shutdown - is used to shutdown the system in a safe way

syntax $ shutdown [OPTIONS] [TIME] [MESSAGE]

To shutdown the system at a specified time 6 P.M $ sudo shutdown 18:00

To schedule a system shutdown in 30 minutes from now $ sudo shutdown +30

To shutdown the system immediately $ sudo shutdown now

To shutdown the system in 30 minutes from now and notify the users with message “system upgrade” $ sudo shutdown +30 "system upgrade"

To halt your system $ sudo shutdown -H

To make shutdown power-off machine $ sudo shutdown -P

To reboot using shutdown $ sudo shutdown -r

To specify a time argument and a custom message $ sudo shutdown -r +10 "system upgrade"

To cancel a scheduled shutdown $ sudo shutdown -c

To cancel a scheduled shutdown, and to broadcast a message to all users $ sudo shutdown -c "reboot is cancelled"

regards, T.Dhanasekar