Genius Idea: Portal Sword

This is the coolest way I can think of to create portals to go places. Please note: the kind of portal I'm referring to isn't the kind from the popular Portal games where you have to have 2 that go together. I'm talking about the kind that you just need the one to walk through and another temporarily appears at the desired destination. With that said, now I'll talk about my idea which is, as you can tell from the title, a sword that creates portals. Preferably, it could take mental commands for when to be a normal sword and when to slice through space in order to make portals, and also so it can know where I want to go. And it should work by magic instead of science because if mind reading technology exists, it could be put into robots, and I don't trust robots (except the ones like R2D2 that have proven their loyalty and/or couldn't do that much damage anyway). In terms of the portals themselves, I want them their size to depend on the length of my slash, and it doesn't matter a lot to me what they look like, but if I got to choose, I would want to be able to see through them like windows to the destination, but I want the rim to be either fiery or shadowy and smokey. It would depend on whether or not I had other magical items / powers and what they looked like, since it would be good to have my magic and stuff match. And I couldn' find any pictures of what I'm thinking of, so sorry about that.