When starting the SageMath REPL, the user is reminded how to launch the Sage Notebook:
$ sage
┌────────────────────────────────────────────────────────────────────┐
│ SageMath Version 6.9, Release Date: 2015-10-10 │
│ Type "notebook()" for the browser-based notebook interface. │
│ Type "help()" for help. │
└────────────────────────────────────────────────────────────────────┘
sage:Is there a command to launch the Jupyter Notebook (formerly IPython Notebook) from Sage?
