NoCmd is a no-op command to just make it valid.

RegisterAlias allows to decorelate the alias from the main command when alias have different command level (different parents) README and manpage refers to them in each subsection (parents are differents, but only one is kept if we use the same object).

SubcommandsRequiredWithSuggestions will ensure we have a subcommand provided by the user and augments it with suggestion for commands, alias and help on root command.