[apple/system_cmds.git] / reboot.tproj / reboot.8

.\" Copyright (c) 1990, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"	@(#)reboot.8	8.1 (Berkeley) 6/9/93
.\" $FreeBSD: src/sbin/reboot/reboot.8,v 1.21 2002/12/27 12:15:33 schweikh Exp $
.\"
.Dd June 9, 1993
.Dt REBOOT 8
.Os
.Sh NAME
.Nm halt ,
.Nm reboot
.Nd stopping and restarting the system
.Sh SYNOPSIS
.Nm halt
.Op Fl lnqu
.Nm reboot
.Op Fl lnq
.Sh DESCRIPTION
The
.Nm halt
and
.Nm reboot
utilities flush the file system cache to disk,
send all running processes a
.Dv SIGTERM
(and subsequently a
.Dv SIGKILL )
and, respectively, halt or restart the system.
The action is logged, including entering a shutdown record into the
.Xr wtmp 5
file.
.Pp
When the system is halted with the halt command, the system is powered off.
.Pp
The options are as follows:
.Bl -tag -width indent
.It Fl l
The halt or reboot is
.Em not
recorded in the system log.
This option is intended for applications such as
.Xr shutdown 8 ,
that call
.Nm reboot
or
.Nm halt
and log this themselves.
.It Fl n
The file system cache is not flushed.
This option should probably not be used.
.It Fl q
The system is halted or restarted quickly and ungracefully, and only
the flushing of the file system cache is performed (if the
.Fl n
option is not specified).
This option should probably not be used.
.It Fl u
The system is halted up until the point of removing system power, but waits 
before removing power for 5 minutes so that an external UPS 
(uninterruptible power supply) can forcibly remove power. 
This simulates a dirty shutdown to permit a later automatic power on. OS X uses
this mode automatically with supported UPSs in emergency shutdowns.
.El
.Pp
Normally, the
.Xr shutdown 8
utility is used when the system needs to be halted or restarted, giving
users advance warning of their impending doom and cleanly terminating
specific programs.
.Sh SIGTERM TO SIGKILL INTERVAL
The
.Dv SIGKILL
will follow the
.Dv SIGTERM
by an intentionally indeterminate period of time.
Programs are expected to take only enough time to flush all dirty data and exit.
Developers are encouraged to file a bug with the OS vendor, should they encounter an issue with this functionality.
.Sh SEE ALSO
.Xr wtmp 5 ,
.Xr shutdown 8 ,
.Xr sync 8
.Sh HISTORY
A
.Nm reboot
utility appeared in
.At v6 .
Commit	Line	Data
1815bff5 A	1	.\" Copyright (c) 1990, 1991, 1993
	2	.\" The Regents of the University of California. All rights reserved.
	3	.\"
	4	.\" Redistribution and use in source and binary forms, with or without
	5	.\" modification, are permitted provided that the following conditions
	6	.\" are met:
	7	.\" 1. Redistributions of source code must retain the above copyright
	8	.\" notice, this list of conditions and the following disclaimer.
	9	.\" 2. Redistributions in binary form must reproduce the above copyright
	10	.\" notice, this list of conditions and the following disclaimer in the
	11	.\" documentation and/or other materials provided with the distribution.
	12	.\" 3. All advertising materials mentioning features or use of this software
	13	.\" must display the following acknowledgement:
	14	.\" This product includes software developed by the University of
	15	.\" California, Berkeley and its contributors.
	16	.\" 4. Neither the name of the University nor the names of its contributors
	17	.\" may be used to endorse or promote products derived from this software
	18	.\" without specific prior written permission.
	19	.\"
	20	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	21	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	22	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	23	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	24	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	25	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	26	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	27	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	28	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	29	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	30	.\" SUCH DAMAGE.
	31	.\"
	32	.\" @(#)reboot.8 8.1 (Berkeley) 6/9/93
20e66415	33	.\" $FreeBSD: src/sbin/reboot/reboot.8,v 1.21 2002/12/27 12:15:33 schweikh Exp $
1815bff5 A	34	.\"
	35	.Dd June 9, 1993
	36	.Dt REBOOT 8
	37	.Os
	38	.Sh NAME
34d340d7 A	39	.Nm halt ,
34d340d7 A	40	.Nm reboot
20e66415	41	.Nd stopping and restarting the system
1815bff5 A	42	.Sh SYNOPSIS
1815bff5 A	43	.Nm halt
b180c247	44	.Op Fl lnqu
34d340d7	45	.Nm reboot
20e66415	46	.Op Fl lnq
1815bff5 A	47	.Sh DESCRIPTION
	48	The
	49	.Nm halt
	50	and
34d340d7 A	51	.Nm reboot
	52	utilities flush the file system cache to disk,
	53	send all running processes a
20e66415 A	54	.Dv SIGTERM
	55	(and subsequently a
	56	.Dv SIGKILL )
	57	and, respectively, halt or restart the system.
	58	The action is logged, including entering a shutdown record into the
	59	.Xr wtmp 5
	60	file.
1815bff5	61	.Pp
83f6dbe8 A	62	When the system is halted with the halt command, the system is powered off.
83f6dbe8 A	63	.Pp
1815bff5	64	The options are as follows:
20e66415 A	65	.Bl -tag -width indent
	66	.It Fl l
	67	The halt or reboot is
	68	.Em not
34d340d7	69	recorded in the system log.
20e66415 A	70	This option is intended for applications such as
	71	.Xr shutdown 8 ,
	72	that call
34d340d7	73	.Nm reboot
20e66415 A	74	or
	75	.Nm halt
	76	and log this themselves.
1815bff5	77	.It Fl n
20e66415	78	The file system cache is not flushed.
1815bff5 A	79	This option should probably not be used.
1815bff5 A	80	.It Fl q
20e66415 A	81	The system is halted or restarted quickly and ungracefully, and only
	82	the flushing of the file system cache is performed (if the
	83	.Fl n
	84	option is not specified).
1815bff5	85	This option should probably not be used.
b180c247 A	86	.It Fl u
	87	The system is halted up until the point of removing system power, but waits
	88	before removing power for 5 minutes so that an external UPS
	89	(uninterruptible power supply) can forcibly remove power.
	90	This simulates a dirty shutdown to permit a later automatic power on. OS X uses
	91	this mode automatically with supported UPSs in emergency shutdowns.
1815bff5 A	92	.El
	93	.Pp
	94	Normally, the
	95	.Xr shutdown 8
	96	utility is used when the system needs to be halted or restarted, giving
20e66415 A	97	users advance warning of their impending doom and cleanly terminating
20e66415 A	98	specific programs.
34d340d7 A	99	.Sh SIGTERM TO SIGKILL INTERVAL
	100	The
	101	.Dv SIGKILL
	102	will follow the
	103	.Dv SIGTERM
	104	by an intentionally indeterminate period of time.
	105	Programs are expected to take only enough time to flush all dirty data and exit.
	106	Developers are encouraged to file a bug with the OS vendor, should they encounter an issue with this functionality.
1815bff5	107	.Sh SEE ALSO
20e66415 A	108	.Xr wtmp 5 ,
	109	.Xr shutdown 8 ,
	110	.Xr sync 8
1815bff5 A	111	.Sh HISTORY
1815bff5 A	112	A
34d340d7	113	.Nm reboot
20e66415	114	utility appeared in
1815bff5	115	.At v6 .