由于Linux原始的防火墙工具iptables过于繁琐，所以 Ubuntu 默认提供了一个基于iptable之上的防火墙工具ufw。

我认为成功的关键在于，既知道如何努力追求很多东西，也知道如何正确地失败。“正确地失败”是指，能够在经历痛苦的失败的过程中吸取重要的教训，从而避免“错误地失败”，即因为失败而被踢出局。

编程之本：变量和函数

变量

Kotlin 中定义一个变量，只允许在变量前声明两种关键字：val和var。

背景

单位买了一个手持的蓝牙 RTK 终端，通过蓝牙可以获取到设备的差分定位信息。

赚钱

花钱消费是人类的本性，因为人要活着，差别是花多花少，活得精不精彩。而赚钱就是反人性的，你需要去工作，去劳动才能赚到钱。你能赚到多少钱取决于你的反人性程度。可以这样说，那些亿万富翁也最反人性的人。

入门

Android

配置：2C2G40G(2120IOPS)

之前的实例一，通过点击按钮实现起飞。而我这边最终的需求是通过点击网页上的按钮来控制无人机的起飞降落。

由于大疆新的无人机采用Mobile SDK 5.x版本(Kotlin)，而之前学习的版本是4.x(Java)，并且大疆对于5.x版本的文档写的实在不怎么样(相比4.x来说)，所以从新记录一下。

The lateinit keyword in Kotlin is used to declare(声明) a property that will be initialized later. It allows you to avoid(避免) null checks or the use of the null type for properties that you are certain will be initialized before use, but for some reason, you can't initialize them immediately(立即) at declaration.

首先在 AndroidManifest.xml 中添加需要的权限

由于大疆 Mobile SDK 5 将 APP 注册等逻辑放到了 MyApplication 中，但是我还是想在 MainActivity 接收注册成功或失败等消息，所以使用 BroadcastReceiver 来广播消息

上周末跟老朋友聚会，谈到技术的时候，有一个共识，软件开发方面真正有价值的进步，应当是有利于用户、有利于项目管理、有利于解决领域问题，而不是有利于程序员。多年以来，主流语言和系统的很多改进，其目的都是为了让写程序的人感觉更爽，而与用户、管理和解决问题毫无关系。C++ 在这方面是带了一个很坏的头，又要追求强大的表达能力，又要追求不打折扣的效率，结果搞出一大堆诸如操作符重载，template meta-programming 之类的东西。老实讲，我也觉得：

ES6 模块主要有两个功能：export和import

全局安装

npm install -g nodemon

运行命令:

When giving a lecture about the significance of punctuation, the academic professor was interrupted and arrested by the police for murdering his wife, a receptionist of a kindergarten. The police found some photos he deleted from their e-album showing that they used to have a gay life. But, fed up with her wrinkled face, he murdered her instead of divorcing her to avoid fortune division. He cut up a kind of seashell with a sharpened knife, and hammered it into powder on a skateboard, and made at most one gram, which was enough to accelerate one’s pulse until he or she dies. This kind of poison can date back to 10,000 BC when people rubbed it on spears to kill beasts. The professor mixed the poison with onion, watermelon and yogurt for his wife. Howling and scratching her chest, she felt dizzy and died soon.

An ambassador and a referee were consulting a professor on the caption of a Buddhistic alphabet when a sobbing woman stopped them to sell an antique musical bathtub. Her dirty garment and the handkerchief around herwaist were badly in need of sending to a laundry. The ambassador uncomfortably gave her a handful of pence from his wallet and said, “Take this fortune away, troublesome woman.”

I set about working in the current Patent Office after resigning from the court personnel. Competent and dynamic, I never feel passive while diving into the identifications of whether applications are valid and practical according to the new version of the criteria.