this post was submitted on 15 Jan 2025
565 points (98.5% liked)

linuxmemes

21826 readers
1356 users here now

Hint: :q!

Sister communities:

Community rules (click to expand)

1. Follow the site-wide rules

2. Be civil
  • Understand the difference between a joke and an insult.
  • Do not harrass or attack members of the community for any reason.
  • Leave remarks of "peasantry" to the PCMR community. If you dislike an OS/service/application, attack the thing you dislike, not the individuals who use it. Some people may not have a choice.
  • Bigotry will not be tolerated.
  • These rules are somewhat loosened when the subject is a public figure. Still, do not attack their person or incite harrassment.
    • 3. Post Linux-related content
  • Including Unix and BSD.
  • Non-Linux content is acceptable as long as it makes a reference to Linux. For example, the poorly made mockery of sudo in Windows.
  • No porn. Even if you watch it on a Linux machine.
    • 4. No recent reposts
  • Everybody uses Arch btw, can't quit Vim, <loves/tolerates/hates> systemd, and wants to interject for a moment. You can stop now.
    •  

    Please report posts and comments that break these rules!

    Important: never execute code or follow advice that you don't understand or can't verify, especially here. The word of the day is credibility. This is a meme community -- even the most helpful comments might just be shitposts that can damage your system. Be aware, be smart, don't fork-bomb your computer.

    founded 2 years ago
    MODERATORS
    poopsmith
    zephyr
    rtxn
    565
    My heart goes out to shell programmers who have to support posix sh (lemmy.world)
    submitted 1 day ago by renzev to c/linuxmemes
    95 comments fedilink hide all child comments
     

    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.

    (page 2) 45 comments
    sorted by: hot top controversial new old
    [–] Phoenix3875 9 points 1 day ago (1 children)

    A lot of people call set -euo pipefail the "strict mode" for bash programming, as a reference to "use strict"; in JavaScript.

    In other words, always add this if you want to stay sane unless you're a shellcheck user.

    [–] [email protected] 9 points 1 day ago

    People call set -euo pipefail strict mode but, it's just another footgun in a language full of footguns. Shellcheck is a fucking blessing from heaven though. I wish I could forcibly install it on every developer's system.

    [–] [email protected] 5 points 1 day ago (2 children)

    I have written 5 shell scripts ever, and only 1 of them has been more complex than "I want to alias this single command"

    I can't imagine being an actual shell dev

    [–] marcos 4 points 1 day ago (1 children)

    only 1 of them has been more complex than “I want to alias this single command”

    I have some literal shell aliases that took me hours to debug...

    [–] [email protected] 1 points 1 day ago (1 children)

    I do not envy you.

    [–] marcos 3 points 1 day ago

    Nah, it's in the past.

    But people, if you are writing a command that detects a terminal to decide to color its output or not, please add some overriding parameters to it.

    [–] [email protected] 1 points 1 day ago

    It really isn't bad especially if you use ash

    [–] [email protected] -1 points 21 hours ago* (last edited 18 hours ago) (3 children)

    just use python instead.

    • wrap around subprocess.run(), to call to system utils
    • use pathlib.Path for file paths and reading/writing to files
    • use shutil.which() to resolve utilities from your Path env var

    Here's an example of some python i use to launch vscode (and terminals, but that requires dbus)

    
from pathlib import Path
from shutil import which
from subprocess import run

def _run(cmds: list[str], cwd=None):
    p = run(cmds, cwd=cwd)

    # raises an error if return code is non-zero
    p.check_returncode()

    return p

VSCODE = which('code')
SUDO   = which('sudo')
DOCKER = which('docker')

proj_dir = Path('/path/to/repo')

docker_compose = proj_dir / 'docker/'

windows = [
  proj_dir / 'code',
  proj_dir / 'more_code',
  proj_dir / 'even_more_code/subfolder',
]
for w in windows:
  _run([VSCODE, w])

_run([SUDO, DOCKER, 'compose', 'up', '-d'], cwd=docker_compose)
    load more comments (3 replies)
    [–] [email protected] -1 points 1 day ago (3 children)

    #!/usr/bin/python

    load more comments (3 replies)
    load more comments
    view more: ‹ prev next ›