/sys$common/syshlp/helplib.hlb AUTOGEN, Execution Modes, Description  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    To invoke AUTOGEN, use the following syntax to enter a command at
    the DCL command prompt:

    $ @SYS$UPDATE:AUTOGEN [start-phase] [end-phase] [execution-mode]

    You are returned to DCL level when the command has finished
    processing unless you specify SHUTDOWN or REBOOT as the end-phase
    parameter.