way all the text on my screen doesn't scroll off the top.