Solved How to Send a Text to Arduino

Hello friends
I've done this before on Linux but apparently I have to do something else on FreeBSD and I couldn't find any articles on the internet and our friends at Matrix couldn't help me. I have connected an arduino to the LCD and I want my FreeBSD IP to be displayed on the LCD. i really need that. When I run this command to prepare the connection port, I get no output on stdout and keep waiting to send an interrupt and exit the process.
exec 3<> /dev/ttyU0
And when I send a text to ttyU0, the arduino just resets. echo $ip > /dev/ttyU0

I have 3 files like ttyU0 :
# ls /dev/ | grep ttyU0
thanks for your help,