On Thu, 2 Oct 2025 23:46:30 +0200, Mike Jonkmans wrote:
> > On Tue, 23 Sep 2025 05:07:18 +0200 (CEST), Pourko wrote:
> > > On Thu, 18 Sep 2025 15:26:16 -0400 Chet Ramey wrote:
> > > > There isn't a good way for a shell script to determine whether or not
> > > > it's in the foreground or background, and whether it is in the same
> > > > process group as the terminal.
> > > 
> > > Attached is the patch that does it.
> > > [...]
> > > Now...
> > > [ -t 0 ] && [ ! -T 0 ]
> > > ...means we are running in the background.
> 
> It is not a common case.
> 
> Can't that check be done with something like:
>         trap '' SIGTTIN
>         if read -rd '' -n 0; then
>                 echo Foreground
>         else
>                 echo Background
>         fi
>         trap SIGTTIN

To my surprise, and contrarily to what Chet said (above), yes, one could do 
a check the way you suggested, and it works. But I will use Chet's words to 
wiggle my way out by making a distinction between "a way" and "a good way".
I still feel that [ -T 0 ] is a useful thing to have.

Best regards,
Pourko



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