Re: Threaded versions of cp, mv, ls for high latency / parallel filesystems?

[Andrew McGill]

On Thursday 13 November 2008 14:52:44 Ralf Wildenhues wrote:
> Hello Andrew,
>
> Andrew McGill <list2008 <at> lunch.za.net> writes:
> >     find -type f -print0 |
> >         xargs -0 -n 8 --max-procs=16 md5sum >& ~/md5sums
> >
> >     sort -k2 < md5sums > md5sums.sorted
>
> To avoid losing output, use append mode for writing:
>      : > ~/md5sums
>
>      find -type f -print0 |
>          xargs -0 -n 8 --max-procs=16 md5sum >> ~/md5sums 2>&1
>
>      sort -k2 < md5sums > md5sums.sorted
>
> This just recently came up in Autoconf:
> <http://thread.gmane.org/gmane.comp.shells.bash.bugs/11958>
Ah!  I see!  So without O_APPEND, things don't work quite right.

At the risk of drifting off topic - is there ever a benefit in the shell 
implementing a ">"-redirection with just O_TRUNC , rather than O_TRUNC | 
O_APPEND ?   Does the output process ever need to seek() back in stdout?  (If 
this off topic, please feel free to flame me, and/or direct me to the correct 
forum -- but I did freely send a bug report to the bash folks, even though 
I'll bet they're not alone in omitting O_APPEND with O_TRUNC).

&:-)