SORT nested SORT.

Hi everybody. 

In MF COBOL , how to write a Sort nested Sort ?

Thanks so much.

Not quite sure what you have in mind. If the input or output procedure for a currently executing SORT statement attempts to do another SORT, you will get a run-time error 220 "Attempt to execute more than one SORT or MERGE simultaneously".
A SORT statement can of course have multiple keys, including split keys.