lumberjack.lua

if turtle.getFuelLevel() < 100 then
        error("please refuel to at least 100 units first")
end

count = 0
while true do
    if not turtle.detect() then
        while count > 0 do
        count = count-1
        turtle.digDown()
        turtle.down()
        end
        error()
    end
    count = count+1
    turtle.dig()
    turtle.digUp()
    turtle.up()


end