Shutting Down the Database Server Immediately with the -u Option
The -u option causes immediate shutdown. This option brings the database server to quiescent mode without waiting for users to finish their sessions. Their current transactions are rolled back, and their sessions are terminated.
A prompt asks for confirmation. Another prompt asks for confirmation to kill user threads before the database server comes to quiescent mode. If you want to eliminate these prompts, execute the -y option with the -s option.