tree -I 'node_modules' prevents the
node_modules folder from appearing in the output. Likewise,
tree -I 'app/ui/bower_components' prevents
app/ui/bower_components from appearing in the output.
tree -I 'node_modules' -I 'app/ui/bower_components' doesn't prevent both from appearing in the output. Instead, it appears the last one is used.
So, how do you ignore multiple folders using