Linux comes with various utilities that allow a system administrator to reboot, halt or poweroff the system. One must be root or a member of wheel group in order to run reboot command.
Reboot Linux command
You must login as root to reboot the system. Open the terminal application (or login to remote box using ssh client) and type any one of the following command to reboot the system immediately:
# /sbin/shutdown -r now
You can also use sudo command under Ubuntu/Debian/Fedora and other Linux based distros:
$ sudo reboot
It is a good idea to provide notification to all logged-in users that 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.
How do I reboot remote Linux server?
Simply login as the root user using ssh command:
$ ssh email@example.com /sbin/reboot
$ ssh firstname.lastname@example.org /sbin/shutdown -r now