machinename:~ username$ jupyter-notebook list
 http://localhost:8888 :: /Users/username/your/notebook/path
 http://localhost:8889 :: /Users/username/your/other/notebook/path
 ...

from notebook import notebookapp
servers = list(notebookapp.list_running_servers())
print servers

[{u'base_url': u'/',
  u'hostname': u'localhost',
  u'notebook_dir': u'/Users/username/your/notebook/path',
  u'pid':123,
  u'port': 8888,
  u'secure': False,
  u'url': u'http://localhost:8888/'},
 ...
 {u'base_url': u'/',
  u'hostname': u'localhost',
  u'notebook_dir': u'/Users/username/your/other/notebook/path',
  u'pid': 1234,
  u'port': 8889,
  u'secure': True,
  u'url': u'http://localhost:8889/'}]