/usr/bin/script eating 100% cpu with portupgrade and xargs

[Kostik Belousov]

On Sun, Sep 18, 2011 at 02:54:34PM +0300, Mikolaj Golub wrote:
> 
> On Sun, 18 Sep 2011 13:25:26 +0200 Ronald Klop wrote:
> 
>  RK> It is a while since I programmed C, but why will writing 0 bytes give
>  RK> the reader an end-of-file? Shouldn't the fd be closed to indicate
>  RK> end-of-file?
> 
> AFAIR, this trick with writing 0 to emulate EOF because we can't close the fd
> -- we still want to read from it.  Poor shutdown(2) for non-socket :-).
> 
> Colin might tell more...

Please note that interpreting the receiving of 0 bytes on the terminal 
as EOF is only a convention. If done absolutely properly, script shall
not interpret zero-byte read as EOF. Might be, the reasonable thing to
do would be to only look at the stdin once in a second after receiving
zero-bytes, and switching it back to normal mode if something is read.
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