Thanks for the info. I am a bit weary of my use of the terminal. Many have given advise that people (not to be accusing you) will give commands to put into that program that can cause trouble to the uninformed. Uninformed would be my label, I know nothing about the use of terminal code.
However it that code did what you purport it to do, without any damage, it would be a workable solution for my problem.
I really have no use for the loud blast of sound when the iMac starts. I think it is a trick Apple uses to make us think things start fast, which only the sound come quickly, but for the system to be usable it involved more time.
Thanks