One . The first method

1. Switch to oracle user

su – oracle

2. Get into sqlplus window

sqlplus / as sysdba

3. perform sql command , see trace file location ：background_dump_dest It’s the background log

show parameter dump;

4. Switch to trace Under the table of contents

cd /u01/app/oracle/diag/rdbms/prod/PROD/trace

5. Look at the pictures with alert Keyword file ,alert_INSTANCENAME.ora That is alert The name of the Journal

ls alert*

6. Consider using tail Command view alert After the log 500 That’s ok , then -f Represents a real-time refresh

tail -500f alert_PROD.log

Two . The second method (oracle Provides adrci Tools )

1. Switch to oracle user

2. perform adrci command

3.show homes See what you can see right now home （adrci Very powerful , You can see the monitoring log and alert Log etc. , I won’t go into details here ）

 4.set oracle alert journal home

5. Execute the following command to view in real time alert After the log 500 That’s ok

6.ctrl+c Quit the command

7. sign out adrci Command line