VMS Help STOP, Qualifier, /IDENTIFICATION  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /IDENTIFICATION=pid

    Specifies the system-assigned process identification (PID)
    code. When you create a process with the RUN command, the RUN
    command displays the PID code of the newly created process. The
    /IDENTIFICATION qualifier can be used in place of the process
    name parameter.

    You can omit any leading zeros in specifying the PID code.