How to find PSU Version ?

Patch Set Updates are referenced by their 5-place version number. You may use the below commands depending on hte ORACLE_HOME.
Database PSU:

$opatch lsinventory -bugs_fixed | grep -i 'DATABASE PSU'

CRS (Cluster Ready Services) PSU:

$opatch lsinventory -bugs_fixed | grep -i 'TRACKING BUG' | grep -i 'PSU'

GI (Grid Infrastructure) PSU:

$opatch lsinventory -bugs_fixed | grep -i 'GI PSU'

Enterprise Manager Agent PSU:

$ opatch lsinventory -bugs_fixed | grep -i 'ENTERPRISE MANAGER AGENT' | grep -i 'PSU'

Enterprise Manager OMS PSU:

$opatch lsinventory -bugs_fixed | grep -i 'ENTERPRISE MANAGER OMS' | grep -i 'PSU'
WebLogic Server PSU: