[HHYTS]/u01/app/oracle/product/11.2.0/dbhome_1/oui/bin $ sudo su -
[root@hhytsdb1 ~]# cd /u01/app/oracle/patchdepot
[root@hhytsdb1 patchdepot]# export PATH=$PATH:/u01/app/188.8.131.52/grid/OPatch
[root@hhytsdb1 patchdepot]# opatch apply 13513783
The user is root. OPatch cannot continue if the user is root.
OPatch failed with error code 255
[root@vfxadb03 patchdepot]# whoami
Solution: OPatch can not run as user root. When "opatch apply" statement runs, it initiates Java OPatch and Java OPatch can not run as user root. But when "opatch auto" statement runs, it initiates "autopatch" and autopatch can run as user root. So when you get this error, it means you must use "opatch auto".