SHUTDOWN(8) NetBSD System Manager's Manual SHUTDOWN(8)
shutdown -- close down the system at a given time
shutdown [-Ddfhknprvxz] [-b bootstr] time [message ... | -]
shutdown provides an automated shutdown procedure for super-users to nicely notify users when the system is shutting down, saving them from system administrators, hackers, and gurus, who would otherwise not bother with such niceties. Available friendlinesses: -b bootstr The given bootstr is passed to reboot(8) for the benefit of those systems that can pass boot arguments to the firmware. Currently, this only affects sun3 and sparc machines. -d shutdown will pass the -d flag to reboot(8) or halt(8) to request a kernel core dump. If neither the -h or -r flags are specified, then -d also implies -r. -f shutdown arranges, in the manner of fastboot(8), for the file systems not to be checked on reboot. -h The system is halted at the specified time, using halt(8). -k Kick everybody off. The -k option does not actually halt the system, but leaves the system multi-user with logins disabled (for all but super-user). -n Prevent the normal sync(2) before stopping. -p The system is powered down at the specified time, using poweroff(8). If the powerdown fails, or the system does not support software powerdown, the system will simply halt instead. -r The system is rebooted at the specified time, using reboot(8). -v To enable verbose messages on the console, pass -v to reboot(8) or halt(8). -x To enable debugging messages on the console, pass -x to reboot(8) or halt(8). -z To silence some shutdown messages on the console, pass -z to reboot(8) or halt(8). -D Prevents shutdown from detaching from the tty with fork(2)/ exit(3). time Time is the time at which shutdown will bring the system down and may be the word now or a future time in one of two formats: +number, or [[[[[cc]yy]mm]dd]hh]mm, where the century, year, month, day, and hour may be defaulted to the current system val- ues. The first form brings the system down number minutes from the current time; the second brings the system down at the abso- lute time specified. If the century is not specified, it defaults to 1900 for years between 69 and 99, or 2000 for years between 0 and 68. A leading zero in the ``yy'' value is not optional. message ... Any other arguments comprise the warning message that is broad- cast to users currently logged into the system. - If - is supplied as the only argument after the time, the warn- ing message is read from the standard input.
At intervals, becoming more frequent as apocalypse approaches and start- ing at ten hours before shutdown, warning messages are displayed on the terminals of all users logged in. Five minutes before shutdown, or imme- diately if shutdown is in less than 5 minutes, logins are disabled by creating /etc/nologin and copying the warning message there. If this file exists when a user attempts to log in, login(1) prints its contents and exits. The file is removed just before shutdown exits. At shutdown time, a message is written in the system log containing the time of shutdown, who initiated the shutdown, and the reason. Next a message is printed announcing the start of the system shutdown hooks. Then the shutdown hooks in /etc/rc.shutdown are run, and a message is printed indicating that they have completed. After a short delay, shutdown runs halt(8) or reboot(8), or sends a terminate signal to init(8) to bring the system down to single-user mode, depending on the choice of options. The time of the shutdown and the warning message are placed in /etc/nologin and should be used to tell the users why the system is going down, when it will be back up, and to share any other pertinent informa- tion.
/etc/nologin tells login(1) not to let anyone log in /fastboot tells rc(8) not to run fsck(8) when rebooting /etc/rc.shutdown System shutdown commands
login(1), wall(1), fastboot(8), halt(8), init(8), poweroff(8), reboot(8), rescue(8)
The hours and minutes in the second time format may be separated by a colon (``:'') for backward compatibility.
A shutdown command was originally written by Ian Johnstone for UNSW's modified AT&T UNIX 6th Edn, modified, and then incorporated in 4.1BSD. NetBSD 8.1 September 12, 2016 NetBSD 8.1
You can also request any man page by name and (optionally) by section: