Bash-wrapped AppleScript to toggle the "built-in trackpad disabled" accessibility setting.

tbit.sh

# Built-in Trackpad toggle script
# https://github.com/Ryderpro/Apple-Scripts

osascript  <<'END'
tell application "System Preferences"
    quit
    delay 1
end tell

tell application "System Preferences"
    reveal anchor "Mouse" of pane id "com.apple.preference.universalaccess"
    activate
end tell

set checkboxNumber to 3

tell application "System Events" to tell process "System Preferences"
    repeat while not (exists of checkbox checkboxNumber of group 1 of window "Accessibility")
        delay 0.1
    end repeat
    set theCheckbox to checkbox checkboxNumber of group 1 of window "Accessibility"
    tell theCheckbox
        # If the checkbox is not checked, check it to turn grayscale on
        if not (its value as boolean) then
            set checked to true
            click theCheckbox
        else # else turn grayscale off
            set checked to false
            click theCheckbox
        end if
    end tell
end tell

tell application "System Preferences"
    quit
end tell

if checked = true then
    display notification "Ignoring built-in trackpad while mouse or wireless trackpad is present."
else
    display notification "Built-in trackpad is now active."
end if
END