The KB (keyboard) record redirects input from the input file to the keyboard. After the KB (or KB ON) record, all input to be processed comes from the keyboard until another KB (or KB OFF) record is processed.
Example:
...
.CKT * beginning of circuit description
...
.END * end of circuit description.
.GO * specified analysis is done here.
.KB * switch input to keyboard. New plots, title, and / or
* element alter records can be input and executed.
* After a .KB record is input from the keyboard,
* the next line of the input file is processed:
.NEXT
...