Required Options 

If you do not enter all the required user data as options, or if you were unable to log on to the database instance with that user data, the SAP DB tools will react as follows:

You should always start DBMCLI entering the options -d, -u and, if required, -n when calling the tool (Options (DBMCLI)).

When you call the tool, you should always start the REPMCLI by entering the required options -d and -b (Options (REPMCLI)).