View difference between Paste ID: ZUDKLf6b and VY2tUpuC

 glass = peripheral.wrap( "bottom" )
 
 rednet.open( "back" )
 
 -- Constants
 pos_x = 40
 pos_y = 55
 pos_inc = 10
 local color = {}
 color["on"] = 0x229000
 color["off"] = 0xFF0000
 
 -- Devices
 local devices = { "Quarry" }
 
 -- Device status
 local status = {}
 for i, device in ipairs( devices ) do
   status[device] = glass.addText( pos_x, pos_y, device, color["off"] )
   pos_y = pos_y + pos_inc
 end
 
 while true do
   local command = ""
   local device = ""
   local status = ""
 
   senderID, message, distance = rednet.receive()
   print( senderID .. ": " .. message )
 
   for i in string.gmatch( message,  "%S+" ) do
-    if not command then
+    if command ~= "" and device ~= "" then
       status = i
-    elseif not device then
+
     if command ~= "" and device == "" then
-    else
+
     end
     if command == "" and device == "" then
       command = i
     end
   end
 
   if not device then
     print( "Something fubared the rednet message: " .. message )
   else
     status[device].setColor( color[status] )
   end
 end
 
 rednet.close( "back" )