WinMerge

WinMerge is a differencing and merging tool that is able to detect changes between files and folders and, in the final stage, selectively merge those changes. So, whenever you are in need of comparing two files or two folders, all you have to do is drag and drop those files/ folders in the application, visualize the differences and merge selected differences if you want.

As you may have assumed, this app also comes with a built-in text editor. Another useful features enables users to select two different files or folders, right click on them and choose the WinMerge command from within shell.

Additional filters and command line options speed up the process of differencing and merging.