-- This program will break blocks below it matching the block in slot # 1 and then return to the starting point

local moveFwd = 0

local function tryMoveFwd()
    while turtle.detect() do
        if turtle.dig() then
        sleep(0.05)
        end
    end
    turtle.forward(1)
    moveFwd = moveFwd + 1
end

-- This is the main process loop of the program where blocks are checked and broken

turtle.select( 1 )
if turtle.getItemCount() < 1 then
    print("please place desired harvest block in slot # 1")
    return
end

while turtle.compareDown() do
    turtle.digDown()
    tryMoveFwd()
end

-- the next section returns the turtle to its starting point

for i = 1, moveFwd do
    turtle.back()
end