Are you searching ‘iPod music transfer‘ on Google?
Well it’s exactly what I did in the last 2 hours and I’ve finally found a free software in order to transfer music from my iPod to a folder on my Mac (OS X El Capitan)
PodTrans (download link)
Be sure you download PodTrans and not AnyTrans, because PodTrans is free and it has no limits.
I tried Senuti, but the free version transfers only 1000 mp3.