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[#]: collector: (lujun9972)
[#]: translator: (GraveAccent)
[#]: reviewer: (wxy)
[#]: publisher: (wxy)
[#]: url: (https://linux.cn/article-10664-1.html)
[#]: subject: (JSON vs XML vs TOML vs CSON vs YAML)
[#]: via: (https://www.zionandzion.com/json-vs-xml-vs-toml-vs-cson-vs-yaml/)
[#]: author: (Tim Anderson https://www.zionandzion.com)
JSON、XML、TOML、CSON、YAML 大比拼
======
### 一段超级严肃的关于样本序列化的集合、子集和超集的文字
我是一名开发者，我读代码，我写代码，我写会写代码的代码，我写会写出供其它代码读的代码的代码。这些都非常火星语，但是有其美妙之处。然而，最后一点，写会写出供其它代码读的代码的代码，可以很快变得比这段文字更费解。有很多方法可以做到这一点。一种不那么复杂而且开发者社区最爱的方式是数据序列化。对于那些不了解我刚刚抛给你的时髦词的人，数据序列化是从一个系统获取一些信息，将其转换为其它系统可以读取的格式，然后将其传递给其它系统的过程。
虽然[数据序列化格式][1]多到可以埋葬哈利法塔，但它们大多分为两类：
* 易于人类读写，
* 易于机器读写。
很难两全其美，因为人类喜欢让我们更具表现力的松散类型和灵活格式标准，而机器倾向于被确切告知一切事情而没有二义性和细节缺失，并且认为“严格规范”才是它们最爱的口味。
由于我是一名 web 开发者，而且我们是一个创建网站的机构，我们将坚持使用 web 系统可以理解或不需要太多努力就能理解的特殊格式，而且对人类可读性特别有用的格式：XML、JSON、TOML、CSON 以及 YAML。每个都有各自的优缺点和适当的用例场景。
### 事实最先
回到互联网的早期，[一些非常聪明的家伙][2]决定整合一种让每个系统都能理解的标准语言，并创造性地将其命名为<ruby>标准通用标记语言<rt>Standard Generalized Markup Language</rt></ruby>（简称 SGML）。SGML 非常灵活，发布者也很好地定义了它。它成为了 XML、SVG 和 HTML 等语言之父。所有这三个都符合 SGML 规范，可是它们都是规则更严格、灵活性更少的子集。
最终，人们开始看到非常小、简洁、易读且易于生成的数据的好处，这些数据可以在系统之间以编程的方式共享，而开销很小。大约在那个时候，JSON 诞生了并且能够满足所有的需求。而另一方面，其它语言也开始出现以处理更多的专业用例，如 CSON，TOML 和 YAML。
### XML：不行了
原本，XML 语言非常灵活且易于编写，但它的缺点是冗长，人类难以阅读、计算机非常难以读取，并且有很多语法对于传达信息并不是完全必要的。
今天，它在 web 上的数据序列化的用途已经消失了。除非你在编写 HTML 或者 SVG，否则你不太能在许多其它地方看到 XML。一些过时的系统今天仍在使用它，但是用它传递数据往往太重了。
我已经可以听到 XML 老爷爷开始在它们的石碑上乱写为什么 XML 是了不起的，所以我将提供一个小小的补充：XML 可以很容易地由系统和人读写。然而，真的，我的意思是荒谬的，很难创建一个可以规范的读取它的系统。这是一个简单美观的 XML 示例：
```
<book id="bk101">
<author>Gambardella, Matthew</author>
<title>XML Developer's Guide</title>
<genre>Computer</genre>
<price>44.95</price>
<publish_date>2000-10-01</publish_date>
<description>An in-depth look at creating applications
with XML.</description>
</book>
```
太棒了。易于阅读、理解、写入，也容易编码一个可以读写它的系统。但请考虑这个例子：
```
<!DOCTYPE r [ <!ENTITY y "a]>b"> ]>
<r>
<a b="&y;>" />
<![CDATA[[a>b <a>b <a]]>
<?x <a> <!-- <b> ?> c --> d
</r>
```
这上面是 100% 有效的 XML。几乎不可能阅读、理解或推理。编写可以使用和理解这个的代码将花费至少 36 根头发和 248 磅咖啡渣。我们没有那么多时间或咖啡，而且我们大多数老程序员们现在都是秃头。所以，让它活在我们的记忆里，就像 [css hacks][3]、[IE 6 浏览器][4] 和[真空管][5]一样好了。
### JSON：并列聚会
好吧，我们都同意，XML = 差劲。那么，好的替代品是什么？<ruby>JavaScript 对象表示法<rt>JavaScript Object Notation</rt></ruby>，简称 JSON。JSON（读起来像 Jason 这个名字） 是 Brendan Eich 发明的，并且得到了伟大而强力的 [JavaScript 意见领袖][6] Douglas Crockford 的推广。它现在几乎用在任何地方。这种格式很容易由人和机器编写，按规范中的严格规则[解析][7]也相当容易，并且灵活 —— 允许深层嵌套数据，支持所有的原始数据类型，及将集合解释为数组或对象。JSON 成为了将数据从一个系统传输到另一个系统的事实标准。几乎所有语言都有内置读写它的功能。
JSON语法很简单。方括号表示数组，花括号表示记录，由冒号分隔的两个值分别表示属性或“键”（在左边）、值（在右边）。所有键必须用双引号括起来：
```
{
"books": [
{
"id": "bk102",
"author": "Crockford, Douglas",
"title": "JavaScript: The Good Parts",
"genre": "Computer",
"price": 29.99,
"publish_date": "2008-05-01",
"description": "Unearthing the Excellence in JavaScript"
}
]
}
```
这对你来说应该是完全有意义的。它简洁明了，并且从 XML 中删除了大量额外废话，并传达相同数量的信息。JSON 现在是王道，本文剩下的部分会介绍其它语言格式，这些格式只不过是 JSON 的简化版，尝试让其更简洁或对人类更易读，可结构还是非常相似的。
### TOML: 缩短到彻底的利他主义
TOML（<ruby>Tom 的显而易见的最小化语言<rt>Tom’s Obvious, Minimal Language</rt></ruby>）允许以相当快捷、简洁的方式定义深层嵌套的数据结构。名字中的 Tom 是指发明者 [Tom Preston Werner][8]，他是一位活跃于我们行业的创造者和软件开发人员。与 JSON 相比，语法有点尴尬，更类似 [ini 文件][9]。这不是一个糟糕的语法，但是需要一些时间适应。
```
[[books]]
id = 'bk101'
author = 'Crockford, Douglas'
title = 'JavaScript: The Good Parts'
genre = 'Computer'
price = 29.99
publish_date = 2008-05-01T00:00:00+00:00
description = 'Unearthing the Excellence in JavaScript'
```
TOML 中集成了一些很棒的功能，例如多行字符串、保留字符的自动转义、日期、时间、整数、浮点数、科学记数法和“表扩展”等数据类型。最后一点是特别的，是 TOML 如此简洁的原因：
```
[a.b.c]
d = 'Hello'
e = 'World'
```
以上扩展到以下内容：
```
{
"a": {
"b": {
"c": {
"d": "Hello"
"e": "World"
}
}
}
}
```
使用 TOML，你可以肯定在时间和文件长度上会节省不少。很少有系统使用它或非常类似的东西作为配置，这是它最大的缺点。根本没有很多语言或库可以用来解释 TOML。
### CSON: 特定系统所包含的简单样本
首先，有两个 CSON 规范。 一个代表 CoffeeScript Object Notation，另一个代表 Cursive Script Object Notation。后者不经常使用，所以我们不会关注它。我们只关注 CoffeeScript。
[CSON][10] 需要一点介绍。首先，我们来谈谈 CoffeeScript。[CoffeeScript][11] 是一种通过运行编译器生成 JavaScript 的语言。它允许你以更加简洁的语法编写 JavaScript 并[转译][12]成实际的 JavaScript，然后你可以在你的 web 应用程序中使用它。CoffeeScript 通过删除 JavaScript 中必需的许多额外语法，使编写 JavaScript 变得更容易。CoffeeScript 摆脱的一个大问题是花括号 —— 不需要它们。同样，CSON 是没有大括号的 JSON。它依赖于缩进来确定数据的层次结构。CSON 非常易于读写，并且通常比 JSON 需要更少的代码行，因为没有括号。
CSON 还提供一些 JSON 不提供的额外细节。多行字符串非常容易编写，你可以通过使用 `#` 符号开始一行来输入[注释][13]，并且不需要用逗号分隔键值对。
```
books: [
id: 'bk102'
author: 'Crockford, Douglas'
title: 'JavaScript: The Good Parts'
genre: 'Computer'
price: 29.99
publish_date: '2008-05-01'
description: 'Unearthing the Excellence in JavaScript'
]
```
这是 CSON 的大问题。它是 <ruby>CoffeScript 对象表示法<rt>CoffeeScript Object Notation</rt></ruby>。也就是说你要用 CoffeeScript 解析/标记化/lex/转译或其它方式来使用 CSON。CoffeeScript 是读取数据的系统。如果数据序列化的目的是允许数据从一个系统传递到另一个系统，这里我们有一个只能由单个系统读取的数据序列化格式，这使得它与防火火柴、防水海绵或者叉匙恼人的脆弱叉子部分一样有用。
如果这种格式被其它系统也采用，那它在开发者世界中可能非常有用。但到目前为止这基本上没有发生，所以在 PHP 或 JAVA 等替代语言中使用它是不行的。
### YAML：年轻人的呼喊
开发人员感到高兴，因为 YAML 来自[一个 Python 的贡献者][14]。YAML 具有与 CSON 相同的功能集和类似的语法，有一系列新功能，以及几乎所有 web 编程语言都可用的解析器。它还有一些额外的功能，如循环引用、软包装、多行键、类型转换标签、二进制数据、对象合并和[集合映射][15]。它具有非常好的可读性和可写性，并且是 JSON 的超集，因此你可以在 YAML 中使用完全合格的 JSON 语法并且一切正常工作。你几乎不需要引号，它可以解释大多数基本数据类型（字符串、整数、浮点数、布尔值等）。
```
books:
- id: bk102
author: Crockford, Douglas
title: 'JavaScript: The Good Parts'
genre: Computer
price: 29.99
publish_date: !!str 2008-05-01
description: Unearthing the Excellence in JavaScript
```
业界的年轻人正在迅速采用 YAML 作为他们首选的数据序列化和系统配置格式。他们这样做很机智。YAML 具有像 CSON 一样简洁的所有好处，以及与 JSON 一样的数据类型解释的所有功能。YAML 像加拿大人容易相处一样容易阅读。
YAML 有两个问题，对我而言，第一个是大问题。在撰写本文时，YAML 解析器尚未内置于多种语言，因此你需要使用第三方库或扩展来为你选择的语言解析 .yaml 文件。这不是什么大问题，可似乎大多数为 YAML 创建解析器的开发人员都选择随机将“附加功能”放入解析器中。有些允许[标记化][16]，有些允许[链引用][17]，有些甚至允许内联计算。这一切都很好（某种意义上），只是这些功能都不是规范的一部分，因此很难在其他语言的其他解析器中找到。这导致系统限定，你最终遇到了与 CSON 相同的问题。如果你使用仅在一个解析器中找到的功能，则其他解析器将无法解释输入。大多数这些功能都是无意义的，不属于数据集，而是属于你的应用程序逻辑，因此最好简单地忽略它们和编写符合规范的 YAML。
第二个问题是很少有解析器完全实现规范。所有的基本要素都有，但是很难找到一些更复杂和更新的东西，比如软包装、文档标记和首选语言的循环引用。我还没有看到对这些东西的刚需，所以希望它们不让你很失望。考虑到上述情况，我倾向于保持 [1.1 规范][18] 中呈现的更成熟的功能集，而避免在 [1.2 规范][19] 中找到的新东西。然而，编程是一个不断发展的怪兽，所以当你读完这篇文章时，你或许就可以使用 1.2 规范了。
### 最终哲学
这是最后一段话。每个序列化语言都应该以个案标准的方式评价。当涉及机器的可读性时，有些<ruby>无出其右<rt>the bee’s knees</rt></ruby>。对于人类可读性，有些<ruby>名至实归<rt>the cat’s meow</rt></ruby>，有些只是<ruby>金玉其外<rt>gilded turds</rt></ruby>。以下是最终细分：如果你要编写供其他代码阅读的代码，请使用 YAML。如果你正在编写能写出供其他代码读取的代码的代码，请使用 JSON。最后，如果你正在编写将代码转译为供其他代码读取的代码的代码，请重新考虑你的人生选择。
--------------------------------------------------------------------------------
via: https://www.zionandzion.com/json-vs-xml-vs-toml-vs-cson-vs-yaml/
作者：[Tim Anderson][a]
选题：[lujun9972][b]
译者：[GraveAccent](https://github.com/GraveAccent)
校对：[wxy](https://github.com/wxy)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://www.zionandzion.com
[b]: https://github.com/lujun9972
[1]: https://en.wikipedia.org/wiki/Comparison_of_data_serialization_formats
[2]: https://en.wikipedia.org/wiki/Standard_Generalized_Markup_Language#History
[3]: https://www.quirksmode.org/css/csshacks.html
[4]: http://www.ie6death.com/
[5]: https://en.wikipedia.org/wiki/Vacuum_tube
[6]: https://twitter.com/BrendanEich/status/773403975865470976
[7]: https://en.wikipedia.org/wiki/Parsing#Parser
[8]: https://en.wikipedia.org/wiki/Tom_Preston-Werner
[9]: https://en.wikipedia.org/wiki/INI_file
[10]: https://github.com/bevry/cson#what-is-cson
[11]: http://coffeescript.org/
[12]: https://en.wikipedia.org/wiki/Source-to-source_compiler
[13]: https://en.wikipedia.org/wiki/Comment_(computer_programming)
[14]: http://clarkevans.com/
[15]: http://exploringjs.com/es6/ch_maps-sets.html
[16]: https://www.tutorialspoint.com/compiler_design/compiler_design_lexical_analysis.htm
[17]: https://en.wikipedia.org/wiki/Fluent_interface
[18]: http://yaml.org/spec/1.1/current.html
[19]: http://www.yaml.org/spec/1.2/spec.html

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Python 的 ChatOps 库：Opsdroid 和 Errbot
======
> 学习一下 Python 世界里最广泛使用的 ChatOps 库：每个都能做什么，如何使用。
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/idea_innovation_mobile_phone.png?itok=RqVtvxkd)
ChatOps 是基于会话导向而进行的开发。其思路是你可以编写能够对聊天窗口中的某些输入进行回复的可执行代码。作为一个开发者，你能够用 ChatOps 从 Slack 合并拉取请求，自动从收到的 Facebook 消息中给某人分配支持工单，或者通过 IRC 检查开发状态。
在 Python 世界，最为广泛使用的 ChatOps 库是 Opsdroid 和 Errbot。在这个月的 Python 专栏，让我们一起聊聊使用它们是怎样的体验，它们各自适用于什么方面以及如何着手使用它们。
### Opsdroid
[Opsdroid][2] 是一个相对年轻的（始于 2016）Python 开源聊天机器人库。它有着良好的开发文档，不错的教程，并且包含能够帮助你对接流行的聊天服务的插件。
#### 它内置了什么
库本身并没有自带所有你需要上手的东西，但这是故意的。轻量级的框架鼓励你去运用它现有的连接器（Opsdroid 所谓的帮你接入聊天服务的插件）或者去编写你自己的，但是它并不会因自带你所不需要的连接器而自贬身价。你可以轻松使用现有的 Opsdroid 连接器来接入：
+ 命令行
+ Cisco Spark
+ Facebook
+ GitHub
+ Matrix
+ Slack
+ Telegram
+ Twitter
+ Websocket
Opsdroid 会调用使聊天机器人能够展现它们的“技能”的函数。这些技能其实是异步 Python 函数，并使用 Opsdroid 叫做“匹配器”的匹配装饰器。你可以设置你的 Opsdroid 项目，来使用同样从你设置文件所在的代码中的“技能”。你也可以从外面的公共或私人仓库调用这些“技能”。
你同样可以启用一些现存的 Opsdroid “技能”，包括 [seen][3] —— 它会告诉你聊天机器人上次是什么时候看到某个用户的，以及 [weather][4] —— 会将天气报告给用户。
最后，Opdroid 允许你使用现存的数据库模块设置数据库。现在 Opdroid 支持的数据库包括：
+ Mongo
+ Redis
+ SQLite
你可以在你的 Opdroid 项目中的 `configuration.yaml` 文件设置数据库、技能和连接器。
#### Opsdroid 的优势
**Docker 支持：**从一开始 Opsdroid 就打算在 Docker 中良好运行。在 Docker 中的指导是它 [安装文档][5] 中的一部分。使用 Opsdroid 和 Docker Compose 也很简单：将 Opsdroid 设置成一种服务，当你运行 `docker-compose up` 时，你的 Opsdroid 服务将会开启你的聊天机器人也将就绪。
```
version: "3"
services:
opsdroid:
container_name: opsdroid
build:
context: .
dockerfile: Dockerfile
```
**丰富的连接器：** Opsdroid 支持九种像 Slack 和 Github 等从外部接入的服务连接器。你所要做的一切就是在你的设置文件中启用那些连接器，然后把必须的口令或者 API 密匙传过去。比如为了启用 Opsdroid 以在一个叫做 `#updates` 的 Slack 频道发帖，你需要将以下代码加入你设置文件的 `connectors` 部分：
```
- name: slack
    api-token: "this-is-my-token"
    default-room: "#updates"
```
在设置 Opsdroid 以接入 Slack 之前你需要[添加一个机器人用户][6]。
如果你需要接入一个 Opsdroid 不支持的服务，在[文档][7]里有有添加你自己的连接器的教程。
**相当不错的文档：** 特别是对于一个在积极开发中的新兴库来说，Opsdroid 的文档十分有帮助。这些文档包括一篇带你创建几个不同的基本技能的[教程][8]。Opsdroid 在[技能][9]、[连接器][7]、[数据库][10]，以及[匹配器][11]方面的文档也十分清晰。
它所支持的技能和连接器的仓库为它的技能提供了富有帮助的示范代码。
**自然语言处理：** Opsdroid 的技能里面能使用正则表达式，但也同样提供了几个包括 [Dialogflow][12]，[luis.ai][13]，[Recast.AI][14] 以及 [wit.ai][15] 的 NLP API。
#### Opsdroid 可能的不足
Opsdroid 对它的一部分连接器还没有启用全部的特性。比如说，Slack API 允许你向你的消息添加颜色柱、图片以及其他的“附件”。Opsdroid Slack 连接器并没有启用“附件”特性，所以如果那些特性对你来说很重要的话，你需要编写一个自定义的 Slack 连接器。如果连接器缺少一个你需要的特性，Opsdroid 将欢迎你的[贡献][16]。文档中可以使用更多的例子，特别是对于预料到的使用场景。
#### 示例用法
```
from opsdroid.matchers import match_regex
import random
@match_regex(r'hi|hello|hey|hallo')
async def hello(opsdroid, config, message):
text = random.choice(["Hi {}", "Hello {}", "Hey {}"]).format(message.user)
await message.respond(text)
```
*hello/\_\_init\_\_.py*
```
connectors:
- name: websocket
skills:
- name: hello
repo: "https://github.com/<user_id>/hello-skill"
```
*configuration.yaml*
### Errbot
[Errbot][17] 是一个功能齐全的开源聊天机器人。Errbot 发行于 2012 年，并且拥有人们从一个成熟的项目能期待的一切，包括良好的文档、优秀的教程以及许多帮你连入现有的流行聊天服务的插件。
#### 它内置了什么
不像采用了较轻量级方式的 Opsdroid，Errbot 自带了你需要可靠地创建一个自定义机器人的一切东西。
Errbot 包括了对于本地 XMPP、IRC、Slack、Hipchat 以及 Telegram 服务的支持。它通过社区支持的后端列出了另外十种服务。
#### Errbot 的优势
**良好的文档：** Errbot 的文档成熟易读。
**动态插件架构：** Errbot 允许你通过和聊天机器人交谈安全地安装、卸载、更新、启用以及禁用插件。这使得开发和添加特性十分简便。感谢 Errbot 的颗粒性授权系统，出于安全意识这所有的一切都可以被锁闭。
当某个人输入 `!help`，Errbot 使用你的插件的文档字符串来为可获取的命令生成文档，这使得了解每行命令的作用更加简便。
**内置的管理和安全特性：** Errbot 允许你限制拥有管理员权限的用户列表，甚至细粒度访问控制。比如说你可以限制特定用户或聊天房间访问特定命令。
**额外的插件框架：** Errbot 支持钩子、回调、子命令、webhook、轮询以及其它[更多特性][18]。如果那些还不够，你甚至可以编写[动态插件][19]。当你需要基于在远程服务器上的可用命令来启用对应的聊天命令时，这个特性十分有用。
**自带测试框架：** Errbot 支持 [pytest][20]，同时也自带一些能使你简便测试插件的有用功能。它的“[测试你的插件][21]”的文档出于深思熟虑，并提供了足够的资料让你上手。
#### Errbot 可能的不足
**以 “!” 开头：** 默认情况下，Errbot 命令发出时以一个惊叹号打头（`!help` 以及 `!hello`）。一些人可能会喜欢这样，但是另一些人可能认为这让人烦恼。谢天谢地，这很容易关掉。
**插件元数据** 首先，Errbot 的 [Hello World][22] 插件示例看上去易于使用。然而我无法加载我的插件，直到我进一步阅读了教程并发现我还需要一个 `.plug` 文档，这是一个 Errbot 用来加载插件的文档。这可能比较吹毛求疵了，但是在我深挖文档之前，这对我来说都不是显而易见的。
### 示例用法
```
import random
from errbot import BotPlugin, botcmd
class Hello(BotPlugin):
@botcmd
def hello(self, msg, args):
text = random.choice(["Hi {}", "Hello {}", "Hey {}"]).format(message.user)
return text
```
*hello.py*
```
[Core]
Name = Hello
Module = hello
[Python]
Version = 2+
[Documentation]
Description = Example "Hello" plugin
```
*hello.plug*
你用过 Errbot 或 Opsdroid 吗？如果用过请留下关于你对于这些工具印象的留言。
--------------------------------------------------------------------------------
via: https://opensource.com/article/18/3/python-chatops-libraries-opsdroid-and-errbot
作者：[Jeff Triplett][a], [Lacey Williams Henschel][1]
译者：[tomjlw](https://github.com/tomjlw)
校对：[wxy](https://github.com/wxy)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]:https://opensource.com/users/laceynwilliams
[1]:https://opensource.com/users/laceynwilliams
[2]:https://opsdroid.github.io/
[3]:https://github.com/opsdroid/skill-seen
[4]:https://github.com/opsdroid/skill-weather
[5]:https://opsdroid.readthedocs.io/en/stable/#docker
[6]:https://api.slack.com/bot-users
[7]:https://opsdroid.readthedocs.io/en/stable/extending/connectors/
[8]:https://opsdroid.readthedocs.io/en/stable/tutorials/introduction/
[9]:https://opsdroid.readthedocs.io/en/stable/extending/skills/
[10]:https://opsdroid.readthedocs.io/en/stable/extending/databases/
[11]:https://opsdroid.readthedocs.io/en/stable/matchers/overview/
[12]:https://opsdroid.readthedocs.io/en/stable/matchers/dialogflow/
[13]:https://opsdroid.readthedocs.io/en/stable/matchers/luis.ai/
[14]:https://opsdroid.readthedocs.io/en/stable/matchers/recast.ai/
[15]:https://opsdroid.readthedocs.io/en/stable/matchers/wit.ai/
[16]:https://opsdroid.readthedocs.io/en/stable/contributing/
[17]:http://errbot.io/en/latest/
[18]:http://errbot.io/en/latest/features.html#extensive-plugin-framework
[19]:http://errbot.io/en/latest/user_guide/plugin_development/dynaplugs.html
[20]:http://pytest.org/
[21]:http://errbot.io/en/latest/user_guide/plugin_development/testing.html
[22]:http://errbot.io/en/latest/index.html#simple-to-build-upon

