How would I go about making a CLI

This may be the wrong topic but I was wondering how I would go about making a CLI (Command Line Interface) I want to make something like cmdr but I don’t like using free things in my games. Any ideas how to start a project like this. any help is appreciated thank you.

There’s nothing wrong with using Cmdr. It’s not really meant to be used by itself, you supposed to add your own commands to it. It doesn’t make sense to recreate the wheel. It also does not have a watermark like HD Admin or whatever that’s called. Most people in your game won’t even know cmdr is in your game, and you could go a step further by adding an if statement to require the cmdr client module if the client is the game owner:

local cmdr;
local Owner_id = 2056437332
if Owner_id == game:GetService("Players").LocalPlayer.UserId then
   cmdr = require(game:GetService("ReplicatedStorage"):WaitForChild("CmdrClient"))
end