If you are speaking about the 12c Cloud Control.
The location for the emctl would be <Middleware_Home>/oms/bin
From the above location you need to run the command "./emctl status oms"
The database 12c does not have DBConsole but EM Express and the emctl command is not available anymore in this release. See for more info 2 day DBA documentation, Configuring the HTTPS Port for EM Express.
For more info and FAQ see http://www.oracle.com/technetwork/database/manageability/emx-intro-1965965.html