If you set “stty erase ^H” on unix prompt and it works fine on unix prompt. But not working on SQLPLUS then you need to put “stty erase ^H” in .kshrc file as following.
-> pwd
/home/oracle
oem.localdomain:OEMDB:/home/oracle
-> more .kshrc
stty erase ^H
oem.localdomain:OEMDB:/home/oracle
->