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Re: The difference between `X=x f | cat` and `{ X=x; f; } | cat`


From: alex xmb ratchev
Subject: Re: The difference between `X=x f | cat` and `{ X=x; f; } | cat`
Date: Thu, 19 Jan 2023 18:37:18 +0100

On Thu, Jan 19, 2023, 6:36 PM Kerin Millar <kfm@plushkava.net> wrote:

> On Thu, 19 Jan 2023 10:53:42 -0500
> Greg Wooledge <greg@wooledge.org> wrote:
>
> > On Thu, Jan 19, 2023 at 03:49:06PM +0000, Kerin Millar wrote:
> > > time for ((i=0; i < 1000; i++)); do X=x f | cat >/dev/null; done
> > > time for ((i=0; i < 1000; i++)); do { X=x; f; } | cat >/dev/null; done
> > >
> > > Obviously, you may need to tune the number of iterations in order to
> incur an acceptably substantive wall time.
> >
> > I'd also move the >/dev/null outside the loop.  You're adding 1000x
> > the number of times it takes to make that system call to the execution
> > times, which might distort things a tiny bit.
>
> I posted it so deliberately but, now that you mention it, I'm not entirely
> sure what I was thinking. A sterling observation then.
>

lol

>
> --
> Kerin Millar
>

xmb

>


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