A debugger command procedure can contain any debugger commands,
    including another execute procedure (@) command. The debugger
    executes commands from the command procedure until it reaches an
    EXIT or QUIT command or reaches the end of the command procedure.
    At that point, the debugger returns control to the command stream
    that invoked the command procedure. A command stream can be the
    terminal, an outer (containing) command procedure, a DO clause in
    a command such as SET BREAK, or a DO clause in a screen display
    definition.

    By default, commands read from a command procedure are not
    echoed. If you enter the SET OUTPUT VERIFY command, all commands
    read from a command procedure are echoed on the current output
    device, as specified by DBG$OUTPUT (the default output device is
    SYS$OUTPUT).

    For information about passing parameters to command procedures,
    see the DECLARE command.

    Related commands:

       DECLARE
       (SET,SHOW) ATSIGN
       SET OUTPUT [NO]VERIFY
       SHOW OUTPUT