Falsecolor -d option

I was trying to output a few false colour images and when I try to use option –d of falsecolor I receive a bad option "-d” message
Is –d not an option at all or anymore? Or what could be the reason for that?
Thank you for your help

It is one of the newer options, in fact. Are you sure you are not using or somehow accessing an older version, before this option existed?

Hi Greg
that was it, I just installed the current official release and the -d option works
Thank you