PowerOff

Poweroff refers to the act of turning off the power supply to a computer or device, typically after a controlled shutdown to prevent data loss. In computing, poweroff is also the name of a command found on many Unix-like systems. Running poweroff initiates the system shutdown sequence, stops services, unmounts filesystems, terminates processes, and finally sends a signal to the hardware to disconnect from the power supply. Most implementations require root privileges or administrative access.

In Linux and other Unix-like operating systems, poweroff is commonly a wrapper that invokes the system's init or init-like manager to shut down and power down. On systemd-based systems, the command often calls systemctl poweroff; on BusyBox-based systems, it may execute the appropriate shutdown sequence directly; in some distributions, poweroff is a symlink to halt or to systemctl poweroff. The effect is to instruct the hardware to power down after the shutdown completes.

Common alternatives include shutdown -P now, which schedules a power-down, and systemctl poweroff. The command should be used when a graceful shutdown is desired, rather than a forced power-off, which can lead to data loss.

In environments such as servers or embedded devices, poweroff is part of power management interfaces such as ACPI, which notify firmware to cut power after the OS has halted. Security considerations emphasize that the command should only be executable by trusted administrators.

See also: shutdown, reboot, halt, systemctl, ACPI.