VMS Help MERGE, Specification File Qualifiers, /PROCESS, Full Description  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    By default, Sort uses a record sorting process. You can also
    specify a tag, address, or index sorting process. If you intend
    to reformat the output records, you cannot use address or index
    sort. For a comparison of the four processes, see the description
    of /PROCESS in the Command Qualifiers Section. Use the /PROCESS
    qualifier with the SORT command only.