Didier Kryn <kryn@???> writes:
> Le 08/03/2016 17:32, dev a écrit :
>>
>> $ ls -l /dev/tty[1-6]
>> crw--w---- 1 root tty 4, 1 Mar 8 08:08 /dev/tty1
>> crw--w---- 1 root tty 4, 2 Mar 8 10:09 /dev/tty2
>> crw--w---- 1 root tty 4, 3 Mar 8 08:08 /dev/tty3
>> crw--w---- 1 root tty 4, 4 Mar 8 08:08 /dev/tty4
>> crw--w---- 1 root tty 4, 5 Mar 8 08:08 /dev/tty5
>> crw--w---- 1 root tty 4, 6 Mar 8 08:08 /dev/tty6
>

>     A device write-only for group looks strange.

Not really. That's what you get when running mesg y in a used tty so
that other people cane use write(1) to send message to you but not read
from your terminal.