I have a issue using ionic on my mac. I've cloned my repo and started it with ionic serve. But if I use control C and stop the command ant start it again I get this error "Cannot read property 'IONIC_CONFIG_DIRECTORY' of undefined".
Same problem here. Found the solution: https://forum.ionicframework.com/t/ionic-commands-not-working-after-update-ionic/146492/3
Solution:
npm uninstall ionic cordova
npm install ionic cordova