Re: read with redirected stdin

[Pier Paolo Grassi <pierpaolog@gmail.com>]

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thanks Bart for this explanation and the solution, I wasn't so sure how to
explain what I was looking for because I was missing this mechanic.

Pier Paolo Grassi


Il giorno mar 10 gen 2023 alle ore 03:46 Bart Schaefer <
schaefer@brasslantern.com> ha scritto:

> On Mon, Jan 9, 2023 at 2:47 PM Jim <linux.tech.guy@gmail.com> wrote:
> >
> > I haven't seen anything that shows ttys pointing to a process. It may
> exist, but I don't
> > know where you would find it if it does. I just know that processes
> attach tty devices
> > via file descriptors on Linux and Unix systems.
>
> Although the foregoing is correct, once a process is attached to a tty
> the corresponding descriptor can be closed or duplicated without
> detaching the process from the tty again.  All descendants of that
> process form a "process group" (unless one of them explicitly takes
> over as a new "group leader") and all processes in a group are
> eligible to receive signals such as INT and QUIT and TSTP generated by
> the terminal (usually by keyboard interaction).
>
> So Pier wants to know what tty is associated with the current
> process's group, not what tty may be performing i/o with any of the
> currently open descriptors.  The simplest way to do that is to use the
> coreutils "tty" command:  tty < /dev/tty
>

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