1. Universal Inter-Process Interface: Arbitrary program composition via the Standard Input / Output / Error interface, and "everything is a file" abstraction... None of the rest is possible without some such core design decision ("everything is an object" is the fraternal twin).
2. Widespread standard utilities: The broad availability of core util tools designed to cooperate via the same abstraction is a close second. Along with some default scripting language, that is also built for the same computing model.
3. Language of choice: Important for ease of access, but a distant third in terms of raw power, be it bash, perl, awk, node, clojure (babashka) etc. That's icing on the cake, because if one had no choice in the matter, the shell program would still be awesomely powerful. Proof is in the pudding---"scripts that matter" are always /bin/sh.
Generally speaking, the pain of learning to avoid sh and bash footguns is primarily a matter of some basic research reading: manuals, lore, and warnings (I love BashPitfalls). Well, either that, or learning the hard way by copy-pasting code, and if luck runs out, rm -rf ing something you shouldn't have.
There is no substitute to taking the day or so to read the manual, so you know it's a lot, but it ain't magic, and you can eat that elephant one bite at a time, at your own pace. Seriously... the wall-clock time of trial and error with BashPitfalls (about a day or so), is nothing compared to learning to use---and then having to re-learn every so often---the python or node or whatever ecosystem without losing it. Besides, the former knowledge is stable and so are the programs --- my Bash code will keep working the same way, forever, practically speaking.
I'd even drop the "if" from their footnote version, and go with simply
npm install || (echo "boom" && exit)
(Not exactly equivalent because there won't be an "exit" if echo fails, but it's my preferred instict over ";") Also, "(" starts a subshell, if we are being pedantic.I believe the answer is the same as to why Python remains hugely popular despite all the well-documented shortcomings: batteries included.
Shell languages include so many neat and concise ways to execute commands, deal with their input, output and exit codes, allow simple traversal of deep directory structures with globs and advanced tools like 'find' or 'xargs', that everything else is very unergonomic.
And niche by default (until it gets used widely enough), so even your LANG-OF-CHOICE-expert you recruit, they will not know a thing about that shell-focused library in LANG-OF-CHOICE.
If scripting were to be excluded, the belittling of GUIs falls a bit flat. I'd like to see graphic design work be done via CLI.
If you take nothing else away from this, memorize the syntax of one-liner for loops, it has saved me so many times.
For example
> At a fundamental level, I wasn’t able to tell my computer to accomplish anything that involved logic or stitching together multiple programs
How can that be true if you are telling it to boot on into a os? It doesn't involve logic? Or stiching together multiple programs?
Using a shell =\= telling a machine what to do on a broad level. You are just using the abstractions provided by the os. If you mean get better at shell so you can use it more efficiently than okay cool but that doesn't someone who uses a GUI doesn't "tell" the machine what to do as much as you.
Scripting in the terminal can manipulate windows too (e.g. xdg-open with KWin), or send notification locally (e.g. notify-send) to any devices (again or ntfy), or open dialogs (e.g. kdialog), or controlling other devices (e.g. curl to HomeAssistant API) so indeed it opens up an entire new world of possibilities... and it's combinatorial.
Also for another bit of context, scripting works ... on the weirdest newest devices, e.g. a Meta Quest on Android thanks to Termux. If there is an OS there is surely a terminal in there somewhere, and if there is, you can script on it. So... scripting isn't "just" for your desktop or a remote server, it's everywhere.