merging in the --lua-exec feature for ncat.

ncat/scripts/echo.lua

@@ -0,0 +1,14 @@
+--Emulates the RFC 862 echo service, behaving like Unix's "cat" tool.
+
+while true do
+
+    data = io.stdin:read(512)
+
+    if data == nil then
+        break
+    end
+
+    io.stdout:write(data)
+    io.stdout:flush()
+
+end