diff --git a/scripts/asn-query.nse b/scripts/asn-query.nse
index 05e47fa28..20e154471 100644
--- a/scripts/asn-query.nse
+++ b/scripts/asn-query.nse
@@ -366,7 +366,7 @@ function get_prefix_length( range )
   last = ipOps.ip_to_bin( last ):reverse()
 
   local hostbits = 0
-  for pos = 1, string.len( first ), 1 do
+  for pos = 1, # first , 1 do
 
     if first:sub( pos, pos ) == "0" and last:sub( pos, pos ) == "1" then
       hostbits = hostbits + 1
@@ -376,7 +376,7 @@ function get_prefix_length( range )
 
   end
 
-  return ( string.len( first ) - hostbits )
+  return ( # first  - hostbits )
 
 end
 
@@ -394,7 +394,7 @@ function get_assignment( ip, prefix )
   if err then return nil, err end
 
   prefix = tonumber( prefix )
-  if not prefix or ( prefix < 0 ) or ( prefix > string.len( some_ip ) ) then
+  if not prefix or ( prefix < 0 ) or ( prefix > # some_ip  ) then
     return nil, "Error in get_assignment: Invalid prefix length."
   end
 
diff --git a/scripts/dns-random-srcport.nse b/scripts/dns-random-srcport.nse
index ab02f0173..c312f2a05 100644
--- a/scripts/dns-random-srcport.nse
+++ b/scripts/dns-random-srcport.nse
@@ -83,7 +83,7 @@ action = function(host, port)
         -- Now we need to "parse" the results to check to see if they are good
 
         -- We need a minimum of 5 bytes...
-        if (string.len(result) < 5) then
+        if (#result < 5) then
            if (nmap.verbosity() >= 2 or nmap.debugging() >= 1) then
                 return "ERROR: Malformed response"
            else
@@ -133,7 +133,7 @@ action = function(host, port)
         end
 
         -- We need a minimum of 128 bytes...
-        if (string.len(result) < 128) then
+        if (#result < 128) then
            if (nmap.verbosity() >= 2 or nmap.debugging() >= 1) then
                 return "ERROR: Truncated response"
            else
@@ -171,7 +171,7 @@ action = function(host, port)
         local txtlen = string.byte(result, 128)
 
         -- We now need a minimum of 128 + txtlen bytes + 1...
-        if (string.len(result) < 128 + txtlen) then
+        if (#result < 128 + txtlen) then
            if (nmap.verbosity() >= 2 or nmap.debugging() >= 1) then
                 return "ERROR: Truncated response"
            else
diff --git a/scripts/dns-random-txid.nse b/scripts/dns-random-txid.nse
index 19ff303c6..151451a52 100644
--- a/scripts/dns-random-txid.nse
+++ b/scripts/dns-random-txid.nse
@@ -83,7 +83,7 @@ action = function(host, port)
         -- Now we need to "parse" the results to check to see if they are good
 
         -- We need a minimum of 5 bytes...
-        if (string.len(result) < 5) then
+        if (#result < 5) then
            if (nmap.verbosity() >= 2 or nmap.debugging() >= 1) then
                 return "ERROR: Malformed response"
            else
@@ -133,7 +133,7 @@ action = function(host, port)
         end
 
         -- We need a minimum of 128 bytes...
-        if (string.len(result) < 128) then
+        if (#result < 128) then
            if (nmap.verbosity() >= 2 or nmap.debugging() >= 1) then
                 return "ERROR: Truncated response"
            else
@@ -171,7 +171,7 @@ action = function(host, port)
         local txtlen = string.byte(result, 128)
 
         -- We now need a minimum of 128 + txtlen bytes + 1...
-        if (string.len(result) < 128 + txtlen) then
+        if (#result < 128 + txtlen) then
            if (nmap.verbosity() >= 2 or nmap.debugging() >= 1) then
                 return "ERROR: Truncated response"
            else
diff --git a/scripts/dns-zone-transfer.nse b/scripts/dns-zone-transfer.nse
index bbe037f88..289923a69 100644
--- a/scripts/dns-zone-transfer.nse
+++ b/scripts/dns-zone-transfer.nse
@@ -228,7 +228,7 @@ function build_domain(host)
 
     -- prepend each element with its length
     while i <= #abs_name do
-        buf = buf .. string.char(string.len(abs_name[i])) .. abs_name[i]
+        buf = buf .. string.char(#abs_name[i]) .. abs_name[i]
         i = i + 1
     end
 
