Is it possible to only show a portion of a texture?

Like say I create a 4x4 texture but then only want a portion of it to appear on a 4x1 mesh how do I do this? By default the texture is just resized to be made to fit on the smaller mesh. How can I prevent this and only view the portion of the texture I want shown?

The best tutorial for this https://www.youtube.com/watch?v=bu8kGs1ap54

Learn about Texture Coordinates