/dev/xcons

[trost at reed.edu]

    > # 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...).