This is a fork of Hannes Landeholm’s Unison OS X unison-fsmonitor adapter that works with Python 3.
It has been tested to work successfully with Unison 2.51.2 (the latest public release as of July 2018) and Python 3.6.5 on macOS Sierra 10.12.6.
pip install macfsevents
curl -o /usr/local/bin/unison-fsmonitor https://raw.githubusercontent.com/debajit/unison-fsmonitor-mac/master/unox-python3.py
chmod +x /usr/local/bin/unison-fsmonitor