Thanks a lot, KenEwald.

I went to /opt/oracle/product/9.2.0 and
"find . -name listener.log -exec ls -l {} \;"
The listener.log file is the file I was watching.

May be like what you said, I have to put the listener.log file in my listener.ora to start the log permanently. If I modify my listener.ora file, shall I shut down the database, modify it and then open the database?

My disk space keeps growing, now /opt is 87%. I checked the files you mentiond. In ORACLE_HOME directory, I didn't find the .trc and core dump files. As for $OH/rdbms/audit/*.aud, the size is not large, I paste it here. Should I remove them? Is there any disadvantage if I remove them?

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tr_db_active@/opt/oracle/product/9.2.0/rdbms/audit > ls -la
total 108
drwxr-xr-x 2 oracle dba 53248 Feb 24 00:07 .
drwxr-xr-x 13 oracle dba 4096 Mar 29 2004 ..
-rw-r----- 1 oracle dba 645 Feb 23 00:07 ora_10111.aud
-rw-r----- 1 oracle dba 645 Feb 23 00:07 ora_10112.aud
-rw-r----- 1 oracle dba 645 Feb 23 00:07 ora_10113.aud
-rw-r----- 1 oracle dba 645 Feb 23 00:07 ora_10114.aud
-rw-r----- 1 oracle dba 645 Feb 23 00:07 ora_10115.aud
-rw-r----- 1 oracle dba 645 Feb 23 00:07 ora_10116.aud
-rw-r----- 1 oracle dba 645 Feb 24 00:07 ora_19656.aud
-rw-r----- 1 oracle dba 645 Feb 24 00:07 ora_19657.aud
-rw-r----- 1 oracle dba 645 Feb 24 00:07 ora_19658.aud
-rw-r----- 1 oracle dba 645 Feb 24 00:07 ora_19659.aud
-rw-r----- 1 oracle dba 645 Feb 24 00:07 ora_19660.aud
-rw-r----- 1 oracle dba 645 Feb 24 00:07 ora_19661.aud

***********************************************

I just found a file "snapcf_ladb.f" in $ORACLE_HOME/dbs directory, the size looks large and date is today's date. I can't read the content of it, it is unreadable code. I paste the info regarding it here. Don't you think the file suspectable?

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tr_db_active@/opt/oracle/product/9.2.0/dbs > ls -la
total 4948
drwxr-xr-x 2 oracle dba 4096 Feb 24 11:29 .
drwxr-xr-x 50 oracle dba 4096 Mar 29 2004 ..
-rw-r--r-- 1 oracle dba 12920 Mar 9 2002 initdw.ora
-rw-r--r-- 1 oracle dba 5117 Mar 31 2004 initladb.ora
-rw-r--r-- 1 oracle dba 8385 Mar 9 2002 init.ora
-rw-rw---- 1 oracle dba 24 Jan 27 18:33 lkLADB
-rwSr----- 1 oracle dba 2048 Mar 30 2004 orapwladb
-rw-r----- 1 oracle dba 4909056 Feb 24 00:37 snapcf_ladb.f
-rw-r--r-- 1 oracle dba 84053 Jan 27 18:31 sqlnet.log

***************************************************************

thank you so much for your help.

jwu1023