The manager key value store is a set of definable keys and associated values. mg_kvget returns the value of a specific key by interacting with a manager server. Some keys (e.g. title) have specific meaning. If it helps your experiment, however, you are welcome to define your own keys and use either this or the REST API to obtain the values of those keys at run-time.
The host and user parameters select the server by host and the user that started it while key selects the key to obtain.
On success, the value of the key is output to stdout