Linux comes with various utilities that allow a system administrator to reboot, halt or poweroff the system.
Reboot Linux commandYou must login as root to reboot the system. Open the terminal and type any one of the following command to reboot the system (following is immediate reboot):
# /sbin/shutdown -r now
You can also use sudo command under Ubuntu Linux:
$ sudo reboot
It is a good idea to provide notification to all logged-in usersthat the system is going down and, within the last five minutes of TIME, new logins are prevented. Type the following command:
# shutdown -r +5
Broadcast message from firstname.lastname@example.org (/dev/pts/1) at 13:21 ... The system is going down for reboot in 5 minutes!
TIME may have different formats, the most common is simply the word now which will bring the system down immediately. Other valid formats are +m, where m is the number of minutes to wait until shutting down and hh:mm which specifies the time on the 24hr clock.