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如何打造更小巧的容器镜像
======
> 五种优化 Linux 容器大小和构建更小的镜像的方法。
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/containers_scale_performance.jpg?itok=R7jyMeQf)
[Docker][1] 近几年的爆炸性发展让大家逐渐了解到容器和容器镜像的概念。尽管 Linux 容器技术在很早之前就已经出现，但这项技术近来的蓬勃发展却还是要归功于 Docker 对用户友好的命令行界面以及使用 Dockerfile 格式轻松构建镜像的方式。纵然 Docker 大大降低了入门容器技术的难度，但构建一个兼具功能强大、体积小巧的容器镜像的过程中，有很多技巧需要了解。
### 第一步：清理不必要的文件
这一步和在普通服务器上清理文件没有太大的区别，而且要清理得更加仔细。一个小体积的容器镜像在传输方面有很大的优势，同时，在磁盘上存储不必要的数据的多个副本也是对资源的一种浪费。因此，这些技术对于容器来说应该比有大量专用内存的服务器更加需要。
清理容器镜像中的缓存文件可以有效缩小镜像体积。下面的对比是使用 `dnf` 安装 [Nginx][2] 构建的镜像，分别是清理和没有清理 yum 缓存文件的结果：
```
# Dockerfile with cache
FROM fedora:28
LABEL maintainer Chris Collins <collins.christopher@gmail.com>
RUN dnf install -y nginx
-----
# Dockerfile w/o cache
FROM fedora:28
LABEL maintainer Chris Collins <collins.christopher@gmail.com>
RUN dnf install -y nginx \
&& dnf clean all \
&& rm -rf /var/cache/yum
-----
[chris@krang] $ docker build -t cache -f Dockerfile .
[chris@krang] $ docker images --format "{{.Repository}}: {{.Size}}"
| head -n 1
cache: 464 MB
[chris@krang] $ docker build -t no-cache -f Dockerfile-wo-cache .
[chris@krang] $ docker images --format "{{.Repository}}: {{.Size}}" | head -n 1
no-cache: 271 MB
```
从上面的结果来看，清理缓存文件的效果相当显著。和清除了元数据和缓存文件的容器镜像相比，不清除的镜像体积接近前者的两倍。除此以外，包管理器缓存文件、Ruby gem 的临时文件、nodejs 缓存文件，甚至是下载的源码 tarball 最好都全部清理掉。
### 层：一个潜在的隐患
很不幸（当你往下读，你会发现这是不幸中的万幸），根据容器中的层的概念，不能简单地向 Dockerfile 中写一句 `RUN rm -rf /var/cache/yum` 就完事儿了。因为 Dockerfile 的每一条命令都以一个层的形式存储，并一层层地叠加。所以，如果你是这样写的：
```
RUN dnf install -y nginx
RUN dnf clean all
RUN rm -rf /var/cache/yum
```
你的容器镜像就会包含三层，而 `RUN dnf install -y nginx` 这一层仍然会保留着那些缓存文件，然后在另外两层中被移除。但缓存实际上仍然是存在的，当你把一个文件系统挂载在另外一个文件系统之上时，文件仍然在那里，只不过你见不到也访问不到它们而已。
在上一节的示例中，你会看到正确的做法是将几条命令链接起来，在产生缓存文件的同一条 Dockerfile 指令里把缓存文件清理掉：
```
RUN dnf install -y nginx \
&& dnf clean all \
&& rm -rf /var/cache/yum
```
这样就把几条命令连成了一条命令，在最终的镜像中只占用一个层。这样只会浪费一点缓存的好处，稍微多耗费一点点构建容器镜像的时间，但被清理掉的缓存文件就不会留存在最终的镜像中了。作为一个折衷方法，只需要把一些相关的命令（例如 `yum install` 和 `yum clean all`、下载文件、解压文件、移除 tarball 等等）连接成一个命令，就可以在最终的容器镜像中节省出大量体积，你也能够利用 Docker 的缓存加快开发速度。
层还有一个更隐蔽的特性。每一层都记录了文件的更改，这里的更改并不仅仅已有的文件累加起来，而是包括文件属性在内的所有更改。因此即使是对文件使用了 `chmod` 操作也会被在新的层创建文件的副本。
下面是一次 `docker images` 命令的输出内容。其中容器镜像 `layer_test_1` 是在 CentOS 基础镜像中增加了一个 1GB 大小的文件后构建出来的镜像，而容器镜像 `layer_test_2` 是使用了 `FROM layer_test_1` 语句创建出来的，除了执行一条 `chmod u+x` 命令没有做任何改变。
```
layer_test_2 latest e11b5e58e2fc 7 seconds ago 2.35 GB
layer_test_1 latest 6eca792a4ebe 2 minutes ago 1.27 GB
```
如你所见，`layer_test_2` 镜像比 `layer_test_1` 镜像大了 1GB 以上。尽管事实上 `layer_test_1` 只是 `layer_test_2` 的前一层，但隐藏在这第二层中有一个额外的 1GB 的文件。在构建容器镜像的过程中，如果在单独一层中进行移动、更改、删除文件，都会出现类似的结果。
### 专用镜像和公用镜像
有这么一个亲身经历：我们部门重度依赖于 [Ruby on Rails][3]，于是我们开始使用容器。一开始我们就建立了一个正式的 Ruby 的基础镜像供所有的团队使用，为了简单起见（以及在“这就是我们自己在服务器上瞎鼓捣的”想法的指导下），我们使用 [rbenv][4] 将 Ruby 最新的 4 个版本都安装到了这个镜像当中，目的是让开发人员只用这个单一的镜像就可以将使用不同版本 Ruby 的应用程序迁移到容器中。我们当时还认为这是一个虽然非常大但兼容性相当好的镜像，因为这个镜像可以同时满足各个团队的使用。
实际上这是费力不讨好的。如果维护独立的、版本略微不同的镜像中，可以很轻松地实现镜像的自动化维护。同时，选择特定版本的特定镜像，还有助于在引入破坏性改变，在应用程序接近生命周期结束前提前做好预防措施，以免产生不可控的后果。庞大的公用镜像也会对资源造成浪费，当我们后来将这个庞大的镜像按照 Ruby 版本进行拆分之后，我们最终得到了共享一个基础镜像的多个镜像，如果它们都放在一个服务器上，会额外多占用一点空间，但是要比安装了多个版本的巨型镜像要小得多。
这个例子也不是说构建一个灵活的镜像是没用的，但仅对于这个例子来说，从一个公共镜像创建根据用途而构建的镜像最终将节省存储资源和维护成本，而在受益于公共基础镜像的好处的同时，每个团队也能够根据需要来做定制化的配置。
### 从零开始：将你需要的内容添加到空白镜像中
有一些和 Dockerfile 一样易用的工具可以轻松创建非常小的兼容 Docker 的容器镜像，这些镜像甚至不需要包含一个完整的操作系统，就可以像标准的 Docker 基础镜像一样小。
我曾经写过一篇[关于 Buildah 的文章][5]，我想在这里再一次推荐一下这个工具。因为它足够的灵活，可以使用宿主机上的工具来操作一个空白镜像并安装打包好的应用程序，而且这些工具不会被包含到镜像当中。
Buildah 取代了 `docker build` 命令。可以使用 Buildah 将容器的文件系统挂载到宿主机上并进行交互。
下面来使用 Buildah 实现上文中 Nginx 的例子（现在忽略了缓存的处理）：
```
#!/usr/bin/env bash
set -o errexit
# Create a container
container=$(buildah from scratch)
# Mount the container filesystem
mountpoint=$(buildah mount $container)
# Install a basic filesystem and minimal set of packages, and nginx
dnf install --installroot $mountpoint --releasever 28 glibc-minimal-langpack nginx --setopt install_weak_deps=false -y
# Save the container to an image
buildah commit --format docker $container nginx
# Cleanup
buildah unmount $container
# Push the image to the Docker daemon’s storage
buildah push nginx:latest docker-daemon:nginx:latest
```
你会发现这里使用的已经不再是 Dockerfile 了，而是普通的 Bash 脚本，而且是从框架（或空白）镜像开始构建的。上面这段 Bash 脚本将容器的根文件系统挂载到了宿主机上，然后使用宿主机的命令来安装应用程序，这样的话就不需要把软件包管理器放置到容器镜像中了。
这样所有无关的内容（基础镜像之外的部分，例如 `dnf`）就不再会包含在镜像中了。在这个例子当中，构建出来的镜像大小只有 304 MB，比使用 Dockerfile 构建的镜像减少了 100 MB 以上。
```
[chris@krang] $ docker images |grep nginx
docker.io/nginx buildah 2505d3597457 4 minutes ago 304 MB
```
注：这个镜像是使用上面的构建脚本构建的，镜像名称中前缀的 `docker.io` 只是在推送到镜像仓库时加上的。
对于一个 300MB 级别的容器基础镜像来说，能缩小 100MB 已经是很显著的节省了。使用软件包管理器来安装 Nginx 会带来大量的依赖项，如果能够使用宿主机直接从源代码对应用程序进行编译然后构建到容器镜像中，节省出来的空间还可以更多，因为这个时候可以精细的选用必要的依赖项，非必要的依赖项一概不构建到镜像中。
[Tom Sweeney][6] 有一篇文章《[用 Buildah 构建更小的容器][7]》，如果你想在这方面做深入的优化，不妨参考一下。
通过 Buildah 可以构建一个不包含完整操作系统和代码编译工具的容器镜像，大幅缩减了容器镜像的体积。对于某些类型的镜像，我们可以进一步采用这种方式，创建一个只包含应用程序本身的镜像。
### 使用静态链接的二进制文件来构建镜像
按照这个思路，我们甚至可以更进一步舍弃容器内部的管理和构建工具。例如，如果我们足够专业，不需要在容器中进行排错调试，是不是可以不要 Bash 了？是不是可以不要 [GNU 核心套件][8]了？是不是可以不要 Linux 基础文件系统了？如果你使用的编译型语言支持[静态链接库][9]，将应用程序所需要的所有库和函数都编译成二进制文件，那么程序所需要的函数和库都可以复制和存储在二进制文件本身里面。
这种做法在 [Golang][10] 社区中已经十分常见，下面我们使用由 Go 语言编写的应用程序进行展示：
以下这个 Dockerfile 基于 golang:1.8 镜像构建一个小的 Hello World 应用程序镜像：
```
FROM golang:1.8
ENV GOOS=linux
ENV appdir=/go/src/gohelloworld
COPY ./ /go/src/goHelloWorld
WORKDIR /go/src/goHelloWorld
RUN go get
RUN go build -o /goHelloWorld -a
CMD ["/goHelloWorld"]
```
构建出来的镜像中包含了二进制文件、源代码以及基础镜像层，一共 716MB。但对于应用程序运行唯一必要的只有编译后的二进制文件，其余内容在镜像中都是多余的。
如果在编译的时候通过指定参数 `CGO_ENABLED=0` 来禁用 `cgo`，就可以在编译二进制文件的时候忽略某些函数的 C 语言库：
```
GOOS=linux CGO_ENABLED=0 go build -a goHelloWorld.go
```
编译出来的二进制文件可以加到一个空白（或框架）镜像：
```
FROM scratch
COPY goHelloWorld /
CMD ["/goHelloWorld"]
```
来看一下两次构建的镜像对比：
```
[ chris@krang ] $ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
goHello scratch a5881650d6e9 13 seconds ago 1.55 MB
goHello builder 980290a100db 14 seconds ago 716 MB
```
从镜像体积来说简直是天差地别了。基于 golang:1.8 镜像构建出来带有 goHelloWorld 二进制的镜像（带有 `builder` 标签）体积是基于空白镜像构建的只包含该二进制文件的镜像的 460 倍！后者的整个镜像大小只有 1.55MB，也就是说，有 713MB 的数据都是非必要的。
正如上面提到的，这种缩减镜像体积的方式在 Golang 社区非常流行，因此不乏这方面的文章。[Kelsey Hightower][11] 有一篇[文章][12]专门介绍了如何处理这些库的依赖关系。
### 压缩镜像层
除了前面几节中讲到的将多个命令链接成一个命令的技巧，还可以对镜像进行压缩。镜像压缩的实质是导出它，删除掉镜像构建过程中的所有中间层，然后保存镜像的当前状态为单个镜像层。这样可以进一步将镜像缩小到更小的体积。
在 Docker 1.13 之前，压缩镜像层的的过程可能比较麻烦，需要用到 `docker-squash` 之类的工具来导出容器的内容并重新导入成一个单层的镜像。但 Docker 在 Docker 1.13 中引入了 `--squash` 参数，可以在构建过程中实现同样的功能：
```
FROM fedora:28
LABEL maintainer Chris Collins <collins.christopher@gmail.com>
RUN dnf install -y nginx
RUN dnf clean all
RUN rm -rf /var/cache/yum
[chris@krang] $ docker build -t squash -f Dockerfile-squash --squash .
[chris@krang] $ docker images --format "{{.Repository}}: {{.Size}}" | head -n 1
squash: 271 MB
```
通过这种方式使用 Dockerfile 构建出来的镜像有 271MB 大小，和上面连接多条命令的方案构建出来的镜像体积一样，因此这个方案也是有效的，但也有一个潜在的问题，而且是另一种问题。
“什么？还有另外的问题？”
好吧，有点像以前一样的问题，以另一种方式引发了问题。
### 过头了：过度压缩、太小太专用了
容器镜像之间可以共享镜像层。基础镜像或许大小上有几 Mb，但它只需要拉取/存储一次，并且每个镜像都能复用它。所有共享基础镜像的实际镜像大小是基础镜像层加上每个特定改变的层的差异内容，因此，如果有数千个基于同一个基础镜像的容器镜像，其体积之和也有可能只比一个基础镜像大不了多少。
因此，这就是过度使用压缩或专用镜像层的缺点。将不同镜像压缩成单个镜像层，各个容器镜像之间就没有可以共享的镜像层了，每个容器镜像都会占有单独的体积。如果你只需要维护少数几个容器镜像来运行很多容器，这个问题可以忽略不计；但如果你要维护的容器镜像很多，从长远来看，就会耗费大量的存储空间。
回顾上面 Nginx 压缩的例子，我们能看出来这种情况并不是什么大的问题。在这个镜像中，有 Fedora 操作系统和 Nginx 应用程序，没有缓存，并且已经被压缩。但我们一般不会使用一个原始的 Nginx，而是会修改配置文件，以及引入其它代码或应用程序来配合 Nginx 使用，而要做到这些，Dockerfile 就变得更加复杂了。
如果使用普通的镜像构建方式，构建出来的容器镜像就会带有 Fedora 操作系统的镜像层、一个安装了 Nginx 的镜像层（带或不带缓存）、为 Nginx 作自定义配置的其它多个镜像层，而如果有其它容器镜像需要用到 Fedora 或者 Nginx，就可以复用这个容器镜像的前两层。
```
[ App 1 Layer ( 5 MB) ] [ App 2 Layer (6 MB) ]
[ Nginx Layer ( 21 MB) ] ------------------^
[ Fedora Layer (249 MB) ]
```
如果使用压缩镜像层的构建方式，Fedora 操作系统会和 Nginx 以及其它配置内容都被压缩到同一层里面，如果有其它容器镜像需要使用到 Fedora，就必须重新引入 Fedora 基础镜像，这样每个容器镜像都会额外增加 249MB 的大小。
```
[ Fedora + Nginx + App 1 (275 MB)] [ Fedora + Nginx + App 2 (276 MB) ]
```
当你构建了大量在功能上趋于分化的的小型容器镜像时，这个问题就会暴露出来了。
就像生活中的每一件事一样，关键是要做到适度。根据镜像层的实现原理，如果一个容器镜像变得越小、越专用化，就越难和其它容器镜像共享基础的镜像层，这样反而带来不好的效果。
对于仅在基础镜像上做微小变动构建出来的多个容器镜像，可以考虑共享基础镜像层。如上所述，一个镜像层本身会带有一定的体积，但只要存在于镜像仓库中，就可以被其它容器镜像复用。这种情况下，数千个镜像也许要比单个镜像占用更少的空间。
```
[ specific app ] [ specific app 2 ]
[ customizations ]--------------^
[ base layer ]
```
一个容器镜像变得越小、越专用化，就越难和其它容器镜像共享基础的镜像层，最终会不必要地占用越来越多的存储空间。
```
[ specific app 1 ] [ specific app 2 ] [ specific app 3 ]
```
### 总结
减少处理容器镜像时所需的存储空间和带宽的方法有很多，其中最直接的方法就是减小容器镜像本身的大小。在使用容器的过程中，要经常留意容器镜像是否体积过大，根据不同的情况采用上述提到的清理缓存、压缩到一层、将二进制文件加入在空白镜像中等不同的方法，将容器镜像的体积缩减到一个有效的大小。
--------------------------------------------------------------------------------
via: https://opensource.com/article/18/7/building-container-images
作者：[Chris Collins][a]
选题：[lujun9972](https://github.com/lujun9972)
译者：[HankChow](https://github.com/HankChow)
校对：[wxy](https://github.com/wxy)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]:https://opensource.com/users/clcollins
[1]:https://www.docker.com/
[2]:https://www.nginx.com/
[3]:https://rubyonrails.org/
[4]:https://github.com/rbenv/rbenv
[5]:https://opensource.com/article/18/6/getting-started-buildah
[6]:https://twitter.com/TSweeneyRedHat
[7]:https://opensource.com/article/18/5/containers-buildah
[8]:https://www.gnu.org/software/coreutils/coreutils.html
[9]:https://en.wikipedia.org/wiki/Static_library
[10]:https://golang.org/
[11]:https://twitter.com/kelseyhightower
[12]:https://medium.com/@kelseyhightower/optimizing-docker-images-for-static-binaries-b5696e26eb07

22
translated/tech/20190125 Get started with Freeplane, an open source mind mapping application.md → published/20190125 Get started with Freeplane, an open source mind mapping application.md
View File

@ -1,40 +1,40 @@
[#]: collector: (lujun9972)
[#]: translator: (geekpi)
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: reviewer: (wxy)
[#]: publisher: (wxy)
[#]: url: (https://linux.cn/article-10648-1.html)
[#]: subject: (Get started with Freeplane, an open source mind mapping application)
[#]: via: (https://opensource.com/article/19/1/productivity-tool-freeplane)
[#]: author: (Kevin Sonney https://opensource.com/users/ksonney (Kevin Sonney))
开始使用 Freeplane，一款开源思维导图
开始使用 Freeplane 吧，一款开源思维导图
======
使用 Freeplane 进行头脑风暴，这是我们开源工具系列中的第 13 个，它将使你在 2019 年更高效。
> 使用 Freeplane 进行头脑风暴，这是我们开源工具系列中的第 13 个，它将使你在 2019 年更高效。
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/brain_data.png?itok=RH6NA32X)
每年年初似乎都有疯狂的冲动，想方设法提高工作效率。新年的决议，开始一年的权利，当然，“与旧的，与新的”的态度都有助于实现这一目标。通常的一轮建议严重偏向封闭源和专有软件。它不一定是这样。
每年年初似乎都有疯狂的冲动想提高工作效率。新年的决心，渴望开启新的一年，当然，“抛弃旧的，拥抱新的”的态度促成了这一切。通常这时的建议严重偏向闭源和专有软件，但事实上并不用这样。
这是我挑选出的 19 个新的（或者对你而言新的）开源工具中的第 13 个工具来帮助你在 2019 年更有效率。
### Freeplane
[思维导图][1]是我用于快速头脑风暴和捕捉数据的最有价值的工具之一。思维导图是一个灵活的过程，有助于显示事物的相关性，并可用于快速组织相互关联的信息。从规划角度来看，思维导图让你快速将大脑中的单个概念，想法或技术表达除了。
[思维导图][1]是我用于快速头脑风暴和捕捉数据的最有价值的工具之一。思维导图是一个灵活的过程，有助于显示事物的相关性，并可用于快速组织相互关联的信息。从规划角度来看，思维导图让你快速将大脑中的单个概念、想法或技术表达出来。
![](https://opensource.com/sites/default/files/uploads/freeplane-1.png)
[Freeplane][2] 是一款桌面应用，可以轻松创建、查看、编辑和共享思维导图。它是 [FreeMind][3] 这款很长时间内都是思维导图首选应用的重新设计。
[Freeplane][2] 是一款桌面应用，可以轻松创建、查看、编辑和共享思维导图。它是 [FreeMind][3] 这款很长时间内都是思维导图首选应用的重新打造。
安装 Freeplane 非常简单。它是一个 [Java][4] 应用，并使用 ZIP 文件分发，可使用脚本在 Linux、Windows 和 MacOS 上启动。在第一次启动它时，主窗口会包含一个示例思维导图，其中包含指向你可以使用 Freeplane 执行的所有不同操作的文档的链接。
![](https://opensource.com/sites/default/files/uploads/freeplane-2.png)
创建新思维导图时，你可以选择模板。标准模板（可能位于列表底部）适用于大多数情况。你只需开始输入开头的想法或短语，你的文本就会替换中心的文本。按“插入”键将从中心添加一个分支（或节点），其中包含一个空白字段，你可以在其中填写与该想法相关的内容。再次按“插入”将添加另一个节点到第一个上。在节点上按“回车”键将添加与该节点平行的节点。
创建新思维导图时，你可以选择模板。标准模板（可能位于列表底部）适用于大多数情况。你只需开始输入开头的想法或短语，你的文本就会替换中心的文本。按“Insert”键将从中心添加一个分支（或节点），其中包含一个空白字段，你可以在其中填写与该想法相关的内容。再次按“Insert”将添加另一个节点到第一个上。在节点上按回车键将添加与该节点平行的节点。
![](https://opensource.com/sites/default/files/uploads/freeplane-3.png)
在添加节点时，你可能会想到与主题相关的另一个想法。使用鼠标或箭头键，返回到导图的中心，然后按“插入”键。这将在主题之外创建一个新节点。
在添加节点时，你可能会想到与主题相关的另一个想法。使用鼠标或箭头键，返回到导图的中心，然后按“Insert”键。这将在主题之外创建一个新节点。
如果你想使用 Freeplane 其他功能，请右键单击任何节点以显示该节点的“属性”菜单。工具窗口（在视图 ->控制菜单下激活）包含丰富的自定义选项，包括线条形状和粗细、边框形状、颜色等等。“日历”选项允许你在节点中插入日期，并为节点设置到期提醒。 （请注意，提醒仅在 Freeplane 运行时有效。）思维导图可以导出为多种格式，包括常见的图像、XML、Microsoft Project、Markdown 和 OPML。
@ -49,7 +49,7 @@ via: https://opensource.com/article/19/1/productivity-tool-freeplane
作者：[Kevin Sonney][a]
选题：[lujun9972][b]
译者：[geekpi](https://github.com/geekpi)
校对：[校对者ID](https://github.com/校对者ID)
校对：[wxy](https://github.com/wxy)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出

20
translated/tech/20190131 19 days of productivity in 2019- The fails.md → published/20190131 19 days of productivity in 2019- The fails.md
View File

@ -1,28 +1,30 @@
[#]: collector: (lujun9972)
[#]: translator: (geekpi)
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: reviewer: (wxy)
[#]: publisher: (wxy)
[#]: url: (https://linux.cn/article-10654-1.html)
[#]: subject: (19 days of productivity in 2019: The fails)
[#]: via: (https://opensource.com/article/19/1/productivity-tool-wish-list)
[#]: author: (Kevin Sonney https://opensource.com/users/ksonney (Kevin Sonney))
2019 年的 19 个高效日：失败了
======
以下是开源世界没有做到的一些工具。
> 以下是开源世界没有做到的一些工具。
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/tools_sysadmin_cloud.png?itok=sUciG0Cn)
每年年初似乎都有疯狂的冲动想提高工作效率。新年的决心，渴望开启新的一年，当然，“抛弃旧的，拥抱新的”的态度促成了这一切。通常这时的建议严重偏向闭源和专有软件，但事实上并不用这样。
保持高效一部分是接受失败发生。我是 [Howard Tayler's][1] 的第 70 条座右铭的支持者：“失败不是一种选择，它是一定的。可以选择的是是否让失败成为你做的最后一件事。”我对这个系列的有很多话想多，但是我没有找到好的答案。
保持高效一部分是接受失败。我是 [Howard Tayler][1] 的第 70 条座右铭的支持者：“失败不是一种选择，它是一定的。可以选择的是是否让失败成为你做的最后一件事。”在这个系列中我想谈的很多事情都没有找到好的答案。
关于我的 19 个新的（或对你而言新的）帮助你在 2019 年更高效的工具的最终版，我想到了一些我想要的，但是没有找到的。我希望读者你能够帮我找到下面这些项目的好的方案。如果你发现了，请在下面的留言中分享。
关于我的 19 个新的（或对你而言新的）帮助你在 2019 年更高效的工具的最终版，我想到了一些我想要，但是有没有找到的。我希望读者你能够帮我找到下面这些项目的好的方案。如果你发现了，请在下面的留言中分享。
### 日历
![](https://opensource.com/sites/default/files/uploads/thunderbird-1.png)
如果开源世界有一件事缺乏，那就是日历。我尝试过的日历程序和尝试电子邮件程序的数量一样多。共享日历基本上有三个很好的选择：[Evolution][2]、[Thunderbird 中的 Lightning 附加组件][3] 或 [KOrganizer][4]。我尝试过的所有其他应用 (包括 [Orage][5]、[Osmo][6] 以及几乎所有 [Org 模式][7]附加组件) 似乎只可靠地支持对远程日历的只读访问。如果共享日历使用 [Google 日历][8] 或 [Microsoft Exchange][9] 作为服务器，那么前三个是唯一易于配置的选择（即便如此，通常还需要其他附加组件）。
如果开源世界有一件事缺乏，那就是日历。我尝试过的日历程序和电子邮件程序的数量一样多。共享日历基本上有三个很好的选择：[Evolution][2]、[Thunderbird 中的 Lightning 附加组件][3] 或 [KOrganizer][4]。我尝试过的所有其他应用 (包括 [Orage][5]、[Osmo][6] 以及几乎所有 [Org 模式][7]附加组件) 似乎只能可靠地支持对远程日历的只读访问。如果共享日历使用 [Google 日历][8] 或 [Microsoft Exchange][9] 作为服务器，那么前三个是唯一易于配置的选择（即便如此，通常还需要其他附加组件）。
### Linux 内核的系统
@ -36,7 +38,7 @@
![](https://opensource.com/sites/default/files/uploads/opennms_jira_dashboard-3.png)
对于大大小小的公司来说，客户服务是一件大事。现在，随着近来对 DevOps 的关注，有必要使用工具来弥补差距。我工作的几乎每家公司都使用 [Jira][15]、[GitHub][16] 或 [GitLab][17] 来提代码问题，但这些工具都不是很擅长客户支持工单（没有很多工作）。虽然围绕客户支持工单和问题设计了许多应用，但大多数（如果不是全部）应用都是与其他系统不兼容的孤岛，同样没有大量工作。
对于大大小小的公司来说，客户服务是一件大事。现在，随着近来对 DevOps 的关注，有必要使用工具来弥补差距。我工作的几乎每家公司都使用 [Jira][15]、[GitHub][16] 或 [GitLab][17] 来报告代码问题，但这些工具都不是很擅长于客户支持工单（除非付出大量的工作）。虽然围绕客户支持工单和问题设计了许多应用，但大多数（如果不是全部）应用都是与其他系统不兼容的孤岛（同样除非付出了大量的工作）。
我的愿望是有一个开源解决方案，它能让客户、支持人员和开发人员一起工作，而无需笨重的代码将多个系统粘合在一起。
@ -53,7 +55,7 @@ via: https://opensource.com/article/19/1/productivity-tool-wish-list
作者：[Kevin Sonney][a]
选题：[lujun9972][b]
译者：[geekpi](https://github.com/geekpi)
校对：[校对者ID](https://github.com/校对者ID)
校对：[wxy](https://github.com/wxy)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出

65
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@ -1,8 +1,8 @@
[#]: collector: (lujun9972)
[#]: translator: (FSSlc)
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: reviewer: (wxy)
[#]: publisher: (wxy)
[#]: url: (https://linux.cn/article-10651-1.html)
[#]: subject: (4 Methods To Change The HostName In Linux)
[#]: via: (https://www.2daygeek.com/four-methods-to-change-the-hostname-in-linux/)
[#]: author: (Magesh Maruthamuthu https://www.2daygeek.com/author/magesh/)
@ -10,9 +10,7 @@
Linux 中改变主机名的 4 种方法
======
昨天我们已经在我们的网站中写过[如何在 Linux 中修改主机名的文章][1]。
今天，我们将向你展示使用不同的方法来修改主机名。你可以从中选取最适合你的方法。
昨天我们已经在我们的网站中写过[如何在 Linux 中修改主机名的文章][1]。今天，我们将向你展示使用不同的方法来修改主机名。你可以从中选取最适合你的方法。
使用 `systemd` 的系统自带一个名为 `hostnamectl` 的好用工具，它可以使我们能够轻易地管理系统的主机名。
@ -24,31 +22,29 @@ Linux 中改变主机名的 4 种方法
`hostnamectl` 命令允许在 Linux 中设置三类主机名，它们的细节如下：
* **`静态：`** 这是静态主机名，由系统管理员添加。
* **`瞬时/动态：`** 这个由 DHCP 或者 DNS 服务器在运行时赋予。
* **`易读形式：`** 它可以由系统管理员赋予。这个是自由形式的主机名，以一种易读形式来表示服务器，例如 `JBOSS UAT Server` 这样的名字。
* **静态：** 这是静态主机名，由系统管理员添加。
* **瞬时/动态：** 这个由 DHCP 或者 DNS 服务器在运行时赋予。
* **易读形式：** 它可以由系统管理员赋予。这个是自由形式的主机名，以一种易读形式来表示服务器，例如 “JBOSS UAT Server” 这样的名字。
这些都可以使用下面 4 种方法来设置。
* **`hostnamectl 命令：`** `hostnamectl` 命令控制系统主机名。
* **`nmcli 命令：`** `nmcli` 是一个控制 `NetworkManager` 的命令行工具。
* **`nmtui 命令：`** `nmtui` 是一个控制 `NetworkManager` 的文本用户界面。
* **`/etc/hostname 文件：`** 这个文件中包含系统的静态主机名。
* `hostnamectl` 命令：控制系统主机名。
* `nmcli` 命令：是一个控制 NetworkManager 的命令行工具。
* `nmtui` 命令：是一个控制 NetworkManager 的文本用户界面。
* `/etc/hostname` 文件：这个文件中包含系统的静态主机名。
### 方法 1：在 Linux 中使用 hostnamectl 来改变主机名
### 方法 1：在 Linux 中使用 `hostnamectl` 来改变主机名
`hostnamectl` 可被用来查询和改变系统的主机名，以及相关设定。
只需运行 `hostnamectl` 便可以查看系统的主机名了。
`hostnamectl` 可被用来查询和改变系统的主机名，以及相关设定。只需运行 `hostnamectl` 便可以查看系统的主机名了。
```
$ hostnamectl
```
或者使用下面的命令
或者使用下面的命令：
```
$ hostnamectl status
Static hostname: daygeek-Y700
Icon name: computer-laptop
Chassis: laptop
@ -61,7 +57,7 @@ $ hostnamectl status
假如你想改变主机名，可以使用下面的命令格式：
**一般的语法：**
语法格式：
```
$ hostnamectl set-hostname [YOUR NEW HOSTNAME]
@ -87,9 +83,9 @@ $ hostnamectl
Architecture: x86-64
```
### 方法 2：在 Linux 中使用 `nmcli` 命令来更改主机名
### 方法 2：在 Linux 中使用 nmcli 命令来更改主机名
`nmcli` 是一个命令行工具，旨在控制 `NetworkManager` 并报告网络状态。
`nmcli` 是一个命令行工具，旨在控制 NetworkManager 并报告网络状态。
`nmcli` 被用来创建、展示、编辑、删除、激活和注销网络连接，同时还可以用来控制和展示网络设备的状态。另外，它也允许我们更改主机名。
@ -100,7 +96,7 @@ $ nmcli general hostname
daygeek-Y700
```
**一般语法：**
语法格式：
```
$ nmcli general hostname [YOUR NEW HOSTNAME]
@ -125,9 +121,9 @@ $ nmcli general hostname
magi-laptop
```
### 方法 3：在 Linux 中使用 `nmtui` 来更改主机名
### 方法 3：在 Linux 中使用 nmtui 来更改主机名
`nmtui` 是一个基于 `curses` 库的 TUI 应用，被用来和 `NetworkManager` 交互。当启动 `nmtui` 后，它将提醒用户选择执行某项活动，除非指定了 `nmtui` 的第一个命令行参数。
`nmtui` 是一个基于 `curses` 库的 TUI 应用，被用来和 NetworkManager 交互。当启动 `nmtui` 后，如果没有指定 `nmtui` 的第一个命令行参数，它将提醒用户选择执行某项活动。
在终端中运行下面的命令来开启文本用户界面。
@ -135,19 +131,24 @@ magi-laptop
$ nmtui
```
使用带有 `向下箭头标记` 的按键来选择 `Set system hostname` 这个选项，然后敲击 `Enter` 键。
使用向下箭头按键来选择 “Set system hostname” 这个选项，然后敲击回车键。
![][3]
下面的截图展示的是原来的主机名。
![][4]
我们需要做的就是删除原来的主机名，再输入新的主机名，然后选中 `OK` 敲击确认就可以了。
我们需要做的就是删除原来的主机名，再输入新的主机名，然后选中 “OK” 敲击回车确认就可以了。
![][5]
然后它将在屏幕中向你展示更新后的主机名，再次选中 `OK` 敲击确认就完成更改了。
然后它将在屏幕中向你展示更新后的主机名，再次选中 “OK” 敲击回车确认就完成更改了。
![][6]
最后，选中 `Quit` 按钮来从 `nmtui` 终端界面离开。
最后，选中 “Quit” 按钮来从 `nmtui` 终端界面离开。
![][7]
它可以在不重启设备的情况下生效，但为了安全目的，需要重启 `systemd-hostnamed` 服务来使得更改生效。
@ -170,7 +171,7 @@ $ hostnamectl
Architecture: x86-64
```
### 方法 4：在 Linux 中使用 `/etc/hostname` 来更改主机名
### 方法 4：在 Linux 中使用 /etc/hostname 来更改主机名
除了上面的方法外，我们还可以通过修改 `/etc/hostname` 文件来达到修改主机名的目的。但这个方法需要服务器重启才能生效。
@ -210,7 +211,7 @@ via: https://www.2daygeek.com/four-methods-to-change-the-hostname-in-linux/
作者：[Magesh Maruthamuthu][a]
选题：[lujun9972][b]
译者：[FSSlc](https://github.com/FSSlc)
校对：[校对者ID](https://github.com/校对者ID)
校对：[wxy](https://github.com/wxy)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出

64
translated/tech/20190220 Set up two-factor authentication for SSH on Fedora.md → published/20190220 Set up two-factor authentication for SSH on Fedora.md
View File

@ -1,26 +1,26 @@
[#]: collector: (lujun9972)
[#]: translator: (MjSeven)
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: reviewer: (wxy)
[#]: publisher: (wxy)
[#]: url: (https://linux.cn/article-10646-1.html)
[#]: subject: (Set up two-factor authentication for SSH on Fedora)
[#]: via: (https://fedoramagazine.org/two-factor-authentication-ssh-fedora/)
[#]: author: (Curt Warfield https://fedoramagazine.org/author/rcurtiswarfield/)
在 Fedora 上为 SSH 设置双因素验证
在 Fedora 上为 SSH 设置双因子验证
======
![](https://fedoramagazine.org/wp-content/uploads/2019/02/twofactor-auth-ssh-816x345.png)
每天似乎都有一个安全漏洞的新闻报道，说我们的数据会因此而存在风险。尽管 SSH 是一种远程连接系统的安全方式，但你仍然可以使它更安全。本文将向你展示如何做到这一点。
此时双因素验证（2FA）就有用武之地了。即使你禁用密码并只允许使用公钥和私钥进行 SSH 连接，但如果未经授权的用户偷窃了你的密钥，他仍然可以借此访问系统。
此时<ruby>双因子验证<rt>two-factor authentication</rt></ruby>（2FA）就有用武之地了。即使你禁用密码并只允许使用公钥和私钥进行 SSH 连接，但如果未经授权的用户偷窃了你的密钥，他仍然可以借此访问系统。
使用双因素验证，你不能仅使用 SSH 密钥连接到服务器，你还需要提供手机上验证器应用程序随机生成的数字。
使用双因子验证，你不能仅仅使用 SSH 密钥连接到服务器，你还需要提供手机上的验证器应用程序随机生成的数字。
本文展示的方法是基于时间的一次性密码算法（TOTP）。[Google Authenticator][1] 用作服务器应用程序。默认情况下，Google Authenticator 在 Fedora 中是可用的。
本文展示的方法是<ruby>基于时间的一次性密码<rt>Time-based One-time Password</rt></ruby>（TOTP）算法。[Google Authenticator][1] 用作服务器应用程序。默认情况下，Google Authenticator 在 Fedora 中是可用的。
至于手机，你可以使用与 TOTP 兼容的任何可以双向验证的应用程序。Andorid 或 IOS 有许多可以与 TOTP 和 Google Authenticator 配合使用的免费应用程序。本文与 [FreeOTP][2] 为例。
至于手机，你可以使用与 TOTP 兼容的任何可以双路验证的应用程序。Andorid 或 iOS 有许多可以与 TOTP 和 Google Authenticator 配合使用的免费应用程序。本文与 [FreeOTP][2] 为例。
### 安装并设置 Google Authenticator
@ -36,18 +36,19 @@ $ google-authenticator
```
该应用程序提供了一系列问题。下面的片段展示了如何进行合理的安全设置：
```
Do you want authentication tokens to be time-based (y/n) y
Do you want me to update your "/home/user/.google_authenticator" file (y/n)? y
```
这个应用程序为你提供一个密钥，验证码和恢复码。把它们放在安全的地方。如果你丢失了手机，恢复码是访问服务器的**唯一**方式。
这个应用程序为你提供一个密钥、验证码和恢复码。把它们放在安全的地方。如果你丢失了手机，恢复码是访问服务器的**唯一**方式。
### 设置手机验证
在你的手机上安装 authenticator 应用程序（FreeOTP）。如果你有一台安卓手机，那么你可以在 Google Play 中找到它，也可以在苹果 iPhone 的 iTunes 商店中找到它。
在你的手机上安装验证器应用程序（FreeOTP）。如果你有一台安卓手机，那么你可以在 Google Play 中找到它，也可以在苹果 iPhone 的 iTunes 商店中找到它。
Google Authenticator 会在屏幕上显示一个二维码。打开手机上的 FreeOTP 应用程序，选择添加新账户，在应用程序顶部选择二维码形状工具，然后扫描二维码即可。设置完成后，在每次远程连接服务器时，你必须提供 authenticator 应用程序生成的随机数。
Google Authenticator 会在屏幕上显示一个二维码。打开手机上的 FreeOTP 应用程序，选择添加新账户，在应用程序顶部选择二维码形状工具，然后扫描二维码即可。设置完成后，在每次远程连接服务器时，你必须提供验证器应用程序生成的随机数。
### 完成配置
@ -61,82 +62,87 @@ If the computer that you are logging into isn't hardened against brute-force log
Do you want to enable rate-limiting (y/n) y
```
现在，你必须设置 SSH 来利用新的双向验证。
现在，你必须设置 SSH 来利用新的双路验证。
### 配置 SSH
在完成此步骤之前，**确保你已使用公钥建立了一个可用的 SSH 连接**，因为我们将禁用密码连接。如果出现问题或错误，一个已经建立的连接将允许你修复问题。
在你的服务器上，使用 [sudo][3] 编辑 /etc/pam.d/sshd 文件。
在你的服务器上，使用 [sudo][3] 编辑 `/etc/pam.d/sshd` 文件。
```
$ sudo vi /etc/pam.d/ssh
```
注释掉 auth substack password-auth 这一行：
注释掉 `auth substack password-auth` 这一行：
```
#auth       substack     password-auth
```
将以下行添加到文件底部。
将以下行添加到文件底部：
```
auth sufficient pam_google_authenticator.so
```
保存并关闭文件。然后编辑 /etc/ssh/sshd_config 文件。
保存并关闭文件。然后编辑 `/etc/ssh/sshd_config` 文件：
```
$ sudo vi /etc/ssh/sshd_config
```
找到 ChallengeResponseAuthentication 这一行并将其更改为 yes。
找到 `ChallengeResponseAuthentication` 这一行并将其更改为 `yes`：
```
ChallengeResponseAuthentication yes
```
找到 PasswordAuthentication 这一行并将其更改为 no。
找到 `PasswordAuthentication` 这一行并将其更改为 `no`：
```
PasswordAuthentication no
```
将以下行添加到文件底部。
将以下行添加到文件底部：
```
AuthenticationMethods publickey,password publickey,keyboard-interactive
```
保存并关闭文件，然后重新启动 SSH。
保存并关闭文件，然后重新启动 SSH：
```
$ sudo systemctl restart sshd
```
### 测试双因素验证
### 测试双因子验证
当你尝试连接到服务器时，系统会提示你输入验证码：
```
[user@client ~]$ ssh user@example.com
Verification code:
```
验证码由你手机上的 authenticator 应用程序随机生成。由于这个数字每隔几秒就会发生变化，因此你需要在它变化之前输入它。
验证码由你手机上的验证器应用程序随机生成。由于这个数字每隔几秒就会发生变化，因此你需要在它变化之前输入它。
![][4]
如果你不输入验证码，你将无法访问系统，你会收到一个权限被拒绝的错误：
```
[user@client ~]$ ssh user@example.com
Verification code:
Verification code:
Verification code:
Permission denied (keyboard-interactive).
[user@client ~]$
```
### 结论
通过添加这种简单的双向验证，现在未经授权的用户访问你的服务器将变得更加困难。
通过添加这种简单的双路验证，现在未经授权的用户访问你的服务器将变得更加困难。
--------------------------------------------------------------------------------
@ -145,7 +151,7 @@ via: https://fedoramagazine.org/two-factor-authentication-ssh-fedora/
作者：[Curt Warfield][a]
选题：[lujun9972][b]
译者：[MjSeven](https://github.com/MjSeven)
校对：[校对者ID](https://github.com/校对者ID)
校对：[wxy](https://github.com/wxy)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出

