That is correct. First use the installer's uninstall opetion, uninstall all the packages, then go to the point $ORACLE_BASE

issue rm -rf * would recursively delete all the files. But be aware the you do not want to give this command if you have other than oracle installed under the oracle base directory. Like other oracle products like oas/ias and etc.

On such case go to the appropriate directory and start removing files as said above. Then do a fresh install of oracle again.

Sam