I use an app called Synergy, it is a KVM switch that works without hardware over your network. I went to update Synergy on the Mac the other day, because it always breaks with OSX updates, and they have gone from free software to no longer free software. They are calling it a donation I believe, but thats BS cover. Charging for whatever reason is still a fee/cost of a product, don’t hide behind the wording. It is a small fee I will say though, currently (as of this posting) $5.00. Or head over to their site and grab a nightly for free, if you don’t mind betas. It is a great piece of software, very handy with multiple machines on the same desk I must say.