参数解释：

-C 3：显示ORA- 报错上三行以及下三行信息

-n 100：100行中寻找是否有ORA-报错信息

[oracle@xiong:/oracle/app/oracle/diag/rdbms/itpuxdb/itpuxdb/trace]$ tail -n 100 alert_itpuxdb.log |grep -C 3 ORA-

Time drifts can result in an unexpected behavior such as time-outs. Please check trace file for more details.

Tue Mar 17 14:58:27 2020

ALTER DATABASE CLEAR LOGFILE GROUP 1

ORA-1624 signalled during: ALTER DATABASE CLEAR LOGFILE GROUP 1...

Tue Mar 17 20:59:06 2020

Warning: VKTM detected a time drift.

Time drifts can result in an unexpected behavior such as time-outs. Please check trace file for more details.

[oracle@xiong:/oracle/app/oracle/diag/rdbms/itpuxdb/itpuxdb/trace]$