You can verify jobs that are running in the background by using the command:
jobs
Like this:
root@server1:/var/www/nodebb# jobs
[1]+ Running shutdown -r 17:00 &
Here is a good resource on learning how to use jobs, and manage background jobs in general:
http://www.cyberciti.biz/faq/linux-command-line-run-in-background/
Keep in mind that the job is tied to your session, if you close it ( AKA close the shell ) your job wont run. A better option for me would be to use cron to schedule the reboot.
Edit your crontab:
crontab -e
Now enter the cron entry... this will reboot the box every day at 5pm. (17:00)
* 17 * * * shutdown
Thats it for cron! You can view your crontab via:
crontab -l