NAME

shutdown - shut down system, change system state

SYNOPSIS

/usr/sbin/shutdown [ -y ] [ -ggrace_period [ -iinit_state ]

DESCRIPTION

This command is executed by the super-user to change the state of the machine. In most cases, it is used to change from the multi-user state (state 2) to another state (see below). By default, it brings the system to a state where only the console has access to the UNIX system. This state is called single-user (see below).

The command sends a warning message and a final message before it starts actual shutdown activities. By default, the command asks for confirmation before it starts shutting down daemons and killing processes. The options are used as follows:

-y pre-answers the confirmation question so the command can be run without user intervention. A default of 60 seconds is allowed between the warning message and the final message. Another 60 seconds is allowed between the final message and the confirmation.

-ggrace_period

allows the super-user to change the number of seconds from the 60-second default.

-iinit_state

specifies the state that init is to be put in following the warnings, if any. By default, system state ``s'' is used.

Other recommended system state definitions are:

state 0

     Shut the machine down so  it  is  safe  to  remove  the
     power.   Have  the machine remove power if it can.  The
     rc0 procedure is called to do this work.

state 1

State 1 is referred to as the administrative state. In state 1 filesystems required for multi-user operations are mounted, and logins requiring access to multi-user filesystems can be used. When the system comes up from firmware mode into state 1, only the console is active and other multi-user (state 2) services are unavailable. Note that not all user processes are stopped when transitioning from multi-user state to state 1.

state s, S

State s (or S) is referred to as the single-user state. All user processes are stopped on transitions to this state. In the single-user state, filesystems required for multi-user logins are unmounted and the system can only be accessed through the console. Logins requiring access to multi-user file systems cannot be used.

state 5

Stop the UNIX system and go to firmware mode.

state 6

Stop the UNIX system and reboot to the state defined by the initdefault entry in /sbin/inittab; configure a new bootable operating system, if necessary, before the reboot. The rc6 procedure is called to do this work.

SEE ALSO

init(1M), rc0(1M), rc2(1M), rc6(1M), inittab(4).