VA11 check

local filename = shell.getRunningProgram() -- Get the name of this Lua script file
local fileToMonitor = filename -- Set the file to monitor as this Lua script file

local interval = 5 -- Interval in seconds

while true do
  if fs.exists(fileToMonitor) then
    -- Your code to send a message or perform actions when the file is found
    -- For example: redstone.setOutput("back", true)
    print("File found!")
  else
    -- Your code to run when the file is not found
    -- For example: shell.run("program_to_execute")
    print("File not found!")
  end

  os.startTimer(interval)
  os.pullEvent("timer")
end