Awesome guide - my throughts following it:
step 1
gunzip ./raven-2.1.1-arm-linux-gnueabihf.tar.gz
gunzip didn't work for me just left me with raven-2.1.1-arm-linux-gnueabihf.tar
I ended up using: tar -xvzf raven-2.1.1-arm-linux-gnueabihf.tar.gz
step 3
Ravend - should be ravend