Do you have a sql*plus user who really needs an April Fool’s joke played on them? With a little editing to their glogin.sql, every sql*plus session will exit with what appears to be a pseudo-random TNS error.
(Note: assumes a *nix environment that has sed, grep, awk installed and oerr properly working.)
[oracle@localhost ~]$ cd $ORACLE_HOME/sqlplus/admin [oracle@localhost admin]$ mv glogin.sql glogin.old [oracle@localhost admin]$ vim glogin.sql --Added by APRIL FOOL set echo off set feedback off set verify off set head off col the_err new_value myerrno col the_user new_value uname set termout off select '125' || decode( to_char(sysdate,'SS'),'01','61','06','64','07', '66','17','69','30','70','53','71','59','82', to_char(sysdate,'SS')) as the_err from dual; select user as the_user from dual; set termout on clear columns prompt ERROR: host oerr ora &myerrno | grep -v '//' | sed 's/"//g' | awk -F, '{print "ORA-" $1 ": " $3}' prompt SP2-0751: Unable to connect to Oracle. Exiting SQL*Plus exit &myerrno --End added by APRIL FOOL :wq [oracle@localhost admin]$ sqlplus "/ as sysdba" SQL*Plus: Release 12.1.0.2.0 Production on Thu Mar 31 17:50:39 2016 Copyright (c) 1982, 2014, Oracle. All rights reserved. Connected to: Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options ERROR: ORA-12539: TNS:buffer over- or under-flow SP2-0751: Unable to connect to Oracle. Exiting SQL*Plus Disconnected from Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options [oracle@localhost admin]$ sqlplus "/ as sysdba" SQL*Plus: Release 12.1.0.2.0 Production on Thu Mar 31 17:50:52 2016 Copyright (c) 1982, 2014, Oracle. All rights reserved. Connected to: Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options ERROR: ORA-12552: TNS:operation was interrupted SP2-0751: Unable to connect to Oracle. Exiting SQL*Plus Disconnected from Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options [oracle@localhost admin]$ sqlplus "/ as sysdba" SQL*Plus: Release 12.1.0.2.0 Production on Thu Mar 31 17:51:02 2016 Copyright (c) 1982, 2014, Oracle. All rights reserved. Connected to: Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options ERROR: ORA-12502: TNS:listener received no CONNECT_DATA from client SP2-0751: Unable to connect to Oracle. Exiting SQL*Plus Disconnected from Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options
Disclaimer – use at your own risk to workplace harmony!