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From: Roman Perepelitsa <roman.perepelitsa@gmail.com>
To: Pier Paolo Grassi <pierpaolog@gmail.com>
Cc: Zsh-Users List <zsh-users@zsh.org>
Subject: Re: read with redirected stdin
Date: Sat, 7 Jan 2023 14:44:11 +0100	[thread overview]
Message-ID: <CAN=4vMo5EJTiExmGxt2cxD2=_5PC0b=NCSEdZQRda+kvshg2=Q@mail.gmail.com> (raw)
In-Reply-To: <CAP+y1xBo2fS--G8k+PbwEwJJx2d_s7ZxAJWrTNTJpE+MBB2x2w@mail.gmail.com>

On Sat, Jan 7, 2023 at 2:32 PM Pier Paolo Grassi <pierpaolog@gmail.com> wrote:
>
> Hello, I have a script that asks to create a target dir if it doesn't exist.
> to that extend I inserted an
> read -k1
> in the script.
> To be able to ask the user for confirm even when the script stdin is connected to a pipe I did
> read -k1 < /dev/tty

Note that this redirect doesn't affect `read -k1`. It'll read from the
terminal either way.

You can do something like this in your script:

  if [[ -r $TTY ]]; then
    read -k1
  else
    read -k1 -u0
  fi

There is a corner case when you log in as root and then su to a
non-privileged user. $TTY won't be readable even though the process
has a TTY. Since you are redirecting stdin anyway, this corner case
shouldn't affect you.

Roman.


  reply	other threads:[~2023-01-07 13:45 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-07 13:31 Pier Paolo Grassi
2023-01-07 13:44 ` Roman Perepelitsa [this message]
2023-01-07 17:21   ` Pier Paolo Grassi
2023-01-07 17:31     ` Roman Perepelitsa
2023-01-07 17:36       ` Pier Paolo Grassi
2023-01-07 17:52         ` Roman Perepelitsa
2023-01-08 13:23       ` Daniel Shahaf
2023-01-08 13:48         ` Roman Perepelitsa
2023-01-08 14:21           ` Daniel Shahaf
2023-01-08 14:42             ` Roman Perepelitsa
2023-01-07 17:33     ` Pier Paolo Grassi
2023-01-08  4:28     ` Jim
2023-01-08  4:44       ` Pier Paolo Grassi
2023-01-08 21:18         ` Jim
2023-01-09 16:01           ` Pier Paolo Grassi
2023-01-09 22:47             ` Jim
2023-01-10  2:46               ` Bart Schaefer
2023-01-10  6:03                 ` Pier Paolo Grassi
2023-01-08 14:44       ` Ray Andrews
2023-01-08 15:06         ` Roman Perepelitsa
2023-01-08 20:23           ` Ray Andrews

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