minetest.register_chatcommand("timeban", {
    params = "<time> <name_or_ip> <reason>";
    description = "Ban a user for a certain amount of time";
    privs = {ban=true};
    func = function ( name, param )
        local user, reason = param:gmatch("(%S+)%s(.*)");
        if (not user) then
            minetest.chat_send_player(name, "Usage: /ban30 <name_or_ip> [<reason>]");
            return;
        end
        reason = reason or "No reason given.";
        minetest.chat_send_player(user, "You have been banned for 30 minutes. Reason: "..reason);
        minetest.after(60*30, function ( )
            minetest.unban_player_or_ip(user);
            minetest.chat_send_player(name, "Player "..user.." has been unbanned.");
        end)
        minetest.ban_player(user);
    end;
});