Ionic -serve keeps failing (by port 8100, which is NOT in use however)


I have the following issue on Ubuntu 15.04 after upgrading to ionic@1.7.15, while requesting :
ionic serve

The port 8100 was taken on the host localhost - using port instead Live Reload failed to start, error: Error: watch /home/hmachefer/.../www/css ENOSPC Ionic serve failed - error: Error: watch /home/hmachefer/.../www/css ENOSPC Ionic server commands, enter: restart or r to restart the client app from the root ... quit or q to shutdown the server and exit

Although 8080 is (definitively) not busy however: another whatever node instance may run by listening on this port. I tried other ports nevertheless for the sake of experimenting:
killall ionic then
ionic serve -p 8080 -l 8081 -a