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:<

Answer 1

Given the OP's scenario where they have two branches, but want to merge only the history of dir-1 from branch-a into branch-b:

# Make sure you are in the branch with the changes you want
git checkout branch-a

# Split the desired folder into its own temporary branch
# This replays all commits, so it could take a while
git subtree split -P dir-1 -b temp-branch

# Enter the branch where you want to merge the desired changes into
git checkout branch-b

# Merge the changes from the temporary branch
git subtree merge -P dir-1 temp-branch

# Handle any conflicts
git mergetool

# Commit
git commit -am "Merged dir-1 changes from branch-a"

# Delete temp-branch
git branch -d temp-branch