I used to see this is bash scripts all the time. It’s somewhat gone out of favor (along with using long bash scripts).

If you had to prompt a user for a password, you’d read it in, use it, then thrash the value.

    read -p “Password: “ PASSWD
    # do something with $PASSWD
    PASSWD=“XXXXXXXXXXXXXXXXXX”

It’s not pretty, but a similar concept. (I also don't know how helpful it actually is, but that's another question...)