# merge master changes into branch
git -c "user.name=Circle CI" -c "user.email=example@example.com" pull --no-edit --no-ff origin refs/heads/master

# Get changed directories, assuming each dir is an app, you could also do a for loop after to check for certain files which define those directories as apps, e.g. if [ -f "$APP/app.json" ]
CHANGED_APPS=$(git diff --name-status master..$(git symbolic-ref --short HEAD) | awk '{print $2}' | xargs basename)

# run builds for $CHANGED_APPS