If you occasionally need to reboot a Linux box as a one off one evening you can perform the following commands using the at command. Note if you set a time that has just past it will perform the reboot the following day. So lets say its 16:15 and you want to schedule a reboot at 21:00 that evening, to do this you can do run these commands.
# at 21:00
at> shutdown -r now
Hit Ctrl + D
You’ll now see its been created:
job 1 at Tue Nov 3 21:00:00 2015
To check on any at commands that are scheduled you can run:
1 Tue Nov 3 21:00:00 2015 a root