A Slug and a Shell

In news which will be of no surprise to those following my painting progress, I've gone back and reworked a painting of mine due to dissatisfaction with how it turned out. The painting in question is my blue glaucus painting, which I already reworked to add a shadow. Turns out I was never satisfied with the way the shadow looked, as it came out very gray and solid, so I decided to try redoing it with a thin black glaze today. I used some ivory black, which is the only black I have listed as anything less than “opaque” (it's “semi-opaque”). I think it worked out fairly well, you can judge for yourself below:

The old version…

…and the newly-blackened shadow.

This way the shadow looks a lot more distinct from the slug casting it, which is also quite silvery-gray. It'd probably have been good to make the shadow more out-of-focus from the start, but at this point I think I'm happy with it.

And what's the shell mentioned in the title, you may be asking? In computer terms, a shell is (to massively simplify, since I'm not even sure I understand it completely) essentially a program that you can use to send commands to the computer by typing them into a terminal window. These commands are pretty low-level, and are immensely powerful, to the point where you can easily save yourself hundreds or thousands of actions if you know what you're doing.

Shells are comparatively ancient in computer history terms, so there are a few common ones and several less commons variants floating around out there. The generally most common one is called Bash, which came out the year I was born in 1989 and stands for Bourne Again SHell (as it was written to be a free software replacement for the then-popular Bourne shell, which came out a decade earlier). This is by far the most common one encountered, as it comes as the default shell in most Linux distributions and macOS, and it's the one I've got the most experience with.

A few days ago I came across another shell called “xonsh” (pronounced “konsh” in a play on “conch shell;” perhaps the ‘x’ is meant to represent a Greek χ?). It had the intriguing premise of being written in Python, the language I've been using at work for quite a few years now, and being able to execute Python code directly in the shell while still retaining access to familiar Bash routines. In Bash you need to open the Python interpreter directly before being able to type and evaluate Python code, and you lose access to Bash's lower-level functions like being able to change directories or list their contents while doing so (technically Bash simply calls little executable programs for that, but you can't do so directly in the Python interpreter). Xonsh offers an alluring alternative where Python code and lower-level functions can be called and mixed freely, so I installed it on my desktop at home this weekend and intend to give it a try. I actually do run into situations in my PhD where I'd love to be able to execute some Python code at the terminal while using Bash, so it'll be interesting to see if this goes anywhere.

The caveat of any non-Bash shell, of course, is adoption; any other shell is not as popular, and therefore won't have as many resources about it online or people familiar with it to ask. I doubt I'll be ditching Bash anytime soon, but maybe I'll be surprised and find I can really replace it entirely. We'll see! A hui hou!