Here are list of commands that can be used to shutdown or reboot a system.
Note: All the commands require superuser privileges, hence use sudo for all of them.
The command halt will shutdown the system immediately.
The command reboots the system
The command can be used to shutdown as well as reboot the system by passing the correct options as given below
To shutdown immediately
To shutdown after a time interval
This will shutdown the system after 15 minutes
To reboot :
To reboot after a time interval
This will reboot the system after 15 seconds.
To reboot using init run
This will reboot the system immediately.
This will poweroff the system immediately just like the halt command