[racket] fun with ports and (system ..) calls

> When you use `(for/list ((line (in-lines in))) ...)` the `in-lines`
> sequence doesn't end until an EOF is available --- but a line can be
> received anyway, as long as newline is found to terminate the line.

Damn, I'm accumulating here! Subtle but I think I get it now! Sensible behavior but I bet this won't be the last time I trip over it. 

Thanks!