# thumb wheel up => increase volume and unmute
"xdotool key --clearmodifiers XF86AudioRaiseVolume"
   b:6

# thumb wheel down => lower volume
"xdotool key --clearmodifiers XF86AudioLowerVolume"
   b:7

# backward button => previous song
"xte 'key XF86AudioPrev'"
   b:8

# forward button => next song
"xte 'key XF86AudioNext'"
   b:9