diff between 2 directories excluding few file extensions

Question

diff between 2 directories and I want to exclude few file extension.

I want to exclude few file extension and make a diff

.bak
.bak-extract.txt
.*-extract.txt
.json

I tried

diff dir1 dir2 | sed '.txt.bak' 

I am not able to get correct diff

Answer 1

You can try to exclude those files

 diff -r --exclude="bak*.txt" dir1 dir2