SQL> SHUT IMMEDIATE
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL>
SQL>
SQL> STARTUP
ORACLE instance started.

Total System Global Area 1071333376 bytes
Fixed Size                  1406436 bytes
Variable Size             494930460 bytes
Database Buffers          570425344 bytes
Redo Buffers                4571136 bytes
Database mounted.
ORA-03113: end-of-file on communication channel
Process ID: 5080
Session ID: 5 Serial number: 3