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.Dd December 20, 2017 29.Dt REBOOT 8 30.Os 31.Sh NAME 32.Nm reboot , 33.Nm halt , 34.Nm fastboot , 35.Nm fasthalt 36.Nd stopping and restarting the system 37.Sh SYNOPSIS 38.Nm halt 39.Op Fl lNnpq 40.Op Fl k Ar kernel 41.Nm 42.Op Fl cdlNnpqr 43.Op Fl k Ar kernel 44.Nm fasthalt 45.Op Fl lNnpq 46.Op Fl k Ar kernel 47.Nm fastboot 48.Op Fl dlNnpq 49.Op Fl k Ar kernel 50.Sh DESCRIPTION 51The 52.Nm halt 53and 54.Nm 55utilities flush the file system cache to disk, send all running processes 56a 57.Dv SIGTERM 58(and subsequently a 59.Dv SIGKILL ) 60and, respectively, halt or restart the system. 61The action is logged, including entering a shutdown record into the user 62accounting database. 63.Pp 64The options are as follows: 65.Bl -tag -width indent 66.It Fl c 67The system will turn off the power and then turn it back on if it can. 68If the power down action fails, the system 69will halt or reboot normally, depending on whether 70.Nm halt 71or 72.Nm 73was called. 74At the present time, only the 75.Xr ipmi 4 76driver implements the power cycle functionality and only on hardware 77with a BMC that supports power cycling. 78Unlike power off, the amount of hardware that supports power cycling 79is small. 80.It Fl d 81The system is requested to create a crash dump. 82This option is 83supported only when rebooting, and it has no effect unless a dump 84device has previously been specified with 85.Xr dumpon 8 . 86.It Fl k Ar kernel 87Boot the specified 88.Ar kernel 89on the next system boot. 90If the kernel boots successfully, the 91.Em default 92kernel will be booted on successive boots, this is a one-shot option. 93If the boot fails, the system will continue attempting to boot 94.Ar kernel 95until the boot process is interrupted and a valid kernel booted. 96This may change in the future. 97.It Fl l 98The halt or reboot is 99.Em not 100logged to the system log. 101This option is intended for applications such as 102.Xr shutdown 8 , 103that call 104.Nm 105or 106.Nm halt 107and log this themselves. 108.It Fl N 109The file system cache is not flushed during the initial process clean-up, 110however the kernel level 111.Xr reboot 2 112is still processed with a sync. 113This option can be useful for performing a 114.Dq best-effort 115reboot when devices might be unavailable. 116This can happen when devices have been disconnected, such as with 117.Xr iscsi 4 . 118.It Fl n 119The file system cache is not flushed. 120This option should probably not be used. 121.It Fl p 122The system will turn off the power if it can. 123If the power down action fails, the system 124will halt or reboot normally, depending on whether 125.Nm halt 126or 127.Nm 128was called. 129.It Fl q 130The system is halted or restarted quickly and ungracefully, and only 131the flushing of the file system cache is performed (if the 132.Fl n 133option is not specified). 134This option should probably not be used. 135.It Fl r 136The system kills all processes, unmounts all filesystems, mounts the new 137root filesystem, and begins the usual startup sequence. 138After changing vfs.root.mountfrom with 139.Xr kenv 1 , 140.Nm Fl r 141can be used to change the root filesystem while preserving kernel state. 142This requires the 143.Xr tmpfs 5 144kernel module to be loaded because 145.Xr init 8 146needs a place to store itself after the old root is unmounted, but 147before the new root is in place. 148.El 149.Pp 150The 151.Nm fasthalt 152and 153.Nm fastboot 154utilities are nothing more than aliases for the 155.Nm halt 156and 157.Nm 158utilities. 159.Pp 160Normally, the 161.Xr shutdown 8 162utility is used when the system needs to be halted or restarted, giving 163users advance warning of their impending doom and cleanly terminating 164specific programs. 165.Sh EXAMPLES 166Replace current root filesystem with UFS mounted from 167.Pa /dev/ada0s1a : 168.Bd -literal -offset indent 169kenv vfs.root.mountfrom=ufs:/dev/ada0s1a 170reboot -r 171.Ed 172.Pp 173This mechanism can also be used with NFS, with a caveat that 174it only works with NFSv4, and requires a numeric IPv4 address: 175.Bd -literal -offset indent 176kenv vfs.root.mountfrom=nfs:192.168.1.1:/share/name 177reboot -r 178.Ed 179.Sh SEE ALSO 180.Xr kenv 1 , 181.Xr getutxent 3 , 182.Xr ipmi 4 , 183.Xr boot 8 , 184.Xr dumpon 8 , 185.Xr nextboot 8 , 186.Xr savecore 8 , 187.Xr shutdown 8 , 188.Xr sync 8 189.Sh HISTORY 190A 191.Nm 192utility appeared in 193.Bx 4.0 . 194