Detach move subdirectory into separate git repo

Question

I have a git repo which consists of many subdirectories. I recently found out that one of the subdirectories is not relevant and now I’m trying to remove it from the repo. How do I go about this?

Answer 1

Clone your repo first and the use git filter-branch to mark everything but the subdirectory that you want in your new repo to be garbage-collected.

Step 1 - To clone your local repository:

         git clone /XYZ /ABC

step 2 - Let us preserve the interesting branches which we want to rewrite as well, and then remove the origin to avoid pushing there and to make sure that old commits will not be referenced by the origin:

cd /ABC
for i in branch1 br2 br3; do git branch -t $i origin/$i; done
git remote rm origin

or for all remote branches:

cd /ABC
for i in $(git branch -r | sed "s/.*origin\///"); do git branch -t $i origin/$i; done
git remote rm origin

step 3 - Then use filter-branch and reset to exclude the other files, so they can be pruned

git filter-branch --tag-name-filter cat --prune-empty --subdirectory-filter ABC HEAD

step 4 - Then delete the backup reflogs so the space can be truly reclaimed (although now the operation is destructive)

git reset --hard
git for-each-ref --format="%(refname)" refs/original/ | xargs -n 1 git update-ref -d
git reflog expire --expire=now --all
git gc --aggressive --prune=now

Answer 2

git filter-branch --prune-empty --subdirectory-filter <YOUR_SUBDIR_TO_KEEP> master
git push <MY_NEW_REMOTE_URL> -f .

this will remove the subdirectories you don't want and then push to the new remote.