at jobs

how to schedule a reboot using the at jobs ?

Which part are you stuck with? Do you not know how to create an at job? Or do you not know what command to use to reboot?

suppose you'd like to run a find command at five o'clock tomorrow morning:

$ at 0500
at> cd /;sync;sync;init 6
at> ^D (press Control-D while at the beginning of a line)

When you're at the "at" prompt, just type the command you want to run. Try a few tests with the at command until you become comfortable with the way
it works.

# echo "shutdown -r now" | at reboot_time