xinput list
...
⎜   ↳ TPPS/2 IBM TrackPoint                     id=15   [slave  pointer  (2)]
⎜   ↳ SynPS/2 Synaptics TouchPad                id=13   [slave  pointer  (2)]

xinput set-prop 15 "Device Enabled" 1
xinput set-prop 13 "Device Enabled" 1

xinput set-prop 15 "Device Enabled" 0
xinput set-prop 13 "Device Enabled" 0

#!/bin/bash
id=$(xinput | grep -i "TouchPad" | cut -f 2 | cut -d= -f 2)
status=$(xinput --list-props $id | grep "Device Enabled" | cut -f 3)
if [ $status -eq 1 ]; then
    xinput --disable $id
else
    xinput --enable $id
fi