Also, the last time I tried, to do similar with FIFOs (no /tmp | whatever storage like other e.g.s here https://news.ycombinator.com/item?id=37211687), GNU parallel needed some - for me - specially compiled Perl interpreter with threads enabled to use its `parcat` program which is also probably slow. Besides the nagware insanity, `parallel` seems just not a very compelling tool in either machine|human overheads unless -- maybe -- you already know Perl (which I always found a supremely forgettable language).