reboot - stopping and restarting the system
/sbin/reboot [ -lqnhdarsfRD ]
/sbin/halt [ -lqndars ]
/sbin/fastboot [ -lqndarsRD ]
2.11BSD is started by placing it in memory at location zero and transferring to its entry
point. Since the system is not reentrant, it is necessary to read it in from disk or tape
each time it is to be boot strapped.
Rebooting a running system: When the system is running and a reboot is desired, shut-
down(8) is normally used to stop time sharing and put the system into single user mode.
If there are no users then /sbin/reboot can be used without shutting the system down
Reboot normally causes the disks to be synced and allows the system to perform other shut-
down activities such as resynchronizing hardware time-of-day clocks. A multi-user reboot
(as described below) is then initiated. This causes a system to be booted and an auto-
matic disk check to be performed. If all this succeeds without incident, the system is
then brought up for multi-user operation.
Options to reboot are:
-l Don't try to tell syslogd(8) what's about to happen.
-q Reboot quickly and ungracefully, without shutting down running processes first.
-n Don't sync before rebooting. This can be used if a disk or the processor is on
-h Don't reboot, simply halt the processor.
-d Dump memory onto the dump device, usually part of swap, before rebooting. The dump
is done in the same way as after a panic.
-a Have the system booter ask for the name of the system to be booted, rather than
immediately booting the default system (/unix).
-r Mount the root file system as read only when the system reboots. This is not sup-
ported by the kernel in 2.11BSD.
-s Don't enter multi-user mode after system has rebooted - stay in single user mode.
-f Fast reboot. Omit the automatic file system consistency check when the system
reboots and goes multi-user. This is accomplished by passing a fast reboot flag on
to the rebooting kernel. This currently prevents the use of -f flag in conjunction
with the -h (halt) flag.
-D Set the autoconfig(8) debug flag. This is normally not used unless one is debug-
ging the autoconfig program.
-R Tells the kernel to use the compiled in root device. Normally the system uses the
device from which it was booted as the root/swap/pipe/dump device.
Reboot normally places a shutdown record in the login accounting file /usr/adm/wtmp. This
is inhibited if the -q or -n options are present. Note that the -f (fast reboot) and -n
(don't sync) options are contradictory; the request for a fast reboot is ignored in this
Halt and fastboot are synonymous with ``reboot -h'' and ``reboot -f'', respectively.
Power fail and crash recovery: Normally, the system will reboot itself at power-up or
after crashes if the contents of low memory are intact. An automatic consistency check of
the file systems will be performed, and unless this fails, the system will resume multi-
autoconfig(8), sync(2), utmp(8), shutdown(8), syslogd(8)
3rd Berkeley Distribution May 24, 1996 REBOOT(8)