Thanks for the answer,

It could be an intentional change, but compared with the previous version
or bash the behavior is quite different, and it can cause issues with
several scripts.
Also, I didn’t find the change in behavior listed in the changelog for 5.9,
so it may be a new bug or regression.

I just use that line to define my PROMPT and I can easily update, but I
worry that the change could be more troublesome for other packages or
automation scripts.

On Mon, Jun 20, 2022 at 4:54 PM Stephane Chazelas <stephane@chazelas.org>
wrote:

> 2022-06-20 15:32:32 -0300, Paulo Diovani:
> [...]
> > In version 5.9 the [[ ]] operator is behaving unexpectedly for the
> > following case:
> >
> > $ watch ls &
> > $ [ $(jobs -l | wc -l) -gt 0 ] && echo jobs found || echo no jobs
> > jobs found
> > $ [[ $(jobs -l | wc -l) -gt 0 ]] && echo jobs found || echo no jobs
> > no jobs
> [...]
>
> While I agree that looks like a bug (the output of jobs seems to
> be empty when the command substitution is expanded inside
> [[...]] or ((...)) or a[$(jobs)]=... at least in my tests), a
> better approach here would be to use:
>
> if (( $#jobstates > 0 )); then
>   echo jobs found
> else
>   echo no jobs
> fi
>
> --
> Stephane
>


-- 
Paulo Diovani Gonçalves,
blog.diovani.com / @paulodiovani <http://twitter.com/paulodiovani>