59
published/20190301 Blockchain 2.0- An Introduction -Part 1.md Normal file
View File

@ -0,0 +1,59 @@
[#]: collector: (lujun9972)
[#]: translator: (sanfusu)
[#]: reviewer: (wxy)
[#]: publisher: (wxy)
[#]: url: (https://linux.cn/article-10650-1.html)
[#]: subject: (Blockchain 2.0: An Introduction [Part 1])
[#]: via: (https://www.ostechnix.com/blockchain-2-0-an-introduction/)
[#]: author: (ostechnix https://www.ostechnix.com/author/editor/)
区块链 2.0：介绍（一）
==============
![](https://www.ostechnix.com/wp-content/uploads/2019/03/blockchain-introduction-720x340.png)
### 区块链 2.0：下一个计算范式
**区块链**现在显然被认为是一种转型技术，它将为人们使用互联网的方式带来革新。本系列文章将探讨即将到来的基于区块链 2.0 的技术和应用浪潮。不同的涉众对它表现出的极大兴趣证明了区块链的存在。
对于任何打算使用互联网做任何事情的人来说，了解它是什么以及它是如何工作的都是至关重要的。即使你所做的只是盯着 Instagram 上朋友们的早餐照片，或者寻找下一个最好的视频片段，你也需要知道这项技术能对这些提供什么样的帮助。
尽管区块链的基本概念早在上世纪 90 年代就被学术界提及，但它之所以成为网民热词，要归功于诸如**比特币**和**以太币**等支付平台的崛起。
比特币最初是一种去中心化的数字货币。它的出现意味着你基本上可以通过互联网进行完全匿名、安全可靠的支付。不过，在比特币这个简单的金融令牌系统背后，是区块链。您可以将比特币技术或任何加密货币看作是 3 层结构。区块链基础技术可以验证、记录和确认交易，在这个基础之上是协议，本质上来讲是一个规则或在线礼仪，用来兑现、记录和确认交易，当然，最重要的是通常被称作比特币的加密货币令牌。一旦记录了协议相关的事务，则由区块链生成令牌。
虽然大多数人只看到了最顶层，即代表比特币真正含义的硬币或代币，但很少有人知道，在区块链基础技术的帮助下，金融交易只是众多此类可能性中的一种。目前正在探讨这些可能性，以产生和开发所有去中心化交易方式的新标准。
在最基本的层面上，区块链可以被认为是一个包含所有记录和交易的账簿。这实际上意味着区块链理论上可以处理所有类型的记录。未来这方面的发展可能会导致各种硬资产（如房地产契约、实物钥匙等）和软无形资产（如身份记录、专利、商标、预约等）被编码为数字资产，通过区块链进行保护和转让。
对于不熟悉区块链的人来说，区块链上的事务本质上被认为是无偏见的永久记录。这是可能的，因为协议中内置了**共识系统**。所有交易均由系统参与者确认、审核和记录，在比特币加密货币平台中，该角色由**矿工**和交易所负责。这可能因不同的平台或区块链而异。构建该平台的协议栈是由开源代码所定义的，并且对任何具有技术能力的人都是免费的。与目前互联网上运行的许多其他平台不同，公开透明被内置进了该系统。
一旦事务被记录并编码到区块链中，它们就会被看到。参与者有义务按照它们最初的执行方式履行其交易和合约。除非原来的规则禁止了它，否则执行本身将由平台自动处理，因为它是硬编码的。区块链平台对于试图篡改记录、记录的持久性等方面的恢复能力，在因特网上是闻所未闻的。当这项技术的支持者们宣称其日益重要的意义时，这种能力是经常被提及的附加信任层。
这些特性并不是最近才被发现的隐藏的平台潜力，而是从一开始就被设想出来的。传说中的比特币创造者<ruby>中本聪<rt>Satoshi Nakamoto</rt></ruby>在一份公报中说**“我花了数年的时间来构造一个用来支撑巨大的各种可能事务类型的设计……如果比特币能够流行起来，这些就是我们未来要探索的……但是它们在最初就设计，以确保它们将来能够实现。”**。这些特性被设计并融入到已经存在的协议中的事实印证了这些话。关键的想法是，去中心化的事务分类账就像区块链的功能一样，可以用于传输、部署和执行各种形式的合约。
领先的机构目前正在探索重新发明股票、养老金和衍生品等金融工具的可能性，而世界各国政府更关注区块链的防篡改和永久性保存记录的潜力。该平台的支持者声称，一旦开发达到一个关键的门槛，从你的酒店钥匙卡到版权和专利，那时起，一切都将通过区块链记录和实现。
**Ledra Capital**在[这个][1]页面上汇编并维护了几乎完整的项目和细节列表，这些项目和细节理论上可以通过区块链模型实现。想要真正意识到区块链对我们生活的影响有多大是一项艰巨的任务，但看看这个清单就会再次证明这么做的重要性。
现在，上面提到的所有官僚和商业用途可能会让你相信，这样的技术只会出现在政府和大型私营企业领域。然而，事实远非如此。鉴于该系统的巨大潜力使其对此类用途具有吸引力，而区块链还具有其它可能性和特性。还有一些与该技术相关的更复杂的概念，如 DApp、DAO、DAC、DAS 等，本系列文章将深入讨论这些概念。
基本上，开发正在如火如荼地进行，任何人对基于区块链的系统的定义、标准和功能进行指点以便进行更广泛的推广还为时尚早，但是这种可能性及其即将产生的影响无疑是存在的。甚至有人谈到基于区块链的智能手机和选举期间的民意调查。
这只是一个简短的对这个平台能力的鸟瞰。我们将通过一系列这样详细的帖子和文章来研究这些不同的可能性。关注[本系列的下一篇文章][2]，它将探索区块链是如何革新交易和契约的。
---
via: https://www.ostechnix.com/blockchain-2-0-an-introduction/
作者：[ostechnix][a]
选题：[lujun9972][b]
译者：[sanfusu](https://github.com/sanfusu)
校对：[wxy](https://github.com/wxy)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux 中国](https://linux.cn/) 荣誉推出
[a]: https://www.ostechnix.com/author/editor/
[b]: https://github.com/lujun9972
[1]: http://ledracapital.com/blog/2014/3/11/bitcoin-series-24-the-mega-master-blockchain-list
[2]: https://www.ostechnix.com/blockchain-2-0-revolutionizing-the-financial-system/

31
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View File

@ -1,18 +1,19 @@
[#]: collector: (lujun9972)
[#]: translator: (qhwdw)
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: reviewer: (wxy)
[#]: publisher: (wxy)
[#]: url: (https://linux.cn/article-10645-1.html)
[#]: subject: (Learn Linux with the Raspberry Pi)
[#]: via: (https://opensource.com/article/19/3/learn-linux-raspberry-pi)
[#]: author: (Andersn Silva https://opensource.com/users/ansilva)
用树莓派学 Linux
树莓派使用入门：用树莓派学 Linux
======
我们的《树莓派使用入门》的第四篇文章将进入到 Linux 命令行。
> 我们的《树莓派使用入门》的第四篇文章将进入到 Linux 命令行。
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/command_line_prompt.png?itok=wbGiJ_yg)
在本系列的 [第三篇文章][1] 中开始了我们的树莓派探索之旅，我分享了如何安装 `Raspbian`，它是树莓派的官方 Linux 版本。现在，你已经安装好了 `Raspbian` 并用它引导你的新树莓派，你已经具备学习 Linux 相关知识的条件了。
在本系列的 [第三篇文章][1] 中开始了我们的树莓派探索之旅，我分享了如何安装 Raspbian，它是树莓派的官方 Linux 版本。现在，你已经安装好了 Raspbian 并用它引导你的新树莓派，你已经具备学习 Linux 相关知识的条件了。
在这样简短的文章中去解决像“如何使用 Linux” 这样的宏大主题显然是不切实际的，因此，我只是给你提供一些如何使用树莓派来学习更多的 Linux 知识的一些创意而已。
@ -22,17 +23,15 @@
如果你想成为一个 Linux 用户，从终端中尝试以下的命令行开始：
* 使用像 **ls**、**cd**、和 **pwd** 这样的命令导航到你的 Home 目录。
* 使用 **mkdir**、**rm**、**mv**、和 **cp** 命令创建、删除、和重命名目录。
* 使用像 `ls`、`cd` 和 `pwd` 这样的命令导航到你的 Home 目录。
* 使用 `mkdir`、`rm`、`mv` 和 `cp` 命令创建、删除、和重命名目录。
* 使用命令行编辑器（如 Vi、Vim、Emacs 或 Nano）去创建一个文本文件。
* 尝试一些其它命令，比如 **chmod**、**chown**、**w**、**cat**、**more**、**less**、**tail**、**free**、**df**、**ps**、**uname**、和 **kill**。
* 尝试一下 **/bin** 和 **/usr/bin** 目录中的其它命令。
* 尝试一些其它命令，比如 `chmod`、`chown`、`w`、`cat`、`more`、`less`、`tail`、`free`、`df`、`ps`、`uname` 和 `kill`。
* 尝试一下 `/bin` 和 `/usr/bin` 目录中的其它命令。
学习命令行的最佳方式还是阅读它的 “man 手册”（简称手册）；在命令行中输入 `man <command>` 就可以像上面那样打开它。并且在互联网上搜索 Linux 命令速查表可以让你更清楚地了解命令的用法 —— 你应该会找到一大堆能帮你学习的资料。
学习命令行的最佳方式还是阅读它的 “man 手册”（简称手册）；在命令行中输入 **man <command>** 就可以像上面那样打开它。并且在互联网上搜索 Linux 命令速查表可以让你更清楚地了解命令的用法 — 你应该会找到一大堆能帮你学习的资料。
Raspbian 就像主流的 Linux 发行版一样有非常多的命令，假以时日，你最终将比其他人会用更多的命令。我使用 Linux 命令行已经超过二十年了，即便这样仍然有些一些命令我从来没有使用过，即便是那些我使用的过程中一直就存在的命令。
Raspbian 就像主流的 Linux 发行版一样有非常多的命令，假以时日，你最终将比其他人会用更多的命令。我使用 Linux 命令行已经超过二十年了，即便这样仍然有一些命令我从来没有使用过，即便是那些我使用的过程中就一直存在的命令。
最后，你可以使用图形环境去更快地工作，但是只有深入到 Linux 命令行，你才能够获得操作系统真正的强大功能和知识。
@ -43,11 +42,11 @@ via: https://opensource.com/article/19/3/learn-linux-raspberry-pi
作者：[Andersn Silva][a]
选题：[lujun9972][b]
译者：[qhwdw](https://github.com/qhwdw)
校对：[校对者ID](https://github.com/校对者ID)
校对：[wxy](https://github.com/wxy)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://opensource.com/users/ansilva
[b]: https://github.com/lujun9972
[1]: https://opensource.com/article/19/2/how-boot-new-raspberry-pi
[1]: https://linux.cn/article-10644-1.html
[2]: https://opensource.com/article/18/8/window-manager

101
translated/tech/20190305 5 Ways To Generate A Random-Strong Password In Linux Terminal.md → published/20190305 5 Ways To Generate A Random-Strong Password In Linux Terminal.md
View File

@ -1,8 +1,8 @@
[#]: collector: (lujun9972)
[#]: translator: (leommxj)
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: reviewer: (wxy)
[#]: publisher: (wxy)
[#]: url: (https://linux.cn/article-10657-1.html)
[#]: subject: (5 Ways To Generate A Random/Strong Password In Linux Terminal)
[#]: via: (https://www.2daygeek.com/5-ways-to-generate-a-random-strong-password-in-linux-terminal/)
[#]: author: (Magesh Maruthamuthu https://www.2daygeek.com/author/magesh/)
@ -10,9 +10,7 @@
在 Linux 终端下生成随机/强密码的五种方法
======
最近我们在网站上发表过一篇关于 **[密码强度与密码分数检查][1]** 的文章。
它可以帮助你检查你的密码的强度和分数。
最近我们在网站上发表过一篇关于 [检查密码复杂性/强度和评分][1] 的文章。它可以帮助你检查你的密码的强度和评分。
我们可以手工创建我们需要的密码。但如果你想要为多个用户或服务器生成密码，解决方案是什么呢？
@ -20,57 +18,55 @@
这些工具可以为你生成高强度随机密码。如果你想要为多个用户和服务器更新密码，请继续读下去。
这些工具易于使用，这也是我喜欢用它们的原因。默认情况下它们会生成一个足够强壮的密码，你也可以通过使用其他可用的选项来生成一个超强的密码。
这些工具易于使用，这也是我喜欢用它们的原因。默认情况下它们会生成一个足够健壮的密码，你也可以通过使用其他可用的选项来生成一个超强的密码。
它会帮助你生成符合下列要求的超强密码。密码长度至少有 12-15 个字符，包括字母（大写及小写），数字及特殊符号。
工具如下：
* `pwgen:` pwgen 程序生成易于人类记忆并且尽可能安全的密码。
* `openssl:` openssl 是一个用来从 shell 中调用 OpenSSL 加密库提供的多种密码学函数的命令行工具。
* `gpg:` OpenPGP 加密/签名工具。
* `mkpasswd:` 生成新密码，可以选择直接应用给一名用户。
* `makepasswd:` makepasswd 使用 /dev/urandom 生成真随机密码，比起好记它更重视安全性。
* `/dev/urandom file` 两个特殊的字符文件 /dev/random 和 /dev/urandom （自 Linux 1.3.30 起） 提供了内核随机数生成器的接口。
* `md5sum:` md5sum 是一个用来计算及校验 128-bit MD5 哈希的程序。
* `sha256sum:` sha256sum 被设计用来使用 SHA-256 算法（SHA-2系列，摘要长度为256位）校验数据完整性。
* `sha1pass:` sha1pass 生成一个 SHA1 密码哈希。在命令缺少盐值的情况下，将会生成一个随机的盐值向量。
* `pwgen`：生成易于人类记忆并且尽可能安全的密码。
* `openssl`：是一个用来从 shell 中调用 OpenSSL 加密库提供的多种密码学函数的命令行工具。
* `gpg`：OpenPGP 加密/签名工具。
* `mkpasswd`：生成新密码，可以选择直接设置给一名用户。
* `makepasswd`：使用 `/dev/urandom` 生成真随机密码，比起好记它更重视安全性。
* `/dev/urandom` 文件：两个特殊的字符文件 `/dev/random` 和 `/dev/urandom` （自 Linux 1.3.30 起出现）提供了内核随机数生成器的接口。
* `md5sum`：是一个用来计算及校验 128 位 MD5 哈希的程序。
* `sha256sum`：被设计用来使用 SHA-256 算法（SHA-2 系列，摘要长度为 256 位）校验数据完整性。
* `sha1pass`：生成一个 SHA1 密码哈希。在命令缺少盐值的情况下，将会生成一个随机的盐值向量。
### 怎么用 pwgen 命令在 linux 下生成一个随机的强壮密码？
pwgen 程序生成易于人类记忆并且尽可能安全的密码。
`pwgen` 程序生成易于人类记忆并且尽可能安全的密码。
易于人类记忆的密码永远都不会像完全随机的密码一样安全。
使用 `-s` 选项来生成完全随机，难于记忆的密码。由于我们记不住，这些密码应该只用于机器。
在 **`Fedora`** 系统中，使用 **[DNF 命令][2]** 来安装 pwgen。
在 Fedora 系统中，使用 [DNF 命令][2] 来安装 `pwgen`。
```
$ sudo dnf install pwgen
```
在 **`Debian/Ubuntu`** 系统中，使用 **[APT-GET 命令][3]** 或 **[APT 命令][4]** 来安装 pwgen。
在 Debian/Ubuntu 系统中，使用 [APT-GET 命令][3] 或 [APT 命令][4] 来安装 `pwgen`。
```
$ sudo apt install pwgen
```
在 **`Arch Linux`** 系统中，使用 **[Pacman 命令][5]** 来安装 pwgen。
在 Arch Linux 系统中，使用 [Pacman 命令][5] 来安装 `pwgen`。
```
$ sudo pacman -S pwgen
```
在 **`RHEL/CentOS`** 系统中，使用 **[YUM 命令][6]** 来安装 pwgen。
在 RHEL/CentOS 系统中，使用 [YUM 命令][6] 来安装 `pwgen`。
```
$ sudo yum install pwgen
```
在 **`openSUSE Leap`** 系统中，使用 **[Zypper 命令][7]** 来安装pwgen。
在 openSUSE Leap 系统中，使用 [Zypper 命令][7] 来安装 `pwgen`。
```
$ sudo zypper install pwgen
@ -106,7 +102,7 @@ Sid1aeji mohj4Ko7 lieDi0pe Zeemah6a thuevu2E phi4Ohsh paiKeix1 ooz1Ceph
ahV4yore ue2laePh fu1eThui qui7aePh Fahth1nu ohk9puLo aiBeez0b Neengai5
```
生成安全的随机密码，使用 pwgen 命令的 `-s` 选项。
生成安全的随机密码，使用 `pwgen` 命令的 `-s` 选项。
```
$ pwgen -s
@ -132,14 +128,14 @@ C6RqDQMy gKt28c9O ZCi0tQKE 0Ekdjh3P ox2vWOMI 14XF4gwc nYA0L6tV rRN3lekn
lmwZNjz1 4ovmJAr7 shPl9o5f FFsuNwj0 F2eVkqGi 7gw277RZ nYE7gCLl JDn05S5N
```
假设你想要生成五个14字符长的密码，方法如下。
假设你想要生成 5 个 14 字符长的密码，方法如下：
```
$ pwgen -s 14 5
7YxUwDyfxGVTYD em2NT6FceXjPfT u8jlrljbrclcTi IruIX3Xu0TFXRr X8M9cB6wKNot1e
```
如果你真的想要生成20个超强随机密码，方法如下。
如果你真的想要生成 20 个超强随机密码，方法如下：
```
$ pwgen -cnys 14 20
@ -151,16 +147,16 @@ mQ3E=vfGfZ,5[B #zmj{i5|ZS){jg Ht_8i7OqJ%N`~2 443fa5iJ\W-L?] ?Qs$o=vz2vgQBR
### 如何在 Linux 下使用 openssl 命令生成随机强密码？
openssl 是一个用来从 shell 中调用 OpenSSL 加密库提供的多种密码学函数的命令行工具。
`openssl` 是一个用来从 shell 中调用 OpenSSL 加密库提供的多种密码学函数的命令行工具。
像下面这样运行 openssl 命令可以生成一个14字符长的随机强密码。
像下面这样运行 `openssl` 命令可以生成一个 14 字符长的随机强密码。
```
$ openssl rand -base64 14
WjzyDqdkWf3e53tJw/c=
```
如果你想要生成十个14字符长的随机强密码，将 openssl 命令与 for 循环结合起来使用。
如果你想要生成 10 个 14 字符长的随机强密码，将 `openssl` 命令与 `for` 循环结合起来使用。
```
$ for pw in {1..10}; do openssl rand -base64 14; done
@ -178,9 +174,9 @@ ktpBpCSQFOD+5kIIe7Y=
### 如何在 Linux 下使用 gpg 命令生成随机强密码？
gpg 是 Gnu Privacy Guard （GnuPG） 中的 OpenPGP 实现部分。它是一个提供 OpenPGP 标准的数字加密与签名服务的工具。gpg 具有完整的密钥管理功能和其他完整 OpenPGP 实现应该具备的全部功能。
`gpg` 是 Gnu Privacy Guard （GnuPG） 中的 OpenPGP 实现部分。它是一个提供 OpenPGP 标准的数字加密与签名服务的工具。`gpg` 具有完整的密钥管理功能和其他完整 OpenPGP 实现应该具备的全部功能。
下面这样执行 gpg 命令来生成一个14字符长的随机强密码。
下面这样执行 `gpg` 命令来生成一个 14 字符长的随机强密码。
```
$ gpg --gen-random --armor 1 14
@ -189,7 +185,7 @@ $ gpg2 --gen-random --armor 1 14
jq1mtY4gBa6gIuJrggM=
```
如果想要使用 gpg 生成十个14字符长的随机强密码，像下面这样使用 for 循环。
如果想要使用 `gpg` 生成 10 个 14 字符长的随机强密码，像下面这样使用 `for` 循环。
```
$ for pw in {1..10}; do gpg --gen-random --armor 1 14; done
@ -209,33 +205,33 @@ eJjhtA6oHhBrUpLY4fM=
### 如何在 Linux 下使用 mkpasswd 命令生成随机强密码？
mkpasswd 生成密码并可以自动将其应用在用户上。不加任何参数的情况下，mkpasswd 返回一个新的密码。它是 expect 软件包的一部分，所以想要使用 mkpasswd 命令，你需要安装 expect 软件包。
`mkpasswd` 生成密码并可以自动将其为用户设置。不加任何参数的情况下，`mkpasswd` 返回一个新的密码。它是 expect 软件包的一部分，所以想要使用 `mkpasswd` 命令，你需要安装 expect 软件包。
在 **`Fedora`** 系统中，使用 **[DNF 命令][2]** 来安装 mkpasswd。
在 Fedora 系统中，使用 [DNF 命令][2] 来安装 `mkpasswd`。
```
$ sudo dnf install expect
```
在 **`Debian/Ubuntu`** 系统中，使用 **[APT-GET 命令][3]** 或 **[APT 命令][4]** 来安装 mkpasswd。
在 Debian/Ubuntu 系统中，使用 [APT-GET 命令][3] 或 [APT 命令][4] 来安装 `mkpasswd`。
```
$ sudo apt install expect
```
在 **`Arch Linux`** 系统中，使用 **[Pacman 命令][5]** 来安装 mkpasswd。
在 Arch Linux 系统中，使用 [Pacman 命令][5] 来安装 `mkpasswd`。
```
$ sudo pacman -S expect
```
在 **`RHEL/CentOS`** 系统中，使用 **[YUM 命令][6]** 来安装 mkpasswd。
在 RHEL/CentOS 系统中，使用 [YUM 命令][6] 来安装 `mkpasswd`。
```
$ sudo yum install expect
```
在 **`openSUSE Leap`** 系统中，使用 **[Zypper 命令][7]** 来安装 mkpasswd。
在 openSUSE Leap 系统中，使用 [Zypper 命令][7] 来安装 `mkpasswd`。
```
$ sudo zypper install expect
@ -248,21 +244,21 @@ $ mkpasswd
37_slQepD
```
像下面这样执行 mkpasswd 命令可以生成一个14字符长的随机强密码。
像下面这样执行 `mkpasswd` 命令可以生成一个 14 字符长的随机强密码。
```
$ mkpasswd -l 14
W1qP1uv=lhghgh
```
像下面这样执行 mkpasswd 命令 来生成一个14字符长，包含大小写字母、数字和特殊字符的随机强密码。
像下面这样执行 `mkpasswd` 命令 来生成一个 14 字符长，包含大小写字母、数字和特殊字符的随机强密码。
```
$ mkpasswd -l 14 -d 3 -C 3 -s 3
3aad!bMWG49"t,
```
如果你想要生成十个14字符长的随机强密码(包括大小写字母、数字和特殊字符)，使用 for 循环和 mkpasswd 命令。
如果你想要生成 10 个 14 字符长的随机强密码（包括大小写字母、数字和特殊字符），使用 `for` 循环和 `mkpasswd` 命令。
```
$ for pw in {1..10}; do mkpasswd -l 14 -d 3 -C 3 -s 3; done
@ -278,10 +274,9 @@ $of?Rj9kb2N(1J
Tu9m56+Ev_Yso(
```
### How To Generate A Random Strong Password In Linux Using makepasswd Command?
### 如何在 Linux 下使用 makepasswd 命令生成随机强密码？
makepasswd 使用 /dev/urandom 生成真随机密码，跟易于记忆相比它更注重安全性。它也可以加密命令行中给出的明文密码。
`makepasswd` 使用 `/dev/urandom` 生成真随机密码，与易于记忆相比它更注重安全性。它也可以加密命令行中给出的明文密码。
在终端中执行 `makepasswd` 命令来生成一个随机密码。
@ -290,14 +285,14 @@ $ makepasswd
HdCJafVaN
```
在终端中像下面这样执行 makepasswd 命令来生成14字符长的随机强密码。
在终端中像下面这样执行 `makepasswd` 命令来生成 14 字符长的随机强密码。
```
$ makepasswd --chars 14
HxJDv5quavrqmU
```
像下面这样执行 makepasswd 来生成十个14字符长的随机强密码。
像下面这样执行 `makepasswd` 来生成 10 个 14 字符长的随机强密码。
```
$ makepasswd --chars 14 --count 10
@ -317,28 +312,28 @@ M2TMCEoahzLNYC
如果你还在寻找其他的方案，下面的工具也可以用来在 Linux 中生成随机密码。
**使用 md5sum** md5sum 是一个用来计算及校验 128-bit MD5 哈希的程序。
使用 `md5sum`：它是一个用来计算及校验 128 位 MD5 哈希的程序。
```
$ date | md5sum
9baf96fb6e8cbd99601d97a5c3acc2c4 -
```
**使用 /dev/urandom:** 两个特殊的字符文件 /dev/random 和 /dev/urandom （自 Linux 1.3.30 起） 提供了内核随机数生成器的接口。/dev/random 的主设备号为1，次设备号为8。/dev/urandom 主设备号为1，次设备号为9。
使用 `/dev/urandom`: 两个特殊的字符文件 `/dev/random` 和 `/dev/urandom` （自 Linux 1.3.30 起出现）提供了内核随机数生成器的接口。`/dev/random` 的主设备号为 1，次设备号为 8。`/dev/urandom` 主设备号为 1，次设备号为 9。
```
$ cat /dev/urandom | tr -dc 'a-zA-Z0-9' | head -c 14
15LQB9J84Btnzz
```
**使用 sha256sum:** sha256sum 被设计用来使用 SHA-256 算法（SHA-2系列，摘要长度为256位）校验数据完整性。
使用 `sha256sum`：它被设计用来使用 SHA-256 算法（SHA-2 系列，摘要长度为 256 位）校验数据完整性。
```
$ date | sha256sum
a114ae5c458ae0d366e1b673d558d921bb937e568d9329b525cf32290478826a -
```
**使用 sha1pass:** sha1pass 生成一个 SHA1 密码哈希。在命令缺少盐值的情况下，将会生成一个随机的盐值向量。
使用 `sha1pass`：它生成一个 SHA1 密码哈希。在命令缺少盐值的情况下，将会生成一个随机的盐值向量。
```
$ sha1pass
@ -351,14 +346,14 @@ via: https://www.2daygeek.com/5-ways-to-generate-a-random-strong-password-in-lin
作者：[Magesh Maruthamuthu][a]
选题：[lujun9972][b]
译者：[leommx](https://github.com/leommxj)
校对：[校对者ID](https://github.com/校对者ID)
译者：[leommxj](https://github.com/leommxj)
校对：[wxy](https://github.com/wxy)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://www.2daygeek.com/author/magesh/
[b]: https://github.com/lujun9972
[1]: https://www.2daygeek.com/how-to-check-password-complexity-strength-and-score-in-linux/
[1]: https://linux.cn/article-10623-1.html
[2]: https://www.2daygeek.com/dnf-command-examples-manage-packages-fedora-system/
[3]: https://www.2daygeek.com/apt-get-apt-cache-command-examples-manage-packages-debian-ubuntu-systems/
[4]: https://www.2daygeek.com/apt-command-examples-manage-packages-debian-ubuntu-systems/

30
translated/tech/20190305 5 ways to teach kids to program with Raspberry Pi.md → published/20190305 5 ways to teach kids to program with Raspberry Pi.md
View File

