- cross-posted to:
- shell@programming.dev
- cross-posted to:
- shell@programming.dev
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@zephyr
echo "${HOME}/docs"This is the best way. It’s also the way the Shellcheck
wantssometimes recommends.This isn’t true. Shellcheck doesn’t insist on braces unless it thinks you need them.
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.zinstead 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 inarray, rather than (Bash:) the number of positional parameters, then the string'array[3]'.
I will always write
${x}_$y.zinstead of${x}_${y}.z:The difference between the two seems different to what’s in the OP. Is there a typo here?
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"$HOME"/docs). Many people prefer to always include braces around the parameter name out of consistency, instead of only when they are required.My comment explained why my habit is to only include braces when they are necessary.
- Syntax highlighting and shellcheck have always caught the cases I need to add braces to prevent
find “$(echo $HOME > variable_holder.txt && cat variable_holder.txt)/$(cat alphabet.txt | grep “d”) $(cat alphabet.txt | grep “o”)$(cat alphabet.txt | grep “c”)$(cat alphabet.txt | grep “s”)”
This is the easiest method
@ilega_dh You don’t need
catin cases whengrep "d" alphabet.txtcan read from file too. Edit: But obviously your comment was more of a joke to over complicate it. So never mind then.To be safe, should probably output grep to a file, then cat that.
What should I search to better understand what is written here? Don’t mind learning myself, just looking for the correct keywords. Thanks!
This comment is a joke and you wouldn’t want to do it like that in reality, but here are some related keywords you could look up: “Unix cat”, “Unix pipeline”, “grep”, “output redirection”, “command substitution”.
First one, then the other, then I forget the quotes, then I put them in single quotes by accident, then I utilize that “default value” colon syntax in case I’m missing HOME , then I just stick to ~ for the rest of the file.
Typically
find "$HOME/docs", but with a few caveats:-
In Zsh or Fish, the quotes are unnecessary:
find $HOME/docs -
If I’m using anything potentially destructive:
mv "${HOME:?}/bin" ... -
Of course, if it’s followed by a valid identifier character, I’ll add braces:
"${basename}_$num.txt"
-
