While applying a patch to oracle binary using opatch utility, got below error.
Solution : While applying patch using opatch, all processes using that ORACLE_HOME should be done. If any of the processes are still using the ORACLE_HOME, It will fail with above error.
If this command shows any process id , then those need to be killed also.
Now retry the opatch :
# $ORACLE_HOME/OPatch/opatch apply
We have applied the patch successfully.
P.S. : So before running the opatch apply command directly, it is better to run the below command, to check whether any process using the oracle binary or not.