cmd_runner contains a simple Arduino program that listens to commands sent over the serial/USB connection. The main command is ‘reset’ which will initate a reset procedure by switcing a servo. See the source of cmd_runner for details.
Install the Arduino IDE on Linux via
$ apt-get intall arduino
and then run ‘arduino’ from the command line. This will open the Arduino IDE where you can open the cmd_runner program.
Attach the Arduino board and upload the program. See https://www.arduino.cc/ for more documentation.
The Servo shield requires the Adafruit PWM Servo Driver Library
Download the release from GitHub, extract it and rename the folder to Adafruit_PWMServoDriver. Then, place it in the libraries folder of your Arduino IDE installation. Restart the IDE.