Move a folder from one Git project to another preserving history

move_folder_between_projects.sh

# Clone repo 1
git clone repo1
cd repo1

# Use subtree on the folder you want to move
git subtree split -P dir1 -b split-dir1-branch

# Check out branch and move files
git checkout split-dir1-branch
mkdir dir1
mv * dir1/
git add .
git commit -m "Moved all dir1 files back to dir1"

# In repo 2, pull down files
git clone repo2
cd repo2
git remote add repo1-origin
git pull repo1-origin split-dir1-branch

# Caveat: git log only shows the last commit
# To view the history, use `--follow`:
git log --follow dir1