How to shut down my computer at 18h30? How to reboot in console mode ?

You must be root

nadir@ipower:~$ sudo -s
Password:
root@ipower:~#

Reboot

Option -r now(reboot now) allows you to reboot now

root@ipower:~# shutdown -r now

Shut Down

Option -h now(halt now) allows you to stop now

root@ipower:~# shutdown -h now

Schedule a shut down or a reboot

To reboot your computer in 13 minutes:

root@ipower:~# shutdown -r +13

Broadcast message from root (pts/1) (Mon Oct 17 18:03:22 2005):

The system is going DOWN for reboot in 13 minutes!

To shut down your computer in 13 minutes:

root@ipower:~# shutdown -h +13

Broadcast message from root (pts/1) (Mon Oct 17 18:02:58 2005):

The system is going DOWN for system halt in 13 minutes!

To reboot your computer at 18:30:

root@ipower:~# shutdown -r 18:30

Toshut down your computer at 18:30

root@ipower:~# shutdown -h 18:30

Cancel a reboot or a shutdown

To cancel reboot or shutdown schedules, you must use -c option

root@ipower:~# shutdown -c