How to pipe stderr to a command in Bourne or Korn shell

[Dan Bernstein]

In article <1990Oct8.204053.15797 at athena.mit.edu> jik at athena.mit.edu (Jonathan I. Kamens) writes:
>   In csh, one possible way to do it (when working at a tty) would be:

But who said there's a tty around? What if Pim wanted to pipe his output
through yet another command?

> A similar approach will work in sh (and probably ksh), although there's
> probably some better way to do it with various hideous file descriptor
> reassignments (I don't use the bourne shell a lot, so I don't qualify to
> invent hideous file descriptor reassignments :-):

I use the bourne shell a lot, so I guess I qualify. It isn't too
hideous, though, if you write it clearly:

  ( exec 5>&1; exec 1>&2; exec 2>&5; foo ) | err-processor

Even you :-) should be able to recognize the swap idiom there. Start
from basic constructs like this and soon you'll be piping stdout and
stderr through separate commands. Someday you may even learn to use
multitee... [grin]

---Dan