Homogenize scripts a little.

src/main/scripts/bin/export.lua

@@ -4,11 +4,11 @@ local devices = require("devices")
 local device = devices:find("file_import_export")
 
 if not device then
-    io.write("A File Import/Export Card is required for this functionality.\n")
-    return
+    io.stderr:write("A File Import/Export Card is required for this functionality.\n")
+    os.exit(1)
 end
 
-if not arg[1] then
+if #arg == 0 then
     io.write("Usage: export.lua filename\n")
     os.exit(1)
 end

src/main/scripts/bin/import.lua

@@ -4,8 +4,8 @@ local devices = require("devices")
 local device = devices:find("file_import_export")
 
 if not device then
-    io.write("A File Import/Export Card is required for this functionality.\n")
-    return
+    io.stderr:write("A File Import/Export Card is required for this functionality.\n")
+    os.exit(1)
 end
 
 device:reset()

src/main/scripts/bin/redstone.lua

@@ -1,38 +1,39 @@
 #!/usr/bin/lua
 
 local devices = require('devices')
-
 local rs = devices:find("redstone")
+
 if not rs then
-	io.stderr:write("This program requires a Redstone Interface Card or Redstone Interface.\n")
-	return 1
+	io.stderr:write("This program requires a Redstone Interface Block or Card.\n")
+    os.exit(1)
 end
 
-local args = table.pack(...)
-if #args == 0 then
-	io.write("Usage:\n")
-	io.write("  redstone <side name> [<value>]\n")
-	return
+if #arg == 0 then
+	io.write("Usage: redstone.lua side [value]\n")
+    os.exit(1)
 end
 
-if #args > 0 then
-	local side = string.lower(args[1])
-	sides = {["up"]=true,["down"]=true,["north"]=true,["south"]=true,["west"]=true,["east"]=true,
-		["front"]=true,["back"]=true,["left"]=true,["right"]=true}
-	if not sides[side] then
-		io.stderr:write("invalid side\n")
-		return
-	end
-	
-	local value = args[2]
-	if value then 
-		if tonumber(value) then
-			value = tonumber(value)
-		else
-			value = ({["true"]=true,["on"]=true,["yes"]=true})[value] and 15 or 0
-		end
-		rs:setRedstoneOutput(side, value)
-	end
-	io.write("in: " .. math.ceil(rs:getRedstoneInput(side)) .. "\n")
-	io.write("out: " .. math.ceil(rs:getRedstoneOutput(side)) .. "\n")
+local function set_of(...)
+    local set = {}
+    for _, value in pairs(table.pack(...)) do
+        set[value] = true
+    end
+    return set
 end
+
+local side = string.lower(arg[1])
+local sides = set_of("up", "down", "north", "south", "west", "east", "front", "back", "left", "right")
+if not sides[side] then
+    io.stderr:write("Invalid side argument.\n")
+    os.exit(1)
+end
+
+local value = arg[2]
+if value then
+    local on = set_of("true", "on", "yes")
+    value = tonumber(value) or on[value] and 15 or 0
+    rs:setRedstoneOutput(side, value)
+end
+
+io.write("in: " .. math.ceil(rs:getRedstoneInput(side)) .. "\n")
+io.write("out: " .. math.ceil(rs:getRedstoneOutput(side)) .. "\n")

src/main/scripts/bin/setup-network.lua

@@ -74,7 +74,7 @@ if dhcpServer == "y" or dhcpServer == "Y" then
         end
 
         if not dhcpRangeStart:match("%d+%.%d+%.%d+%.%d+") then
-            io.write("Invalid IP address format.")
+            io.stderr:write("Invalid IP address format.")
         else
             break
         end
@@ -90,7 +90,7 @@ if dhcpServer == "y" or dhcpServer == "Y" then
         end
 
         if not dhcpRangeEnd:match("%d+%.%d+%.%d+%.%d+") then
-            io.write("Invalid IP address format.")
+            io.stderr:write("Invalid IP address format.")
         else
             break
         end