Boot, reboot, and shut down a system normally

Some examples:
1) Shutdown the system immediately.

# shutdown -h now

2) Reboot the system now

# shutdown -r now

3) or you can use reboot command

# reboot

4) Delayed shutdown by 2 minutes

# shutdown -h 120

5) Shutdown at 10:00PM

# shutdown -h 22:00

6) Requests that the system be powered off explicitly.

# shutdown -P now

7) Force the filesystem check during reboot

# shutdown -Fr now

In CentOS/RHEL 6, with new Upstart utility both poweroff and halt commands pointed to reboot command. These programs allow a system administrator to reboot, halt or poweroff the system.

# shutdown -P now

is quite equal to

# poweroff

and

# shutdown -r now

is quite equal to

# reboot