People often want to know how they can tell what versions (including patches) of software they are running in their different environments. Fortunately, there is a simple standard way to get this information for all software that uses the Oracle Universal Installer. The method I speak of uses the OPatch utility that is standard for all Oracle products that use the universal installer. This includes most, if not all of Fusion Middleware 11g and all of the 11g Identity Management packages.
OPatch is the utility used to patch Oracle products that utilize the Oracle Universal Installer. It is included in most product/package installs under that package’s ORACLE_HOME/OPatch.
Now, keep in mind that when you execute OPatch it will operate on the ORACLE_HOME that is set in the environment. So, if you are operating in an environment where you have multiple products/packages installed under one Fusion Middleware Home (FMW_HOME) you want to make sure that you have an ORACLE_HOME environment variable pointed to the product/package you are interested in patching or analyzing.
To get information on the version and patch levels of your Oracle product/packages run ‘opatch lsinventory’. Again, make sure that ORACLE_HOME is set to the product/package that you want the information for. If it is not set, then OPatch picks some default ORACLE_HOME from your FMW_HOME in a manor I have yet to figure out.
You can also use OPatch to tell you all the ORACLE_HOMEs that exist under your FMW_HOME by running ‘opatch lsinventory -all’.
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Courtesy:http://fusionsecurity.blogspot.com/2011/01/tell-what-patches-are-installed-in-your.html?utm_source=feedburner&utm_medium=twitter&utm_campaign=Feed%3A+OracleFusionMiddlewareSecurity+%28Oracle+Fusion+Middleware+Security%29&utm_content=Twitter