@ -1,40 +1,42 @@
[#]: collector: (lujun9972)
[#]: translator: (qhwdw)
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: reviewer: (wxy)
[#]: publisher: (wxy)
[#]: url: (https://linux.cn/article-10653-1.html)
[#]: subject: (5 ways to teach kids to program with Raspberry Pi)
[#]: via: (https://opensource.com/article/19/3/teach-kids-program-raspberry-pi)
[#]: author: (Anderson Silva https://opensource.com/users/ansilva)
教孩子们使用树莓派学编程的 5 种方法。
树莓派使用入门：教孩子们用树莓派学编程的 5 种方法
======
这是我们的《树莓派入门指南》系列的第五篇文章，它探索了帮助孩子们学习编程的一些资源。
> 这是我们的《树莓派入门指南》系列的第五篇文章，它探索了帮助孩子们学习编程的一些资源。
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/rh_003588_01_rd3os.combacktoschoolseriesgen_rh_032x_0.png?itok=cApG9aB4)
无数的学校、图书馆和家庭已经证明，树莓派是让孩子们接触编程的最好方式。在本系列的前四篇文章中，你已经学习了如何去[购买][1]、[安装][2]、和[配置][3]一个树莓派。在第五篇文章中，我们将分享一些帮助孩子们使用树莓派编程的入门级资源。
### Scratch
[Scratch][4] 是让孩子们了解编程基本概念（比如变量、布尔逻辑、循环等等）的一个很好的方式。你在 Raspbian 中就可以找到它，并且在互联网上你可以找到非常多的有关 Scratch 的文章和教程，包括在 `Opensource.com` 上的 [今天的 Scratch 是不是像“上世纪八十年代教孩子学LOGO编程”?][5]。
[Scratch][4] 是让孩子们了解编程基本概念（比如变量、布尔逻辑、循环等等）的一个很好的方式。你在 Raspbian 中就可以找到它，并且在互联网上你可以找到非常多的有关 Scratch 的文章和教程，包括在 Opensource.com 上的 [今天的 Scratch 是不是像“上世纪八十年代教孩子学 LOGO 编程”?][5]。
![](https://opensource.com/sites/default/files/uploads/scratch2.png)
### Code.org
[Code.org][6] 是另一个非常好的教孩子学编程的在线资源。这个组织的使命是让更多的人通过课程、教程和流行的一小时学编程来接触编程。许多学校 — 包括我五年级的儿子就读的学校 — 都使用它，让更多的孩子学习编程和计算机科学的概念。
[Code.org][6] 是另一个非常好的教孩子学编程的在线资源。这个组织的使命是让更多的人通过课程、教程和流行的一小时学编程来接触编程。许多学校（包括我五年级的儿子就读的学校）都使用它，让更多的孩子学习编程和计算机科学的概念。
### 阅读
读书是学习编程的另一个很好的方式。学习如何编程并不需要你会说英语，当然，如果你会英语的话，学习起来将更容易，因为大多数的编程语言都是使用英文关键字去描述命令的。如果你的英语很好，能够轻松地阅读接下来的这个树莓派系列文章，那么你就完全有能力去阅读有关编程的书籍、论坛和其它的出版物。我推荐一本由 `Jason Biggs` 写的书： [儿童学 Python：非常有趣的 Python 编程入门][7]。
读书是学习编程的另一个很好的方式。学习如何编程并不需要你会说英语，当然，如果你会英语的话，学习起来将更容易，因为大多数的编程语言都是使用英文关键字去描述命令的。如果你的英语很好，能够轻松地阅读接下来的这个树莓派系列文章，那么你就完全有能力去阅读有关编程的书籍、论坛和其它的出版物。我推荐一本由 Jason Biggs 写的书： [儿童学 Python：非常有趣的 Python 编程入门][7]。
### Raspberry Jam
另一个让你的孩子进入编程世界的好方法是在聚会中让他与其他人互动。树莓派基金会赞助了一个称为 [Raspberry Jams][8] 的活动，让世界各地的孩子和成人共同参与在树莓派上学习。如果你所在的地区没有 `Raspberry Jam`，基金会有一个[指南][9]和其它资源帮你启动一个 `Raspberry Jam`。
另一个让你的孩子进入编程世界的好方法是在聚会中让他与其他人互动。树莓派基金会赞助了一个称为 [Raspberry Jams][8] 的活动，让世界各地的孩子和成人共同参与在树莓派上学习。如果你所在的地区没有 Raspberry Jam，基金会有一个[指南][9]和其它资源帮你启动一个 Raspberry Jam。
### 游戏
最后一个（是本文的最后一个，当然还有其它的方式），[Minecraft][10] 有一个树莓派版本。<ruby>我的世界<rt>Minecraft</rt></ruby>已经从一个多玩家的、类似于”数字乐高“这样的游戏，成长为一个任何人都能使用 Pythonb 和其它编程语言去构建我自己的虚拟世界。更多内容查看 [Minecraft Pi 入门][11] 和 [Minecraft 一小时入门教程][12]。
最后一个（是本文的最后一个，当然还有其它的方式），[Minecraft][10] 有一个树莓派版本。<ruby>我的世界<rt>Minecraft</rt></ruby>已经从一个多玩家的、类似于”数字乐高“这样的游戏，成长为一个任何人都能使用 Python 和其它编程语言去构建我自己的虚拟世界。更多内容查看 [Minecraft Pi 入门][11] 和 [Minecraft 一小时入门教程][12]。
你还有教孩子用树莓派学编程的珍藏资源吗？请在下面的评论区共享出来吧。
@ -45,15 +47,15 @@ via: https://opensource.com/article/19/3/teach-kids-program-raspberry-pi
作者：[Anderson Silva][a]
选题：[lujun9972][b]
译者：[qhwdw](https://github.com/qhwdw)
校对：[校对者ID](https://github.com/校对者ID)
校对：[wxy](https://github.com/wxy)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://opensource.com/users/ansilva
[b]: https://github.com/lujun9972
[1]: https://opensource.com/article/19/2/how-buy-raspberry-pi
[2]: https://opensource.com/article/19/2/how-boot-new-raspberry-pi
[3]: https://opensource.com/article/19/3/learn-linux-raspberry-pi
[1]: https://linux.cn/article-10615-1.html
[2]: https://linux.cn/article-10644-1.html
[3]: https://linux.cn/article-10645-1.html
[4]: https://scratch.mit.edu/
[5]: https://opensource.com/article/17/3/logo-scratch-teach-programming-kids
[6]: https://code.org/

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[#]: collector: (lujun9972)
[#]: translator: (qhwdw)
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: reviewer: (wxy)
[#]: publisher: (wxy)
[#]: url: (https://linux.cn/article-10661-1.html)
[#]: subject: (3 popular programming languages you can learn with Raspberry Pi)
[#]: via: (https://opensource.com/article/19/3/programming-languages-raspberry-pi)
[#]: author: (Anderson Silva https://opensource.com/users/ansilva)
可以使用树莓派学习的 3 种流行编程语言
树莓派使用入门：可以使用树莓派学习的 3 种流行编程语言
======
通过树莓派学习编程，让你在就业市场上更值钱。
> 通过树莓派学习编程，让你在就业市场上更值钱。
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/programming_language_c.png?itok=mPwqDAD9)
在本系列的上一篇文章中，我分享了 [教孩子们使用树莓派编程][1] 的一些方式。理论上，这些资源并不局限于只适用于孩子们，成人也是可以使用的。但是学习就业市场上急需的编程语言，可以让你得到更好的机会。
@ -24,7 +26,7 @@
### Java
虽然 [Java][6] 已经不像以前那样引人注目了，但它仍然在世界各地的大学和企业中占据着重要的地位。因此，即便是一些人对我建议新手学习 Java 持反对意见，但我仍然强烈推荐大家去学习 Java；之所以这么做，原因之一是，它仍然很流行，原因之二是，它有大量的便于你学习的图书、课程、和其它的可用信息。在树莓派上学习它，你可以从使用 Java 集成开发环境 [BlueJ][7] 开始。
虽然 [Java][6] 已经不像以前那样引人注目了，但它仍然在世界各地的大学和企业中占据着重要的地位。因此，即便是一些人对我建议新手学习 Java 持反对意见，但我仍然强烈推荐大家去学习 Java；之所以这么做，原因之一是，它仍然很流行，原因之二是，它有大量的便于你学习的图书、课程和其它的可用信息。在树莓派上学习它，你可以从使用 Java 集成开发环境 [BlueJ][7] 开始。
![](https://opensource.com/sites/default/files/uploads/bluejayide.png)
@ -34,7 +36,7 @@
### 其它编程语言
如果这里没有列出你想学习的编程语言，别失望。你可以使用你的树莓派去编译或解释任何你选择的语言，包括 C、C++、PHP、和 Ruby，这种可能性还是很大的。
如果这里没有列出你想学习的编程语言，别失望。你可以使用你的树莓派去编译或解释任何你选择的语言，包括 C、C++、PHP 和 Ruby，这种可能性还是很大的。
微软的 [Visual Studio Code][11] 也可以运行在 [树莓派][12] 上。它是来自微软的开源代码编辑器，它支持多种标记和编程语言。
@ -45,13 +47,13 @@ via: https://opensource.com/article/19/3/programming-languages-raspberry-pi
作者：[Anderson Silva][a]
选题：[lujun9972][b]
译者：[qhwdw](https://github.com/qhwdw)
校对：[校对者ID](https://github.com/校对者ID)
校对：[wxy](https://github.com/wxy)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://opensource.com/users/ansilva
[b]: https://github.com/lujun9972
[1]: https://opensource.com/article/19/2/teach-kids-program-raspberry-pi
[1]: https://linux.cn/article-10653-1.html
[2]: https://opensource.com/resources/python
[3]: https://www.economist.com/graphic-detail/2018/07/26/python-is-becoming-the-worlds-most-popular-coding-language
[4]: https://thonny.org/

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[#]: collector: (lujun9972)
[#]: translator: (geekpi)
[#]: reviewer: (wxy)
[#]: publisher: (wxy)
[#]: url: (https://linux.cn/article-10663-1.html)
[#]: subject: (Get cooking with GNOME Recipes on Fedora)
[#]: via: (https://fedoramagazine.org/get-cooking-with-gnome-recipes-on-fedora/)
[#]: author: (Ryan Lerch https://fedoramagazine.org/introducing-flatpak/)
在 Fedora 上使用 GNOME Recipes 烹饪
======
![](https://fedoramagazine.org/wp-content/uploads/2019/03/gnome-recipes-816x345.jpg)
你喜欢烹饪吗？在 Fedora 中寻找管理食谱的更好方法么？ GNOME Recipes 是一个非常棒的应用，可以在 Fedora 中安装，用于保存和组织你的食谱。
![][1]
GNOME Recipes 是 GNOME 项目中的食谱管理工具。它有现代 GNOME 应用的视觉风格，类似于 GNOME “软件”，但它是针对食物的。
### 安装 GNOME Recipes
Recipes 可从第三方 Flathub 仓库安装。如果你之前从未安装过 Flathub 的应用，请使用以下指南进行设置：
- [在 Fedora 上安装 Flathub 应用](https://fedoramagazine.org/install-flathub-apps-fedora/)
正确设置 Flathub 作为软件源后，你将能够通过 GNOME “软件”搜索和安装 Recipes。
### 食谱管理
Recipes 能让你手动添加自己的食谱集合，包括照片、配料、说明，以及更多的元数据，如准备时间、烹饪风格和辛辣程度。
![][2]
当输入新的食谱时，GNOME Recipes 可为该食谱选择一系列不同的测量单位，如温度等，让你可以轻松地切换单位。
### 社区食谱
除了手动输入你喜欢的菜肴供你自己使用外，它还能让你查找、使用和贡献食谱给社区。此外，你可以标记你的喜爱的食谱，并通过大量的食谱元数据搜索菜谱。
![][3]
### 分步指导
GNOME Recipes 中一个非常棒的小功能是分步全屏模式。当你准备做饭时，只需激活此模式，将笔记本电脑拿到厨房，你就可以全屏显示烹饪方法中的当前步骤。此外，当食物在烤箱中时，你可以在这个模式下设置定时器。
![][4]
--------------------------------------------------------------------------------
via: https://fedoramagazine.org/get-cooking-with-gnome-recipes-on-fedora/
作者：[Ryan Lerch][a]
选题：[lujun9972][b]
译者：[geekpi](https://github.com/geekpi)
校对：[wxy](https://github.com/wxy)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://fedoramagazine.org/introducing-flatpak/
[b]: https://github.com/lujun9972
[1]: https://fedoramagazine.org/wp-content/uploads/2019/03/Screenshot-from-2019-03-06-19-45-06-1024x727.png
[2]: https://fedoramagazine.org/wp-content/uploads/2019/03/gnome-recipes1-1024x727.png
[3]: https://fedoramagazine.org/wp-content/uploads/2019/03/Screenshot-from-2019-03-06-20-08-45-1024x725.png
[4]: https://fedoramagazine.org/wp-content/uploads/2019/03/Screenshot-from-2019-03-06-20-39-44-1024x640.png

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[#]: collector: (lujun9972)
[#]: translator: (qhwdw)
[#]: reviewer: (wxy)
[#]: publisher: (wxy)
[#]: url: (https://linux.cn/article-10655-1.html)
[#]: subject: (13 open source backup solutions)
[#]: via: (https://opensource.com/article/19/3/backup-solutions)
[#]: author: (Don Watkins https://opensource.com/users/don-watkins)
13 个开源备份解决方案
======
> 读者们推荐了超过一打的他们喜欢的数据保护解决方案。
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/server_data_system_admin.png?itok=q6HCfNQ8)
最近，我发起了一个 [投票][1]，让读者投票选出他们最喜欢的开源备份解决方案。在我们的 [版主社区][2] 上，我们提供了六个推荐的解决方案 —— Cronopete、Deja Dup、Rclone、Rdiff-backup、Restic、和 Rsync，而参与的读者也在评论区分享了一些其它的选择。并且读者提供的这 13 个其它的解决方案，（到目前为止）我们要么是没有想到，要么是没有听说过。
到目前为止，最受欢迎的推荐是 [BorgBackup][3]。它是一个带有压缩和加密特性以用具有数据去重功能的备份解决方案。它基于 BSD 许可证，支持 Linux、MacOS 和 BSD。
第二个是 [UrBackup][4]，它可以做镜像和文件的完整和增量备份；你可以保存整个分区或单个目录。它有 Windows、Linux、和 MacOS 客户端，并且采用 GNU Affero 公共许可证。
第三个是 [LuckyBackup][5]；根据其网站介绍，“它是一个易于使用、快速（只传输变化部分，而不是全部数据）、安全（在做任何数据操作之前，先检查所有需要备份的目录，以确保数据安全）、可靠和完全可定制的备份解决方案。它在 GPL 许可证下发行。
[Casync][6] 是一个可寻址内容的同步解决方案 —— 它设计用于备份、同步、存储和检索大文件系统的多个相关版本。它使用 GNU Lesser 公共许可证。
[Syncthing][7] 是用于在两台计算机之间同步文件。它基于 Mozilla 公共许可证使用，根据其网站介绍，它是安全和私密的。它可以工作于 MacOS、Windows、Linux、FreeBSD、Solaris 和 OpenBSD。
[Duplicati][8] 是一个可工作于 Windows、MacOS 和 Linux 上的、并且支持多种标准协议（比如 FTP、SSH、WebDAV 和云服务）、免费的备份解决方案。它的特性是强大的加密功能，并且它使用 GPL 许可证。
[Dirvish][9] 是一个基于磁盘的虚拟镜像备份系统，它使用 OSL-3.0 许可证。它要求必须安装有 Rsync、Perl5、SSH。
[Bacula][10] 的网站上介绍说：”它是允许系统管理员去管理备份、恢复、和跨网络的不同种类计算机上的多种数据的一套计算机程序“，它支持在 Linux、FreeBSD、Windows、MacOS、OpenBSD 和 Solaris 上运行，并且它的大部分源代码都是基于 AGPLv3 许可证的。
[BackupPC][11] 的网站上介绍说：”它是一个高性能的、企业级的、可以备份 Linux、Windows 和 MacOS 系统的 PC 和笔记本电脑上的数据到服务器磁盘上的备份解决方案“。它是基于 GPLv3 许可证的。
[Amanda][12] 是一个使用 C 和 Perl 写的备份系统，它允许系统管理员去备份整个网络中的客户端到一台服务器上的磁带、磁盘或基于云的系统。它是由马里兰大学于 1991 年开发并拥有版权，并且它有一个 BSD 式的许可证。
[Back in Time][13] 是一个为 Linux 设计的简单的备份实用程序。它提供了命令行和图形用户界面，它们都是用 Python 写的。去执行一个备份，只需要指定存储快照的位置、需要备份的文件夹，和备份频率即可。它使用的是 GPLv2 许可证。
[Timeshift][14] 是一个 Linux 上的备份实用程序，它类似于 Windows 上的系统恢复和 MacOS 上的时间胶囊。它的 GitHub 仓库上介绍说：“Timeshift 通过定期递增的文件系统快照来保护你的系统。这些快照可以在日后用于数据恢复，以撤销某些对文件系统的修改。”
[Kup][15] 是一个能够帮助用户备份它们的文件到 USB 驱动器上的备份解决方案，但它也可以用于执行网络备份。它的 GitHub 仓库上介绍说：”当插入你的外部硬盘时，Kup 将自动启动并复制你的最新的修改。“
感谢大家在我们的投票中分享你们喜爱的开源备份解决方案！如果还有其它的、没有提到的开源备份解决方案，请在下面的评论区分享它们。
--------------------------------------------------------------------------------
via: https://opensource.com/article/19/3/backup-solutions
作者：[Don Watkins][a]
选题：[lujun9972][b]
译者：[qhwdw](https://github.com/qhwdw)
校对：[wxy](https://github.com/wxy)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://opensource.com/users/don-watkins
[b]: https://github.com/lujun9972
[1]: https://opensource.com/article/19/2/linux-backup-solutions
[2]: https://opensource.com/opensourcecom-team
[3]: https://www.borgbackup.org/
[4]: https://www.urbackup.org/
[5]: http://luckybackup.sourceforge.net/
[6]: http://0pointer.net/blog/casync-a-tool-for-distributing-file-system-images.html
[7]: https://syncthing.net/
[8]: https://www.duplicati.com/
[9]: http://dirvish.org/
[10]: https://www.bacula.org/
[11]: https://backuppc.github.io/backuppc/
[12]: http://www.amanda.org/
[13]: https://github.com/bit-team/backintime
[14]: https://github.com/teejee2008/timeshift
[15]: https://github.com/spersson/Kup

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[#]: collector: (lujun9972)
[#]: translator: (geekpi)
[#]: reviewer: (wxy)
[#]: publisher: (wxy)
[#]: url: (https://linux.cn/article-10665-1.html)
[#]: subject: (How to keep your Raspberry Pi updated)
[#]: via: (https://opensource.com/article/19/3/how-raspberry-pi-update)
[#]: author: (Anderson Silva https://opensource.com/users/ansilva)
树莓派使用入门：如何更新树莓派
======
> 在我们的树莓派入门指南的第七篇学习如何给树莓派打补丁。
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/computer_happy_sad_developer_programming.png?itok=72nkfSQ_)
像平板电脑、手机和笔记本电脑一样，你需要更新树莓派。最新的增强功能不仅可以使你的派运行顺畅，还可以让它更安全，特别是在如果你连接到网络的情况下。我们的树莓派入门指南中的第七篇会分享两条关于让派良好运行的建议。
### 更新 Raspbian
更新 Raspbian 有[两步][1]：
1. 在终端中输入：`sudo apt-get update`。
该命令的 `sudo` 让你以管理员（也就是 root）运行 `apt-get update`。请注意，`apt-get update` 不会在系统上安装任何新东西，而是将更新需要更新的包和依赖项列表。
2. 接着输入：`sudo apt-get dist-upgrade`。
摘自文档：“一般来说，定期执行此操作将使你的安装保持最新，因为它将等同于 [raspberrypi.org/downloads][2] 中发布的最新镜像。”
![](https://opensource.com/sites/default/files/uploads/update_sudo_rpi.png)
### 小心 rpi-update
Raspbian 带有另一个名为 [rpi-update][3] 的更新工具。此程序可用于将派升级到最新固件，不管该固件是不是有损坏或问题。你可能会发现一些如何使用它的信息，但是建议你永远不要使用这个程序，除非你有充分的理由这样做。
一句话：保持系统更新！
--------------------------------------------------------------------------------
via: https://opensource.com/article/19/3/how-raspberry-pi-update
作者：[Anderson Silva][a]
选题：[lujun9972][b]
译者：[geekpi](https://github.com/geekpi)
校对：[wxy](https://github.com/wxy)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://opensource.com/users/ansilva
[b]: https://github.com/lujun9972
[1]: https://www.raspberrypi.org/documentation/raspbian/updating.md
[2]: https://www.raspberrypi.org/downloads/
[3]: https://github.com/Hexxeh/rpi-update

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[#]: collector: (lujun9972)
[#]: translator: (zhs852)
[#]: reviewer: (wxy)
[#]: publisher: (wxy)
[#]: url: (https://linux.cn/article-10656-1.html)
[#]: subject: (How to host your own webfonts)
[#]: via: (https://opensource.com/article/19/3/webfonts)
[#]: author: (Seth Kenlon (Red Hat, Community Moderator) https://opensource.com/users/seth)
托管你自己的在线字体
======
> 使用自托管的开源字体来定制你的网页。
![开源字体][1]
字体对许多计算机用户来说可能都是很神秘的东西。举个例子，你在制作好一张很酷的传单之后，你需要将它送到某个地方去打印，结果发现，你设计的所有字体都变成了 Arial，这多半是因为打印店没用安装你设计用到的那些字体。不过，我们仍有很多方法来避免这种情况：你可以将这些使用特定字体的单词转换为路径，你也可以将它封装为 PDF，或是把开源字体封装到你的设计文件中，或者至少列出所需字体。不过，我们总会忘记一些事情，所以这仍是一个问题。
Web 上也有类似的问题。如果你对 CSS 有所了解，你可能会见过这种声明：
```
h1 { font-family: "Times New Roman", Times, serif; }
```
这是设计师正在尝试定义网站使用要用到的特定字体，如果用户没有安装 Times New Roman 这个字体，便会回落到另一个字体；如果用户也没有安装 Times 这个字体，便再次回落。它比使用图片而不是文本更好一些，但是在没有字体托管的情况下，这仍是一种棘手且不雅观的方法。不过，在早期的互联网时代，我们不得不这样做。
### 在线字体
在线字体的登场，把字体管理从客户端搬上了服务端。如今网页上的字体通常由服务器为客户端渲染，而不是要求浏览器从用户的系统中查找字体。谷歌和其它供应商托管了许多开源字体，网站设计师们可以很轻松的用 CSS 来引用它们。
不过，问题是，引用这些字体并不是不花费任何代价的。虽然引用它们免费，但是像谷歌这样的巨头喜欢跟踪那些引用它们资源的网站，其中就包括了字体资源。如果你不想你的网站帮谷歌记录每个人的活动，你可以自己托管在线字体。别觉得这很难，它其实是很简单的，大概流程就是上传字体到你的主机，再使用一个简单的 CSS 便可完成。这样做还有个好处，你的网站能更快地加载，因为它会在加载每个页面的时候进行更少的外部调用。
### 自托管在线字体
首先，你需要一个开源字体。如果你没有了解过那些令人费解的软件协议，你可能会感到很疑惑，特别是很多字体看起来都是免费的。我们中应该很少有人有字体付费意识，但是他们却在电脑上安装了一些高价的字体。不过，由于授权协议，它使得你的电脑也许带着一些 [法律上不允许复制和再分发][2] 的字体。像 Arial、Verdana、Calibri、Georgia、Impact、Lucida 和 Lucida Grande、Times 和 Times New Roman、Trebuchet、Geneva 以及其它的很多字体都是被微软、苹果和 Adobe 这种大公司所拥有的。如果你购买了一台预装了 Windows 或 macOS 的电脑，你就获得了使用这些字体的权利，但是你并没有拥有那些字体，也没有被许可上传它们至服务器（除非额外说明）。
幸运的事，开源热潮在很久以前就席卷了字体界。然后就有了许多优秀的开源字体的合集和项目，比如 [The League of Moveable Type][3]、[Font Library][4] 以及 [Omnibus Type][5]，甚至还有一些来自 [Google][6] 和 [Adobe][7] 的字体。
常见的字体格式有 TTF、OTF、WOFF、EOT 等。因为 Sorts Mill Goudy 发行过 <ruby>WOFF<rt>Web Open Font Format</rt></ruby>（互联网开放字体格式，Mozilla 参与了部分开发）版本，所以下文中我会用它来做例子。当然，其它字体的方法也是一样的。
假设你想在你的网站上使用 [Sorts Mill Goudy][8] 这个字体：
1、将字体文件 `GoudyStM-webfont.woff` 上传至你的服务器：
```
scp GoudyStM-webfont.woff seth@example.com:~/www/fonts/
```
你的主机可能带有像 cPanel 这样的图形化工具，通过它们上传也是一样的。
2、在你网站的 CSS 文件中，添加 `@font-face` 语句，添加后应该和这个差不多：
```
@font-face {
  font-family: "titlefont";
  src: url("../fonts/GoudyStM-webfont.woff");
}
```
`font-family` 的值是你来决定的。这是一个易于理解的名字，它用于放在使用字体名的地方。我在这里使用 “titlefont” 作为例子，是因为我希望它被用来显示标题字体。你也可以使用 “officialfont” 和 “myfont” 这样的名字。
`src` 值是你字体文件的路径。这是你服务器上字体的路径。在这里，我用 `fonts` 目录来作为示例，它和 `css` 在一个文件夹里。你服务器的文件结构可能和我的不一样，所以你需要调整一下这个路径。记住一点，一个点意味着*工作目录*，两个点则代表*父目录*。
3、现在，你已经定义了字体的名字和目录，你可以在任何指定的 CSS 类或 ID 来调用它了。举个例子，如果你希望以 Sorts Mill Goudy 字体来渲染 `<h1>`，只需要在 CSS 规则中加入你自己的字体名称：
```
h1 { font-family: "titlefont", serif; }
```
现在，你已经成功地托管并使用你自己的字体了。
![在线字体的实际效果][10]
--------------------------------------------------------------------------------
via: https://opensource.com/article/19/3/webfonts
作者：[Seth Kenlon (Red Hat, Community Moderator)][a]
选题：[lujun9972][b]
译者：[zhs852](https://github.com/zhs852)
校对：[wxy](https://github.com/wxy)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://opensource.com/users/seth
[b]: https://github.com/lujun9972
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/life_typography_fonts.png?itok=Q1jMys5G (Open source fonts)
[2]: https://docs.microsoft.com/en-us/typography/fonts/font-faq
[3]: https://www.theleagueofmoveabletype.com/
[4]: https://fontlibrary.org/
[5]: https://www.omnibus-type.com
[6]: https://github.com/googlefonts
[7]: https://github.com/adobe-fonts
[8]: https://www.theleagueofmoveabletype.com/sorts-mill-goudy
[9]: /file/426056
[10]: https://opensource.com/sites/default/files/uploads/webfont.jpg (Web fonts on a website)

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[#]: collector: (lujun9972)
[#]: translator: (luckyele)
[#]: reviewer: (wxy)
[#]: publisher: (wxy)
[#]: url: (https://linux.cn/article-10658-1.html)
[#]: subject: (How to add new disk in Linux)
[#]: via: (https://kerneltalks.com/hardware-config/how-to-add-new-disk-in-linux/)
[#]: author: (kerneltalks https://kerneltalks.com)
如何在 Linux 中添加新磁盘
======
> 在 Linux 机器中添加磁盘的逐步过程。
![New disk addition in Linux][1]
本文将向你介绍在 Linux 机器中添加新磁盘的步骤。将原始磁盘添加到 Linux 机器可能非常依赖于你所拥有的服务器类型，但是一旦将磁盘提供给机器，将其添加到挂载点的过程几乎相同。
**目标**：向服务器添加新的 10GB 磁盘，并使用 lvm 和新创建的卷组创建 5GB 装载点。
### 向 Linux 机器添加原始磁盘
如果你使用的是 AWS EC2 Linux 服务器，可以 [按照以下步骤][2] 添加原始磁盘。如果使用的是 VMware Linux VM，那么需要按照不同的步骤来添加磁盘。如果你正在运行物理机架设备/刀片服务器，那么添加磁盘将是一项物理任务。
一旦磁盘物理/虚拟地连接到 Linux 机器上，它将被内核识别，就可以开始了。
### 识别 Linux 最新添加的磁盘
原始磁盘连接后，需要让内核去 [扫描新磁盘][3]。在新版中，它主要是由内核自动完成。
第一件事是在内核中识别新添加的磁盘及其名称。实现这一点的方法有很多，以下作少量列举：
* 可以在添加/扫描磁盘前后观察 `lsblk` 输出，以获取新的磁盘名。
* 检查 `/dev` 文件系统中新创建的磁盘文件。匹配文件和磁盘添加时间的时间戳。
* 观察 `fdisk-l` 添加/扫描磁盘前后的输出，以获取新的磁盘名。
在本示例中，我使用的是 AWS EC2 服务器，向服务器添加了 5GB 磁盘。我的 lsblk 输出如下：
```
[root@kerneltalks ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda 202:0 0 10G 0 disk
├─xvda1 202:1 0 1M 0 part
└─xvda2 202:2 0 10G 0 part /
xvdf 202:80 0 10G 0 disk
```
可以看到 `xvdf` 是新添加的磁盘。完整路径是 `/dev/xvdf`。
### 在 LVM 中添加新磁盘
我们这里使用 LVM，因为它是 Linux 平台上广泛使用的非常灵活的卷管理器。确认 lvm 或 lvm2 软件包[已经安装在系统上][4]。如未安装，请 [安装 lvm/lvm2 程序包][5]。
现在，我们将在逻辑卷管理器中添加这个原始磁盘，并从中创建 10GB 的挂接点。所用到的命令如下：
* [pvcreate][6]
* [vgcreate][7]
* [lvcreate][8]
如果要将磁盘添加到现有挂接点，并使用其空间来[扩展挂接点][9] ，则 `vgcreate` 应替换为 `vgextend`。
会话示例输出如下：
```
[root@kerneltalks ~]# pvcreate /dev/xvdf
Physical volume "/dev/xvdf" successfully created.
[root@kerneltalks ~]# vgcreate vgdata /dev/xvdf
Volume group "vgdata" successfully created
[root@kerneltalks ~]# lvcreate -L 5G -n lvdata vgdata
Logical volume "lvdata" created.
```
现在，已完成逻辑卷创建。你需要使用所选的文件系统格式化它，并将其挂载。在这里选择 ext4 文件系统，并使用 `mkfs.ext4` 进行格式化。
```
[root@kerneltalks ~]# mkfs.ext4 /dev/vgdata/lvdata
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
327680 inodes, 1310720 blocks
65536 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=1342177280
40 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736
Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
```
### 在挂载点上从新磁盘挂载卷
使用 `mount` 命令，在 `/data` 安装点上安装已创建并格式化的 5GB 逻辑卷。
```
[root@kerneltalks ~]# mount /dev/vgdata/lvdata /data
[root@kerneltalks ~]# df -Ph /data
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vgdata-lvdata 4.8G 20M 4.6G 1% /data
```
使用 `df` 命令验证挂载点。如上所述，你都完成了！你可以在 [/etc/fstab][10] 中添加一个条目，以便在重新启动时保持此装载。
你已将 10GB 磁盘连接到 Linux 计算机，并创建了 5GB 挂载点！
--------------------------------------------------------------------------------
via: https://kerneltalks.com/hardware-config/how-to-add-new-disk-in-linux/
作者：[kerneltalks][a]
选题：[lujun9972][b]
译者：[luckyele](https://github.com/luckyele)
校对：[wxy](https://github.com/wxy)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://kerneltalks.com
[b]: https://github.com/lujun9972
[1]: https://i1.wp.com/kerneltalks.com/wp-content/uploads/2019/03/How-to-add-new-disk-in-Linux.png?ssl=1
[2]: https://kerneltalks.com/cloud-services/how-to-add-ebs-disk-on-aws-linux-server/
[3]: https://kerneltalks.com/disk-management/howto-scan-new-lun-disk-linux-hpux/
[4]: https://kerneltalks.com/tools/check-package-installed-linux/
[5]: https://kerneltalks.com/tools/package-installation-linux-yum-apt/
[6]: https://kerneltalks.com/disk-management/lvm-command-tutorials-pvcreate-pvdisplay/
[7]: https://kerneltalks.com/disk-management/lvm-commands-tutorial-vgcreate-vgdisplay-vgscan/
[8]: https://kerneltalks.com/disk-management/lvm-commands-tutorial-lvcreate-lvdisplay-lvremove/
[9]: https://kerneltalks.com/disk-management/extend-file-system-online-lvm/
[10]: https://kerneltalks.com/config/understanding-etcfstab-file/

