When you have to reboot a Solaris you can use multiple commands as root user.
This command will not ask, you can interrupt it with ^C:
$ shutdown -i6 -g0
-i6 turns to State 6, the state 6 stops the operating system and reboots to the state defined by the initdefault entry in /etc/inittab.
-g0 permits to set a period to shutdown, the default is 60 seconds.
-y would not ask you for Y/N before rebooting.
$ shutdown -i5 -g0
This turns the machine into state 5, which means a state in which the machine can be turned off, and it turns the machine off.