halt

Halt the system

$ halt

$ halt -p

$ halt --reboot

$ halt -f

$ halt -w

halt [options]

halt instructs the system to stop all processes and halt the CPU. On modern systems with systemd, halt is a symlink to systemctl and triggers a proper shutdown sequence.
The difference between halt, poweroff, and reboot:
- halt - Stops the CPU but may leave power on
- poweroff - Stops the CPU and powers off the machine
- reboot - Restarts the machine
In practice, most systems treat halt and poweroff similarly, powering off the machine.

-p, --poweroff

Power off the machine (equivalent to poweroff)

Reboot the machine (equivalent to reboot)

Halt immediately without init/systemd

Only write wtmp record, don't actually halt

Don't write wtmp record

Don't send wall message before halt

Using -f bypasses the normal shutdown sequence, which may cause data loss. On systemd systems, these commands are wrappers around systemctl. Running halt typically requires root privileges.

halt is a traditional Unix command dating back to early Unix systems. On modern Linux distributions using systemd, halt, poweroff, and reboot are symlinks to systemctl, providing backwards compatibility while using systemd's shutdown mechanisms.

poweroff(8), reboot(8), shutdown(8), systemctl(1)