Chatbox Commands

Hello Everyone, 

       I'd like to know how can I add custom commands to the chatbox. 

I'd like to add a specific command for Moderators to warn a user in-chat. 

For Example:

Input: /warn Username
Output in Chat: Username has been given a warning by Eugeo Ayano

and to a command to undo it that says

Input: /unwarn Username
Ouput: The Warning on Username has been nullified by Eugeo Ayano


Which would be the proper codes to make this possible?

yea it is possible to write a script for this but in the end it wont be worth it .. the chat keep refreshing so every time it refreshes it would flash between /warning username and your message over and over again .. it would be very annoying unless u turned archives on permanently to aviod the refresh ... there is a chat on avacweb that uses forumotion chat that will let you add your own commands and has tons more options and plugins you should check it out see if it fits your needs