Disable Automatic Startup of OEM (OMS and Agent)

vi /etc/oragchomelist

Comment "#" out the home directory entries.

Example:

[oracle@hostname ~]$ vi /etc/oragchomelist

#/opt/oracle/middleware_13.2

#/opt/oracle/agent_13.2/agent_13.2.0.0.0:/opt/oracle/agent_13.2/agent_inst

#/opt/oracle/product/agent13c/agent_13.2.0.0.0:/opt/oracle/product/agent13c/agent_inst

Save and exit