step
The step command continues running the program by executing
 the next line of source code, and then stops.
Syntax
step [ count ]
- count defines the number of lines to execute before stopping.
 
Usage
The step command allows you to "step" through your program, executing
 one line of source code at a time.
When a function call appears within the line of code, that function is also stepped through.
A common technique is to set a breakpoint prior to the section or function that is causing problems, run the program till it reaches the breakpoint, and then step through it line by line.
Using a count parameter will repeat the step command
     count times.
s is an alias for the step command.
Example
(fgldb) step 
4     CALL add_customer(cust_rec.*)
(fgldb) step 2
6     MESSAGE "Customer record was added"