I really appreciate your response. I've only used xargs before for tricky pipes and to get the -n 1 feature. I see what you mean about CPU time on this issue, now that I've run it a few times.

If, in a case where I find it does pay off to run the script with multiple tasks, is there a good detailed overview of how the I/O is handled on duped filehandles or between processes? What I've read so far still doesn't explain the 'why it do dat' of my program, and I'd like to fill in the holes in my understanding for future cases.

>If you possibly can, “Jest get ’er done.”
I wish I'd asked sooner. Sometimes it's helpful to be reminded of the goal and not caught up on the implementation details!