It is assumed that the MBED device is mounted at /media/MBED. This is the case for the machines at The University of Essex.
Download mbed-watcher.sh.
Give it execute permissions if needed.
chmod +x mbed-watcher.sh
Run the script.
./mbed-watcher.sh
Use GTKTerm (Serial Port Terminal).
Choose port /dev/ttyACM0 (this may vary for systems not at The University of Essex).