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bug#18808: implement 'tail -r' as synonym for 'tac'
From: |
Bernhard Voelker |
Subject: |
bug#18808: implement 'tail -r' as synonym for 'tac' |
Date: |
Fri, 24 Oct 2014 08:11:11 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.1.0 |
On 10/24/2014 12:52 AM, Eric Blake wrote:
> On 10/23/2014 03:59 PM, Pádraig Brady wrote:
> [...]. So among existing POSIX-certified systems, 'tail -r' is
> the more popular extension at the moment.
>
>> Saying that, I'm 50:50 for implementing `tail -r` for compat reasons.
>
> Yes, this alone is reason enough to implement it in GNU, regardless of
> the direction POSIX takes.
I'm also worried about such an extension. 'tail -r' might be a useful
thing - when -r is the only option being used, but looking at all the
other options GNU tail already got over the years, adding -r doesn't
fit well. You proposed to make -n available to tac and then jump into
it from 'tail -r'. Well, what about -c? --follow={name|descriptor}?
--retry, --pid=PID? To make -r fit well into tail, we'd have to add
every single feature of it to tac. This sounds not like a good idea.
tail does a good job, and so does tac. I'd almost prefer to fork+pipe
internally instead, similar to what e.g. 'sort --compress-program=PROG'
does.
Have a nice day,
Berny