Reading and writing files

--To use with Redpower Managers to prevent
--continuous item movement in tubesystem.
fn = "state"

--When no state file exists, info variable
--contains the first state of the tube
local info = {"closed",0}
local cycleCnt = 0
local step = 10 --resolution (in seconds)

--time while tube is closed = Step * maxClosed
local maxClosed = 11

--time while tube is open = Step * maxOpen
local maxOpen = 360

--redstone output for opener motor
tubeOpenerMotor = "left"

--redstone output for closer motor
tubeCloserMotor = "top"

function writeFile(table)
  fh = fs.open(fn,"w")
  for i=1, #table do
	fh.writeLine(tostring(table[i]))
  end
  fh.close()
end
function readFile()
  local table = {}
  local cnt = 1
  fh = fs.open(fn,"r")
  table[1] = fh.readLine()
  table[2] = tonumber(fh.readLine())
  fh.close()
  return table
end
function pushOut()
  rs.setOutput(tubeOpenerMotor,true)
  sleep(0.5)
  rs.setOutput(tubeOpenerMotor,false)
end
function pullIn()
  rs.setOutput(tubeCloserMotor,true)
  sleep(0.5)
  rs.setOutput(tubeCloserMotor,false)
end

if not fs.exists(fn) then
  writeFile(info)
else
  info = readFile()
end
term.clear()
term.setCursorPos(1,2)
print("Tube-mover is running!")
while true do
  if info[1] == "closed" then
	term.setCursorPos(2,3)
	term.clearLine()
	term.write("The tube is closed")
	pullIn()
	for cycleCnt = info[2], maxClosed do
	  term.setCursorPos(2,4)
	  term.clearLine()
	  term.write("Step: "..cycleCnt.."/"..maxClosed)
	  sleep(step)
	  info[2] = cycleCnt + 1
	  writeFile(info)  
	end
	pushOut()
	info[1] = "open"
	info[2] = 0
	writeFile(info)
  end

  if info[1] == "open" then
	term.setCursorPos(2,3)
	term.clearLine()
	term.write("The tube is open!")
	pushOut()
	for cycleCnt = info[2], maxOpen do
	  term.setCursorPos(2,4)
	  term.clearLine()
	  term.write("Step: "..cycleCnt.."/"..maxOpen)
	  sleep(step)
	  info[2] = cycleCnt + 1
	  writeFile(info)
	end
	pullIn()
	info[1] = "closed"
	info[2] = 0
	writeFile(info)
  end
end