Hi,
1. Use "wall" command to send messages to all logged in users about server going down.
2. Confirm using who command whether all users are logged out
3. Use "ps -ef | more" command to check whether any critical/important processes are still running
4. Confirm there are no activities going on the attached I/O devices.
5. Then finally # shutdown -y -h 0
Regards,
You need to know a lot to actually know how little you know