First, if cat is slower than redirection from file (<file) - then I'd say something is amiss. But more to the point - I think it's really a bug that tools like gzip, grep, awk etc work on files at all. We do need a tool to feed files to pipes (I think cat is a fine candidate for that - also when we only con-cat-enate one file (the identity cat, if you will).

Maybe there are cases where a long string of awk|something|other|sort|uniq is not the problem, but forking an extra process for cat is.

And maybe there's a mismatch between pipes, files and mmap today. Splice seems like a reasonable fix (if we splice all the things, awk, grep etc).

Finally, I just think:

  cat input.txt \
   | filter1 args \
   | filter2 args \
   | reduction \
   | ouput-formater

Reads better than having to tack on an <input.txt at the end, or special-case the first filter to be (... And also open a file).