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From: Erwan Legrand <freebsd@erwanlegrand.com>
Date: Thu, 28 Sep 2017 10:26:55 +0200
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Subject: Re: Possible bug in tail(1)
To: Matthias Apitz <guru@unixarea.de>, list@museum.rain.com, 
 FreeBSD Questions <freebsd-questions@freebsd.org>
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On Wed, Sep 27, 2017 at 10:28 PM, Matthias Apitz <guru@unixarea.de> wrote:
> The essence of the issue seems to be if tail(1) is reading a file/stdin
> or a pipe:
>
> $ cat foor
>
> 3
> 2
> 1
> $ tail -r foor
> 1
> 2
> 3
>
> $ tail -r < foor
> 1
> 2
> 3
>
> $ cat foor | tail -r
> 1
> 2
>
> 3

This works for me with 11.0-RELEASE-p12:

[erwan@melkor  /tmp]% cat foor

3
2
1
[erwan@melkor  /tmp]% tail -r foor
1
2
3

[erwan@melkor  /tmp]% cat foor | tail -r
1
2
3

[erwan@melkor  /tmp]% type tail
tail is /usr/bin/tail


But then, I use zsh, not bash.