Spyke
IanTwenty
piefed.social

$() for me, to quote from

https://www.shellcheck.net/wiki/SC2006

Backtick command substitution `...` is legacy syntax with several issues.

  1. It has a series of undefined behaviors related to quoting in POSIX.
  2. It imposes a custom escaping mode with surprising results.
  3. It's exceptionally hard to nest.

$(...) command substitution has none of these problems, and is therefore strongly encouraged.

18
confusedpuppyreply
lemmy.dbzer0.com

Shellcheck is a great tool for scripting.

When I'm building a new script, I usually add the following function to the script and run the function before anything else. The script will exit immediately if any issues are found so I have a chance to correct things. If no issues are found, the script will simply continue.

It's small and simple so it's easy to remove when I'm done building a script.

script_check() {
    if ! shellcheck "${0}"; then
        exit 1
    fi
}

script_check

Shellcheck has helped me learn a lot about scripting and I strongly recommend using it too.

4
IanTwentyreply
piefed.social

That's good. There are also editors that can run it for you and highlight the issues whilst you type, neovim being one.

5
nousreply
programming.dev

Why wrap it in a function at all? Why not just put the if at the top of the file?

3
trevor (he/they)reply
lemmy.blahaj.zone

I prefer this as well, but just adding that Fish also supports $() for those that don't know.

I keep hearing people that haven't used modern versions of Fish say that it's somewhat different from Bash and strays from POSIX compatibility quite a bit. While the latter is true, Fish has added many bash-isms over the years, so most scripting idioms you're familiar with will work there too.

2
excess0680
lemmy.world

By some sheer coincidence, I searched this topic today. I’ve been a consistent user of the parenthesis expansion, but never thought of why I preferred one or the other.

I suppose the primary advantage is that $() will expand in a consistent way. You can even nest quotes and more expansions in one, while you’d struggle the same with backtick notation.

So I’ll just keep using parentheses.

3

You reached the end

Which command substitution do you prefer in shell scripts: backquotes `` or $() syntax? | Spyke