vinberg88 Works if i have key in usb... If i dont have Key I can't login or use sudo =]
That's what is supposed to happen if you performed the steps in the Reddit post you linked to. Generally, that's what how the Yubikey operates. If it is plugged in, you can use it for passwords and whatever else you set it up to do. Without it plugged in, you can't. The post itself says
"- Open en new terminal and type sudo -s. Without the Yubikey present you shouldn't be able to elevate your rights. "
If you have further questions, please ask and please be specific and provide detail.