Comment 48 for bug 1368402

because the gui options for "Reverse scroll direction" didnt work...

for those looking to automate setup via .bashrc, or alias, or whatever

here's what i used based on suggestions above... I have Kensington Orbit Wireless Trackball...
This way, regardless if id changes, i'm grepping and awking that number...
I have no idea what the "8 1" options are...

xinput --set-int-prop $(xinput list | grep "MOSART Semi. Orbit" | awk '{print $9}' | tr -d 'id=') "libinput Natural Scrolling Enabled" 8 1

so seems to work great for me...