That subject was broached several times during the talks of the last Univention Summit a couple of weeks ago. At the moment this isn’t possible. Univention is aware that this is something a lot of people would really like to see, though, and they have stated that it is their goal to have a CLI version available
Note that there is something that looks like a CLI version of the system diagnosis module — but it isn’t really. The system check scripts are tools developed for use by their support team for quickly gathering an overview of the state of a system. As such it works more or less independent of the UCS version it is run on — unlike the UMC module “system diagnosis” which is highly version dependent. Both tools contain a different set of checks. If I remember correctly, the stated goal is to unify both code bases and to provide a CLI tool equivalent of what the UMC module “system diagnosis” does in the future.