/dev/Arduino

I noticed that if I unplugged Arduino from my Ubuntu-box and then plugged it back, the /dev name for Arduino changed from /dev/ttyUSB0 to /dev/ttyUSB1. Fortunately this was easy to fix. The problem was solved by adding a file 97-arduino.rules in /etc/udev/rules.d/ and adding the following rule (all in one line):

kernel=="ttyUSB*", SYSFS{idVendor}=="0403", 
SYSFS{idProduct}=="6001", 
SYMLINK="Arduino"

So now I can always trust that Arduino is in /dev/Arduino. If you have two Arduinos,you can use serial numbers in order to recognize them (see link below).

Original source:
http://www.arduino.cc/playground/Linux/Udev