You don't, because the kernel doesn't write the motd file.
> At the moment every time the computer is rebooted it re-writes this file. O
>ther U*nx's
> don't do this , why Linux??
Linux doesn't. The distribution you used has something silly in the motd,
like
uname -a > /etc/motd
grep /etc/motd out of your rc files and remove the offending line.
>
>Thanks
>
>L.Hudson