Re: Close *all* file descriptors

[Zach Riggle <zachriggle@gmail.com>]

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Unfortunately, macOS does not support proofs, so there’s no nice way to do
it the way you recommended.

I can just force-close the first 1024 file descriptors that I don’t care
about, and hope that it’s sufficient.

On Sat, May 21, 2022 at 3:02 PM Bart Schaefer <schaefer@brasslantern.com>
wrote:

> On Fri, May 20, 2022 at 11:32 PM Zach Riggle <zachriggle@gmail.com> wrote:
> >
> > This is probably an usual request, but is there any way to close (or
> redirect to /dev/null) all open file descriptors known / opened by zsh?
>
> I expected this to work if you have /proc/:
>
> opened=(/proc/self/fd/*(:t)) wanted=(0 1 2 10)
> for close in ${^${opened:|wanted}}; exec {close}>&-
>
> But zsh temporarily opens a file descriptor (for xtrace output, I
> believe) during the assignment to $opened, and it's not possible to
> predict what number that descriptor will have, which means one of
> those exec is going to error on bad file descriptor and kill the loop.
>
> So ... the following seems to be pretty good, though on repeated tries
> I have sometimes seen descriptors remain open:
>
> integer close
> for close in /proc/self/fd/*(:t); [[ -h /proc/self/fd/$close && ! -t
> $close ]] && exec {close}>&-
>
> > Is there a way to close all of them in a concise way that does not
> affect e.g. shell pipelines and redirection (i.e., stdout and stderr)?
>
> No guarantees about that.  If there are descriptors open for temporary
> files, etc., that are needed by coproc or whatever, this could break
> it.
>
-- 

*Zach Riggle*

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