@7JD You mean you want people to stop sending any commands? Plugins such as PEX do this by forcing the player to have a permission in order to send commands. If you mean you do not want people to be able to use the autocomplete tab feature, you will have to make a request in the plugin request section for this type of plugin.
Hey ! How Are You U can use plugins that blocks commands like: http://dev.bukkit.org/bukkit-plugins/block-commands/ And u can search for other plugins in bukkit