How do I merge a sub directory in git?

Question

Is it possible to merge only the changes for a sub-directory from a local git branch to a remote git branch or is it "all or nothing"?

For example, I have:

branch-a
 - content-1
 - dir-1
   - content-2

and

branch-b
 - content-1
 - dir-1
   - `content-2

I only want to merge the contents of branch-a dir-1 with the contents of branch-b dir-1.

Answer 1

I think this is a duplicate of this other question:

how-do-you-merge-selective-files-with-git-merge