Heroku env export & import

# Instructions:
# Make sure you have the Heroku CLI installed and configured (https://devcenter.heroku.com/articles/heroku-cli)
# Replace source-heroku-app and target-heroku-app with your app name

# 1. Export existing app’s variables to config.txt. 
heroku config -s -a source-heroku-app > config.txt

# 2. Review and push to another app
cat config.txt | tr '\n' ' ' | xargs heroku config:set -a target-heroku-app

# 3. Remove the config.txt file (especially if it holds sensitive information such as DB credentials)
rm config.txt