[salmo]

As an old Unix guy this is exactly how I see jq: a gateway to a fantastic library of text processing tools. I see a lot of complicated things done inside the language, which is a valid approach. But I don’t need it to be a programming language itself, just a transform to meet my next command after the pipe.

If I want logic beyond that, then I skip the shell and write “real” software.

I personally find those both to be more readable and easier to fit in my head than long complex jq expressions. But that’s completely subjective and others may find the jq expression language easier to read than shell or (choose your programming language).

[digdugdirk]

Your comment made me go look up jq (even more than the article did) and the first paragraph of the repo [0] feels like a secret club's secret language.

I'm very interested, but not a Linux person, do you know of any good resources for learning the Linux shell as a programming language?

[0] https://jqlang.github.io/jq/

[salmo]

I’ll say, I did shell scripting for years from copy/paste, cribbing smarter people, and reading online guides. But I didn’t really understand until I read The Unix Programming Environment by Brian Kernighan and Rob Pike.

It’s a very old book and the audience was using dumb terminals. But it made me understand why and how. I think I’ve read every Kernighan book at this point and most he was involved in because he is just so amazing and not just conveying facts, but teaching how to think idiomatically in the topic.

I also used awk for 2 decades, kind of like how I use jq now. But when I read his memoir I suddenly “got it.” What I make with it now is intentional and not just me banging on the keyboard until it works. A great middle ground for something a little sophisticated, but not worth writing a full program for.

Something else that helped me was to install a minimal distro… actually a base FreeBSD install would be great… and read the man pages for all the commands. I don’t remember the details, but I learned that things existed. I have many man pages that I look at the same options on every few months because I’m not positive I remember right. Heck, I ‘man test’ all the time still. (‘test’ and ‘[‘ are the same thing)

I also had an advantage of 2 great coworkers. They’d been working on Unix since the 80s and their feedback helped me be more efficient, clean, and avoid “useless use of cat” problems.

I also highly recommend using shellcheck. I sometimes disagree with it when I’m intentionally abusing shell behavior, but it’s a great way to train good habits and prevent bugs that only crop up with bad input, scale, etc. I get new devs to use it and it’s helped them “ramp up” quickly, with me explaining the “why” from time to time.

But yeah. The biggest problem I see is that people think there is more syntax than there really is (like my test and [ comment). And remember it’s all text, processes, and files. Except when we pretend it’s not ;).

[metadat]

Really love your comment, so much that I wanted to check out the books you mentioned.

After searching z-lib for "The UNIX Programming Environment", all I found was a janky and grainy PDF. Then I searched archive.org and discovered this high fidelity PDF version:

https://archive.org/details/UnixProgrammingEnviornment

Note: Sadly, the EPUB version is 10x larger (370MB) and is corrupted, not able to be opened / viewed.

[boneitis]

Much thanks for this. I've been struggling to grasp what's happening down in the engine room beneath me as I operate a modern Linux environment and only knew that there have been different waves of evolutions over the decades. I instead only see today's pretty deck up top, outside.

I'm only ten pages in, but that's mostly because the format and approach of this book is quickly yielding me tons of conversation fodder for ChatGPT4, where I've been endlessly asking it to clarify or point out holes in my mental model of everything I'm doing in the terminal, and still working out things such as why Backspace, Ctrl+H, Ctrl+/, Ctrl+?, Ctrl+-, and Ctrl+_ all together seem to have some overlap or differences in what's happening, depending on terminal contexts. I always had working notions of raw versus cooked sessions, the line discipline, etc., but I'm finding ways to play with the machinery with silly exercises that I otherwise couldn't have come up with.

For example, I just opened up three terminal windows:

  1) `man ascii`
  2) `nc -lvp 9001 | xxd -c1`
  3) `stty raw -echo; nc -nv 127.0.0.1 9001`

Then, reproducing the whole "Hex" column of the manpage, in order, using my keystrokes. And, observing the multi-byte payloads of some of the other keys. I feel like a kid again :)

[pcthrowaway]

> The Unix Programming Environment

How does this compare to The Art of Unix Programming, if you've read both?

[salmo]

I don’t find that book to be very useful at all.

I’m kind of annoyed by the bait and switch of the title. It’s a play on Knuth’s classic but then turns into showing why Unix/Linux is better than Windows, etc.

As a disclaimer: I really don’t respect ESR and his work, and admire Brian Kernighan immensely. Very odd to be in a situation where those names are put side by side. Just want to call out that I do have bias on the people here. Don’t want to get into why as that’s not constructive.

[pcthrowaway]

I wasn't aware of the bait and switch at the time I read it, but I did really enjoy the history of how the Unix/Linux ethic came together and evolved over time. Had I heard of The Unix Programming Environment when I read it in 2014 I may have gone with that instead, as I was looking for something more along the lines of a technical handbook rather than a code of ethics.

[salmo]

Yeah and ESR can be revisionist in his history, projecting intention on something organic. He alienated a lot of people over time with this… and other behavior.

The book I recommended is both a handbook and a “how to think.” It applies forward to things introduced well after the book. But it also helped me understand why the Byzantine behavior of a tty is what it is.

If you are interested in the history from a first person perspective, I do recommend Kernighan’s “Unix: A History and a Memoir”. He went from originally trying to write something objective to realizing it was necessarily his personal experience. Even the culture aspect of his story has influenced how I try to foster teamwork. It was an engaging read for me.

[NortySpock]

So, grab yourself a Linux box (I suggest Debian), a large CSV file or JSON lines file you need to slice up, and an hour of time, and start trying out some bash one-liners on your data. Set some goals like "find the Yahoo email addresses in the data and sort by frequency" or "find error messages that look like X" or "find how many times Ben Franklin mentions his wife in his autobiography"

Here's the thing. These tools have been used since the '70s to slice, dice and filter log files, CSVs, or other semi-structured data. They can be chained together with the pipe command. Sys admins were going through 100MB logs with these tools before CPUs hit the gigahertz

These tools are blisteringly fast, and they are basically installed on every Linux machine.

https://github.com/onceupon/Bash-Oneliner

And for a different play-by-play example:

https://adamdrake.com/command-line-tools-can-be-235x-faster-...

[coldtea]

>Your comment made me go look up jq (even more than the article did) and the first paragraph of the repo [0] feels like a secret club's secret language.

Or one of the most old standing widespread clubs of computing open standard language :)

"jq is like sed for JSON data - you can use it to slice and filter and map and transform structured data with the same ease that sed, awk, grep and friends let you play with text."

Translation:

JQ is like a (UNIX/POSIX staple command line text-manipulation tool) but specialized for text structured in JSON format. You can use it to extract parts of a JSON document (slice), keep nodes based on some criteria (filter), transform each element in a list of structured data to get a new list with the transformed versions (map), and do that as easily as you can with the sed (basic command line text manipulation program), awk (command line text manipulation program with a full featured text-processing oriented language), grep (command line program to search for strings), and other assorted unix userland programs.