In some cases you need to deinstall your Oracle Software (to install Oracle Software please read How to Install Oracle Instance article).
In this article I will show you uninstallation process on Oracle 188.8.131.52 on Linux. (For deinstalling on Windows please read the article Deinstalling Oracle Software on Windows)
1. Backup your Oracle Inventory (usually located on $ORACLE_BASE folder). Using command:
#> cd $ORACLE_BASE #> zip -r oraInventory.zip oraInventory
2. Check whether your Oracle Home is registered in the Oracle Inventory
#> $ORACLE_HOME/OPatch/opatch \ lsinventory -all -invPtrLoc $ORACLE_HOME/oraInst.loc
If your Oracle Home registered, it will appear in the Displayed “List of Oracle Homes”. Oracle Home must be registered in order to detach it.
3. Now Detach Oracle Home from Oracle Inventory
#> $ORACLE_HOME/oui/bin/runInstaller \ -silent \ -detachHome ORACLE_HOME=$ORACLE_HOME \ -waitForCompletion \ -invPtrLoc $ORACLE_HOME/oraInst.loc
At the end of this step, you see the message ‘DetachHome’ was successful.
4. Now you can safely remove the Oracle Home Software
#> rm -rf $ORACLE_HOME
You can check by issuing command sqlplus as ora<sid>
For more updated procedure please read SAP Note #1525025.