Computer craft startup edit.

[Dr Drinkwater]

I'm coding a computer with no hard disk attached in new world, and I edited the startup files to to run a program. That program runs properly, but I need to change a variable. I don't know how to do that as the only thing I can do is interact with the program, on which I just type in an answer.
Can someone tell me how to code the console again?

 

[Lorendex]

Press ctrl + t to terminate the programm

 

[draeath]

You have to hold it for several seconds.