A dbx session runs from the time you start dbx until you quit dbx. You can debug any number of programs in succession during a dbx session.
To quit a dbx session, type quit at the dbx prompt.
(dbx) quit
When you start dbx and attach it to a running process by providing the process ID, the process survives and continues when you quit the debugging session. dbx performs an implicit detach before quitting the session.
For more information about quitting dbx, see Quitting Debugging.