can an arduino code be retreveid ?

You'll need to run something like this:

avrdude -b 19200 -c stk500 -p m168 -P /dev/ttyUSB0 -U flash:r:saved.hex:i -vvv

This assumes you at an ATmega168 chip (m168) and have it connected to /dev/ttyUSB0.

Most likely you'll need to make some adjustments.