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[#]: collector: (lujun9972)
[#]: translator: ( )
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: subject: (lawyer The MIT License, Line by Line)
[#]: via: (https://writing.kemitchell.com/2016/09/21/MIT-License-Line-by-Line.html)
[#]: author: (Kyle E. Mitchell https://kemitchell.com/)
lawyer The MIT License, Line by Line
======
### The MIT License, Line by Line
[The MIT License][1] is the most popular open-source software license. Here’s one read of it, line by line.
#### Read the License
If you’re involved in open-source software and haven’t taken the time to read the license from top to bottom—it’s only 171 words—you need to do so now. Especially if licenses aren’t your day-to-day. Make a mental note of anything that seems off or unclear, and keep trucking. I’ll repeat every word again, in chunks and in order, with context and commentary. But it’s important to have the whole in mind.
> The MIT License (MIT)
>
> Copyright (c) <year> <copyright holders>
>
> Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
>
> The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
>
> The Software is provided “as is”, without warranty of any kind, express or implied, including but not limited to the warranties of merchantability, fitness for a particular purpose and noninfringement. In no event shall the authors or copyright holders be liable for any claim, damages or other liability, whether in an action of contract, tort or otherwise, arising from, out of or in connection with the software or the use or other dealings in the Software.
The license is arranged in five paragraphs, but breaks down logically like this:
* **Header**
* **License Title** : “The MIT License”
* **Copyright Notice** : “Copyright (c) …”
* **License Grant** : “Permission is hereby granted …”
* **Grant Scope** : “… to deal in the Software …”
* **Conditions** : “… subject to …”
* **Attribution and Notice** : “The above … shall be included …”
* **Warranty Disclaimer** : “The software is provided ‘as is’ …”
* **Limitation of Liability** : “In no event …”
Here we go:
#### Header
##### License Title
> The MIT License (MIT)
“The MIT License” is a not a single license, but a family of license forms derived from language prepared for releases from the Massachusetts Institute of Technology. It has seen a lot of changes over the years, both for the original projects that used it, and also as a model for other projects. The Fedora Project maintains a [kind of cabinet of MIT license curiosities][2], with insipid variations preserved in plain text like anatomical specimens in formaldehyde, tracing a wayward kind of evolution.
Fortunately, the [Open Source Initiative][3] and [Software Package Data eXchange][4] groups have standardized a generic MIT-style license form as “The MIT License”. OSI in turn has adopted SPDX’ standardized [string identifiers][5] for common open-source licenses, with `MIT` pointing unambiguously to the standardized form “MIT License”. If you want MIT-style terms for a new project, use [the standardized form][1].
Even if you include “The MIT License” or “SPDX:MIT” in a `LICENSE` file, any responsible reviewer will still run a comparison of the text against the standard form, just to be sure. While various license forms calling themselves “MIT License” vary only in minor details, the looseness of what counts as an “MIT License” has tempted some authors into adding bothersome “customizations”. The canonical horrible, no good, very bad example of this is [the JSON license][6], an MIT-family license plus “The Software shall be used for Good, not Evil.”. This kind of thing might be “very Crockford”. It is definitely a pain in the ass. Maybe the joke was supposed to be on the lawyers. But they laughed all the way to the bank.
Moral of the story: “MIT License” alone is ambiguous. Folks probably have a good idea what you mean by it, but you’re only going to save everyone—yourself included—time by copying the text of the standard MIT License form into your project. If you use metadata, like the `license` property in package manager metadata files, to designate the `MIT` license, make sure your `LICENSE` file and any header comments use the standard form text. All of this can be [automated][7].
##### Copyright Notice
> Copyright (c) <year> <copyright holders>
Until the 1976 Copyright Act, United States copyright law required specific actions, called “formalities”, to secure copyright in creative works. If you didn’t follow those formalities, your rights to sue others for unauthorized use of your work were limited, often completely lost. One of those formalities was “notice”: Putting marks on your work and otherwise making it known to the market that you were claiming copyright. The © is a standard symbol for marking copyrighted works, to give notice of copyright. The ASCII character set doesn’t have the © symbol, but `Copyright (c)` gets the same point across.
The 1976 Copyright Act, which “implemented” many requirements of the international Berne Convention, eliminated formalities for securing copyright. At least in the United States, copyright holders still need to register their copyrighted works before suing for infringement, with potentially higher damages if they register before infringement begins. In practice, however, many register copyright right before bringing suit against someone in particular. You don’t lose your copyright just by failing to put notices on it, registering, sending a copy to the Library of Congress, and so on.
Even if copyright notices aren’t as absolutely necessary as they used to be, they are still plenty useful. Stating the year a work was authored and who the copyright belonged to give some sense of when copyright in the work might expire, bringing the work into the public domain. The identity of the author or authors is also useful: United States law calculates copyright terms differently for individual and “corporate” authors. Especially in business use, it may also behoove a company to think twice about using software from a known competitor, even if the license terms give very generous permission. If you’re hoping others will see your work and want to license it from you, copyright notices serve nicely for attribution.
As for “copyright holder”: Not all standard form licenses have a space to write this out. More recent license forms, like [Apache 2.0][8] and [GPL 3.0][9], publish `LICENSE` texts that are meant to be copied verbatim, with header comments and separate files elsewhere to indicate who owns copyright and is giving the license. Those approaches neatly discourage changes to the “standard” texts, accidental or intentional. They also make automated license identification more reliable.
The MIT License descends from language written for releases of code by institutions. For institutional releases, there was just one clear “copyright holder”, the institution releasing the code. Other institutions cribbed these licenses, replacing “MIT” with their own names, leading eventually to the generic forms we have now. This process repeated for other short-form institutional licenses of the era, notably the [original four-clause BSD License][10] for the University of California, Berkeley, now used in [three-clause][11] and [two-clause][12] variants, as well as [The ISC License][13] for the Internet Systems Consortium, an MIT variant.
In each case, the institution listed itself as the copyright holder in reliance on rules of copyright ownership, called “[works made for hire][14]” rules, that give employers and clients ownership of copyright in some work their employees and contractors do on their behalf. These rules don’t usually apply to distributed collaborators submitting code voluntarily. This poses a problem for project-steward foundations, like the Apache Foundation and Eclipse Foundation, that accept contributions from a more diverse group of contributors. The usual foundation approach thus far has been to use a house license that states a single copyright holder—[Apache 2.0][8] and [EPL 1.0][15]—backed up by contributor license agreements—[Apache CLAs][16] and [Eclipse CLAs][17]—to collect rights from contributors. Collecting copyright ownership in one place is even more important under “copyleft” licenses like the GPL, which rely on copyright owners to enforce license conditions to promote software-freedom values.
These days, loads of projects without any kind of institutional or business steward use MIT-style license terms. SPDX and OSI have helped these use cases by standardizing forms of licenses like MIT and ISC that don’t refer to a specific entity or institutional copyright holder. Armed with those forms, the prevailing practice of project authors is to fill their own name in the copyright notice of the form very early on … and maybe bump the year here and there. At least under United States copyright law, the resulting copyright notice doesn’t give a full picture.
The original owner of a piece of software retains ownership of their work. But while MIT-style license terms give others rights to build on and change the software, creating what the law calls “derivative works”, they don’t give the original author ownership of copyright in others’ contributions. Rather, each contributor has copyright in any [even marginally creative][18] work they make using the existing code as a starting point.
Most of these projects also balk at the idea of taking contributor license agreements, to say nothing of signed copyright assignments. That’s both naive and understandable. Despite the assumption of some newer open-source developers that sending a pull request on GitHub “automatically” licenses the contribution for distribution on the terms of the project’s existing license, United States law doesn’t recognize any such rule. Strong copyright protection, not permissive licensing, is the default.
Update: GitHub later changed its site-wide terms of service to include an attempt to flip this default, at least on GitHub.com. I’ve written up some thoughts on that development, not all of them positive, in [another post][19].
To fill the gap between legally effective, well-documented grants of rights in contributions and no paper trail at all, some projects have adopted the [Developer Certificate of Origin][20], a standard statement contributors allude to using `Signed-Off-By` metadata tags in their Git commits. The Developer Certificate of Origin was developed for Linux kernel development in the wake of the infamous SCO lawsuits, which alleged that chunks of Linux’ code derived from SCO-owned Unix source. As a means of creating a paper trail showing that each line of Linux came from a contributor, the Developer Certificate of Origin functions nicely. While the Developer Certificate of Origin isn’t a license, it does provide lots of good evidence that those submitting code expected the project to distribute their code, and for others to use it under the kernel’s existing license terms. The kernel also maintains a machine-readable `CREDITS` file listing contributors with name, affiliation, contribution area, and other metadata. I’ve done [some][21] [experiments][22] adapting that approach for projects that don’t use the kernel’s development flow.
#### License Grant
> Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”),
The meat of The MIT License is, you guessed it, a license. In general terms, a license is permission that one person or legal entity—the “licensor”—gives another—the “licensee”—to do something the law would otherwise let them sue for. The MIT License is a promise not to sue.
The law sometimes distinguishes licenses from promises to give licenses. If someone breaks a promise to give a license, you may be able to sue them for breaking their promise, but you may not end up with a license. “Hereby” is one of those hokey, archaic-sounding words lawyers just can’t get rid of. It’s used here to show that the license text itself gives the license, and not just a promise of a license. It’s a legal [IIFE][23].
While many licenses give permission to a specific, named licensee, The MIT License is a “public license”. Public licenses give everybody—the public at large—permission. This is one of the three great ideas in open-source licensing. The MIT License captures this idea by giving a license “to any person obtaining a copy of … the Software”. As we’ll see later, there is also a condition to receiving this license that ensures others will learn about their permission, too.
The parenthetical with a capitalized term in quotation marks (a “Definition”), is the standard way to give terms specific meanings in American-style legal documents. Courts will reliably look back to the terms of the definition when they see a defined, capitalized term used elsewhere in the document.
##### Grant Scope
> to deal in the Software without restriction,
From the licensee’s point of view, these are the seven most important words in The MIT License. The key legal concerns are getting sued for copyright infringement and getting sued for patent infringement. Neither copyright law nor patent law uses “to deal in” as a term of art; it has no specific meaning in court. As a result, any court deciding a dispute between a licensor and a licensee would ask what the parties meant and understood by this language. What the court will see is that the language is intentionally broad and open-ended. It gives licensees a strong argument against any claim by a licensor that they didn’t give permission for the licensee to do that specific thing with the software, even if the thought clearly didn’t occur to either side when the license was given.
> including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so,
No piece of legal writing is perfect, “fully settled in meaning”, or unmistakably clear. Beware anyone who pretends otherwise. This is the least perfect part of The MIT License. There are three main issues:
First, “including without limitation” is a legal antipattern. It crops up in any number of flavors:
* “including, without limitation”
* “including, without limiting the generality of the foregoing”
* “including, but not limited to”
* many, many pointless variations
All of these share a common purpose, and they all fail to achieve it reliably. Fundamentally, drafters who use them try to have their cake and eat it, too. In The MIT License, that means introducing specific examples of “dealing in the Software”—“use, copy, modify” and so on—without implying that licensee action has to be something like the examples given to count as “dealing in”. The trouble is that, if you end up needing a court to review and interpret the terms of a license, the court will see its job as finding out what those fighting meant by the language. If the court needs to decide what “deal in” means, it cannot “unsee” the examples, even if you tell it to. I’d argue that “deal in the Software without restriction” alone would be better for licensees. Also shorter.
Second, the verbs given as examples of “deal in” are a hodgepodge. Some have specific meanings under copyright or patent law, others almost do or just plain don’t:
* use appears in [United States Code title 35, section 271(a)][24], the patent law’s list of what patent owners can sue others for doing without permission.
* copy appears in [United States Code title 17, section 106][25], the copyright law’s list of what copyright owners can sue others for doing without permission.
* modify doesn’t appear in either copyright or patent statute. It is probably closest to “prepare derivative works” under the copyright statute, but may also implicate improving or otherwise derivative inventions.
* merge doesn’t appear in either copyright or patent statute. “Merger” has a specific meaning in copyright, but that’s clearly not what’s intended here. Rather, a court would probably read “merge” according to its meaning in industry, as in “to merge code”.
* publish doesn’t appear in either copyright or patent statute. Since “the Software” is what’s being published, it probably hews closest to “distribute” under the [copyright statute][25]. That statute also covers rights to perform and display works “publicly”, but those rights apply only to specific kinds of copyrighted work, like plays, sound recordings, and motion pictures.
* distribute appears in the [copyright statute][25].
* sublicense is a general term of intellectual property law. The right to sublicense means the right to give others licenses of their own, to do some or all of what you have permission to do. The MIT License’s right to sublicense is actually somewhat unusual in open-source licenses generally. The norm is what Heather Meeker calls a “direct licensing” approach, where everyone who gets a copy of the software and its license terms gets a license direct from the owner. Anyone who might get a sublicense under the MIT License will probably end up with a copy of the license telling them they have a direct license, too.
* sell copies of is a mongrel. It is close to “offer to sell” and “sell” in the [patent statute][24], but refers to “copies”, a copyright concept. On the copyright side, it seems close to “distribute”, but the [copyright statute][25] makes no mention of sales.
* permit persons to whom the Software is furnished to do so seems redundant of “sublicense”. It’s also unnecessary to the extent folks who get copies also get a direct license.
Lastly, as a result of this mishmash of legal, industry, general-intellectual-property, and general-use terms, it isn’t clear whether The MIT License includes a patent license. The general language “deal in” and some of the example verbs, especially “use”, point toward a patent license, albeit a very unclear one. The fact that the license comes from the copyright holder, who may or may not have patent rights in inventions in the software, as well as most of the example verbs and the definition of “the Software” itself, all point strongly toward a copyright license. More recent permissive open-source licenses, like [Apache 2.0][8], address copyright, patent, and even trademark separately and specifically.
##### Three License Conditions
> subject to the following conditions:
There’s always a catch! MIT has three!
If you don’t follow The MIT License’s conditions, you don’t get the permission the license offers. So failing to do what the conditions say at least theoretically leaves you open to a lawsuit, probably a copyright lawsuit.
Using the value of the software to the licensee to motivate compliance with conditions, even though the licensee paid nothing for the license, is the second great idea of open-source licensing. The last, not found in The MIT License, builds off license conditions: “Copyleft” licenses like the [GNU General Public License][9] use license conditions to control how those making changes can license and distribute their changed versions.
##### Notice Condition
> The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
If you give someone a copy of the software, you need to include the license text and any copyright notice. This serves a few critical purposes:
1. Gives others notice that they have permission for the software under the public license. This is a key part of the direct-licensing model, where each user gets a license direct from the copyright holder.
2. Makes known who’s behind the software, so they can be showered in praises, glory, and cold, hard cash donations.
3. Ensures the warranty disclaimer and limitation of liability (coming up next) follow the software around. Everyone who gets a copy should get a copy of those licensor protections, too.
There’s nothing to stop you charging for providing a copy, or even a copy in compiled form, without source code. But when you do, you can’t pretend that the MIT code is your own proprietary code, or provided under some other license. Those receiving get to know their rights under the “public license”.
Frankly, compliance with this condition is breaking down. Nearly every open-source license has such an “attribution” condition. Makers of system and installed software often understand they’ll need to compile a notices file or “license information” screen, with copies of license texts for libraries and components, for each release of their own. The project-steward foundations have been instrumental in teaching those practices. But web developers, as a whole, haven’t got the memo. It can’t be explained away by a lack of tooling—there is plenty—or the highly modular nature of packages from npm and other repositories—which uniformly standardize metadata formats for license information. All the good JavaScript minifiers have command-line flags for preserving license header comments. Other tools will concatenate `LICENSE` files from package trees. There’s really no excuse.
##### Warranty Disclaimer
> The Software is provided “as is”, without warranty of any kind, express or implied, including but not limited to the warranties of merchantability, fitness for a particular purpose and noninfringement.
Nearly every state in the United States has enacted a version of the Uniform Commercial Code, a model statute of laws governing commercial transactions. Article 2 of the UCC—“Division 2” in California—governs contracts for sales of goods, from used automobiles bought off the lot to large shipments of industrial chemicals to manufacturing plants.
Some of the UCC’s rules about sales contracts are mandatory. These rules always apply, whether those buying and selling like them or not. Others are just “defaults”. Unless buyers and sellers opt out in writing, the UCC implies that they want the baseline rule found in the UCC’s text for their deal. Among the default rules are implied “warranties”, or promises by sellers to buyers about the quality and usability of the goods being sold.
There is a big theoretical debate about whether public licenses like The MIT License are contracts—enforceable agreements between licensors and licensees—or just licenses, which go one way, but may come with strings attached, their conditions. There is less debate about whether software counts as “goods”, triggering the UCC’s rules. There is no debate among licensors on liability: They don’t want to get sued for lots of money if the software they give away for free breaks, causes problems, doesn’t work, or otherwise causes trouble. That’s exactly the opposite of what three default rules for “implied warranties” do:
1. The implied warranty of “merchantability” under [UCC section 2-314][26] is a promise that “the goods”—the Software—are of at least average quality, properly packaged and labeled, and fit for the ordinary purposes they are intended to serve. This warranty applies only if the one giving the software is a “merchant” with respect to the software, meaning they deal in software and hold themselves out as skilled in software.
2. The implied warranty of “fitness for a particular purpose” under [UCC section 2-315][27] kicks in when the seller knows the buyer is relying on them to provide goods for a particular purpose. The goods need to actually be “fit” for that purpose.
3. The implied warranty of “noninfringement” is not part of the UCC, but is a common feature of general contract law. This implied promise protects the buyer if it turns out the goods they received infringe somebody else’s intellectual property rights. That would be the case if the software under The MIT License didn’t actually belong to the one trying to license it, or if it fell under a patent owned by someone else.
[Section 2-316(3)][28] of the UCC requires language opting out of, or “excluding”, implied warranties of merchantability and fitness for a particular purpose to be conspicuous. “Conspicuous” in turn means written or formatted to call attention to itself, the opposite of microscopic fine print meant to slip past unwary consumers. State law may impose a similar attention-grabbing requirement for disclaimers of noninfringement.
Lawyers have long suffered under the delusion that writing anything in `ALL-CAPS` meets the conspicuous requirement. That isn’t true. Courts have criticized the Bar for pretending as much, and most everyone agrees all-caps does more to discourage reading than compel it. All the same, most open-source-license forms set their warranty disclaimers in all-caps, in part because that’s the only obvious way to make it stand out in plain-text `LICENSE` files. I’d prefer to use asterisks or other ASCII art, but that ship sailed long, long ago.
##### Limitation of Liability
> In no event shall the authors or copyright holders be liable for any claim, damages or other liability, whether in an action of contract, tort or otherwise, arising from, out of or in connection with the Software or the use or other dealings in the Software.
The MIT License gives permission for software “free of charge”, but the law does not assume that folks receiving licenses free of charge give up their rights to sue when things go wrong and the licensor is to blame. “Limitations of liability”, often paired with “damages exclusions”, work a lot like licenses, as promises not to sue. But these are protections for the licensor against lawsuits by licensees.
In general, courts read limitations of liability and damages exclusions warily, since they can shift an incredible amount of risk from one side to another. To protect the community’s vital interest in giving folks a way to redress wrongs done in court, they “strictly construe” language limiting liability, reading it against the one protected by it where possible. Limitations of liability have to be specific to stand up. Especially in “consumer” contracts and other situations where those giving up the right to sue lack sophistication or bargaining power, courts have sometimes refused to honor language that seemed buried out of sight. Partly for that reason, partly by sheer force of habit, lawyers tend to give limits of liability the all-caps treatment, too.
Drilling down a bit, the “limitation of liability” part is a cap on the amount of money a licensee can sue for. In open-source licenses, that limit is always no money at all, $0, “not liable”. By contrast, in commercial licenses, it’s often a multiple of license fees paid in the last 12-month period, though it’s often negotiated.
The “exclusion” part lists, specifically, kinds of legal claims—reasons to sue for damages—the licensor cannot use. Like many, many legal forms, The MIT License mentions actions “of contract”—for breaching a contract—and “of tort”. Tort rules are general rules against carelessly or maliciously harming others. If you run someone down on the road while texting, you have committed a tort. If your company sells faulty headphones that burn peoples’ ears off, your company has committed a tort. If a contract doesn’t specifically exclude tort claims, courts sometimes read exclusion language in a contract to prevent only contract claims. For good measure, The MIT License throws in “or otherwise”, just to catch the odd admiralty law or other, exotic kind of legal claim.
The phrase “arising from, out of or in connection with” is a recurring tick symptomatic of the legal draftsman’s inherent, anxious insecurity. The point is that any lawsuit having anything to do with the software is covered by the limitation and exclusions. On the off chance something can “arise from”, but not “out of”, or “in connection with”, it feels better to have all three in the form, so pack ‘em in. Never mind that any court forced to split hairs in this part of the form will have to come up with different meanings for each, on the assumption that a professional drafter wouldn’t use different words in a row to mean the same thing. Never mind that in practice, where courts don’t feel good about a limitation that’s disfavored to begin with, they’ll be more than ready to read the scope trigger narrowly. But I digress. The same language appears in literally millions of contracts.
#### Overall
All these quibbles are a bit like spitting out gum on the way into church. The MIT License is a legal classic. The MIT License works. It is by no means a panacea for all software IP ills, in particular the software patent scourge, which it predates by decades. But MIT-style licenses have served admirably, fulfilling a narrow purpose—reversing troublesome default rules of copyright, sales, and contract law—with a minimal combination of discreet legal tools. In the greater context of computing, its longevity is astounding. The MIT License has outlasted and will outlast the vast majority of software licensed under it. We can only guess how many decades of faithful legal service it will have given when it finally loses favor. It’s been especially generous to those who couldn’t have afforded their own lawyer.
We’ve seen how the The MIT License we know today is a specific, standardized set of terms, bringing order at long last to a chaos of institution-specific, haphazard variations.
We’ve seen how its approach to attribution and copyright notice informed intellectual property management practices for academic, standards, commercial, and foundation institutions.
We’ve seen how The MIT Licenses grants permission for software to all, for free, subject to conditions that protect licensors from warranties and liability.
We’ve seen that despite some crusty verbiage and lawyerly affectation, one hundred and seventy one little words can get a hell of a lot of legal work done, clearing a path for open-source software through a dense underbrush of intellectual property and contract.
I’m so grateful for all who’ve taken the time to read this rather long post, to let me know they found it useful, and to help improve it. As always, I welcome your comments via [e-mail][29], [Twitter][30], and [GitHub][31].
A number of folks have asked where they can read more, or find run-downs of other licenses, like the GNU General Public License or the Apache 2.0 license. No matter what your particular continuing interest may be, I heartily recommend the following books:
* Andrew M. St. Laurent’s [Understanding Open Source & Free Software Licensing][32], from O’Reilly.
I start with this one because, while it’s somewhat dated, its approach is also closest to the line-by-line approach used above. O’Reilly has made it [available online][33].
* Heather Meeker’s [Open (Source) for Business][34]
In my opinion, by far the best writing on the GNU General Public License and copyleft more generally. This book covers the history, the licenses, their development, as well as compatibility and compliance. It’s the book I lend to clients considering or dealing with the GPL.
* Larry Rosen’s [Open Source Licensing][35], from Prentice Hall.
A great first book, also available for free [online][36]. This is the best introduction to open-source licensing and related law for programmers starting from scratch. This one is also a bit dated in some specific details, but Larry’s taxonomy of licenses and succinct summary of open-source business models stand the test of time.
All of these were crucial to my own education as an open-source licensing lawyer. Their authors are professional heroes of mine. Have a read! — K.E.M
I license this article under a [Creative Commons Attribution-ShareAlike 4.0 license][37].
--------------------------------------------------------------------------------
via: https://writing.kemitchell.com/2016/09/21/MIT-License-Line-by-Line.html
作者：[Kyle E. Mitchell][a]
选题：[lujun9972][b]
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本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://kemitchell.com/
[b]: https://github.com/lujun9972
[1]: http://spdx.org/licenses/MIT
[2]: https://fedoraproject.org/wiki/Licensing:MIT?rd=Licensing/MIT
[3]: https://opensource.org
[4]: https://spdx.org
[5]: http://spdx.org/licenses/
[6]: https://spdx.org/licenses/JSON
[7]: https://www.npmjs.com/package/licensor
[8]: https://www.apache.org/licenses/LICENSE-2.0
[9]: https://www.gnu.org/licenses/gpl-3.0.en.html
[10]: http://spdx.org/licenses/BSD-4-Clause
[11]: https://spdx.org/licenses/BSD-3-Clause
[12]: https://spdx.org/licenses/BSD-2-Clause
[13]: http://www.isc.org/downloads/software-support-policy/isc-license/
[14]: http://worksmadeforhire.com/
[15]: https://www.eclipse.org/legal/epl-v10.html
[16]: https://www.apache.org/licenses/#clas
[17]: https://wiki.eclipse.org/ECA
[18]: https://en.wikipedia.org/wiki/Feist_Publications,_Inc.,_v._Rural_Telephone_Service_Co.
[19]: https://writing.kemitchell.com/2017/02/16/Against-Legislating-the-Nonobvious.html
[20]: http://developercertificate.org/
[21]: https://github.com/berneout/berneout-pledge
[22]: https://github.com/berneout/authors-certificate
[23]: https://en.wikipedia.org/wiki/Immediately-invoked_function_expression
[24]: https://www.govinfo.gov/app/details/USCODE-2017-title35/USCODE-2017-title35-partIII-chap28-sec271
[25]: https://www.govinfo.gov/app/details/USCODE-2017-title17/USCODE-2017-title17-chap1-sec106
[26]: https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?sectionNum=2314.&lawCode=COM
[27]: https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?sectionNum=2315.&lawCode=COM
[28]: https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?sectionNum=2316.&lawCode=COM
[29]: mailto:kyle@kemitchell.com
[30]: https://twitter.com/kemitchell
[31]: https://github.com/kemitchell/writing/tree/master/_posts/2016-09-21-MIT-License-Line-by-Line.md
[32]: https://lccn.loc.gov/2006281092
[33]: http://www.oreilly.com/openbook/osfreesoft/book/
[34]: https://www.amazon.com/dp/1511617772
[35]: https://lccn.loc.gov/2004050558
[36]: http://www.rosenlaw.com/oslbook.htm
[37]: https://creativecommons.org/licenses/by-sa/4.0/legalcode

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The Rise and Demise of RSS
======
There are two stories here. The first is a story about a vision of the web’s future that never quite came to fruition. The second is a story about how a collaborative effort to improve a popular standard devolved into one of the most contentious forks in the history of open-source software development.

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A Short History of Chaosnet
======
If you fire up `dig` and run a DNS query for `google.com`, you will get a response somewhat like the following:
```
$ dig google.com
; <<>> DiG 9.10.6 <<>> google.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 27120
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;google.com. IN A
;; ANSWER SECTION:
google.com. 194 IN A 216.58.192.206
;; Query time: 23 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Fri Sep 21 16:14:48 CDT 2018
;; MSG SIZE rcvd: 55
```
The output contains both a section describing the “question” you asked (“What is the IP address of `google.com`?”) and a section describing the answer you received. In the answer section, we see that `dig` found a single record with what looks to be five fields. The record’s type is indicated by the `A` in the fourth field from the left—this is an “address” record. To the right of the `A`, in the fifth field, we can see that the IP address for `google.com` is `216.58.192.206`. The `194` value in the second field specifies how long in seconds this particular record can be cached.
What does the `IN` field tell us? For an embarrassingly long time, I thought `IN` functioned as a preposition, so that every DNS record was saying something like “`google.com` is in `A` and has IP address `216.58.192.206`.” It turns out that `IN` actually stands for “internet.” The `IN` part of a DNS record tells us the record’s class.
Why might a DNS record have a class other than “internet”? What would that even mean? How do you search for a host that isn’t on the internet? It would seem that `IN` is the only value that could possibly make sense here. Indeed, when you try to ask for the address of `google.com` while specifying that you expect a record with a class other than `IN`, the DNS server you are asking will probably complain. In the below, when we try to ask for the IP address of `google.com` using the `HS` class, the name server at `8.8.8.8` (Google Public DNS) returns a status of `SERVFAIL`:
```
$ dig -c HS google.com
; <<>> DiG 9.10.6 <<>> -c HS google.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 31517
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;google.com. HS A
;; Query time: 34 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Tue Sep 25 14:48:10 CDT 2018
;; MSG SIZE rcvd: 39
```
So classes other than `IN` aren’t widely supported. But they do exist. In addition to `IN`, DNS records can have the `HS` class (as we’ve just seen) or the `CH` class. The `HS` class is reserved for use by a system called [Hesiod][1] that stores and distributes simple textual data using the Domain Name System. It is typically used in local environments as a stand-in for [LDAP][2]. The `CH` class is reserved for something called Chaosnet.
Today, the world belongs to TCP/IP. Those two protocols (together with UDP) govern most of the remote communication that happens between computers. But I think it’s wonderful that you can still find, hidden in the plumbing of the internet, traces of this other, long-extinct, evocatively named system. What was Chaosnet? And why did it go the way of the dinosaurs?
### A Machine Room at MIT
Chaosnet was developed in the 1970s by researchers at the MIT Artificial Intelligence Lab. It was created as a part of a larger effort to design and build a machine that could run the Lisp programming language more efficiently than a general-purpose computer.
Lisp was the brainchild of MIT professor John McCarthy, who pioneered the field of artificial intelligence. He first described Lisp to the world in [a paper][3] published in 1960. By 1962, an interpreter and a compiler had been written. Lisp introduced an astounding number of features that today we consider standard for many programming languages. It was the first language to have a garbage collector. It was the first to have a REPL. And it was the first to support dynamic typing. It found favor among programmers working in artificial intelligence and—to name just one example—was used to develop the famous [SHRDLU][4] demonstration, which allowed a human to dictate simple actions involving toy blocks to a computer in natural language.
The problem with Lisp was that it could be slow. Simple operations could take twice as long to execute as was typical with other languages because Lisp variables were type-checked at runtime and not just during compilation. Lisp’s garbage collector was known to take up to an entire second to run on the IBM 7090 at MIT. These performance issues were especially unwelcome because the AI researchers using Lisp were trying to build applications like SHRDLU that interacted with users in real time. In the late 1970s, a group of MIT Artificial Intelligence Lab researchers decided to address these problems by building machines specifically designed to run Lisp programs. These “Lisp machines” had more memory and a compact instruction set better-suited to Lisp. Type-checking would be done by dedicated circuitry, speeding it up by orders of magnitude. And unlike most computer systems at the time, Lisp machines would not be time-shared, since ambitious Lisp programs needed all the resources a computer had available. Each user would be assigned his or her own CPU. In a memo, the Lisp Machine Group at MIT described how this would make Lisp programming significantly easier:
> The Lisp Machine is a personal computer. Personal computing means that the processor and main memory are not time-division multiplexed, instead each person gets his own. The personal computation system consists of a pool of processors, each with its own main memory, and its own disk for swapping. When a user logs in, he is assigned a processor, and he has exclusive use of it for the duration of the session. When he logs out, the processor is returned to the pool, for the next person to use. This way, there is no competition from other users for memory; the pages the user is frequently referring to remain in core, and so swapping overhead is considerably reduced. Thus the Lisp Machine solves a basic problem of the time-sharing Lisp system.
The Lisp machine would be a personal computer in a different sense than the one we think of today. As the Lisp Machine Group originally envisioned it, users would sit down in their offices not in front of their own Lisp machines but in front of terminals. The terminals would be connected to the actual Lisp machine, which would be elsewhere. Even though each user would be assigned his or her own processor, the processors would still be “kept off in a machine room,” since they would make noise and take up space and thus be “unwelcome office companions.” The processors would share access to a file system and to devices like printers via a high-speed local network “with completely distributed control.” That network was Chaosnet.
Chaosnet is both a hardware standard and a software protocol. The hardware standard resembles Ethernet, and in fact the Chaosnet software protocol was eventually run over Ethernet. The software protocol, which specifies both network-layer and transport-layer interactions, was, unlike TCP/IP, always meant to govern a local network. In another memo released by the MIT Artificial Intelligence Lab, David Moon, a member of the Lisp Machine Group, explained that Chaosnet “contains no special provisions for things such as low-speed links, noisy links, multiple paths, and long-distance links with significant transit time.” The focus was instead on designing a protocol that could outperform other protocols on a small network.
Speed was important because Chaosnet sat between each Lisp processor and the file system. Network delays would significantly slow rudimentary operations like viewing the contents of a text document. To be fast enough, Chaosnet incorporated several improvements over the Network Control Program then in use on Arpanet. According to Moon, “it was important to design out bottlenecks such as are found in Arpanet, for instance the control-link which is shared between multiple connections and the need to acknowledge each message before the next message is sent.” The Chaosnet protocol batches packet acknowledgments in much the same way that TCP does today and so reduced the number of packets that needed to be transmitted by a half to a third.
Chaosnet could also get away with a relatively simple routing algorithm, since most hosts on the Lisp machine network were probably connected by a single, short wire. Moon wrote that the Chaosnet routing scheme “is predicated on the assumption that the network geometry is simple, there are few multiple paths, and the length of any path is quite short. This makes more sophisticated schemes unnecessary.” The simplicity of the algorithm meant that implementing the Chaosnet protocol was easy. The implementation program was supposedly half the size of the Arpanet Network Control Program.
The Chaosnet protocol has other idiosyncrasies. A Chaosnet address is only 16 bits, half the size of an IPv4 address, which makes sense given that Chaosnet was only ever meant to work on a local network. Chaosnet also doesn’t use port numbers; instead, a process that wants to connect to another process on a different machine first makes a connection request that specifies a target “contact name.” That contact name is often just the name of a particular service. For example, one host may try to connect to another host using the contact name `TELNET`. In practice, I assume this works more or less just like TCP, since something well-known like port 80 might as well have the contact name `HTTP`.
The Chaosnet DNS class was added to the Domain Name System by [RFC 973][5] in 1986. It replaced another class that had been available early on, the `CSNET` class, which was there to support a network called the Computer Science Network. I haven’t been able to figure out why Chaosnet was picked out for special treatment by the Domain Name System. There were other protocol families that could have been added but never were. For example, Paul Mockapetris, one of the principal architects of the Domain Name System, has written that he originally imagined that DNS would include a class for Xerox’s network protocol. That never happened. Chaosnet may have been added just because so much of the early work on Arpanet and the internet happened at Bolt, Beranek and Newman in Cambridge, Massachusetts, whose employees were often connected in some way with MIT. Chaosnet was probably well-known among the then relatively small group of people working on computer networks.
Usage of Chaosnet presumably waned as Lisp machines became less and less popular. Though Lisp machines were for a short time commercially viable products—sold by companies such as Symbolics and Lisp Machines Inc. during the 1980s—they were soon displaced by cheaper microcomputers that could run Lisp just as quickly without special-purpose circuitry. TCP/IP also fixed many of the issues with the original Arpanet protocols that Chaosnet had been created to circumvent.
### Ghost in the Shell
There unfortunately isn’t a huge amount of information still around about Chaosnet. RFC 675, which was essentially the first draft of TCP/IP, was published in 1974. Chaosnet was first developed in 1975. TCP/IP eventually conquered the world, but Chaosnet seems to have been a technological dead end. Though it’s possible that Chaosnet influenced subsequent work on TCP/IP, I haven’t found any specific examples of that happening.
The only really visible remnant of Chaosnet is the `CH` DNS class. There’s something about that fact that I find strangely fascinating. The `CH` class is a vestigial ghost of an alternative network protocol in a world that has long since settled on TCP/IP. It’s exciting, at least to me, to know that the last traces of Chaosnet still lurk out there in the infrastructure of our networked society. The `CH` DNS class is a fun artifact of digital archaeology. But it’s also a living reminder that the internet was not born fully formed, that TCP/IP is not the only way to connect computers to each other, and that “the internet” is far from the coolest name we could have had for our global communication system.
If you enjoyed this post, more like it come out every two weeks! Follow [@TwoBitHistory][6] on Twitter or subscribe to the [RSS feed][7] to make sure you know when a new post is out.
Previously on TwoBitHistory…
> Where did RSS come from? Why are there so many competing formats? Why don't people seem to use it that much anymore?
>
> Answers to these questions and many more in this week's post about RSS:<https://t.co/BsCN5GQidR>
>
> — TwoBitHistory (@TwoBitHistory) [September 17, 2018][8]
--------------------------------------------------------------------------------
via: https://twobithistory.org/2018/09/30/chaosnet.html
作者：[Two-Bit History][a]
选题：[lujun9972][b]
译者：[译者ID](https://github.com/译者ID)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://twobithistory.org
[b]: https://github.com/lujun9972
[1]: https://en.wikipedia.org/wiki/Hesiod_(name_service)
[2]: https://en.wikipedia.org/wiki/Lightweight_Directory_Access_Protocol
[3]: http://www-formal.stanford.edu/jmc/recursive.pdf
[4]: https://en.wikipedia.org/wiki/SHRDLU
[5]: https://tools.ietf.org/html/rfc973
[6]: https://twitter.com/TwoBitHistory
[7]: https://twobithistory.org/feed.xml
[8]: https://twitter.com/TwoBitHistory/status/1041485204802756608?ref_src=twsrc%5Etfw

