Solaris is usually used as a server operating system. Because of this, you want to make sure that you shut the system down as gracefully as possible to ensure there isn’t any data loss.

For every application that is installed on your server, you should make sure that you have the correct scripts in /etc/rc(x).d to gracefully shut down the service.

Shutdown
You have more than one command option that you can use. The best command is this, executed as root:

shutdown -y -i5 -g0

This will immediately shut the system down. You can also use the older command that still works:

sync;sync;init 5

You can even use:

poweroff

Reboot
If you are trying to reboot the system as opposed to turning it off, you could use:

-y -i6 -g0

Or:

sync;sync;init 6

Or even:

reboot