I followed the instructions found here:
https://seo-michael.co.uk/how-to-setup-adb-on-os-x/
Everything worked as explained, except no device found. Here’s what I got in Terminal:
cd ~/Desktop/android
android Nels$ ./adb devices
* daemon not running. starting it now on port 5037 *
* daemon started successfully *
List of devices attached
android Nels$ adb shell ls /data/data/com.bn.nook.reader.activities/databases/
adb server is out of date. killing...
* daemon started successfully *
error: device not found
Any ideas?