@@ -373,7 +373,7 @@ function responses_iter(data)
     return function()
         local length, remaining, response
 
-        remaining = string.len(data) - offset + 1
+        remaining = #data - offset + 1
         if remaining == 0 then
             return nil
         end
@@ -551,7 +551,7 @@ action = function(host, port)
     local req_id = '\222\173'
     local offset = 1
     local name = build_domain(string.lower(dns_opts.domain))
-    local pkt_len = string.len(name) + 16
+    local pkt_len = #name + 16
 
     -- build axfr request
     local buf = strbuf.new()
@@ -571,7 +571,7 @@ action = function(host, port)
     soc:close()
 
     local response_str = strbuf.dump(response)
-    local length = string.len(response_str)
+    local length = #response_str
 
     -- check server response code
     if length < 6 or
diff --git a/scripts/http-title.nse b/scripts/http-title.nse
index 666af41bd..33f0cef3c 100644
--- a/scripts/http-title.nse
+++ b/scripts/http-title.nse
@@ -75,7 +75,7 @@ action = function(host, port)
 
   if title and title ~= "" then
     result = string.gsub(title , "[\n\r\t]", "")
-    if string.len(title) > 65 then
+    if #title > 65 then
       stdnse.print_debug("http-title.nse: (%s) Title got truncated!", host.targetname or host.ip );
       result = string.sub(result, 1, 62) .. "..."
     end
diff --git a/scripts/iax2-version.nse b/scripts/iax2-version.nse
index dd7302429..fbd3af4eb 100644
--- a/scripts/iax2-version.nse
+++ b/scripts/iax2-version.nse
@@ -32,7 +32,7 @@ action = function(host, port)
 		return
 	end
 
-	if (string.len(recv)) == 12 then
+	if (#recv) == 12 then
 		local byte11 = string.format("%02X", string.byte(recv, 11))
 		local byte12 = string.format("%02X", string.byte(recv, 12))
 
diff --git a/scripts/nbstat.nse b/scripts/nbstat.nse
index 95ba57b2d..e4d07330f 100644
--- a/scripts/nbstat.nse
+++ b/scripts/nbstat.nse
@@ -132,7 +132,7 @@ action = function(host)
 		local names_output = {}
 		names_output['name'] = "Names"
 		for i = 1, #names, 1 do
-			local padding = string.rep(" ", 17 - string.len(names[i]['name']))
+			local padding = string.rep(" ", 17 - #names[i]['name'])
 			local flags_str = netbios.flags_to_string(names[i]['flags'])
 			table.insert(names_output, string.format("%s<%02x>%sFlags: %s", names[i]['name'], names[i]['suffix'], padding, flags_str))
 		end
diff --git a/scripts/p2p-conficker.nse b/scripts/p2p-conficker.nse
index 188a49fc2..289b8b17a 100644
--- a/scripts/p2p-conficker.nse
+++ b/scripts/p2p-conficker.nse
@@ -243,9 +243,9 @@ end
 --@return An integer representing the checksum. 
 local function p2p_checksum(data)
 	local pos, i
-	local hash = string.len(data)
+	local hash = #data
 
-	stdnse.print_debug(2, "Conficker: Calculating checksum for %d-byte buffer", string.len(data))
+	stdnse.print_debug(2, "Conficker: Calculating checksum for %d-byte buffer", #data)
 
 	-- Get the first character
 	pos, i = bin.unpack("<C", data)
@@ -274,7 +274,7 @@ local function p2p_cipher(packet, key1, key2)
 	local i
 	local buf = ""
 
-	for i = 1, string.len(packet), 1 do
+	for i = 1, #packet, 1 do
 		-- Do a 64-bit rotate on key1:key2
 		key2, key1 = rot64(key2, key1)
 
@@ -441,7 +441,7 @@ local function p2p_create_packet(protocol, do_encryption)
 
 	-- Add the length in front if it's TCP
 	if(protocol == "tcp") then
-		packet = bin.pack("<SA", string.len(packet), packet)
+		packet = bin.pack("<SA", #packet, packet)
 	end
 
 	return true, packet
@@ -493,7 +493,7 @@ local function conficker_check(ip, port, protocol)
 		local length
 		_, length = bin.unpack("<S", response, 1)
 
