Arduino resets on every connection from Ubuntu

[JamesNewton]

If you don't use the Dynamixel Shield, and so just communicate on the programming port, under Ubuntu, every echo or write of data to the port /dev/ttyACM0 is a new connection and the hardware for programming does a reset. This, of course, prevents anything from working for the long term.

Possible fixes:

• Use a script to start a cat from the port to a file, and then pickup returned data from that file instead of directly from the port. This would also make it easier to sequence sending a request, and then getting the result.
• Use a port watcher script to transfer data from the port to stdin, stdout. I'm told that screen can be setup to do that in the background, with another call to screen in the foreground passing data to that thread for transmission.

[JamesNewton]

Easy hardware fix: Add a 10uF capacitor between the reset pin and the ground pin. OR add a 100 ohm resistor between the reset pin and the +5 pin.
https://forum.arduino.cc/t/stop-reboot-on-serial-connection-how/370507