Re: es %dup

[Scott Schwartz <schwartz@groucho.cs.psu.edu>]

| now it seems to me like this is wrong:  that is, in these examples, stdin (fd 0)
| is owned by the shell and it shouldn't be touched by the user.

My intuition is that that's too restrictive a position.  I also think
that most shells are not very good at dealing with file descriptors.
For instance, if you had a way to ask for an unused descriptor, you
wouldn't have to worry about colliding with ones that are already in
use.  In other words, if you are going to muck with descriptors,
functionality like that of tcl or perl is prefereable to that of sh.
Es could easily provide that functionality.  That would make it
better than ksh for dealing with coroutines.