1. Download patches

2. backup precheck
   cd precheck
   ps -ef |grep pmon > current_instance.txt
   ps -ef |grep tns > current_tns.txt
   cat /etc/oratab > current_oratab.txt
   $ORACLE_HOME/OPatch/opatch lsinventory > before_current_lsinventory.txt

3. Check conflicts
   export PATH=$ORACLE_HOME/OPatch:$PATH
   opatch version
   unzip <patch.zip> && cd <path folder>
   opatch prereq CheckConflictAgainstOHWithDetail -ph ./

4. Stop oracle database and listeners

5. Check
   ps -ef|grep pmon
   ps -ef|grep tns
   ps -ef|grep exp
   ps -ef|grep rman

6. Apply patch
   opatch apply

7. Check
   opatch lsinventory > after_current_lsinventory.txt

8. Start only oracle database (not the listener)

9. Patch data
   datapatch -verbose

10. Check
    sqlplus / as sysdba
    SET LINESIZE 400
    COLUMN action_time FORMAT A20
    COLUMN action FORMAT A10
    COLUMN status FORMAT A10
    COLUMN description FORMAT A40
    COLUMN version FORMAT A10
    COLUMN bundle_series FORMAT A10

SELECT TO_CHAR(action_time, 'DD-MON-YYYY HH24:MI:SS') AS action_time,action,status,description,patch_id FROM sys.dba_registry_sqlpatch ORDER by action_time;

10. Check stop and start
    sqlplus / as sysdba
    shutdown immediate
    startup
    select name,open_mode from v$database;

11. Start the listener