[Buildroot] Switching to /dev/ttyX

[Thomas De Schampheleire <patrickdepinguin+buildroot@gmail.com>]

On Fri, Apr 15, 2011 at 2:04 AM, Michael J. Hammel
<buildroot@graphics-muse.org> wrote:
> On Thu, 2011-04-14 at 09:50 +0200, Thomas De Schampheleire wrote:
>> In /etc/inittab, you have e.g.
>> tty1::respawn:/sbin/getty 38400 tty1
>> tty2::respawn:/sbin/getty 38400 tty2
>> tty3::respawn:/usr/bin/tail -f /var/log/messages
>> By default I'm connected to the board on a serial line, e.g. /dev/ttyS0
>> My question is: how can I access the other /dev/tty's?
>
> tty's are controlling terminals for processes. ?They need to be attached
> to a vc (virtual console) to use chvt. ?vc's require a display device,
> like an LCD monitor. ?Not positive 'bout that last part, but its
> something like that. ?You can read more about tty's and related devices
> here: http://tldp.org/HOWTO/Text-Terminal-HOWTO-7.html

Then why are different tty's used? If you specify no tty, the default
/dev/console is used. Isn't that enough? Or maybe that's because these
processes should run in parallel?

Still, there must be some standard way to access tty1 or tty2,
otherwise it seems useless to start a getty there!
Conspy is interesting, but not included in buildroot, so I sense there
should be an easier way...

>
> If you're just looking for multiple terminal sessions to work with you
> can try running "screen" on your serial port connection. ?That will give
> you any number of extra terminal sessions. ?I'm not a screen expert so
> can't say if logins (getty's) are possible on those other screen
> sessions. ?But use of screen on serial port connections is very common
> with embedded development. ?I also use it on my desktop so that
> cross-compiled builds I start at home can be viewed from work by
> attaching the the running screen session. ?Very handy. ?And easy to use.
>
>> 'tty' always shows /dev/ttyS0.
>
> That command only shows the terminal connected to the standard input,
> which would be the one you typed the command on.

Thanks,
Thomas