How to check if PSU is applied successfully

opatch apply

cd $ORACLE_HOME/rdbms/admin

sysdba

startup

@catbundle.sql psu apply

exit

before 11.2.0.2

less $ORACLE_HOME/cfgtoollogs/catbundle/`ls -1t $ORACLE_HOME/cfgtoollogs/catbundle | head -n 1 | awk '{print $1}'`|grep -i error

>= 11.2.0.2

less $ORACLE_HOME/cfgtoollogs/opatch/`ls -1t $ORACLE_HOME/cfgtoollogs/opatch/ | head -n 1 | awk '{print $1}'`|grep -i error