Sun Studio 12 Update 1: Debugging a Program With dbx

Following the exec Function

If a child process executes a new program using the exec(2)function or one of its variations, the process id does not change, but the process image does. dbx automatically takes note of a call to the exec() function and does an implicit reload of the newly executed program.

The original name of the executable is saved in $oprog. To return to it, use debug $oprog.