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. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)reboot.8 8.1 (Berkeley) 6/9/93 29.\" 30.Dd December 20, 2017 31.Dt REBOOT 8 32.Os 33.Sh NAME 34.Nm reboot , 35.Nm halt , 36.Nm fastboot , 37.Nm fasthalt 38.Nd stopping and restarting the system 39.Sh SYNOPSIS 40.Nm halt 41.Op Fl lNnpq 42.Op Fl k Ar kernel 43.Nm 44.Op Fl cdlNnpqr 45.Op Fl k Ar kernel 46.Nm fasthalt 47.Op Fl lNnpq 48.Op Fl k Ar kernel 49.Nm fastboot 50.Op Fl dlNnpq 51.Op Fl k Ar kernel 52.Sh DESCRIPTION 53The 54.Nm halt 55and 56.Nm 57utilities flush the file system cache to disk, send all running processes 58a 59.Dv SIGTERM 60(and subsequently a 61.Dv SIGKILL ) 62and, respectively, halt or restart the system. 63The action is logged, including entering a shutdown record into the user 64accounting database. 65.Pp 66The options are as follows: 67.Bl -tag -width indent 68.It Fl c 69The system will turn off the power and then turn it back on if it can. 70If the power down action fails, the system 71will halt or reboot normally, depending on whether 72.Nm halt 73or 74.Nm 75was called. 76At the present time, only the 77.Xr ipmi 4 78driver implements the power cycle functionality and only on hardware 79with a BMC that supports power cycling. 80Unlike power off, the amount of hardware that supports power cycling 81is small. 82.It Fl d 83The system is requested to create a crash dump. 84This option is 85supported only when rebooting, and it has no effect unless a dump 86device has previously been specified with 87.Xr dumpon 8 . 88.It Fl k Ar kernel 89Boot the specified 90.Ar kernel 91on the next system boot. 92If the kernel boots successfully, the 93.Em default 94kernel will be booted on successive boots, this is a one-shot option. 95If the boot fails, the system will continue attempting to boot 96.Ar kernel 97until the boot process is interrupted and a valid kernel booted. 98This may change in the future. 99.It Fl l 100The halt or reboot is 101.Em not 102logged to the system log. 103This option is intended for applications such as 104.Xr shutdown 8 , 105that call 106.Nm 107or 108.Nm halt 109and log this themselves. 110.It Fl N 111The file system cache is not flushed during the initial process clean-up, 112however the kernel level 113.Xr reboot 2 114is still processed with a sync. 115This option can be useful for performing a 116.Dq best-effort 117reboot when devices might be unavailable. 118This can happen when devices have been disconnected, such as with 119.Xr iscsi 4 . 120.It Fl n 121The file system cache is not flushed. 122This option should probably not be used. 123.It Fl p 124The system will turn off the power if it can. 125If the power down action fails, the system 126will halt or reboot normally, depending on whether 127.Nm halt 128or 129.Nm 130was called. 131.It Fl q 132The system is halted or restarted quickly and ungracefully, and only 133the flushing of the file system cache is performed (if the 134.Fl n 135option is not specified). 136This option should probably not be used. 137.It Fl r 138The system kills all processes, unmounts all filesystems, mounts the new 139root filesystem, and begins the usual startup sequence. 140After changing vfs.root.mountfrom with 141.Xr kenv 1 , 142.Nm Fl r 143can be used to change the root filesystem while preserving kernel state. 144This requires the 145.Xr tmpfs 5 146kernel module to be loaded because 147.Xr init 8 148needs a place to store itself after the old root is unmounted, but 149before the new root is in place. 150.El 151.Pp 152The 153.Nm fasthalt 154and 155.Nm fastboot 156utilities are nothing more than aliases for the 157.Nm halt 158and 159.Nm 160utilities. 161.Pp 162Normally, the 163.Xr shutdown 8 164utility is used when the system needs to be halted or restarted, giving 165users advance warning of their impending doom and cleanly terminating 166specific programs. 167.Sh EXAMPLES 168Replace current root filesystem with UFS mounted from 169.Pa /dev/ada0s1a : 170.Bd -literal -offset indent 171kenv vfs.root.mountfrom=ufs:/dev/ada0s1a 172reboot -r 173.Ed 174.Pp 175This mechanism can also be used with NFS, with a caveat that 176it only works with NFSv4, and requires a numeric IPv4 address: 177.Bd -literal -offset indent 178kenv vfs.root.mountfrom=nfs:192.168.1.1:/share/name 179reboot -r 180.Ed 181.Sh SEE ALSO 182.Xr kenv 1 , 183.Xr getutxent 3 , 184.Xr ipmi 4 , 185.Xr boot 8 , 186.Xr dumpon 8 , 187.Xr nextboot 8 , 188.Xr savecore 8 , 189.Xr shutdown 8 , 190.Xr sync 8 191.Sh HISTORY 192A 193.Nm 194utility appeared in 195.Bx 4.0 . 196