Merge

MERGE is a BASIC programming utility that combines two smaller programs into one. Merge utilities were handy tools for BASIC programmers. If you were working on a program, and wanted to include some nifty subroutine that you'd already written—say, a cool title screen or a bullet-proof input routine—you would have needed a merge utility; BASIC didn't give you any way to LOAD subroutines and append them to your existing code in memory. (BASIC 4.0 did introduce an APPEND command, but its purpose was to add data to an existing file on disk.)