It's a methodology from when you had to schedule time for your program to run and at a minimum 24-72 hour turnaround on the smallest change. In that case it's

It's a methodology from when you had to schedule time for your program to run and at a minimum 24-72 hour turnaround on the smallest change. In that case it's worth taking extra time to verify things on paper and institute heavy practices to ensure correctness. Then you can just type "exec" in a terminal that completely changes the equation.