Setting up USB sniffing in linux is useful for seeing what is being communicated to/from USB devices. This ability is built into linux. The designer (Bert) gives the steps involved and how to filter it to get the data we desire.

Simply mount debugfs and insmod the usbmon module:

mount -t debugfs none_debugs /sys/kernel/debug
modprobe usbmon

Then you can just cat USB traffic like this:

cat /sys/kernel/debug/usbmon/1u

See all the project: http://biot.com/blog/usb-sniffing-on-linux