How to run code with Hydrogen


Hi there. I am completely new to Atom.
I installed it and it felt quite easy to use and set up. I read that the Hydrogen package enables functionality similar to the Jupyter Notebook. So I installed the package.
Unfortunately, I have no Idea how to use it. I read the entire documentation (which isnt too extensive) and searched for everything I could.
So here is my problem:
I created a file called
In that file i put the very simle line
just to see how it works. I marked the line and pressed Ctrl+Enter. At the top right, a window pops up saying “Hydrogen Kernels updated: Python 3”.
But then nothing happens. I dont see the result of the code that I tried to run anywhere. I tried different lines of codes, tried differen run-combinations, nothing gives me any results.
I am using arch linux, installed Anaconda through the AUR to /opt/anaconda.
Using the terminal and running
jupyter notebook
for example works just fine and opens a Notebook in Firefox (as it should) and running code that imports modules that came along with Anaconda also work fine once i run them with the script package in Atom
(things like
import numpy as np
is letting me work with all the numpy funtions as expected. So I think that it shouldnt be any issues related to the Anaconda packages itself)
I tried to look everywhere I could, but I do not find any solution on why hydrogen would not give me any results.
Is there anything I am missing or did wrong?
I hope someone might be able to help me, thanks already in advance


I am also an Arch Linux user.

When I run code in Hydrogen, the first thing I do is select the code in the module I want to run – can be multiple functions or single line – then press control-return.

This initializes the Hydrogen/Jupyter environment for the code I am working with.

Once I see the Python 3 Idle status in the status line, I then select code from what I had previously selected that I now want to execute and press control-return. Then I see the result. It prints at the end of the line I selected to execute if the amount of output is small such as your test case.


Thanks for your answer, but this is pretty much exactly what the general instructions provide on the packge documentation itself, so that was the very first thing I did and tried.


When I do this, ‘Hello’ appears at the end of the line containing the print statement.

What version of Atom and Hydrogen are you using?


I know thats what it should do, but unfortunately, it doesn’t.
I am using Atom 1.18 and Hydrogen 1.20


Solved it. My nftables default policy for input and output for the inet filter is drop, had to accept localhost in both. Oh my…


oh my indeed… :grinning: