IANAL, but in most legislations you do not have to register a trademark for it to be valid. It is important that you defend you trademark, and you will lose you

IANAL, but in most legislations you do not have to register a trademark for it to be valid. It is important that you defend you trademark, and you will lose your right to a trademark if you fail to do so. https://en.wikipedia.org/wiki/Trademark#Enforcing_rights https://en.wikipedia.org/wiki/Trademark#Enforcing_rights I do agree with those saying that in the wider audience, GNU screen does not mean anything, including (probably) the large armies of Windows developers. Besides that you should use tmux anyway ;).