Most programming languages have facilities of some sort to enable the developer to execute commands on the OS’s shell prompt. Maybe it’s just me, but I’ve never been able to have an easy time at managing system processes properly (i.e., representing processes individually through the language’s constructs). Representing multiple processes piped from one to the next properly seemed like a pipe dream (sorry). I think the first painless way of doing this, at least among all the different options that I’ve seen, is in Clojure with the clj-commons-exec project. At the moment, it seems like a hidden gem. A side benefit of the project is that the evolution of the code for piping one process to the next, at least for me, is instructive on the difference between object-oriented and functional paradigms.
Since learning Clojure will most often require a lot of experience in coding in Clojure, a practical consideration for any new learner will be having an effective environment for editing code, testing, deploying, etc. On the Clojure development (developer?) website, there are instructions on getting started with Clojure. I believe that these instructions are intended to be the official help resource for everyone, and people are making good effort to keep it up-to-date and authoritative. My attempt, with this post, is to formalize what I know, and then contribute over to the official documentation whatever others might find a useful addition.
There are many ways to dabble in Clojure. My approach has been to read something, retain some fraction of it, and then repeat this process until those fractions equal a whole. When stepping into functional programming for the first time, especially after OOP, it’s not easy to grasp it right away. Sooner or later, the ideas will stick, right? That means learning in multiple passes, where some deeper level of understanding happens during each pass compared to the last. Kind of like iTunes Essentials with “The Basics”, “Next Steps”, and “Deep Cuts”. So that is what I want to present to you, in an ordering that will minimize your difficulty along the way.