MegaSort is an XFCN that must be installed in your stack using a resource copy utility, such as ResCopy or ResEdit.
MegaSort takes a minimum of one parameter and can have up to 6 parameters. The one parameter that is required is the container to be sorted. With no other information, MegaSort will sort the lines of the container using Apple's International Utilities comparison on the whole line.
Parameter 3 is the primary, or record, delimiter. (I know I skipped parameter 2, hold your horses. OK?) In a typical sort, this would be the return character (i.e., sort by lines). This is the default. You could also sort items, words or any other grouping by passing the appropriate character.