backup Oracle Home before Critical Patch

do we need to backup the Oracle Home before applying the Critical Patch SPU?

if so, what is the tar command to do that correctly?

  Hello

you can make it as best practice to backup of ORACLE_HOME(helpful to restore it back to resolve patch issues while server crash issues...) but its not mandatory.

Best way to backup is to take copy using TAR command

eg:-

cd $ORACLE_HOME

tar -cvf <location where you want to save>/dbhome_1.tar  .

or you can take complete tar of directory

eg:- If your ORACLE_HOME is /u01/app/oracle/product/11.2.0.3/db_1