Adding and removing Jupyter kernels

 Using the following command to see the currently installed kernels:

jupyter kernelspec list

And the following command to remove an installed kernel (in my case an updated version has been installed):

jupyter kernelspec uninstall julia-1.9

To add an updated version of Julia kernel into Jupyter, it is sufficient to:

Pkg.build("IJulia")

These simple things need to become part of my muscle memory. 

Interactive computing using C++ within the Atom editor

With the xeus-cling project, it is possible to do interactive computing using C++ inside a Jupyter notebook. With the Hydrogen project, I would think that the same can be done inside the Atom editor. I gave it a try with no luck. The problem was that while xeus-cling created a number of C++ kernels such as "C++ 11", "C++14", and "C++17", it did not create a kernel named "C++", which is what Hydrogen looks for. Follow the suggestion mentioned in this post, I was able to get rid of the error message and get the system to work. Wow!