-		while length > (string.len(response) - 2) do
+		while length > (#response - 2) do
 			local response2
 
 			status, response2 = socket:receive_bytes(2)
diff --git a/scripts/pptp-version.nse b/scripts/pptp-version.nse
index 46f5c7c87..025016a73 100644
--- a/scripts/pptp-version.nse
+++ b/scripts/pptp-version.nse
@@ -71,7 +71,7 @@ action = function(host, port)
 
 		-- get the vendor (should be 64 octets, but capture to end of the string to be safe)
 		local s4, length
-		length = string.len(result)
+		length = #result
 		s4 = string.sub(result, 88, length)
 		vendor = string.match(s4, "(.-)%z")
 	
diff --git a/scripts/smb-psexec.nse b/scripts/smb-psexec.nse
index c95ca5976..4c947e062 100644
--- a/scripts/smb-psexec.nse
+++ b/scripts/smb-psexec.nse
@@ -921,7 +921,7 @@ local function cipher(str, config)
 		c = string.char(bit.bxor(c, string.byte(config.key, config.key_index + 1)))
 
 		config.key_index = config.key_index + 1
-		config.key_index = config.key_index % string.len(config.key)
+		config.key_index = config.key_index % #config.key
 
 		result = result .. c
 	end
diff --git a/scripts/sql-injection.nse b/scripts/sql-injection.nse
index f9181cefa..a0acd7371 100644
--- a/scripts/sql-injection.nse
+++ b/scripts/sql-injection.nse
@@ -177,7 +177,7 @@ local function find_links(list, base_path, page, host)
 	
   for w in string.gmatch(page, 'href%s*=%s*"%s*[^"]+%s*"') do
     s, e = string.find(w, '"')
-    httpurl = string.sub(w, s+1, string.len(w)-1)
+    httpurl = string.sub(w, s+1, #w-1)
     i = 1
 
     -- parse out duplicates, otherwise we'll be here all day 
diff --git a/scripts/sslv2.nse b/scripts/sslv2.nse
index 5c53b5b2a..7af601961 100644
--- a/scripts/sslv2.nse
+++ b/scripts/sslv2.nse
@@ -61,7 +61,7 @@ cyphers = function(cypher_list, len)
 
 	if (len == 0) then return "none"; end
 -- something's got broken along the way if these aren't equal
-	if (len ~= string.len(cypher_list)) then
+	if (len ~= #cypher_list) then
 		return "";
 	end
 
@@ -94,7 +94,7 @@ give_n_bytes = function(idx, n, str)
 
 -- returns the next n bytes of a string
 
-	if (idx + (n - 1) > string.len(str)) then
+	if (idx + (n - 1) > #str) then
 		return (idx + n), string.rep(string.char(0x00), n);
 	end
 
@@ -173,8 +173,8 @@ action = function(host, port)
 		return;
 	end
 --try to get entire hello, if we don't already
-	if (string.len(server_hello) < server_hello_len) then
-		status, tmp = socket:receive_bytes(server_hello_len - string.len(server_hello));
+	if (#server_hello < server_hello_len) then
+		status, tmp = socket:receive_bytes(server_hello_len - #server_hello);
 
 		if (not status) then
 			socket:close();
diff --git a/scripts/whois.nse b/scripts/whois.nse
index 5bed15889..068f5b536 100644
--- a/scripts/whois.nse
+++ b/scripts/whois.nse
@@ -427,7 +427,7 @@ function get_prefix_length( range )
   last = ipOps.ip_to_bin( last ):reverse()
 
   local hostbits = 0
-  for pos = 1, string.len( first ), 1 do
+  for pos = 1, # first , 1 do
 
     if first:sub( pos, pos ) == "0" and last:sub( pos, pos ) == "1" then
       hostbits = hostbits + 1
@@ -437,7 +437,7 @@ function get_prefix_length( range )
 
   end
 
-  return ( string.len( first ) - hostbits )
+  return ( # first  - hostbits )
 
 end
 
@@ -1159,7 +1159,7 @@ function get_assignment( ip, prefix )
   if err then return nil, err end
 
   prefix = tonumber( prefix )
-  if not prefix or ( prefix < 0 ) or ( prefix > string.len( some_ip ) ) then
+  if not prefix or ( prefix < 0 ) or ( prefix > # some_ip  ) then
     return nil, "Error in get_assignment: Invalid prefix length."
   end