How do you diff a directory for only files of a specific type?

Question

I have a question about the diff command if I want a recursive directory diff but only for a specific file type, how to do that?

I tried using the exclude option but can

Answer 1

In case you find it convenient, you could use the following Makefile. Just run: "make patch"

#Makefile for patches

#Exlude following file endings
SUFFIX += o
SUFFIX += so
SUFFIX += exe
SUFFIX += pdf
SUFFIX += swp

#Exlude following folders
FOLDER += bin
FOLDER += lib
FOLDER += Image
FOLDER += models

OPTIONS = Naur

patch: 
    rm test.patch
    diff -$(OPTIONS) \
    $(foreach element, $(SUFFIX) , -x '*.$(element)') \
    $(foreach element, $(FOLDER) , -x '$(element)*') \
        org/ new/ > test.patch  

unpatch: 
    rm test.unpatch
    diff -$(OPTIONS) \
    $(foreach element, $(SUFFIX) , -x '*.$(element)') \
    $(foreach element, $(FOLDER) , -x '$(element)*') \
    new/ org/ > test.unpatch