Or am I missing a fine point here?
According to what OP is trying to do and what mobigeek posted, to unload data from the old database you need to start the database again. The database (ie. dbeng9) and sql tool (ie. dbisql) are separate processes that have to run at the same time, hence it is not sequential.
This being said, it is also possible to tell dbisql to automatically start the database itself. So while connecting to the database, dbisql will figure out that the database isn't actually running so it will launch it using the information you provide and then connect to it. See the "start" connection parameter in the online documentation.