Use one of comparison tools which supports compare directories.
Beyond Compare, Meld, Krusader, ... (http://en.wikipedia.org/wiki/Comparison_of_file_comparison_tools)
Question
No SCM involved!
Assume I have two folders with sources which are the same (same structure, same files). Then I change sources in one folder and want to merge those changes into another folder. How can I achive that?
Usually I use p4merge to merge single files.
I'm using Linux.
Solution
Use one of comparison tools which supports compare directories.
Beyond Compare, Meld, Krusader, ... (http://en.wikipedia.org/wiki/Comparison_of_file_comparison_tools)