xinput listで、タッチパッドのidを調べます。
$ xinput list
⎡ Virtual core pointer id=2 [master pointer (3)]
⎜ ↳ Virtual core XTEST pointer id=4 [slave pointer (2)]
⎜ ↳ System mouse id=6 [slave pointer (2)]
⎜ ↳ GlidePoint id=11 [slave pointer (2)]
⎜ ↳ Logitech USB Receiver id=13 [slave pointer (2)]
⎣ Virtual core keyboard id=3 [master keyboard (2)]
↳ Virtual core XTEST keyboard id=5 [slave keyboard (3)]
↳ System keyboard multiplexer id=7 [slave keyboard (3)]
↳ Power Button id=8 [slave keyboard (3)]
↳ Sleep Button id=9 [slave keyboard (3)]
↳ AT keyboard id=10 [slave keyboard (3)]
↳ Logitech USB Receiver
ここでは、11番につながっているので、11番をoffにします
$ xinput set-prop 11 "Device Enabled" 0