ShearDown

-- shear in slot 1
local shearData = turtle.getItemDetail(1)
local shearType = shearData.name
local data = turtle.getItemDetail(2) -- fuel slot 2
local fuelType = data.name

function checkFuel ()
    if turtle.getFuelLevel() <= 0 then
        print ("no fuel\n")
        for i = 1, 16, 1 do
            if turtle.getItemDetail(i).name == fuelType then
                turtle.select(i)
                turtle.refuel()
                print ("refuel\n")
                return true
            end
        end

        print ("out of fuel\n")
        return false
    end

    return true
end

while true do
    checkFuel()

    local data = turtle.getItemDetail(1)
    if data.name ~= shearType then
        print ("Error! No shear.")
        break
    end
    turtle.select(1)
    turtle.placeDown()
    turtle.suckDown()
end