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[#]: collector: (lujun9972)
[#]: translator: (lujun9972)
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: subject: (IRC vs IRL: How to run a good IRC meeting)
[#]: via: (https://opensource.com/article/19/2/irc-vs-irl-meetings)
[#]: author: (Ben Cotton https://opensource.com/users/bcotton)
IRC vs IRL: How to run a good IRC meeting
======
Internet Relay Chat meetings can be a great way to move a project forward if you follow these best practices.
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/BUSINESS_community_1.png?itok=rT7EdN2m)
There's an art to running a meeting in any format. Many people have learned to run in-person or telephone meetings, but [Internet Relay Chat][1] (IRC) meetings have unique characteristics that differ from "in real life" (IRL) meetings. This article will share the advantages and disadvantages of the IRC format as well as tips that will help you lead IRC meetings more effectively.
Why IRC? Despite the wealth of real-time chat options available today, [IRC remains a cornerstone of open source projects][2]. If your project uses another communication method, don't worry. Most of this advice works for any synchronous text chat mechanism, perhaps with a few tweaks here and there.
### Challenges of IRC meetings
IRC meetings pose certain challenges compared to in-person meetings. You know that lag between when one person finishes talking and the next one begins? It's worse in IRC because people have to type what they're thinking. This is slower than talking and—unlike with talking—you can't tell when someone else is trying to compose a message. Moderators must remember to insert long pauses when asking for responses or moving to the next topic. And someone who wants to speak up should insert a brief message (e.g., a period) to let the moderator know.
IRC meetings also lack the metadata you get from other methods. You can't read facial expressions or tone of voice in text. This means you have to be careful with your word choice and phrasing.
And IRC meetings make it really easy to get distracted. At least when someone is looking at funny cat GIFs during an in-person meeting, you'll see them smile and hear them laugh at inopportune times. In IRC, unless they accidentally paste the wrong text, there's no peer pressure even to pretend to pay attention. With IRC, you can even be in multiple meetings at once. I've done this, but it's dangerous if you need to be an active participant.
### Benefits of IRC meetings
IRC meetings have some unique advantages, too. IRC is a very resource-light medium. It doesn't tax bandwidth or CPU. This lowers the barrier for participation, which is advantageous for both the underprivileged and people who are on the road. For volunteer contributors, it means they may be able to participate during their workday. And it means participants don't need to find a quiet space where they can talk without bothering those around them.
With a meeting bot, IRC can produce meeting minutes instantly. In Fedora, we use Zodbot, an instance of Debian's [Meetbot][3], to log meetings and provide interaction. When a meeting ends, the minutes and full logs are immediately available to the community. This can reduce the administrative overhead of running the meeting.
### It's like a normal meeting, but different
Conducting a meeting via IRC or other text-based medium means thinking about the meeting in a slightly different way. Although it lacks some of the benefits of higher-bandwidth modes of communication, it has advantages, too. Running an IRC meeting provides the opportunity to develop discipline that can help you run any type of meeting.
Like any meeting, IRC meetings are best when there's a defined agenda and purpose. A good meeting moderator knows when to let the conversation follow twists and turns and when it's time to reel it back in. There's no hard and fast rule here—it's very much an art. But IRC offers an advantage in this regard. By setting the channel topic to the meeting's current topic, people have a visible reminder of what they should be talking about.
If your project doesn't already conduct synchronous meetings, you should give it some thought. For projects with a diverse set of time zones, finding a mutually agreeable time to hold a meeting is hard. You can't rely on meetings as your only source of coordination. But they can be a valuable part of how your project works.
--------------------------------------------------------------------------------
via: https://opensource.com/article/19/2/irc-vs-irl-meetings
作者：[Ben Cotton][a]
选题：[lujun9972][b]
译者：[lujun9972](https://github.com/lujun9972)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://opensource.com/users/bcotton
[b]: https://github.com/lujun9972
[1]: https://en.wikipedia.org/wiki/Internet_Relay_Chat
[2]: https://opensource.com/article/16/6/getting-started-irc
[3]: https://wiki.debian.org/MeetBot

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[#]: collector: (lujun9972)
[#]: translator: ( )
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: subject: (How to save time with TiDB)
[#]: via: (https://opensource.com/article/19/3/how-save-time-tidb)
[#]: author: (Morgan Tocker https://opensource.com/users/morgo)
How to save time with TiDB
======
TiDB, an open source-compatible, cloud-based database engine, simplifies many of MySQL database administrators' common tasks.
![Team checklist][1]
Last November, I wrote about key [differences between MySQL and TiDB][2], an open source-compatible, cloud-based database engine, from the perspective of scaling both solutions in the cloud. In this follow-up article, I'll dive deeper into the ways [TiDB][3] streamlines and simplifies administration.
If you come from a MySQL background, you may be used to doing a lot of manual tasks that are either not required or much simpler with TiDB.
The inspiration for TiDB came from the founders managing sharded MySQL at scale at some of China's largest internet companies. Since requirements for operating a large system at scale are a key concern, I'll look at some typical MySQL database administrator (DBA) tasks and how they translate to TiDB.
[![TiDB architecture][4]][5]
In [TiDB's architecture][5]:
* SQL processing is separated from data storage. The SQL processing (TiDB) and storage (TiKV) components independently scale horizontally.
* PD (Placement Driver) acts as the cluster manager and stores metadata.
* All components natively provide high availability, with PD and TiKV using the [Raft consensus algorithm][6].
* You can access your data via either MySQL (TiDB) or Spark (TiSpark) protocols.
### Adding/fixing replication slaves
**tl;dr:** It doesn't happen in the same way as in MySQL.
Replication and redundancy of data are automatically managed by TiKV. You also don't need to worry about creating initial backups to seed replicas, as _both_ the provisioning and replication are handled for you.
Replication is also quorum-based using the Raft consensus algorithm, so you don't have to worry about the inconsistency problems surrounding failures that you do with asynchronous replication (the default in MySQL and what many users are using).
TiDB does support its own binary log, so it can be used for asynchronous replication between clusters.
### Optimizing slow queries
**tl;dr:** Still happens in TiDB
There is no real way out of optimizing slow queries that have been introduced by development teams.
As a mitigating factor though, if you need to add breathing room to your database's capacity while you work on optimization, the TiDB's architecture allows you to horizontally scale.
### Upgrades and maintenance
**tl;dr:** Still required, but generally easier
Because the TiDB server is stateless, you can roll through an upgrade and deploy new TiDB servers. Then you can remove the older TiDB servers from the load balancer pool, shutting down them once connections have drained.
Upgrading PD is also quite straightforward since only the PD leader actively answers requests at a time. You can perform a rolling upgrade and upgrade PD's non-leader peers one at a time, and then change the leader before upgrading the final PD server.
For TiKV, the upgrade is marginally more complex. If you want to remove a node, I recommend first setting it to be a follower on each of the regions where it is currently a leader. After that, you can bring down the node without impacting your application. If the downtime is brief, TiKV will recover with its regional peers from the Raft log. In a longer downtime, it will need to re-copy data. This can all be managed for you, though, if you choose to deploy using Ansible or Kubernetes.
### Manual sharding
**tl;dr:** Not required
Manual sharding is mainly a pain on the part of the application developers, but as a DBA, you might have to get involved if the sharding is naive or has problems such as hotspots (many workloads do) that require re-balancing.
In TiDB, re-sharding or re-balancing happens automatically in the background. The PD server observes when data regions (TiKV's term for chunks of data in key-value form) get too small, too big, or too frequently accessed.
You can also explicitly configure PD to store regions on certain TiKV servers. This works really well when combined with MySQL partitioning.
### Capacity planning
**tl;dr:** Much easier
Capacity planning on a MySQL database can be a little bit hard because you need to plan your physical infrastructure requirements two to three years from now. As data grows (and the working set changes), this can be a difficult task. I wouldn't say it completely goes away in the cloud either, since changing a master server's hardware is always hard.
TiDB splits data into approximately 100MiB chunks that it distributes among TiKV servers. Because this increment is much smaller than a full server, it's much easier to move around and redistribute data. It's also possible to add new servers in smaller increments, which is easier on planning.
### Scaling
**tl;dr:** Much easier
This is related to capacity planning and sharding. When we talk about scaling, many people think about very large _systems,_ but that is not exclusively how I think of the problem:
* Scaling is being able to start with something very small, without having to make huge investments upfront on the chance it could become very large.
* Scaling is also a people problem. If a system requires too much internal knowledge to operate, it can become hard to grow as an engineering organization. The barrier to entry for new hires can become very high.
Thus, by providing automatic sharding, TiDB can scale much easier.
### Schema changes (DDL)
**tl;dr:** Mostly better
The data definition language (DDL) supported in TiDB is all online, which means it doesn't block other reads or writes to the system. It also doesn't block the replication stream.
That's the good news, but there are a couple of limitations to be aware of:
* TiDB does not currently support all DDL operations, such as changing the primary key or some "change data type" operations.
* TiDB does not currently allow you to chain multiple DDL changes in the same command, e.g., _ALTER TABLE t1 ADD INDEX (x), ADD INDEX (y)_. You will need to break these queries up into individual DDL queries.
This is an area that we're looking to improve in [TiDB 3.0][7].
### Creating one-off data dumps for the reporting team
**tl;dr:** May not be required
DBAs loathe manual tasks that create one-off exports of data to be consumed by another team, perhaps in an analytics tool or data warehouse.
This is often required when the types of queries that are be executed on the dataset are analytical. TiDB has hybrid transactional/analytical processing (HTAP) capabilities, so in many cases, these queries should work fine. If your analytics team is using Spark, you can also use the [TiSpark][8] connector to allow them to connect directly to TiKV.
This is another area we are improving with [TiFlash][7], a column store accelerator. We are also working on a plugin system to support external authentication. This will make it easier to manage access by the reporting team.
### Conclusion
In this post, I looked at some common MySQL DBA tasks and how they translate to TiDB. If you would like to learn more, check out our [TiDB Academy course][9] designed for MySQL DBAs (it's free!).
--------------------------------------------------------------------------------
via: https://opensource.com/article/19/3/how-save-time-tidb
作者：[Morgan Tocker][a]
选题：[lujun9972][b]
译者：[译者ID](https://github.com/译者ID)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://opensource.com/users/morgo
[b]: https://github.com/lujun9972
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/checklist_todo_clock_time_team.png?itok=1z528Q0y (Team checklist)
[2]: https://opensource.com/article/18/11/key-differences-between-mysql-and-tidb
[3]: https://github.com/pingcap/tidb
[4]: https://opensource.com/sites/default/files/uploads/tidb_architecture.png (TiDB architecture)
[5]: https://pingcap.com/docs/architecture/
[6]: https://raft.github.io/
[7]: https://pingcap.com/blog/tidb-3.0-beta-stability-at-scale/
[8]: https://github.com/pingcap/tispark
[9]: https://pingcap.com/tidb-academy/

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[#]: collector: (lujun9972)
[#]: translator: ( )
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: subject: (How to transition into a Developer Relations career)
[#]: via: (https://opensource.com/article/19/3/developer-relations-career)
[#]: author: (Mary Thengvall https://opensource.com/users/marygrace-0)
How to transition into a Developer Relations career
======
Combine your love for open source software with your love for the community in a way that allows you to invest your time in both.
![][1]
Let's say you've found an open source project you really love and you want to do more than just contribute. Or you love coding, but you don't want to spend the rest of your life interacting more with your computer than you do with people. How do you combine your love for open source software with your love for the community in a way that allows you to invest your time in both?
### Developer Relations: A symbiotic relationship
Enter community management, or as it's more commonly called in the tech industry, Developer Relations (DevRel for short). The goal of DevRel is, at its core, to empower developers. From writing content and creating documentation to supporting local meetups and bubbling up developer feedback internally, everything that a Developer Relations professional does on a day-to-day basis is for the benefit of the community. That's not to say that it doesn't benefit the company as well! After all, as Developer Relations professionals understand, if the community succeeds, so will the company. It's the best kind of symbiotic relationship!
These hybrid roles have been around since shortly after the open source and free software movements started, but the Developer Relations industry—and the Developer Advocate role, in particular—have exploded over the past few years. So what is Developer Relations exactly? Let's start by defining "community" so that we're all on the same page:
> **Community:** A group of people who not only share common principles, but also develop and share practices that help individuals in the group thrive.
This could be a group of people who have gathered around an open source project, a particular topic such as email, or who are all in a similar job function—the DevOps community, for instance.
As I mentioned, the role of a DevRel team is to empower the community by building up, encouraging, and amplifying the voice of the community members. While this will look slightly different at every company, depending on its goals, priorities, and direction, there are a few themes that are consistent throughout the industry.
1. **Listen:** Before making any plans or goals, take the time to listen.
* _Listen to your company stakeholders:_ What do they expect of your team? What do they think you should be responsible for? What metrics are they accustomed to? And what business needs do they care most about?
* _Listen to your customer community:_ What are customers' biggest pain points with your product? Where do they struggle with onboarding? Where does the documentation fail them?
* _Listen to your product's technical audience:_ What problems are they trying to solve? What could be done to make their work life easier? Where do they get their content? What technological advances are they most excited about?
2. **Gather information**
Based on these answers, you can start making your plan. Find the overlapping areas where you can make your product a better fit for the larger technical audience and also make it easier for your customers to use. Figure out what content you can provide that not only answers your community's questions but also solves problems for your company's stakeholders. Learn about the areas where your co-workers struggle and see where your strengths can supplement those needs.
3. **Make connections**
Above all, community managers are responsible for making connections within the community as well as between community members and coworkers. These connections, or "DevRel qualified leads," are what ultimately shows the business value of a community manager's work. By making connections between community members Marie and Bob, who are both interested in the latest developments in Python, or between Marie and your coworker Phil, who's responsible for developer-focused content on your website, you're making your community a valuable source of information for everyone around you.
By getting to know your technical community, you become an expert on what customer needs your product can meet. With great power comes great responsibility. As the expert, you are now responsible for advocating internally for those needs, and you have the potential to make a big difference for your community.
### Getting started
So now what? If you're still with me, congratulations! You might just be a good fit for a Community Manager or Developer Advocate role. I'd encourage you to take community work for a test drive and see if you like the pace and the work. There's a lot of context switching and moving around between tasks, which can be a bit of an adjustment for some folks.
Volunteer to write a blog post for your marketing team (or for [Opensource.com][2]) or help out at an upcoming conference. Apply to speak at a local meetup or offer to advise on a few technical support cases. Get to know your community members on a deeper level.
Above all, Community Managers are 100% driven by a passion for building technical communities and bringing people together. If that resonates with you, it may be time for a career change!
I love talking to professionals that help others grow through community and Developer Relations practices. Don't hesitate to [reach out to me][3] if you have any questions or send me a [DM on Twitter][4].
--------------------------------------------------------------------------------
via: https://opensource.com/article/19/3/developer-relations-career
作者：[Mary Thengvall][a]
选题：[lujun9972][b]
译者：[译者ID](https://github.com/译者ID)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://opensource.com/users/marygrace-0
[b]: https://github.com/lujun9972
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/resume_career_document_general.png?itok=JEaFL2XI
[2]: https://opensource.com/how-submit-article
[3]: https://www.marythengvall.com/about
[4]: http://twitter.com/mary_grace

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### fuzheng1998 reapplying
10 Games You Can Play on Linux with Wine
======
![](https://www.maketecheasier.com/assets/uploads/2017/09/wine-games-feat.jpg)
Linux _does_ have games. It has a lot of them, actually. Linux is a thriving platform for indie gaming, and it 's not too uncommon for Linux to be supported on day one by top indie titles. In stark contrast, however, Linux is still largely ignored by the big-budget AAA developers, meaning that the games your friends are buzzing about probably won't be getting a Linux port anytime soon.
It's not all bad, though. Wine, the Windows compatibility layer for Linux, Mac, and BSD systems, is making huge strides in both the number of titles supported and performance. In fact, a lot of big name games now work under Wine. No, you won't get native performance, but they are playable and can actually run very well, depending on your system. Here are some games that it might surprise you can run with Wine on Linux.
### 10. World of Warcraft
![World of Warcraft Wine][1]
The venerable king of MMORPGs is still alive and going strong. Even though it might not be the most graphically advanced game, it still takes some power to crank all the settings up to max. World of Warcraft has actually worked under Wine for years. Until this latest expansion, WoW supported OpenGL for its Mac version, making it very easy to get working under Linux. That's not quite the case anymore.
You'll need to run WoW with DX9 and will definitely see some benefit from the [Gallium Nine][2] patches, but you can confidently make the switch over to Linux without missing raid night.
### 9. Skyrim
![Skyrim Wine][3]
Skyrim's not exactly new, but it's still fueled by a thriving modding community. You can now easily enjoy Skyrim and its many, many mods if you have a Linux system with enough resources to handle it all. Remember that Wine uses more system power than running the game natively, so account for that in your mod usage.
### 8. StarCraft II
![StarCraft II Wine][4]
StarCraft II is easily one of the most popular RTS games on the market and works very well under Wine. It is actually one of the best performing games under Wine. That means that you can play your favorite RTS on Linux with minimal hassle and near-native performance.
Given the competitive nature of this game, you obviously need the game to run well. Have no fear there. You should have no problem playing competitively with adequate hardware.
This is an instance where you'll benefit from the "staging" patches, so continue using them when you're getting the game set up.
### 7. Fallout 3/New Vegas
![Fallout 3 Wine][5]
Before you ask, Fallout 4 is on the verge of working. At the time you're reading this, it might. For now, though, Fallout 3 and New Vegas both work great, both with and without mods. These games run very well under Wine and can even handle loads of mods to keep them fresh and interesting. It doesn't seem like a bad compromise to hold you over until Fallout 4 support matures.
### 6. Doom (2016)
![Doom Wine][6]
Doom is one of the most exciting shooters of the past few years, and it run very well under Wine with the latest versions and the "staging" patches. Both single player and multiplayer work great, and you don't need to spend loads of time configuring Wine and tweaking settings. Doom just works. So, if you're looking for a brutal AAA shooter on Linux, consider giving Doom a try.
### 5. Guild Wars 2
![Guild Wars 2 Wine][7]
Guild War 2 is a sort-of hybrid MMO/dungeon crawler without a monthly fee. It's very popular and boasts some really innovative features for the genre. It also runs smoothly on Linux with Wine.
Guild Wars 2 isn't some ancient MMO either. It's tried to keep itself modern graphically and has fairly high resolution textures and visual effects for the genre. All of it looks and works very well under Wine.
### 4. League Of Legends
![League Of Legends Wine][8]
There are two top players in the MOBA world: DoTA2 and League of Legends. Valve ported DoTA2 to Linux some time ago, but League of Legends has never been made available to Linux gamers. If you're a Linux user and a fan of League, you can still play your favorite MOBA through Wine.
League of Legends is an interesting case. The game itself runs fine, but the installer breaks because it requires Adobe Air. There are some installer scripts available from Lutris and PlayOnLinux that get you through the process. Once it's installed, you should have no problem running League and even playing it smoothly in competitive situations.
### 3. Hearthstone
![HearthStone Wine][9]
Hearthstone is a popular and addictive free-to-play digital card game that's available on a variety of platforms … except Linux. Don't worry, it works very well in Wine. Hearthstone is such a lightweight game that it's actually playable through Wine on even the lowest powered systems. That's good news, too, but because Hearthstone is another competitive game where performance matters.
Hearthstone doesn't require any special configuration or even patches. It just works.
### 2. Witcher 3
![Witcher 3 Wine][10]
If you're surprised to see this one here, you're not alone. With the latest "staging" patches, The Witcher 3 finally works. Despite originally being promised a native release, Linux gamers have had to wait a good long while to get the third installment in the Witcher franchise.
Don't expect everything to be perfect just yet. Support for Witcher 3 is _very_ new, and some things might not work as expected. That said, if you only have Linux to game on, and you 're willing to deal with a couple of rough edges, you can enjoy this awesome game for the first time with few, if any, troubles.
### 1. Overwatch
![Overwatch Wine][11]
Finally, there's yet another "white whale" for Linux gamers. Overwatch has been an elusive target that many feel should have been working on Wine since day one. Most Blizzard games have. Overwatch was a very different case. It only ever supported DX11, and that was a serious pain point for Wine.
Overwatch doesn't have the best performance yet, but you can definitely still play Blizzard's wildly popular shooter using a specially-patched version of Wine with the "staging" patches and additional ones just for Overwatch. That means Linux gamers wanted Overwatch so bad that they developed a special set of patches for it.
There were certainly games left off of this list. Most were just due to popularity or only conditional support under Wine. Other Blizzard games, like Heroes of the Storm and Diablo III also work, but this list would have been even more dominated by Blizzard, and that's not the point.
If you're going to try playing any of these games, consider using the "staging" or [Gallium Nine versions][2] of Wine. Many of the games here won't work without them. Even still, the latest patches and improvements land in "staging" long before they make it into the mainstream Wine release. Using it will keep you on the leading edge of progress.
Speaking of progress, right now Wine is making massive strides in DirectX11 support. While that doesn't mean much to Windows gamers, it's a huge deal for Linux. Most new games support DX11 and DX12, and until recently Wine only supported DX9. With DX11 support, Wine is gaining support for loads of games that were previously unplayable. So keep checking regularly to see if your favorite games from Windows started working in Wine. You might be very pleasantly surprised.
--------------------------------------------------------------------------------
via: https://www.maketecheasier.com/games-play-on-linux-with-wine/
作者：[Nick Congleton][a]
译者：[译者ID](https://github.com/译者ID)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]:https://www.maketecheasier.com/author/nickcongleton/
[1]:https://www.maketecheasier.com/assets/uploads/2017/09/wow.jpg (World of Warcraft Wine)
[2]:https://www.maketecheasier.com/install-wine-gallium-nine-linux
[3]:https://www.maketecheasier.com/assets/uploads/2017/09/skyrim.jpg (Skyrim Wine)
[4]:https://www.maketecheasier.com/assets/uploads/2017/09/sc2.jpg (StarCraft II Wine)
[5]:https://www.maketecheasier.com/assets/uploads/2017/09/Fallout_3.jpg (Fallout 3 Wine)
[6]:https://www.maketecheasier.com/assets/uploads/2017/09/doom.jpg (Doom Wine)
[7]:https://www.maketecheasier.com/assets/uploads/2017/09/gw2.jpg (Guild Wars 2 Wine)
[8]:https://www.maketecheasier.com/assets/uploads/2017/09/League_of_legends.jpg (League Of Legends Wine)
[9]:https://www.maketecheasier.com/assets/uploads/2017/09/HearthStone.jpg (HearthStone Wine)
[10]:https://www.maketecheasier.com/assets/uploads/2017/09/witcher3.jpg (Witcher 3 Wine)
[11]:https://www.maketecheasier.com/assets/uploads/2017/09/Overwatch.jpg (Overwatch Wine)

