I already have python3/ipython3 (and notebook) installed. So I followed the instructions, and I did:
$ pip3 install jupyter
jupyter: command not found
$ python3 jupyter
python3: can't open file 'jupyter': [Errno 2] No such file or directory
$ ipython3 jupyter
[TerminalIPythonApp] WARNING | File not found: 'jupyter'
$ ipython jupyter
[TerminalIPythonApp] WARNING | File not found: u'jupyter'
Trying to debug another issue with installing a Golang kernel (gophernotes), I found out it is installed in