signal
The signal command sends an interruption signal to the
  program.
Syntax
signal signalUsage
The signal comment resumes execution where your program stopped, but immediately
gives it the signal signal.
signal can be the name or the number of a signal.
For example, on many systems signal 2 and signal SIGINT are both ways of sending an interrupt
 signal. The signal SIGINT command resumes execution of your program where it
 has stopped, but immediately sends an interrupt signal. The source line that was current when
 the signal was received is displayed.
Note: The current version only allows the 
SIGINT signal.Example
(fgldb) signal SIGINT 
Program exited normally.
16      for i = 1 to 10
(fgldb)