this post was submitted on 26 Aug 2023
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How do you shell expand your variables and why? (lemmy.world)
submitted 1 year ago by [email protected] to c/[email protected]
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[–] [email protected] 3 points 1 year ago (2 children)

This has never stuck with me, and I hadn't thought about why until now. I have two reasons why I will always write ${x}_$y.z instead of ${x}_${y}.z:

  • Syntax highlighting and shellcheck have always caught the cases I need to add braces to prevent $x_ being expanded as ${x_}.
  • I write a lot of Zsh. In Zsh, braces are optional in way more cases. "$#array[3]" actually prints the length of the third item in array, rather than (Bash:) the number of positional parameters, then the string 'array[3]'.
[–] [email protected] 3 points 1 year ago

@gamma I just use them out of consistency and principle, so I don't need to think in which case it is required or not.

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

I will always write ${x}_$y.z instead of ${x}_${y}.z:

The difference between the two seems different to what's in the OP. Is there a typo here?

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

in the OP

My reply is to a commenter who said they prefer "${HOME}/docs" over both options in the original image ("$HOME/docs" or "$HOME"/docs). Many people prefer to always include braces around the parameter name out of consistency, instead of only when they are required.

My comment explained why my habit is to only include braces when they are necessary.