-- command, minGMLevel, syntax
local Table =  {
    ["vipinfo"]     = { 0, ".vipinfo <player name>" },
    ["viplevel"]    = { 1, ".viplevel <player name> <new level>"},
}

-- Here we check if the written command exists in the table
-- If command exists in table then we handle
local function CommandsSystem(event, player, command)
    local cmd, parameters = command:match("([^%s]+)%s?(.*)")
    if not cmd then
        return
    end
    for com,_ in pairs(Table) do
        if (string.find(com, cmd) == 1) then
            player:HandleCommand(com, parameters)
            return false
        end
    end
end

-- Here we handle all available commands
-- We check if player has required gm level to use that command
function Player:HandleCommand(command, parameters)
    if (self:GetGMRank() >= Table[command][1]) then
        if (command == "vipinfo") then
            SendWorldMessage("Here we do something for command vipinfo")
        else
            self:SendBroadcastMessage("|cffFF0000Command not yet handled!")
        end
    end
end

RegisterPlayerEvent(42, CommandsSystem)