[TUHS] etymology of read -u

Dan Cross crossd at gmail.com
Wed Jun 1 01:57:01 AEST 2016

I asked Jeff Korn (David Korn's son), who in turn asked David Korn who
confirmed that 'read -u' comes from ksh and that 'u' stands for 'unit'.

        - Dan C.
Yes, indeed. He says:

*I added -u when I added co processes in the mid '80s.  The u stands for
unit.  It was command to talk about file descriptor unit at that time.*

On Tue, May 31, 2016 at 6:06 AM, Dan Cross <crossd at gmail.com> wrote:

> Hey, did your dad do `read -u`?
> ---------- Forwarded message ----------
> From: Doug McIlroy <doug at cs.dartmouth.edu>
> Date: Tue, May 31, 2016 at 3:27 AM
> Subject: [TUHS] etymology of read -u
> To: tuhs at minnie.tuhs.org
> What's the mnmonic significance, if any, of the u in
> the bash builtin read -u for reading from a specified
> file descriptor? Evidently both f and d had already been
> taken in analogy to usage in some other commands.
> The best I can think of is u as in "tape unit", which
> was common usage back in the days of READ INPUT TAPE 5.
> That would make it the work of an old timer, maybe Dave Korn?
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