Re: [bash 4] 'test -v 1' is never true

[Alejandro Colomar]

On 11/27/22 14:10, David wrote:

On Mon, 28 Nov 2022 at 00:01, Alejandro Colomar <alx.manpa...@gmail.com> wrote:

On 11/27/22 12:41, Alexey wrote:

On 2022-11-26 21:45, Alejandro Colomar wrote:

I could suggest you to use for clarity another construction:
[[ ${1+isset} ]] || echo "not set"

Here "isset" is just for readability. You could place any other string literal
there.

I actually find that very confusing.  What feature is it using?  I couldn't find
it with `info bash | less` then `/\+`.

See:
https://www.gnu.org/software/bash/manual/bash.html#Shell-Parameter-Expansion
- Under heading: ${parameter:+word}
- The parameter is 1
- The word is isset
- The colon ':' is optional, explained by the sentences beginning with
"Omitting the colon" ..

Thanks!

Cheers,

Alex


--
<http://www.alejandro-colomar.es/>

Ahh, it was the optional-ness of ':' that bugged me. I'm also quite unaccustomed to [[ expr ]]. :)

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