How to restrict OS X video output to a specific part of the screen I accidentally bumped my MacBook Pro and now I have several lines on left and bottom sides of the screen.

The effected area is usable but hampers experience. I would like to somehow restrict the output to the working area of the screen.

I remember CRT monitors used to have features to easily, stretch/skew and position output.

How can I do this in OS X 10.10, Yosemite?

Either a built-in feature or a third party application would be welcome.
What you're looking for is called adjusting the overscan; this doesn't technically exist on an LCD screen.

However, I think you can probably manually adjust the usable area of your screen using SwitchResX.
If you're running El Capitan, you have to do an additional step to enable custom resolutions called disabling System Integrity Protection (SIP); search their website for a detailed how to.

SwitchResX has a demo version you can test out before buying.