rc0(1M)               UNIX System V(Essential Utilities)                rc0(1M)


NAME
      rc0 - run commands performed to stop the operating system

SYNOPSIS
      /etc/rc0

DESCRIPTION
      This file is executed at each system state change that needs to have the
      system in an inactive state.  It is responsible for those actions that
      bring the system to a quiescent state, traditionally called ``shutdown''.

      There are three system states that require this procedure.  They are
      state 0 (the system halt state), state 5 (the firmware state), and state
      6 (the reboot state).  Whenever a change to one of these states occurs,
      the rc0 procedure is run.  The entry in /etc/inittab might read:
            r0:056:wait:/etc/rc0 off 1>/dev/sysmrg 2>&1 </dev/console

      Some of the actions performed by rc0 are carried out by files in the
      directory /etc/shutdown.d, and files beginning with K in /etc/rc0.d.
      These files are executed in ASCII order (see FILES below for more
      information), terminating some system service.  The combination of
      commands in rc0 and files in /etc/shutdown.d and /etc/rc0.d determines
      how the system is shut down.

      The recommended sequence for rc0 is:

      Stop System Services and Daemons.
            Various system services (such as 3BNET Local Area Network or LP
            Spooler) are gracefully terminated.
            When new services are added that should be terminated when the
            system is shut down, the appropriate files are installed in
            /etc/shutdown.d and /etc/rc0.d.

      Terminate Processes
            SIGTERM signals are sent to all running processes by killall(1M).
            Processes stop themselves cleanly if sent SIGTERM.

      Kill Processes
            SIGKILL signals are sent to all remaining processes; no process can
            resist SIGKILL.
            At this point the only processes left are those associated with rc0
            and processes 0 and 1, which are special to the operating system.

      Unmount All File Systems
            Only the root file system (/) remains mounted.

      Depending on which system state the systems end up in (0, 5, or 6), the
      entries in /etc/inittab will direct what happens next.  If the
      /etc/inittab has not defined any other actions to be performed as in the
      case of system state 0, then the operating system will have nothing to
      do.  It should not be possible to get the



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rc0(1M)               UNIX System V(Essential Utilities)                rc0(1M)


      system's attention.  The only thing that can be done is to turn off the
      power or possibly get the attention of a firmware monitor.  The command
      can be used only by the super-user.

FILES
      The execution by /usr/bin/sh of any files in /etc/shutdown.d occurs in
      ASCII sort-sequence order.  See rc2(1M) for more information.

SEE ALSO
      killall(1M), rc2(1M), shutdown(1M).












































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