diff --git a/nselib/proxy.lua b/nselib/proxy.lua
index a773b0f8a..73c37bfbc 100644
--- a/nselib/proxy.lua
+++ b/nselib/proxy.lua
@@ -22,8 +22,8 @@ local function check_code(result)
     if result:match( "\r?\n\r?\n" ) then
       result = result:match( "^(.-)\r?\n\r?\n(.*)$" )
     end
-    if string.match(result:lower(),"^http/%d\.%d%s*200") then return true end
-    if string.match(result:lower(),"^http/%d\.%d%s*30[12]") then return true end
+    if result:lower():match("^http/%d\.%d%s*200") then return true end
+    if result:lower():match("^http/%d\.%d%s*30[12]") then return true end
   end
   return false
 end
@@ -34,13 +34,10 @@ end
 --@return true if pattern is found, otherwise false
 local function check_pattern(result, pattern)
   local lines = stdnse.strsplit("\n", result)
-  local i = 1
-  local n = table.getn(lines)
-  while true do
-    if i > n then return false end
-    if string.match(lines[i]:lower(),pattern:lower()) then return true end
-    i = i + 1
+  for i, line in ipairs(lines) do
+    if line:lower():match(pattern:lower()) then return true end
   end
+  return false
 end
 
 --- check, decides what kind of check should be done on the response,
diff --git a/nselib/tftp.lua b/nselib/tftp.lua
index 42a75fecc..17bc9410e 100644
--- a/nselib/tftp.lua
+++ b/nselib/tftp.lua
@@ -133,10 +133,9 @@ local function dispatcher()
 			s_condvar "broadcast"
 		end
 	
-		local n = table.getn(threads)
-		if ( n == 0 ) then break end
-		for i=1,n do
-			local status, res = coroutine.resume(threads[i])
+		if #threads == 0 then break end
+		for i, thread in ipairs(threads) do
+			local status, res = coroutine.resume(thread)
 			if ( not(res) ) then    -- thread finished its task?
 				table.remove(threads, i)
             	break
@@ -336,4 +335,4 @@ function waitFile( filename, timeout )
 	waitLast()
 
 	return false
-end
\ No newline at end of file
+end
diff --git a/nselib/url.lua b/nselib/url.lua
index 29da0c372..1c3dfa025 100644
--- a/nselib/url.lua
+++ b/nselib/url.lua
@@ -257,8 +257,8 @@ function parse_path(path)
 	path = path or ""
 	--path = string.gsub(path, "%s", "")
 	string.gsub(path, "([^/]+)", function (s) table.insert(parsed, s) end)
-	for i = 1, table.getn(parsed) do
-		parsed[i] = unescape(parsed[i])
+	for i, v in ipairs(parsed) do
+		parsed[i] = unescape(v)
 	end
 	if string.sub(path, 1, 1) == "/" then parsed.is_absolute = 1 end
 	if string.sub(path, -1, -1) == "/" then parsed.is_directory = 1 end
@@ -273,7 +273,7 @@ end
 -----------------------------------------------------------------------------
 function build_path(parsed, unsafe)
 	local path = ""
-	local n = table.getn(parsed)
+	local n = #parsed
 	if unsafe then
 		for i = 1, n-1 do
 			path = path .. parsed[i]