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sources/tech/20180719 Building tiny container images.md
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hankchow translating
Building tiny container images
======
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/containers_scale_performance.jpg?itok=R7jyMeQf)
When [Docker][1] exploded onto the scene a few years ago, it brought containers and container images to the masses. Although Linux containers existed before then, Docker made it easy to get started with a user-friendly command-line interface and an easy-to-understand way to build images using the Dockerfile format. But while it may be easy to jump in, there are still some nuances and tricks to building container images that are usable, even powerful, but still small in size.
### First pass: Clean up after yourself
Some of these examples involve the same kind of cleanup you would use with a traditional server, but more rigorously followed. Smaller image sizes are critical for quickly moving images around, and storing multiple copies of unnecessary data on disk is a waste of resources. Consequently, these techniques should be used more regularly than on a server with lots of dedicated storage.
An example of this kind of cleanup is removing cached files from an image to recover space. Consider the difference in size between a base image with [Nginx][2] installed by `dnf` with and without the metadata and yum cache cleaned up:
```
# Dockerfile with cache
FROM fedora:28
LABEL maintainer Chris Collins <collins.christopher@gmail.com>
RUN dnf install -y nginx
-----
# Dockerfile w/o cache
FROM fedora:28
LABEL maintainer Chris Collins <collins.christopher@gmail.com>
RUN dnf install -y nginx \
        && dnf clean all \
        && rm -rf /var/cache/yum
-----
[chris@krang] $ docker build -t cache -f Dockerfile .  
[chris@krang] $ docker images --format "{{.Repository}}: {{.Size}}"
| head -n 1
cache: 464 MB
[chris@krang] $ docker build -t no-cache -f Dockerfile-wo-cache .
[chris@krang] $ docker images --format "{{.Repository}}: {{.Size}}"  | head -n 1
no-cache: 271 MB
```
That is a significant difference in size. The version with the `dnf` cache is almost twice the size of the image without the metadata and cache. Package manager cache, Ruby gem temp files, `nodejs` cache, even downloaded source tarballs are all perfect candidates for cleaning up.
### Layers—a potential gotcha
Unfortunately (or fortunately, as you’ll see later), based on the way layers work with containers, you cannot simply add a `RUN rm -rf /var/cache/yum` line to your Dockerfile and call it a day. Each instruction of a Dockerfile is stored in a layer, with changes between layers applied on top. So even if you were to do this:
```
RUN dnf install -y nginx
RUN dnf clean all
RUN rm -rf /var/cache/yum
```
...you’d still end up with three layers, one of which contains all the cache, and two intermediate layers that "remove" the cache from the image. But the cache is actually still there, just as when you mount a filesystem over the top of another one, the files are there—you just can’t see or access them.
You’ll notice that the example in the previous section chains the cache cleanup in the same Dockerfile instruction where the cache is generated:
```
RUN dnf install -y nginx \
        && dnf clean all \
        && rm -rf /var/cache/yum
```
This is a single instruction and ends up being a single layer within the image. You’ll lose a bit of the Docker (*ahem*) cache this way, making a rebuild of the image slightly longer, but the cached data will not end up in your final image. As a nice compromise, just chaining related commands (e.g., `yum install` and `yum clean all`, or downloading, extracting and removing a source tarball, etc.) can save a lot on your final image size while still allowing you to take advantage of the Docker cache for quicker development.
This layer "gotcha" is more subtle than it first appears, though. Because the image layers document the _changes_ to each layer, one upon another, it’s not just the existence of files that add up, but any change to the file. For example, _even changing the mode_ of the file creates a copy of that file in the new layer.
For example, the output of `docker images` below shows information about two images. The first, `layer_test_1`, was created by adding a single 1GB file to a base CentOS image. The second image, `layer_test_2`, was created `FROM layer_test_1` and did nothing but change the mode of the 1GB file with `chmod u+x`.
```
layer_test_2        latest       e11b5e58e2fc           7 seconds ago           2.35 GB
layer_test_1        latest       6eca792a4ebe           2 minutes ago           1.27 GB
```
As you can see, the new image is more than 1GB larger than the first. Despite the fact that `layer_test_1` is only the first two layers of `layer_test_2`, there’s still an extra 1GB file floating around hidden inside the second image. This is true anytime you remove, move, or change any file during the image build process.
### Purpose-built images vs. flexible images
An anecdote: As my office heavily invested in [Ruby on Rails][3] applications, we began to embrace the use of containers. One of the first things we did was to create an official Ruby base image for all of our teams to use. For simplicity’s sake (and suffering under “this is the way we did it on our servers”), we used [rbenv][4] to install the latest four versions of Ruby into the image, allowing our developers to migrate all of their applications into containers using a single image. This resulted in a very large but flexible (we thought) image that covered all the bases of the various teams we were working with.
This turned out to be wasted work. The effort required to maintain separate, slightly modified versions of a particular image was easy to automate, and selecting a specific image with a specific version actually helped to identify applications approaching end-of-life before a breaking change was introduced, wreaking havoc downstream. It also wasted resources: When we started to split out the different versions of Ruby, we ended up with multiple images that shared a single base and took up very little extra space if they coexisted on a server, but were considerably smaller to ship around than a giant image with multiple versions installed.
That is not to say building flexible images is not helpful, but in this case, creating purpose-build images from a common base ended up saving both storage space and maintenance time, and each team could modify their setup however they needed while maintaining the benefit of the common base image.
### Start without the cruft: Add what you need to a blank image
As friendly and easy-to-use as the _Dockerfile_ is, there are tools available that offer the flexibility to create very small Docker-compatible container images without the cruft of a full operating system—even those as small as the standard Docker base images.
[I’ve written about Buildah before][5], and I’ll mention it again because it is flexible enough to create an image from scratch using tools from your host to install packaged software and manipulate the image. Those tools then never need to be included in the image itself.
Buildah replaces the `docker build` command. With it, you can mount the filesystem of your container image to your host machine and interact with it using tools from the host.
Let’s try Buildah with the Nginx example from above (ignoring caches for now):
```
#!/usr/bin/env bash
set -o errexit
# Create a container
container=$(buildah from scratch)
# Mount the container filesystem
mountpoint=$(buildah mount $container)
# Install a basic filesystem and minimal set of packages, and nginx
dnf install --installroot $mountpoint  --releasever 28 glibc-minimal-langpack nginx --setopt install_weak_deps=false -y
# Save the container to an image
buildah commit --format docker $container nginx
# Cleanup
buildah unmount $container
# Push the image to the Docker daemon’s storage
buildah push nginx:latest docker-daemon:nginx:latest
```
You’ll notice we’re no longer using a Dockerfile to build the image, but a simple Bash script, and we’re building it from a scratch (or blank) image. The Bash script mounts the container’s root filesystem to a mount point on the host, and then uses the hosts’ command to install the packages. This way the package manager doesn’t even have to exist inside the container.
Without extra cruft—all the extra stuff in the base image, like `dnf`, for example—the image weighs in at only 304 MB, more than 100 MB smaller than the Nginx image built with a Dockerfile above.
```
[chris@krang] $ docker images |grep nginx
docker.io/nginx      buildah      2505d3597457    4 minutes ago         304 MB
```
_Note: The image name has`docker.io` appended to it due to the way the image is pushed into the Docker daemon’s namespace, but it is still the image built locally with the build script above._
That 100 MB is already a huge savings when you consider a base image is already around 300 MB on its own. Installing Nginx with a package manager brings in a ton of dependencies, too. For something compiled from source using tools from the host, the savings can be even greater because you can choose the exact dependencies and not pull in any extra files you don’t need.
If you’d like to try this route, [Tom Sweeney][6] wrote a much more in-depth article, [Creating small containers with Buildah][7], which you should check out.
Using Buildah to build images without a full operating system and included build tools can enable much smaller images than you would otherwise be able to create. For some types of images, we can take this approach even further and create images with _only_ the application itself included.
### Create images with only statically linked binaries
Following the same philosophy that leads us to ditch administrative and build tools inside images, we can go a step further. If we specialize enough and abandon the idea of troubleshooting inside of production containers, do we need Bash? Do we need the [GNU core utilities][8]? Do we _really_ need the basic Linux filesystem? You can do this with any compiled language that allows you to create binaries with [statically linked libraries][9]—where all the libraries and functions needed by the program are copied into and stored within the binary itself.
This is a relatively popular way of doing things within the [Golang][10] community, so we’ll use a Go application to demonstrate.
The Dockerfile below takes a small Go Hello-World application and compiles it in an image `FROM golang:1.8`:
```
FROM golang:1.8
ENV GOOS=linux
ENV appdir=/go/src/gohelloworld
COPY ./ /go/src/goHelloWorld
WORKDIR /go/src/goHelloWorld
RUN go get
RUN go build -o /goHelloWorld -a
CMD ["/goHelloWorld"]
```
The resulting image, containing the binary, the source code, and the base image layer comes in at 716 MB. The only thing we actually need for our application is the compiled binary, however. Everything else is unused cruft that gets shipped around with our image.
If we disable `cgo` with `CGO_ENABLED=0` when we compile, we can create a binary that doesn’t wrap C libraries for some of its functions:
```
GOOS=linux CGO_ENABLED=0 go build -a goHelloWorld.go
```
The resulting binary can be added to an empty, or "scratch" image:
```
FROM scratch
COPY goHelloWorld /
CMD ["/goHelloWorld"]
```
Let’s compare the difference in image size between the two:
```
[ chris@krang ] $ docker images
REPOSITORY      TAG             IMAGE ID                CREATED                 SIZE
goHello     scratch     a5881650d6e9            13 seconds ago          1.55 MB
goHello     builder     980290a100db            14 seconds ago          716 MB
```
That’s a huge difference. The image built from `golang:1.8` with the `goHelloWorld` binary in it (tagged "builder" above) is _460_ times larger than the scratch image with just the binary. The entirety of the scratch image with the binary is only 1.55 MB. That means we’d be shipping around 713 MB of unnecessary data if we used the builder image.
As mentioned above, this method of creating small images is used often in the Golang community, and there is no shortage of blog posts on the subject. [Kelsey Hightower][11] wrote [an article on the subject][12] that goes into more detail, including dealing with dependencies other than just C libraries.
### Consider squashing, if it works for you
There’s an alternative to chaining all the commands into layers in an attempt to save space: Squashing your image. When you squash an image, you’re really exporting it, removing all the intermediate layers, and saving a single layer with the current state of the image. This has the advantage of reducing that image to a much smaller size.
Squashing layers used to require some creative workarounds to flatten an image—exporting the contents of a container and re-importing it as a single layer image, or using tools like `docker-squash`. Starting in version 1.13, Docker introduced a handy flag, `--squash`, to accomplish the same thing during the build process:
```
FROM fedora:28
LABEL maintainer Chris Collins <collins.christopher@gmail.com>
RUN dnf install -y nginx
RUN dnf clean all
RUN rm -rf /var/cache/yum
[chris@krang] $ docker build -t squash -f Dockerfile-squash --squash .
[chris@krang] $ docker images --format "{{.Repository}}: {{.Size}}"  | head -n 1
squash: 271 MB
```
Using `docker squash` with this multi-layer Dockerfile, we end up with another 271MB image, as we did with the chained instruction example. This works great for this use case, but there’s a potential gotcha.
“What? ANOTHER gotcha?”
Well, sort of—it’s the same issue as before, causing problems in another way.
### Going too far: Too squashed, too small, too specialized
Images can share layers. The base may be _x_ megabytes in size, but it only needs to be pulled/stored once and each image can use it. The effective size of all the images sharing layers is the base layers plus the diff of each specific change on top of that. In this way, thousands of images may take up only a small amount more than a single image.
This is a drawback with squashing or specializing too much. When you squash an image into a single layer, you lose any opportunity to share layers with other images. Each image ends up being as large as the total size of its single layer. This might work well for you if you use only a few images and run many containers from them, but if you have many diverse images, it could end up costing you space in the long run.
Revisiting the Nginx squash example, we can see it’s not a big deal for this case. We end up with Fedora, Nginx installed, no cache, and squashing that is fine. Nginx by itself is not incredibly useful, though. You generally need customizations to do anything interesting—e.g., configuration files, other software packages, maybe some application code. Each of these would end up being more instructions in the Dockerfile.
With a traditional image build, you would have a single base image layer with Fedora, a second layer with Nginx installed (with or without cache), and then each customization would be another layer. Other images with Fedora and Nginx could share these layers.
Need an image:
```
[   App 1 Layer (  5 MB) ]          [   App 2 Layer (6 MB) ]
[   Nginx Layer ( 21 MB) ] ------------------^
[ Fedora  Layer (249 MB) ]  
```
But if you squash the image, then even the Fedora base layer is squashed. Any squashed image based on Fedora has to ship around its own Fedora content, adding another 249 MB for _each image!_
```
[ Fedora + Nginx + App 1 (275 MB)]      [ Fedora + Nginx + App 2 (276 MB) ]  
```
This also becomes a problem if you build lots of highly specialized, super-tiny images.
As with everything in life, moderation is key. Again, thanks to how layers work, you will find diminishing returns as your container images become smaller and more specialized and can no longer share base layers with other related images.
Images with small customizations can share base layers. As explained above, the base may be _x_ megabytes in size, but it only needs to be pulled/stored once and each image can use it. The effective size of all the images is the base layers plus the diff of each specific change on top of that. In this way, thousands of images may take up only a small amount more than a single image.
```
[ specific app   ]      [ specific app 2 ]
[ customizations ]--------------^
[ base layer     ]
```
If you go too far with your image shrinking and you have too many variations or specializations, you can end up with many images, none of which share base layers and all of which take up their own space on disk.
```
 [ specific app 1 ]     [ specific app 2 ]      [ specific app 3 ]
```
### Conclusion
There are a variety of different ways to reduce the amount of storage space and bandwidth you spend working with container images, but the most effective way is to reduce the size of the images themselves. Whether you simply clean up your caches (avoiding leaving them orphaned in intermediate layers), squash all your layers into one, or add only static binaries in an empty image, it’s worth spending some time looking at where bloat might exist in your container images and slimming them down to an efficient size.
--------------------------------------------------------------------------------
via: https://opensource.com/article/18/7/building-container-images
作者：[Chris Collins][a]
选题：[lujun9972](https://github.com/lujun9972)
译者：[译者ID](https://github.com/译者ID)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]:https://opensource.com/users/clcollins
[1]:https://www.docker.com/
[2]:https://www.nginx.com/
[3]:https://rubyonrails.org/
[4]:https://github.com/rbenv/rbenv
[5]:https://opensource.com/article/18/6/getting-started-buildah
[6]:https://twitter.com/TSweeneyRedHat
[7]:https://opensource.com/article/18/5/containers-buildah
[8]:https://www.gnu.org/software/coreutils/coreutils.html
[9]:https://en.wikipedia.org/wiki/Static_library
[10]:https://golang.org/
[11]:https://twitter.com/kelseyhightower
[12]:https://medium.com/@kelseyhightower/optimizing-docker-images-for-static-binaries-b5696e26eb07

10
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[#]: collector: (lujun9972)
[#]: translator: (runningwater)
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: subject: (What a shell dotfile can do for you)
[#]: via: (https://opensource.com/article/18/9/shell-dotfile)
[#]: author: (H.Waldo Grunenwald https://opensource.com/users/gwaldo)
What a shell dotfile can do for you
======
@ -231,7 +223,7 @@ via: https://opensource.com/article/18/9/shell-dotfile
作者：[H.Waldo Grunenwald][a]
选题：[lujun9972](https://github.com/lujun9972)
译者：[runningwater](https://github.com/runningwater)
译者：[译者ID](https://github.com/译者ID)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出

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[#]: subject: (Arch-Wiki-Man – A Tool to Browse The Arch Wiki Pages As Linux Man Page from Offline)

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[#]: subject: (What does DevOps mean to you?)
[#]: via: (https://opensource.com/article/19/1/what-does-devops-mean-you)
[#]: author: (Girish Managoli https://opensource.com/users/gammay)
What does DevOps mean to you?
======
6 experts break down DevOps and the practices and philosophies key to making it work.
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/innovation_lightbulb_gears_devops_ansible.png?itok=TSbmp3_M)
It's said if you ask 10 people about DevOps, you will get 12 answers. This is a result of the diversity in opinions and expectations around DevOps—not to mention the disparity in its practices.
To decipher the paradoxes around DevOps, we went to the people who know it the best—its top practitioners around the industry. These are people who have been around the horn, who know the ins and outs of technology, and who have practiced DevOps for years. Their viewpoints should encourage, stimulate, and provoke your thoughts around DevOps.
### What does DevOps mean to you?
Let's start with the fundamentals. We're not looking for textbook answers, rather we want to know what the experts say.
In short, the experts say DevOps is about principles, practices, and tools.
[Ann Marie Fred][1], DevOps lead for IBM Digital Business Group's Commerce Platform, says, "to me, DevOps is a set of principles and practices designed to make teams more effective in designing, developing, delivering, and operating software."
According to [Daniel Oh][2], senior DevOps evangelist at Red Hat, "in general, DevOps is compelling for enterprises to evolve current IT-based processes and tools related to app development, IT operations, and security protocol."
[Brent Reed][3], founder of Tactec Strategic Solutions, talks about continuous improvement for the stakeholders. "DevOps means to me a way of working that includes a mindset that allows for continuous improvement for operational performance, maturing to organizational performance, resulting in delighted stakeholders."
Many of the experts also emphasize culture. Ann Marie says, "it's also about continuous improvement and learning. It's about people and culture as much as it is about tools and technology."
To [Dan Barker][4], chief architect and DevOps leader at the National Association of Insurance Commissioners (NAIC), "DevOps is primarily about culture. … It has brought several independent areas together like lean, [just culture][5], and continuous learning. And I see culture as being the most critical and the hardest to execute on."
[Chris Baynham-Hughes][6], head of DevOps at Atos, says, "[DevOps] practice is adopted through the evolution of culture, process, and tooling within an organization. The key focus is culture change, and the key tenants of DevOps culture are collaboration, experimentation, fast-feedback, and continuous improvement."
[Geoff Purdy][7], cloud architect, talks about agility and feedback "shortening and amplifying feedback loops. We want teams to get feedback in minutes rather than weeks."
But in the end, Daniel nails it by explaining how open source and open culture allow him to achieve his goals "in easy and quick ways. In DevOps initiatives, the most important thing for me should be open culture rather than useful tools, multiple solutions."
### What DevOps practices have you found effective?
"Picking one, automated provisioning has been hugely effective for my team. "
The most effective practices cited by the experts are pervasive yet disparate.
According to Ann Marie, "some of the most powerful [practices] are agile project management; breaking down silos between cross-functional, autonomous squads; fully automated continuous delivery; green/blue deploys for zero downtime; developers setting up their own monitoring and alerting; blameless post-mortems; automating security and compliance."
Chris says, "particular breakthroughs have been empathetic collaboration; continuous improvement; open leadership; reducing distance to the business; shifting from vertical silos to horizontal, cross-functional product teams; work visualization; impact mapping; Mobius loop; shortening of feedback loops; automation (from environments to CI/CD)."
Brent supports "evolving a learning culture that includes TDD [test-driven development] and BDD [behavior-driven development] capturing of a story and automating the sequences of events that move from design, build, and test through implementation and production with continuous integration and delivery pipelines. A fail-first approach to testing, the ability to automate integration and delivery processes and include fast feedback throughout the lifecycle."
Geoff highlights automated provisioning. "Picking one, automated provisioning has been hugely effective for my team. More specifically, automated provisioning from a versioned Infrastructure-as-Code codebase."
Dan uses fun. "We do a lot of different things to create a DevOps culture. We hold 'lunch and learns' with free food to encourage everyone to come and learn together; we buy books and study in groups."
### How do you motivate your team to achieve DevOps goals?
```
"Celebrate wins and visualize the progress made."
```
Daniel emphasizes "automation that matters. In order to minimize objection from multiple teams in a DevOps initiative, you should encourage your team to increase the automation capability of development, testing, and IT operations along with new processes and procedures. For example, a Linux container is the key tool to achieve the automation capability of DevOps."
Geoff agrees, saying, "automate the toil. Are there tasks you hate doing? Great. Engineer them out of existence if possible. Otherwise, automate them. It keeps the job from becoming boring and routine because the job constantly evolves."
Dan, Ann Marie, and Brent stress team motivation.
Dan says, "at the NAIC, we have a great awards system for encouraging specific behaviors. We have multiple tiers of awards, and two of them can be given to anyone by anyone. We also give awards to teams after they complete something significant, but we often award individual contributors."
According to Ann Marie, "the biggest motivator for teams in my area is seeing the success of others. We have a weekly playback for each other, and part of that is sharing what we've learned from trying out new tools or practices. When teams are enthusiastic about something they're doing and willing to help others get started, more teams will quickly get on board."
Brent agrees. "Getting everyone educated and on the same baseline of knowledge is essential ... assessing what helps the team achieve [and] what it needs to deliver with the product owner and users is the first place I like to start."
Chris recommends a two-pronged approach. "Run small, weekly goals that are achievable and agreed by the team as being important and [where] they can see progress outside of the feature work they are doing. Celebrate wins and visualize the progress made."
### How do DevOps and agile work together?
```
"DevOps != Agile, second Agile != Scrum."
```
This is an important question because both DevOps and agile are cornerstones of modern software development.
DevOps is a process of software development focusing on communication and collaboration to facilitate rapid application and product deployment, whereas agile is a development methodology involving continuous development, continuous iteration, and continuous testing to achieve predictable and quality deliverables.
So, how do they relate? Let's ask the experts.
In Brent's view, "DevOps != Agile, second Agile != Scrum. … Agile tools and ways of working—that support DevOps strategies and goals—are how they mesh together."
Chris says, "agile is a fundamental component of DevOps for me. Sure, we could talk about how we adopt DevOps culture in a non-agile environment, but ultimately, improving agility in the way software is engineered is a key indicator as to the maturity of DevOps adoption within the organization."
Dan relates DevOps to the larger [Agile Manifesto][8]. "I never talk about agile without referencing the Agile Manifesto in order to set the baseline. There are many implementations that don't focus on the Manifesto. When you read the Manifesto, they've really described DevOps from a development perspective. Therefore, it is very easy to fit agile into a DevOps culture, as agile is focused on communication, collaboration, flexibility to change, and getting to production quickly."
Geoff sees "DevOps as one of many implementations of agile. Agile is essentially a set of principles, while DevOps is a culture, process, and toolchain that embodies those principles."
Ann Marie keeps it succinct, saying "agile is a prerequisite for DevOps. DevOps makes agile more effective."
### Has DevOps benefited from open source?
```
"Open source done well requires a DevOps culture."
```
This question receives a fervent "yes" from all participants followed by an explanation of the benefits they've seen.
Ann Marie says, "we get to stand on the shoulders of giants and build upon what's already available. The open source model of maintaining software, with pull requests and code reviews, also works very well for DevOps teams."
Chris agrees that DevOps has "undoubtedly" benefited from open source. "From the engineering and tooling side (e.g., Ansible), to the process and people side, through the sharing of stories within the industry and the open leadership community."
A benefit Geoff cites is "grassroots adoption. Nobody had to sign purchase requisitions for free (as in beer) software. Teams found tooling that met their needs, were free (as in freedom) to modify, [then] built on top of it, and contributed enhancements back to the larger community. Rinse, repeat."
Open source has shown DevOps "better ways you can adopt new changes and overcome challenges, just like open source software developers are doing it," says Daniel.
Brent concurs. "DevOps has benefited in many ways from open source. One way is the ability to use the tools to understand how they can help accelerate DevOps goals and strategies. Educating the development and operations folks on crucial things like automation, virtualization and containerization, auto-scaling, and many of the qualities that are difficult to achieve without introducing technology enablers that make DevOps easier."
Dan notes the two-way, symbiotic relationship between DevOps and open source. "Open source done well requires a DevOps culture. Most open source projects have very open communication structures with very little obscurity. This has actually been a great learning opportunity for DevOps practitioners around what they might bring into their own organizations. Also, being able to use tools from a community that is similar to that of your own organization only encourages your own culture growth. I like to use GitLab as an example of this symbiotic relationship. When I bring [GitLab] into a company, we get a great tool, but what I'm really buying is their unique culture. That brings substantial value through our interactions with them and our ability to contribute back. Their tool also has a lot to offer for a DevOps organization, but their culture has inspired awe in the companies where I've introduced it."
Now that our DevOps experts have weighed in, please share your thoughts on what DevOps means—as well as the other questions we posed—in the comments.
--------------------------------------------------------------------------------
via: https://opensource.com/article/19/1/what-does-devops-mean-you
作者：[Girish Managoli][a]
选题：[lujun9972][b]
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[b]: https://github.com/lujun9972
[1]: https://twitter.com/DukeAMO
[2]: https://twitter.com/danieloh30?lang=en
[3]: https://twitter.com/brentareed
[4]: https://twitter.com/barkerd427
[5]: https://psnet.ahrq.gov/resources/resource/1582
[6]: https://twitter.com/onlychrisbh?lang=en
[7]: https://twitter.com/geoff_purdy
[8]: https://agilemanifesto.org/

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sources/tech/20190204 Top 5 open source network monitoring tools.md
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sources/tech/20190303 Manage Your Mirrors with ArchLinux Mirrorlist Manager.md
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[#]: collector: (lujun9972)
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[#]: publisher: ( )
[#]: url: ( )
[#]: subject: (Manage Your Mirrors with ArchLinux Mirrorlist Manager)
[#]: via: (https://itsfoss.com/archlinux-mirrorlist-manager)
[#]: author: (John Paul https://itsfoss.com/author/john/)
Manage Your Mirrors with ArchLinux Mirrorlist Manager
======
**ArchLinux Mirrorlist Manager is a simple GUI program that allows you to easily manage mirrors in your Arch Linux system.**
For Linux users, it is important to make sure that you keep your mirror list in good shape. Today we will take a quick look at an application designed to help manage your Arch mirror list.
![ArchLinux Mirrorlist Manager][1]ArchLinux Mirrorlist Manager
### What is a Mirror?
For those new to the world of Linux, Linux operating systems depend on a series of servers placed around the world. These servers contain identical copies of all of the packages and software available for a particular distro. This is why they are called “mirrors”.
The ultimate goal is to have multiple mirrors in each country. This allows local users to quickly update their systems. However, this is not always true. Sometimes mirrors from another country can be faster.
### ArchLinux Mirrorlist Manager makes managing mirrors simpler in Arch Linux
![ArchLinux Mirrorlist Manager][2]Main Screen
[Managing and sorting][3] the available mirrors in Arch is not easy. It involves fairly lengthy commands. Thankfully, someone came up with a solution.
Last year, [Rizwan Hasan][4] created a little Python and Qt application entitled [ArchLinux Mirrorlist Manager][5]. You might recognize Rizwan’s name because it is not the first time that we featured something he created on this site. Over a year ago, I wrote about a new Arch-based distro that Rizwan created named [MagpieOS][6]. I imagine that Rizwan’s experience with MagpieOS inspired him to create this application.
There really isn’t much to ArchLinux Mirrorlist Manager. It allows you to rank mirrors by response speed and limit the results by number and country of origin.
In other words, if you are located in Germany, you can restrict your mirrors to the 3 fastest in Germany.
### Install ArchLinux Mirrorlist Manager
```
It is only for Arch Linux users
Pay attention! ArchLinux Mirrorlist Manager is for Arch Linux distribution only. Don’t try to use it on other Arch-based distributions unless you make sure that the distro uses Arch mirrors. Otherwise, you might face issues that I encountered with Manjaro (explained in the section below).
```
```
Mirrorlist Manager alternative for Manjaro
When it comes to using something Archy, my go-to system is Manjaro. In preparation for this article, I decided to install ArchLinux Mirrorlist Manager on my Manjaro machine. It quickly sorted the available mirror and saved them to my mirror list.
I then proceeded to try to update my system and immediately ran into problems. When ArchLinux Mirrorlist Manager sorted the mirrors my system was using, it replaced all of my Manjaro mirrors with vanilla Arch mirrors. (Manjaro is based on Arch, but has its own mirrors because the dev team tests all package updates before pushing them to the users to ensure there are no system-breaking bugs.) Thankfully, the Manjaro forum helped me fix my mistake.
If you are a Manjaro user, please do not make the same mistake that I did. ArchLinux Mirrorlist Manager is only for Arch and Arch-based distros that use Arch’s mirrors.
Luckily, there is an easy to use terminal application that Manjaro users can use to manage their mirror lists. It is called [Pacman-mirrors][7]. Just like ArchLinux Mirrorlist Manager, you can sort by response speed. Just type `sudo pacman-mirrors --fasttrack`. If you want to limit the results to the five fastest mirrors, you can type `sudo pacman-mirrors --fasttrack 5`. To restrict the results to one or more countries, type `sudo pacman-mirrors --country Germany,Spain,Austria`. You can limit the results to your country by typing `sudo pacman-mirrors --geoip`. You can visit the [Manjaro wiki][7] for more information about Pacman-mirrors.
After you run Pacman-mirrors, you have to synchronize your package database and update your system by typing `sudo pacman -Syyu`.
Note: Pacman-mirrors is for **Manjaro only**.
```
ArchLinux Mirrorlist Manager is available in the [Arch User Repository][8]. More advanced Arch users can download the PKGBUILD directly from [the GitHub page][9].
### Final Thoughts on ArchLinux Mirrorlist Manager
Even though [ArchLinux Mirrorlist Manager][5] isn’t very useful for me, I’m glad it exists. It shows that Linux users are actively trying to make Linux easier to use. As I said earlier, managing a mirror list on Arch is not easy. Rizwan’s little tool will help make Arch more usable by the beginning user.
Have you ever used ArchLinux Mirrorlist Manager? What is your method to manage your Arch mirrors? Please let us know in the comments below.
If you found this article interesting, please take a minute to share it on social media, Hacker News or [Reddit][10].
--------------------------------------------------------------------------------
via: https://itsfoss.com/archlinux-mirrorlist-manager
作者：[John Paul][a]
选题：[lujun9972][b]
译者：[lujun9972](https://github.com/lujun9972)
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[b]: https://github.com/lujun9972
[1]: https://i2.wp.com/itsfoss.com/wp-content/uploads/2019/02/mirrorlist-manager2.png?ssl=1
[2]: https://i0.wp.com/itsfoss.com/wp-content/uploads/2019/02/mirrorlist-manager4.jpg?ssl=1
[3]: https://wiki.archlinux.org/index.php/Mirrors
[4]: https://github.com/Rizwan-Hasan
[5]: https://github.com/Rizwan-Hasan/ArchLinux-Mirrorlist-Manager
[6]: https://itsfoss.com/magpieos/
[7]: https://wiki.manjaro.org/index.php?title=Pacman-mirrors
[8]: https://aur.archlinux.org/packages/mirrorlist-manager
[9]: https://github.com/Rizwan-Hasan/MagpieOS-Packages/tree/master/ArchLinux-Mirrorlist-Manager
[10]: http://reddit.com/r/linuxusersgroup

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sources/tech/20190306 Blockchain 2.0- Revolutionizing The Financial System -Part 2.md
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[#]: subject: (Blockchain 2.0: Revolutionizing The Financial System [Part 2])
[#]: via: (https://www.ostechnix.com/blockchain-2-0-revolutionizing-the-financial-system/)
[#]: author: (EDITOR https://www.ostechnix.com/author/editor/)
Blockchain 2.0: Revolutionizing The Financial System [Part 2]
======
This is the second part of our [**Blockchain 2.0**][1] series. The blockchain can transform how individuals and institutions deal with their finances. This post looks at how the existing monetary system evolved and how new blockchain systems are bringing in change as the next crucial step in the evolution of money.
Two key ideas will lay the foundation for this article. **PayPal** , when it was launched, was revolutionary in terms of its operation. The company would gather, process and confirm massive amounts of consumer data to facilitate online transactions of all kinds, virtually allowing platforms such as eBay to grow into trustful sources for commerce, and laying the benchmark for digital payment systems worldwide. The second, albeit much more important key idea to be highlighted here, is a somewhat existential question. We all use money or rather currency for our day-to-day needs. A ten-dollar bill will get you a cup or two from your favorite coffee shop and get you a head start on your day for instance. We depend on our respective national currencies for virtually everything.
Sure, mankind has come a long way since the **barter system** ruled what you ate for breakfast, but still, what exactly is currency? Who or what gives it it’s a value? And as the popular rumor suggests, does going to a bank and giving them a dollar bill actually get you the true value of whatever that currency “token” stands for?
The answer to most of those questions doesn’t exist. If they do, they’ll to be undependably vague and subjective at best. Back in the day when civilization started off establishing small cities and towns, the local currency deemed legal by the guy who ruled over them, was almost always made of something precious to that community. Indians are thought to have transacted in peppercorns while ancient Greeks and Romans in **salt** [1]. Gradually most of these little prehistoric civilizations adopted precious metals and stones as their tokens to transact. Gold coins, silver heirlooms, and rubies became eponymous with “value”. With the industrial revolution, people started printing these tokens of transaction and we finally seemed to have found our calling in paper currencies. They were dependable and cheap to produce and as long as a nation-state guaranteed its users that the piece of paper, they were holding was just a token for an amount of “value” they had and as long as they were able to show them that this value when demanded could be supported with precious substances such as gold or hard assets, people were happy to use them. However, if you still believe that the currency note you hold in your hand right now has the same guarantee, you’re wrong. We currently live in an age where almost all the major currencies in circulation around the globe are what economists would call a **fiat currency** [2]. Value-less pieces of paper that are only backed by the guarantees of the nation-state you’re residing in. The exact nature of fiat currencies and why they may possibly be a flawed system falls into the domain of economics and we won’t get into that now.
In fact, the only takeaway from all of this history that is relevant to this post is that civilizations started using tokens that hinted or represented value for trading goods and services rather than the non-practical barter system. Tokens. Naturally, this is the crucial concept behind cryptocurrencies as well. They don’t have any inherent value attached to them. Their value is tied to the number of people adopting that particular platform, the trust the adopters have on the system, and of course if released by a supervising entity, the background of the entity itself. The high price and market cap of **Bitcoin (BTC)** isn’t a coincidence, they were among the first in business and had a lot of early adopters. This ultimate truth behind cryptocurrencies is what makes it so important yet so unforgivingly complex to understand. It’s the natural next step in the evolution of “money”. Some understand this and some still like to think of the solid currency concept where “real” money is always backed by something of inherent value.[3] Though there have been countless debates and studies on this dilemma, there is no looking back from a blockchain powered future.
For instance, the country of **Ecuador** made headlines in 2015 for its purported plans to develop and release **its own national cryptocurrency** [4]. Albeit the attempt officially was to aid and support their existing currency system. Since then other countries and their regulatory bodies have or are drafting up papers to control the “epidemic” that is cryptocurrency with some already having published frameworks to the extent of creating a roadmap for blockchain and crypto development. **Germany** is thought to be investing in a long term blockchain project to streamline its taxation and financial systems[5]. Banks in developing countries are joining in on something called a Bank chain, cooperating in creating a **private blockchain** to increase efficiency in and optimize their operations
Now is when we tie both the ends of the stories together, remember the first mention of PayPal before the casual history lesson? Experts have compared Bitcoin’s (BTC) adoption rate with that of PayPal when it was launched. Initial consumer hesitation, where only a few early adopters are ready to jump into using the said product and then all a wider adoption gradually becoming a benchmark for similar platforms. Bitcoin (BTC) is already a benchmark for similar cryptocurrency platforms with major coins such as **Ethereum (ETH)** and **Ripple (XRP)** [6]. Adoption is steadily increasing, legal and regulatory frameworks being made to support it, and active research and development being done on the front as well. And not unlike PayPal, experts believe that cryptocurrencies and platforms utilizing blockchain tech for their digital infrastructure will soon become the standard norm rather than the exception.
Although the rise in cryptocurrency prices in 2018 can be termed as an economic bubble, companies and governments have continued to invest as much or more into the development of their own blockchain platforms and financial tokens. To counteract and prevent such an incident in the future while still looking forward to investing in the area, an alternative to traditional cryptocurrencies called **stablecoins** have made the rounds recently.
Financial behemoth **JP Morgan** came out with their own enterprise ready blockchain solution called **Quorum** handling their stablecoin called **JPM Coin** [7]. Each such JPM coin is tied to 1 USD and their value is guaranteed by the parent organization under supporting legal frameworks, in this case, JP Morgan. Platforms such as this one make it easier for large financial transactions to the tunes of millions or billions of dollars to be transferred instantaneously over the internet without having to rely on conventional banking systems such as SWIFT which involve lengthy procedures and are themselves decades old.
In the same spirit of making the niceties of the blockchain available for everyone, The Ethereum platform allows 3rd parties to utilize their blockchain or derive from it to create and administer their own takes on the triad of the **Blockchain-protocol-token** system thereby leading to wider adoption of the standard with lesser work on its foundations.
The blockchain allows for digital versions of existing financial instruments to be created, recorded, and traded quickly over a network without the need for third-party monitoring. The inherent safety and security features of the system makes the entire process totally safe and immune to fraud and tampering, basically the only reason why third-party monitoring was required in the sector. Another area where governmental and regulatory bodies presided over when it came to financial services and instruments were in regards to transparency and auditing. With blockchain banks and other financial institutes will be able to maintain a fully transparent, layered, almost permanent and tamper-proof record of all their transactions rendering auditing tasks near useless. Much needed developments and changes to the current financial system and services industry can be made possible by exploiting blockchains. The platform being distributed, tamper-proof, near permanent, and quick to execute is highly valuable to bankers and government regulators alike and their investments in this regard seem to be well placed[8].
In the next article of the series, we see how companies are using blockchains to deliver the next generation of financial services. Looking at individual firms creating ripples in the industry, we explore how the future of a blockchain backed economy would look like.
--------------------------------------------------------------------------------
via: https://www.ostechnix.com/blockchain-2-0-revolutionizing-the-financial-system/
作者：[EDITOR][a]
选题：[lujun9972][b]
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[b]: https://github.com/lujun9972
[1]: https://www.ostechnix.com/blockchain-2-0-an-introduction/

