With this plugin, you can add commands or messages to Players config, and when they connect to server, everything from the config will be executed line by line. Main command is "/cache", default permission is "Cachinator.add", for viewing log in chat, you need to have permission "Cachinator.log", if you will have only OP, you won't see it.
"/cache add petulikan1 /say Hi" -> command executed as console
"/cache add petulikan1 Hi" -> Message from console to player
"/cache add petulikan1 yes (command or message)" if the player is online, it won't be executed instantly but after they join the server again.