Triggers the system shutdown procedure. It is normally invoked as shutdown at your binary system directory. This program is a modified copy of s6-linux-init-shutdown.
The 66-shutdown binary is not meant to be called directly. User may prefer to use the 66 halt, 66 poweroff or 66 reboot command.
66-shutdown [ -H ] [ -l live ] [ -h | -p | -r | -k ] [ -a ] [ -t sec ] [ -f | -F ] time [ message ]
66-shutdown -c [ message ]
0. The shutdown procedure happens asynchronously.The 66-shutdown program abides to the standards of the LSB-3.0.0 shutdown interface.
time must be one of these formats: [ now | [+]mins | hh:mm ] where:
now: triggers the shutdown sequence immediately.
mins or +mins: relative time; triggers the shutdown sequence after mins minutes.
hh:mm: absolute time; triggers the shutdown sequence when the time hh:mm occurs. If that time has passed for the current day, it will wait for the next day. hh can have 1 or 2 digits; mm must have 2 digits.
-H: prints this help.
-l live: changes the supervision directory of service to live. By default this will be /run/66. The default can also be changed at compile time by passing the --livedir=live option to ./configure. An existing absolute path is expected and should be within a writable and executable filesystem - likely a RAM filesystem—see 66 scandir.
-a: access control. The shutdown sequence will only be launched if one of the users listed in /etc/66/shutdown.allow is currently logged in (as tracked by utmp). /etc/66/shutdown.allow is a text file which accepts one user per line. Lines starting with # are commented out.
-t sec: have a “grace time” period of sec seconds between the SIGTERM and the SIGKILL at the end of the shutdown sequence when it is time to kill all processes (allows processes to receive SIGTERM to exit cleanly). Default is 3 seconds.
-k: do not shut down; send a warning message to all logged in users.
-h: halt the system at the end of the shutdown sequence.
-p: power off the system at the end of the shutdown sequence. This option is provided as an extension it is not required-by the LSB interface.
-r: reboot the system at the end of the shutdown sequence.
-f: ignored.
-F: ignored.
-c: cancel a planned shutdown. Can only cancel the effect of a previous call to shutdown with a time argument that was not now. This cannot be used to interrupt a shutdown sequence that has already started.
The -f and -F exist for compatibility reasons. The LSB sepcification says they are used to advise the system to skip or enforce a fsck after rebooting. But they are only advisory and for decades now systems have used other methods of evaluating whether they should perform filesystem checks so these options are largely obsolete nowadays.