Explanation for newbies:

  • Shell is the programming language that you use when you open a terminal on linux or mac os. Well, actually “shell” is a family of languages with many different implementations (bash, dash, ash, zsh, ksh, fish, …)

  • Writing programs in shell (called “shell scripts”) is a harrowing experience because the language is optimized for interactive use at a terminal, not writing extensive applications

  • The two lines in the meme change the shell’s behavior to be slightly less headache-inducing for the programmer:

    • set -euo pipefail is the short form of the following three commands:
      • set -e: exit on the first command that fails, rather than plowing through ignoring all errors
      • set -u: treat references to undefined variables as errors
      • set -o pipefail: If a command piped into another command fails, treat that as an error
    • export LC_ALL=C tells other programs to not do weird things depending on locale. For example, it forces seq to output numbers with a period as the decimal separator, even on systems where coma is the default decimal separator (russian, dutch, etc.).

  • The title text references “posix”, which is a document that standardizes, among other things, what features a shell must have. Posix does not require a shell to implement pipefail, so if you want your script to run on as many different platforms as possible, then you cannot use that feature.

  • smeg@feddit.ukEnglish
    161·
    11 hours ago

    Shell is great, but if you’re using it as a programming language then you’re going to have a bad time. It’s great for scripting, but if you find yourself actually programming in it then save yourself the headache and use an actual language!

      • smeg@feddit.ukEnglish
        14·
        11 hours ago

        Your scientists were so preoccupied with whether they could, they didn’t stop to think if they should

        • Badabinski@kbin.earth
          7·
          10 hours ago

          Honestly, the fact that bash exposes low level networking primitives like a TCP socket via /dev/TCP is such a godsend. I’ve written an HTTP client in Bash before when I needed to get some data off of a box that had a fucked up filesystem and only had an emergency shell. I would have been totally fucked without /dev/tcp, so I’m glad things like it exist.

          EDIT: oh, the article author is just using netcat, not doing it all in pure bash. That’s a more practical choice, although it’s way less fun and cursed.

          EDIT: here’s a webserver written entirely in bash. No netcat, just the /bin/bash binary https://github.com/dzove855/Bash-web-server

    • XIN@lemm.ee
      9·
      11 hours ago

      The few times I’ve used shell for programming it was in strict work environments where anything compiled was not allowed without a ton of red tape.

      • smeg@feddit.ukEnglish
        4·
        11 hours ago

        Wouldn’t something interpreted like python be a better solution?

        • Gork@lemm.ee
          4·
          10 hours ago

          For more complicated input/output file handling, certainly.

          Little shell scripts do great though if all you need to do is concatenate files by piping them.

          It’s like the Internet, it’s not one big truck but a series of tubes.

          • smeg@feddit.ukEnglish
            2·
            8 hours ago

            Yep, in my mind piping together other commands is scripting not programming, exactly what shell scripts are for!

            • Gork@lemm.ee
              2·
              5 hours ago

              With enough regex and sed/awk you might be able to make even complicated stuff work. I’m not a regex guru (but I do occasionally dabble in the dark arts).

    • renzev@lemmy.worldOPEnglish
      101·
      11 hours ago

      Alpine linux, one of the most popular distros to use inside docker containers (and arguably good for desktop, servers, and embedded) is held together by shell scripts, and it’s doing just fine. The installer, helper commands, and init scripts are all written for busybox sh. But I guess that falls under “scripting” by your definition.

      • smeg@feddit.ukEnglish
        2·
        7 hours ago

        No clear line, but to me a script is tying together other programs that you run, those programs themselves are the programs. I guess it’s a matter of how complex the logic is too.