uadmin 2 0
sync the filesystems and drops system to ok prompt
uadmin 2 1
sync the filesystems and reboots to multi-user mode
uadmin 2 2
sync the filesystems and reboots interactively
uadmin 2 3
sync the filesystems and reboots to single-user mode
uadmin 2 6
sync the filesystems and powers off the system
uadmin 1 0
do not sync filesystems and drops system to ok prompt
uadmin 1 1
do not sync filesystems and reboots to multi-user mode
uadmin 1 2
do not sync filesystems and reboots interactively
uadmin 1 3
do not sync filesystems and reboots to single-user mode
uadmin 1 6
do not sync filesystems and powers off the system
SAIFUL AZIZ's BLOG 
Want to simulate kernel panic, After below command ..
will system back to normal on reboot or now
uadmin 5 0
uadmin 5 1