/kick command

local Players = game:GetService("Players")

local kickCommand = "/kick "

local function onOwnerChatted(player, message)
    if message:sub(1, kickCommand:len()):lower() == kickCommand:lower() then
        local name = message:sub(kickCommand:len() + 1)
        local playerToKick = Players:FindFirstChild(name)
        if playerToKick then
            playerToKick:Kick("You have been kicked by the owner.")
        else
            -- Couldn't find the player in question
        end
    end
end

local function onPlayerAdded(player)
    -- Restrict this command to only the creator/owner
    if player.UserId == game.CreatorId and game.CreatorType == Enum.CreatorType.User then
        player.Chatted:Connect(function (...)
            onOwnerChatted(player, ...)
        end)
    end
end

-- Listen for players being added
for _, player in pairs(Players:GetPlayers()) do
    onPlayerAdded(player)
end
Players.PlayerAdded:Connect(onPlayerAdded)