On 21 Jan 2023, at 19:27, Clem Cole <clemc@ccc.com> wrote:



On Sat, Jan 21, 2023 at 12:34 PM Warner Losh <imp@bsdimp.com> wrote:
It looks to be a mixed bag in 5th edition. Cc, ac, comm and find all printf the errors. Diff uses writes to fd 2. I didn't catalog further, but this kinda looks like a developing convention, not yet fully realized. .
Fair enough and that makes sense... 

I do remember that pr -p actually read from FD 2. It probably still does.
Very useful to align paper in the printer.

jaap