I want to compare two directories which have similar hierarchy.
With "M-x ediff-directories" within Emacs, I was prompted to input a regexp to constrain the name of files I want to compare. For example, I want to compare the files whose name ends with .c or .h. Then I input ".*.[ch]", However, I find that it only take effects on the top level directory, but i want the regexp take effects on the files lied in all the sub-directories, no matter what the depth it is.