Rednet Spawner Control

-- This program will wait for the "rednet_message" event with the set computer id and emit redstone to the left.
term.clear()
term.setCursorPos(1,1)
local pd, param1, param2 = os.pullEvent()
function cowon()
  rs.setOutput("left", false)
end
function cowoff()
  rs.setOutput("left", true)
end
if pd == "rednet_message" and param1 == 173 and param2 == "cowon" then
  print("Message received to turn on cow spawner.")
  print("Cow spawner is on.")
  cown()
elseif pd == "rednet_message" and param1 == 173 and param2 == "cowoff" then
  print("Message received to turn off cow spawner.")
  print("Cow spawner is off.")
  cowoff()
end
term.clear()
shell.run("startup")