/dev/xcons

[George Robbins]

In article <TROST.91Jun24181628 at brahma.reed.edu> trost at reed.edu writes:
> 
>     > # Direct console output to /usr/adm/messages
>     > tail -f /dev/xcons >>/usr/adm/messages &
> 
>     I think tail depends on seeing the file size change or some other clue
>     that data has been appended to a file.  I don't know that it can be
>     expected to do anything meaningful on a character device.
> 
> (Probably) untrue -- the sources for 4.3 BSD indicate that tail just
> sleeps a second and then read(2)s BUFSIZ bytes from stdin.  Of course,
> it only does that if the lseek(2) above doesn't return an EISPIPE --
> which may or may not occur on the xcons pseudo-device.
> 
> A more compelling argument is that we use "xterm -e tail -f
> /dev/xcons" to redirect our console output, and it works fine.  This
> is Ultrix 4.1, though -- maybe somebody "fixed" something (somehow,
> getting, EISPIPE *does* make sense...).

Well, I don't have any problem with your source reading or logic, but
I would claim that in this case tail isn't going to do anything for
you that cat doesn't.  8-)

-- 
George Robbins - now working for,     uucp:   {uunet|pyramid|rutgers}!cbmvax!grr
but no way officially representing:   domain: grr at cbmvax.commodore.com
Commodore, Engineering Department     phone:  215-431-9349 (only by moonlite)