Command-line tools and scripts that use OS X's FSEvents API.
Alert if any files in a directory are changed.
notifywait /path/; echo "\007"
Automatically rsync files to a remote server if any of them are changed.
auto_rsync . 192.168.1.127:/var/www
Same as above, but don't copy .pyc files.
notify_loop ~/code/directory rsync -avz --exclude="*.pyc" ~/code/directory/ server.example.com:/stuff/