From: Alex Young <alex@...>
Date: 2007-02-22T19:13:16+09:00
Subject: Re: ruby tail

benjohn@fysh.org wrote:
>> Kevin Jackson wrote:
>>>> Actually, I am not sure how this would work.  If I do this, I get no
>>>> output from the file:
>>>>
>>>> `tail -f sim.out`
>>>>
>>>> So there is something basic I am missing here.  Any help?
>>> it shells out to the process and waits for it to return - with -f does
>>> tail ever return? if not you may not be able to use it - AFAIK ` and
>>> exec are the same - someone with better ruby knowledge may be able to
>>> offer a solution - perhaps using threads or something
>> Use IO.popen:
>>
>> IO.popen('tail -f sim.out'){|f|
>> 	while line = f.gets
>> 		p line
>> 	end
>> }
> 
> Out of interest, the blocking call is "gets" here, right? Can you use
> Kernel.select on a bunch of those handles?
> 

I haven't ever done that, but it looks like it from the docs...

-- 
Alex