CC Turtle syncpos program

local xIni, yIni, zIni
local xCur, yCur, zCur
local fCur
local posOut

xIni, yIni, zIni = gps.locate(5)

if not xIni or not yIni or not zIni then
  print("No or insufficient GPS hosts found")
  do return end
end

while not turtle.forward() do
  while not turtle.up() do
    turtle.digUp()
  end
end

xCur, yCur, zCur = gps.locate(5)
if zCur > zIni then
  fCur = 0
elseif xCur < xIni then
  fCur = 1
elseif zCur < zIni then
  fCur = 2
elseif xCur > xIni then
  fCur = 3
else
  exit()
end

while not turtle.back() do
  while not turtle.up() do
    turtle.digUp()
  end
end

xCur, yCur, zCur = gps.locate(5)

if not fs.isDir("data") then
  fs.delete("data")
  fs.makeDir("data")
end

posOut = io.open("data/pos.txt", "w")
posOut:write(textutils.serialize({xCur, yCur, zCur, fCur}))
posOut:close()