Re: Possible bug with grep/sed/tail?

[Matthew Wakeling]

On Thu, 20 Nov 2008, David Corlette wrote:
> Hello there,

Wow, that's quite a cross-post you have there.

> Thoughts?  Is there some limitation of which I am not aware that 
> prevents this from working?  Where does the data go in case D?

It's all to do with buffering. The data is being held in a buffer, and not 
being flushed to the next stage of the pipeline. You see, the middle 
process can only see its stdin and stdout, and neither are terminals, so 
it reverts to an efficient mode of operation of not bothering to flush its 
output buffers. If you could tell the middle processes that they are 
actually outputting to an interactive terminal, then they would flush the 
output as soon as they generate it.

Is there currently a way to do that? This problem has certainly caught me 
out in the past (admittedly about ten years ago).

Matthew

--
To most people, solutions mean finding the answers. But to chemists,
solutions are things that are still all mixed up.