s6-linux-init
Software
skarnet.org

The s6-linux-init-halt program

s6-linux-init-halt triggers the shutdown procedure in order to halt the system; or, with the -f option, it performs an immediate hard shutdown.

Interface

     s6-linux-init-halt [ -h | -p | -r ] [ -d | -w ] [ -W ] [ -f ] [ -R tmpfsdir ]

• If the -f option is present, s6-linux-init-halt halts the system immediately.
• Else, it triggers the machine's shutdown procedure.
• It exits 0. The shutdown procedure happens asynchronously.

This interface follows the traditional sysvinit interface for the halt, poweroff and reboot programs as close as possible.

Exit codes

• 0: shutdown procedure triggered.
• 100: wrong usage, or user does not have root privileges.
• 111: system call failed.

Options

• -h : halt. No matter the name of the command, it will order a halt (i.e. the system will be shut down, but the power will remain up). This is the default for s6-linux-init-halt.
• -p : poweroff. No matter the name of the command, it will order a power off. This is the default for s6-linux-init-poweroff.
• -r : reboot. No matter the name of the command, it will order a reboot. This is the default for s6-linux-init-reboot.
• -d : Do not write a wtmp shutdown entry.
• -w : Only write a wtmp shutdown entry; do not actually shut down the system.
• -W : Do not send a wall message to users before shutting down the system. Some other implementations of the halt, poweroff and reboot commands use the --no-wall long option to achieve this.
• -f : force. The command will not trigger a clean shutdown procedure; it will just sync the filesystems then tell the kernel to immediately halt, poweroff or reboot. This should be the last step in the lifetime of the machine.
• -R tmpfsdir : assume that the root-only boot-time tmpfs has been mounted on tmpfsdir. Default is /run. It is important to get this right, because the contact point with the s6-linux-init-shutdownd daemon, which manages the shutdown procedure, is located under this directory. The halt, poweroff and reboot scripts created by a s6-linux-init-maker invocation automatically use the correct -R option.

Notes

• The s6-linux-init-halt, s6-linux-init-poweroff, s6-linux-init-reboot and s6-linux-init-shutdown binaries are not meant to be called directly by administrators. Instead, their purpose is to be used in halt, poweroff, reboot and shutdown scripts created by s6-linux-init-maker; those scripts will call them with the correct -R tmpfsdir option. The scripts should typically be linked to /sbin after s6-linux-init-maker execution, to provide drop-in replacements for the sysvinit programs with the same names.