Shutdown Command
shutdown schedules a time for the system to be powered down. It may be used to halt, power-off or reboot the machine.
You may specify a time string (which is usually “now” or “hh:mm” for hour/minutes) as the first argument. Additionally, you may set a wall message to be sent to all logged-in users before the system goes down.
Important: If the time argument is used, 5 minutes before the system goes down the /run/nologin file is created to ensure that further logins will not be allowed.
Examples of shutdown commands:
# shutdown # shutdown now # shutdown 13:20 # shutdown -p now #poweroff the machine # shutdown -H now #halt the machine # shutdown -r09:35 #reboot the machine at 09:35am
To cancel a pending shutdown, simply type the command below:
# shutdown -c
Halt Command
halt instructs the hardware to stop all CPU functions but leaves it powered on. You can use it to get the system to a state where you can perform low-level maintenance. In some cases, it completely shuts down the system.
Below are examples of halt commands:
# halt #halt the machine # halt -p #poweroff the machine # halt --reboot #reboot the machine
Power off Command
poweroff sends an ACPI signal which instructs the system to power down.
Examples of poweroff commands:
# poweroff #poweroff the machine # poweroff --halt #halt the machine # poweroff --reboot #reboot the machine
Reboot Command
reboot instructs the system to restart.
# reboot #reboot the machine # reboot --halt #halt the machine # reboot -p #poweroff the machine
That’s all!