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sources/tech/20190306 Get cooking with GNOME Recipes on Fedora.md
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[#]: subject: (Get cooking with GNOME Recipes on Fedora)
[#]: via: (https://fedoramagazine.org/get-cooking-with-gnome-recipes-on-fedora/)
[#]: author: (Ryan Lerch https://fedoramagazine.org/introducing-flatpak/)
Get cooking with GNOME Recipes on Fedora
======
![](https://fedoramagazine.org/wp-content/uploads/2019/03/gnome-recipes-816x345.jpg)
Do you love to cook? Looking for a better way to manage your recipes using Fedora? GNOME Recipes is an awesome application available to install in Fedora to store and organize your recipe collection.
![][1]
GNOME Recipes is an recipe management tool from the GNOME project. It has the visual style of a modern GNOME style application, and feels similar to GNOME Software, but for food.
### Installing GNOME Recipes
Recipes is available to install from the 3rd party Flathub repositories. If you have never installed an application from Flathub before, set it up using the following guide:
[Install Flathub apps on Fedora](https://fedoramagazine.org/install-flathub-apps-fedora/)
After correctly setting up Flathub as a software source, you will be able to search for and install Recipes via GNOME Software.
### Recipe management
Recipes allows you to manually add your own collection of recipes, including photos, ingredients, directions, as well as extra metadata like preparation time, cuisine style, and spiciness.
![][2]
When entering in a new item, GNOME Recipes there are a range of different measurement units to choose from, as well as special tags for items like temperature, allowing you to easily switch units.
### Community recipes
In addition to manually entering in your favourite dishes for your own use, it also allows you to find, use, and contribute recipes to the community. Additionally, you can mark your favourites, and search the collection by the myriad of metadata available for each recipe.
![][3]
### Step by step guidance
One of the awesome little features in GNOME Recipes is the step by step fullscreen mode. When you are ready to cook, simply activate this mode, move you laptop to the kitchen, and you will have a full screen display of the current step in the cooking method. Futhermore, you can set up the recipes to have timers displayed on this mode when something is in the oven.
![][4]
--------------------------------------------------------------------------------
via: https://fedoramagazine.org/get-cooking-with-gnome-recipes-on-fedora/
作者：[Ryan Lerch][a]
选题：[lujun9972][b]
译者：[译者ID](https://github.com/译者ID)
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[a]: https://fedoramagazine.org/introducing-flatpak/
[b]: https://github.com/lujun9972
[1]: https://fedoramagazine.org/wp-content/uploads/2019/03/Screenshot-from-2019-03-06-19-45-06-1024x727.png
[2]: https://fedoramagazine.org/wp-content/uploads/2019/03/gnome-recipes1-1024x727.png
[3]: https://fedoramagazine.org/wp-content/uploads/2019/03/Screenshot-from-2019-03-06-20-08-45-1024x725.png
[4]: https://fedoramagazine.org/wp-content/uploads/2019/03/Screenshot-from-2019-03-06-20-39-44-1024x640.png

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sources/tech/20190307 13 open source backup solutions.md
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[#]: collector: (lujun9972)
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[#]: url: ( )
[#]: subject: (13 open source backup solutions)
[#]: via: (https://opensource.com/article/19/3/backup-solutions)
[#]: author: (Don Watkins https://opensource.com/users/don-watkins)
13 open source backup solutions
======
Readers suggest more than a dozen of their favorite solutions for protecting data.
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/server_data_system_admin.png?itok=q6HCfNQ8)
Recently, we published a [poll][1] that asked readers to vote on their favorite open source backup solution. We offered six solutions recommended by our [moderator community][2]—Cronopete, Deja Dup, Rclone, Rdiff-backup, Restic, and Rsync—and invited readers to share other options in the comments. And you came through, offering 13 other solutions (so far) that we either hadn't considered or hadn't even heard of.
By far the most popular suggestion was [BorgBackup][3]. It is a deduplicating backup solution that features compression and encryption. It is supported on Linux, MacOS, and BSD and has a BSD License.
Second was [UrBackup][4], which does full and incremental image and file backups; you can save whole partitions or single directories. It has clients for Windows, Linux, and MacOS and has a GNU Affero Public License.
Third was [LuckyBackup][5]; according to its website, "it is simple to use, fast (transfers over only changes made and not all data), safe (keeps your data safe by checking all declared directories before proceeding in any data manipulation), reliable, and fully customizable." It carries a GNU Public License.
[Casync][6] is content-addressable synchronization—it's designed for backup and synchronizing and stores and retrieves multiple related versions of large file systems. It is licensed with the GNU Lesser Public License.
[Syncthing][7] synchronizes files between two computers. It is licensed with the Mozilla Public License and, according to its website, is secure and private. It works on MacOS, Windows, Linux, FreeBSD, Solaris, and OpenBSD.
[Duplicati][8] is a free backup solution that works on Windows, MacOS, and Linux and a variety of standard protocols, such as FTP, SSH, and WebDAV, and cloud services. It features strong encryption and is licensed with the GPL.
[Dirvish][9] is a disk-based virtual image backup system licensed under OSL-3.0. It also requires Rsync, Perl5, and SSH to be installed.
[Bacula][10]'s website says it "is a set of computer programs that permits the system administrator to manage backup, recovery, and verification of computer data across a network of computers of different kinds." It is supported on Linux, FreeBSD, Windows, MacOS, OpenBSD, and Solaris and the bulk of its source code is licensed under AGPLv3.
[BackupPC][11] "is a high-performance, enterprise-grade system for backing up Linux, Windows, and MacOS PCs and laptops to a server's disk," according to its website. It is licensed under the GPLv3.
[Amanda][12] is a backup system written in C and Perl that allows a system administrator to back up an entire network of client machines to a single server using tape, disk, or cloud-based systems. It was developed and copyrighted in 1991 at the University of Maryland and has a BSD-style license.
[Back in Time][13] is a simple backup utility designed for Linux. It provides a command line client and a GUI, both written in Python. To do a backup, just specify where to store snapshots, what folders to back up, and the frequency of the backups. BackInTime is licensed with GPLv2.
[Timeshift][14] is a backup utility for Linux that is similar to System Restore for Windows and Time Capsule for MacOS. According to its GitHub repository, "Timeshift protects your system by taking incremental snapshots of the file system at regular intervals. These snapshots can be restored at a later date to undo all changes to the system."
[Kup][15] is a backup solution that was created to help users back up their files to a USB drive, but it can also be used to perform network backups. According to its GitHub repository, "When you plug in your external hard drive, Kup will automatically start copying your latest changes."
Thanks for sharing your favorite open source backup solutions in our poll! If there are still others that haven't been mentioned yet, please share them in the comments.
--------------------------------------------------------------------------------
via: https://opensource.com/article/19/3/backup-solutions
作者：[Don Watkins][a]
选题：[lujun9972][b]
译者：[译者ID](https://github.com/译者ID)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://opensource.com/users/don-watkins
[b]: https://github.com/lujun9972
[1]: https://opensource.com/article/19/2/linux-backup-solutions
[2]: https://opensource.com/opensourcecom-team
[3]: https://www.borgbackup.org/
[4]: https://www.urbackup.org/
[5]: http://luckybackup.sourceforge.net/
[6]: http://0pointer.net/blog/casync-a-tool-for-distributing-file-system-images.html
[7]: https://syncthing.net/
[8]: https://www.duplicati.com/
[9]: http://dirvish.org/
[10]: https://www.bacula.org/
[11]: https://backuppc.github.io/backuppc/
[12]: http://www.amanda.org/
[13]: https://github.com/bit-team/backintime
[14]: https://github.com/teejee2008/timeshift
[15]: https://github.com/spersson/Kup

51
sources/tech/20190307 How to keep your Raspberry Pi updated.md
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[#]: translator: (geekpi)
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: subject: (How to keep your Raspberry Pi updated)
[#]: via: (https://opensource.com/article/19/3/how-raspberry-pi-update)
[#]: author: (Anderson Silva https://opensource.com/users/ansilva)
How to keep your Raspberry Pi updated
======
Learn how to keep your Raspberry Pi patched and working well in the seventh article in our guide to getting started with the Raspberry Pi.
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/computer_happy_sad_developer_programming.png?itok=72nkfSQ_)
Just like your tablet, cellphone, and laptop, you need to keep your Raspberry Pi updated. Not only will the latest enhancements keep your Pi running smoothly, they will also keep you safer, especially if you are connected to a network. The seventh article in our guide to getting started with the Raspberry Pi shares two pieces of advice on keeping your Pi working well.
### Update Raspbian
Updating your Raspbian installation is a [two-step process][1]:
1. In your terminal type: **sudo apt-get update**
The command **sudo** allows you to run **apt-get update** as admin (aka root). Note that **apt-get update** will not install anything new on your system; rather it will update the list of packages and dependencies that need to be updated.
2. Then type: **sudo apt-get dist-upgrade**
From the documentation: "Generally speaking, doing this regularly will keep your installation up to date, in that it will be equivalent to the latest released image available from [raspberrypi.org/downloads][2]."
![](https://opensource.com/sites/default/files/uploads/update_sudo_rpi.png)
### Be careful with rpi-update
Raspbian comes with another little update utility called [rpi-update][3]. This utility can be used to upgrade your Pi to the latest firmware which may or may not be broken/buggy. You may find information explaining how to use it, but as of late it is recommended never to use this application unless you have a really good reason to do so.
Bottom line: Keep your systems updated!
--------------------------------------------------------------------------------
via: https://opensource.com/article/19/3/how-raspberry-pi-update
作者：[Anderson Silva][a]
选题：[lujun9972][b]
译者：[译者ID](https://github.com/译者ID)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://opensource.com/users/ansilva
[b]: https://github.com/lujun9972
[1]: https://www.raspberrypi.org/documentation/raspbian/updating.md
[2]: https://www.raspberrypi.org/downloads/
[3]: https://github.com/Hexxeh/rpi-update

48
sources/tech/20190309 Emulators and Native Linux games on the Raspberry Pi.md
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[#]: collector: (lujun9972)
[#]: translator: (geekpi)
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: subject: (Emulators and Native Linux games on the Raspberry Pi)
[#]: via: (https://opensource.com/article/19/3/play-games-raspberry-pi)
[#]: author: (Anderson Silva https://opensource.com/users/ansilva)
Emulators and Native Linux games on the Raspberry Pi
======
The Raspberry Pi is a great platform for gaming; learn how in the ninth article in our series on getting started with the Raspberry Pi.
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/getting_started_with_minecraft_copy.png?itok=iz4RF7f8)
Back in the [fifth article][1] in our series on getting started with the Raspberry Pi, I mentioned Minecraft as a way to teach kids to program using a gaming platform. Today we'll talk about other ways you can play games on your Raspberry Pi, as it's a great platform for gaming—with and without emulators.
### Gaming with emulators
Emulators are software that allow you to play games from different systems and different decades on your Raspberry Pi. Of the many emulators available today, the most popular for the Raspberry Pi is [RetroPi][2]. You can use it to play games from systems such as Apple II, Amiga, Atari 2600, Commodore 64, Game Boy Advance, and [many others][3].
If RetroPi sounds interesting, check out [these instructions][4] on how to get started, and start having fun today!
### Native Linux games
There are also plenty of native Linux games available on Raspbian, Raspberry Pi's operating system. Make Use Of has a great article on [how to play 10 old favorites][5] like Doom and Nuke Dukem 3D on the Raspberry Pi.
You can also use your Raspberry Pi as a [game server][6]. For example, you can set up Terraria, Minecraft, and QuakeWorld servers on the Raspberry Pi.
--------------------------------------------------------------------------------
via: https://opensource.com/article/19/3/play-games-raspberry-pi
作者：[Anderson Silva][a]
选题：[lujun9972][b]
译者：[译者ID](https://github.com/译者ID)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://opensource.com/users/ansilva
[b]: https://github.com/lujun9972
[1]: https://opensource.com/article/19/3/teach-kids-program-raspberry-pi
[2]: https://retropie.org.uk/
[3]: https://retropie.org.uk/about/systems
[4]: https://opensource.com/article/19/1/retropie
[5]: https://www.makeuseof.com/tag/classic-games-raspberry-pi-without-emulators/
[6]: https://www.makeuseof.com/tag/raspberry-pi-game-servers/

48
sources/tech/20190310 Let-s get physical- How to use GPIO pins on the Raspberry Pi.md
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[#]: collector: (lujun9972)
[#]: translator: ( )
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: subject: (Let's get physical: How to use GPIO pins on the Raspberry Pi)
[#]: via: (https://opensource.com/article/19/3/gpio-pins-raspberry-pi)
[#]: author: (Anderson Silva https://opensource.com/users/ansilva)
Let's get physical: How to use GPIO pins on the Raspberry Pi
======
The 10th article in our series on getting started with Raspberry Pi explains how the GPIO pins work.
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/raspbery_pi_zero_wireless_hardware.jpg?itok=9YFzdxFQ)
Until now, this series has focused on the Raspberry Pi's software side, but today we'll get into the hardware. The availability of [general-purpose input/output][1] (GPIO) pins was one of the main features that interested me in the Pi when it first came out. GPIO allows you to programmatically interact with the physical world by attaching sensors, relays, and other types of circuitry to the Raspberry Pi.
![](https://opensource.com/sites/default/files/uploads/raspberrypi_10_gpio-pins-pi2.jpg)
Each pin on the board either has a predefined function or is designated as general purpose. Also, different Raspberry Pi models have either 26 or 40 pins for you to use at your discretion. Wikipedia has a [good overview of each pin][2] and its functionality.
You can do many things with the Pi's GPIO pins. I've written some other articles about using the GPIOs, including a trio of articles ([Part I][3], [Part II][4], and [Part III][5]) about controlling holiday lights with the Raspberry Pi while using open source software to pair the lights with music.
The Raspberry Pi community has done a great job in creating libraries in different programming languages, so you should be able to interact with the pins using [C][6], [Python][7], [Scratch][8], and other languages.
Also, if you want the ultimate experience to interact with the physical world, pick up a [Raspberry Pi Sense Hat][9]. It is an affordable expansion board for the Pi that plugs into the GPIO pins so you can programmatically interact with LEDs, joysticks, and barometric pressure, temperature, humidity, gyroscope, accelerometer, and magnetometer sensors.
--------------------------------------------------------------------------------
via: https://opensource.com/article/19/3/gpio-pins-raspberry-pi
作者：[Anderson Silva][a]
选题：[lujun9972][b]
译者：[译者ID](https://github.com/译者ID)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://opensource.com/users/ansilva
[b]: https://github.com/lujun9972
[1]: https://www.raspberrypi.org/documentation/usage/gpio/
[2]: https://en.wikipedia.org/wiki/Raspberry_Pi#General_purpose_input-output_(GPIO)_connector
[3]: https://opensource.com/life/15/2/music-light-show-with-raspberry-pi
[4]: https://opensource.com/life/15/12/ssh-your-christmas-tree-raspberry-pi
[5]: https://opensource.com/article/18/12/lightshowpi-raspberry-pi
[6]: https://www.bigmessowires.com/2018/05/26/raspberry-pi-gpio-programming-in-c/
[7]: https://www.raspberrypi.org/documentation/usage/gpio/python/README.md
[8]: https://www.raspberrypi.org/documentation/usage/gpio/scratch2/README.md
[9]: https://opensource.com/life/16/4/experimenting-raspberry-pi-sense-hat

2
sources/tech/20190311 7 resources for learning to use your Raspberry Pi.md
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sources/tech/20190311 Blockchain 2.0- Redefining Financial Services -Part 3.md
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[#]: translator: (sanfusu)
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[#]: url: ( )

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sources/tech/20190311 Learn about computer security with the Raspberry Pi and Kali Linux.md
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[#]: translator: (hopefully2333)
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: subject: (Learn about computer security with the Raspberry Pi and Kali Linux)
[#]: via: (https://opensource.com/article/19/3/computer-security-raspberry-pi)
[#]: author: (Anderson Silva https://opensource.com/users/ansilva)
Learn about computer security with the Raspberry Pi and Kali Linux
======
Raspberry Pi is a great way to learn about computer security. Learn how in the 11th article in our getting-started series.
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/security_privacy_lock.png?itok=ZWjrpFzx)
Is there a hotter topic in technology than securing your computer? Some experts will tell you that there is no such thing as perfect security. They joke that if you want your server or application to be truly secure, then turn off your server, unplug it from the network, and put it in a safe somewhere. The problem with that should be obvious: What good is an app or server that nobody can use?
That's the conundrum around security. How can we make something secure enough and still usable and valuable? I am not a security expert by any means, although I hope to be one day. With that in mind, I thought it would make sense to share some ideas about what you can do with a Raspberry Pi to learn more about security.
I should note that, like the other articles in this series dedicated to Raspberry Pi beginners, my goal is not to dive in deep, rather to light a fire of interest for you to learn more about these topics.
### Kali Linux
When it comes to "doing security things," one of the Linux distributions that comes to mind is [Kali Linux][1]. Kali's development is primarily focused on forensics and penetration testing. It has more than 600 preinstalled [penetration-testing programs][2] to test your computer's security, and a [forensics mode][3], which prevents it from touching the internal hard drive or swap space of the system being examined.
![](https://opensource.com/sites/default/files/uploads/raspberrypi_11_kali.png)
Like Raspbian, Kali Linux is based on the Debian distribution, and you can find directions on installing it on the Raspberry Pi in its main [documentation portal][4]. If you installed Raspbian or another Linux distribution on your Raspberry Pi, you should have no problem installing Kali. Kali Linux's creators have even put together [training, workshops, and certifications][5] to help boost your career in the security field.
### Other Linux distros
Most standard Linux distributions, like Raspbian, Ubuntu, and Fedora, also have [many security tools available][6] in their repositories. Some great tools to explore include [Nmap][7], [Wireshark][8], [auditctl][9], and [SELinux][10].
### Projects
There are many other security-related projects you can run on your Raspberry Pi, such as [Honeypots][11], [Ad blockers][12], and [USB sanitizers][13]. Take some time and learn about them!
--------------------------------------------------------------------------------
via: https://opensource.com/article/19/3/computer-security-raspberry-pi
作者：[Anderson Silva][a]
选题：[lujun9972][b]
译者：[译者ID](https://github.com/译者ID)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://opensource.com/users/ansilva
[b]: https://github.com/lujun9972
[1]: https://www.kali.org/
[2]: https://en.wikipedia.org/wiki/Kali_Linux#Development
[3]: https://docs.kali.org/general-use/kali-linux-forensics-mode
[4]: https://docs.kali.org/kali-on-arm/install-kali-linux-arm-raspberry-pi
[5]: https://www.kali.org/penetration-testing-with-kali-linux/
[6]: https://linuxblog.darkduck.com/2019/02/9-best-linux-based-security-tools.html
[7]: https://nmap.org/
[8]: https://www.wireshark.org/
[9]: https://linux.die.net/man/8/auditctl
[10]: https://opensource.com/article/18/7/sysadmin-guide-selinux
[11]: https://trustfoundry.net/honeypi-easy-honeypot-raspberry-pi/
[12]: https://pi-hole.net/
[13]: https://www.circl.lu/projects/CIRCLean/

49
sources/tech/20190312 Do advanced math with Mathematica on the Raspberry Pi.md
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[#]: collector: (lujun9972)
[#]: translator: (geekpi)
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: subject: (Do advanced math with Mathematica on the Raspberry Pi)
[#]: via: (https://opensource.com/article/19/3/do-math-raspberry-pi)
[#]: author: (Anderson Silva https://opensource.com/users/ansilva)
Do advanced math with Mathematica on the Raspberry Pi
======
Wolfram bundles a version of Mathematica with Raspbian. Learn how to use it in the 12th article in our series on getting started with Raspberry Pi.
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/edu_math_formulas.png?itok=B59mYTG3)
In the mid-'90s, I started college as a math major, and, even though I graduated with a computer science degree, I had taken enough classes to graduate with a minor—and only two classes short of a double-major—in math. At the time, I was introduced to an application called [Mathematica][1] by [Wolfram][2], where we would take many of our algebraic and differential equations from the blackboard into the computer. I spent a few hours a month in the lab learning the Wolfram Language and solving integrals and such on Mathematica.
Mathematica was closed source and expensive for a college student, so it was a nice surprise to see almost 20 years later Wolfram bundling a version of Mathematica with Raspbian and the Raspberry Pi. If you decide to use another Debian-based distribution, you can [download it][3] on your Pi. Note that this version is free for non-commercial use only.
The Raspberry Pi Foundation's [introduction to Mathematica][4] covers some basic concepts such as variables and loops, solving some math problems, creating graphs, doing linear algebra, and even interacting with the GPIO pins through the application.
![](https://opensource.com/sites/default/files/uploads/raspberrypi_12_mathematica_batman-plot.png)
To dive deeper into Mathematica, check out the [Wolfram Language documentation][5]. If you just want to solve some basic calculus problems, [check out its functions][6]. And read this tutorial if you want to [plot some 2D and 3D graphs][7].
Or, if you want to stick with open source tools while doing math, check out the command-line tools **expr** , **factor** , and **bc**. (Remember to use the [**man** command][8] to read up on these utilities.) And if you want to graph something, [Gnuplot][9] is a great option.
--------------------------------------------------------------------------------
via: https://opensource.com/article/19/3/do-math-raspberry-pi
作者：[Anderson Silva][a]
选题：[lujun9972][b]
译者：[译者ID](https://github.com/译者ID)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://opensource.com/users/ansilva
[b]: https://github.com/lujun9972
[1]: https://en.wikipedia.org/wiki/Wolfram_Mathematica
[2]: https://wolfram.com/
[3]: https://www.wolfram.com/raspberry-pi/
[4]: https://projects.raspberrypi.org/en/projects/getting-started-with-mathematica/
[5]: https://www.wolfram.com/language/
[6]: https://reference.wolfram.com/language/guide/Calculus.html
[7]: https://reference.wolfram.com/language/howto/PlotAGraph.html
[8]: https://opensource.com/article/19/3/learn-linux-raspberry-pi
[9]: http://gnuplot.info/

2
sources/tech/20190314 14 days of celebrating the Raspberry Pi.md
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sources/tech/20190318 10 Python image manipulation tools.md
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sources/tech/20190318 How to host your own webfonts.md
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[#]: subject: (How to host your own webfonts)
[#]: via: (https://opensource.com/article/19/3/webfonts)
[#]: author: (Seth Kenlon (Red Hat, Community Moderator) https://opensource.com/users/seth)
How to host your own webfonts
======
### Customize your website by self-hosting openly licensed fonts.
![Open source fonts][1]
Fonts are often a mystery to many computer users. For example, have you designed a cool flyer and, when you take the file somewhere for printing, find all the titles rendered in Arial because the printer doesn't have the fancy font you used in your design? There are ways to prevent this, of course: you can convert words in special fonts into paths, bundle fonts into a PDF, bundle open source fonts with your design files, or—at least—list the fonts required. And yet it's still a problem because we're human and we're forgetful.
The web has the same sort of problem. If you have even a basic understanding of CSS, you've probably seen this kind of declaration:
```
h1 { font-family: "Times New Roman", Times, serif; }
```
This is a designer's attempt to define a specific font, provide a fallback if a user doesn't have Times New Roman installed, and offer yet another fallback if the user doesn't have Times either. It's better than using a graphic instead of text, but it's still an awkward, inelegant method of font non-management, However, in the early-ish days of the web, it's all we had to work with.
### Webfonts
Then webfonts happened, moving font management from the client to the server. Fonts on websites were rendered for the client by the server, rather than requiring the web browser to find a font on the user's system. Google and other providers even host openly licensed fonts, which designers can include on their sites with a simple CSS rule.
The problem with this free convenience, of course, is that it doesn't come without cost. It's $0 to use, but major sites like Google love to keep track of who references their data, fonts included. If you don't see a need to assist Google in building a record of everyone's activity on the web, the good news is you can host your own webfonts, and it's as simple as uploading fonts to your host and using one easy CSS rule. As a side benefit, your site may load faster, as you'll be making one fewer external call upon loading each page.
### Self-hosted webfonts
The first thing you need is an openly licensed font. This can be confusing if you're not used to thinking or caring about obscure software licenses, especially since it seems like all fonts are free. Very few of us have consciously paid for a font, and yet most people have high-priced fonts on their computers. Thanks to licensing deals, your computer may have shipped with fonts that [you aren't legally allowed to copy and redistribute][2]. Fonts like Arial, Verdana, Calibri, Georgia, Impact, Lucida and Lucida Grande, Times and Times New Roman, Trebuchet, Geneva, and many others are owned by Microsoft, Apple, and Adobe. If you purchased a computer preloaded with Windows or MacOS, you paid for the right to use the bundled fonts, but you don't own those fonts and are not permitted to upload them to a web server (unless otherwise stated).
Fortunately, the open source craze hit the font world long ago, and there are excellent collections of openly licensed fonts from collectives and projects like [The League of Moveable Type][3], [Font Library][4], [Omnibus Type][5], and even [Google][6] and [Adobe][7].
You can use most common font file formats, including TTF, OTF, WOFF, EOT, and so on. Since Sorts Mill Goudy includes a WOFF (Web Open Font Format, developed in part by Mozilla) version, I'll use it in this example. However, other formats work the same way.
Assuming you want to use [Sorts Mill Goudy][8] on your web page:
1. Upload the **GoudyStM-webfont.woff** file to your web server:
```
scp GoudyStM-webfont.woff seth@example.com:~/www/fonts/
```
Your host may also provide a graphical upload tool through cPanel or a similar web control panel.
2. In your site's CSS file, add an **@font-face** rule, similar to this:
```
@font-face {
  font-family: "titlefont";
  src: url("../fonts/GoudyStM-webfont.woff");
}
```
The **font-family** value is something you make up. It's a human-friendly name for whatever the font face represents. I am using "titlefont" in this example because I imagine this font will be used for the main titles on an imaginary site. You could just as easily use "officialfont" or "myfont."
The **src** value is the path to the font file. The path to the font must be appropriate for your server's file structure; in this example, I have the **fonts** directory alongside a **css** directory. You may not have your site structured that way, so adjust the paths as needed, remembering that a single dot means _this folder_ and two dots mean _a folder back_.
3. Now that you've defined the font face name and the location, you can call it for any given CSS class or ID you desire. For example, if you want **< h1>** to render in the Sorts Mill Goudy font, then make its CSS rule use your custom font name:
```
h1 { font-family: "titlefont", serif; }
```
You're now hosting and using your own fonts.
![Web fonts on a website][10]
_Thanks to Alexandra Kanik for teaching me about @font-face and most everything else I know about good web design._
--------------------------------------------------------------------------------
via: https://opensource.com/article/19/3/webfonts
作者：[Seth Kenlon (Red Hat, Community Moderator)][a]
选题：[lujun9972][b]
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[a]: https://opensource.com/users/seth
[b]: https://github.com/lujun9972
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/life_typography_fonts.png?itok=Q1jMys5G (Open source fonts)
[2]: https://docs.microsoft.com/en-us/typography/fonts/font-faq
[3]: https://www.theleagueofmoveabletype.com/
[4]: https://fontlibrary.org/
[5]: https://www.omnibus-type.com
[6]: https://github.com/googlefonts
[7]: https://github.com/adobe-fonts
[8]: https://www.theleagueofmoveabletype.com/sorts-mill-goudy
[9]: /file/426056
[10]: https://opensource.com/sites/default/files/uploads/webfont.jpg (Web fonts on a website)

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[#]: collector: (lujun9972)
[#]: translator: ( )
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: subject: (How to add new disk in Linux)
[#]: via: (https://kerneltalks.com/hardware-config/how-to-add-new-disk-in-linux/)
[#]: author: (kerneltalks https://kerneltalks.com)
How to add new disk in Linux
======
* * *
_Step by step procedure to add disk in Linux machine_
![New disk addition in Linux][1]
In this article we will walk you through steps to add new disk in Linux machine. Adding raw disk to linux machine may very depending upon the type of server you have but once disk is presented to machine, procedure of getting it to mount points is almost same.
**Objective** : Add new 10GB disk to server and create 5GB mount point out of it using LVM and newly created volume group.
* * *
### Adding raw disk to Linux machine
If you are using AWS EC2 Linux server, you may [follow these steps][2] to add raw disk. If you are on VMware Linux VM you will have different set of steps to follow to add disk. If you are running physical rack mount/blade server then adding disk will be a physical task.
Now once the disk is attached to Linux machine physically/virtually, it will be identified by kernel and then our rally starts.
* * *
### Identifying newly added disk in Linux
After attachment of raw disk, you need to ask kernel to [scan new disk][3]. Mostly its done now automatically by kernel in new versions.
First thing is to identify newly added disk and its name in kernel. There are numerous ways to achieve this. I will list few –
* You can observer `lsblk` output before and after adding/scanning disk to get new disk name.
* Check newly created disk files in `/dev` filesystem. Match timestamp of file and disk addition time.
* Observer `fdisk -l` output before and after adding/scanning disk to get new disk name.
For our example I am using AWS EC2 server and I added 5GB disk to my server. here is my lsblk output –
```
[root@kerneltalks ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda 202:0 0 10G 0 disk
├─xvda1 202:1 0 1M 0 part
└─xvda2 202:2 0 10G 0 part /
xvdf 202:80 0 10G 0 disk
```
You can see xvdf is our newly added disk. Full path for disk is `/dev/xvdf`.
* * *
### Add new disk in LVM
We are using LVM here since its widely used and flexible volume manager on Linux plateform. Make sure you have `lvm` or `lvm2` [package installed on your system][4]. If not, [install lvm/lvm2 package][5].
Now, we are going to add this RAW disk in Logical Volume Manager and create 10GB of mount point out of it. List of commands you need to follow are –
* [pvcreate][6]
* [vgcreate][7]
* [lvcreate][8]
If you are willing to add disk to existing mount point and use its space to [extend mount point][9] then `vgcreate` should be replaced by `vgextend`.
Sample outputs from my session –
```
[root@kerneltalks ~]# pvcreate /dev/xvdf
Physical volume "/dev/xvdf" successfully created.
[root@kerneltalks ~]# vgcreate vgdata /dev/xvdf
Volume group "vgdata" successfully created
[root@kerneltalks ~]# lvcreate -L 5G -n lvdata vgdata
Logical volume "lvdata" created.
```
Now, you have logical volume created. You need to format it with filesystem on your choice and mount it. We are choosing ext4 filesystem here and formatting using `mkfs.ext4` .
```
[root@kerneltalks ~]# mkfs.ext4 /dev/vgdata/lvdata
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
327680 inodes, 1310720 blocks
65536 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=1342177280
40 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736
Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
```
* * *
### Mounting volume from new disk on mount point
Lets mount the logical volume of 5GB which we created and formatted on /data mount point using `mount` command.
```
[root@kerneltalks ~]# mount /dev/vgdata/lvdata /data
[root@kerneltalks ~]# df -Ph /data
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vgdata-lvdata 4.8G 20M 4.6G 1% /data
```
Verify your mount point with df command as above and you are all done! You can always add an entry in [/etc/fstab][10] to make this mount persistent over reboots.
You have attached 10GB disk to Linux machine and created 5GB mount point out of it!
--------------------------------------------------------------------------------
via: https://kerneltalks.com/hardware-config/how-to-add-new-disk-in-linux/
作者：[kerneltalks][a]
选题：[lujun9972][b]
译者：[译者ID](https://github.com/译者ID)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://kerneltalks.com
[b]: https://github.com/lujun9972
[1]: https://i1.wp.com/kerneltalks.com/wp-content/uploads/2019/03/How-to-add-new-disk-in-Linux.png?ssl=1
[2]: https://kerneltalks.com/cloud-services/how-to-add-ebs-disk-on-aws-linux-server/
[3]: https://kerneltalks.com/disk-management/howto-scan-new-lun-disk-linux-hpux/
[4]: https://kerneltalks.com/tools/check-package-installed-linux/
[5]: https://kerneltalks.com/tools/package-installation-linux-yum-apt/
[6]: https://kerneltalks.com/disk-management/lvm-command-tutorials-pvcreate-pvdisplay/
[7]: https://kerneltalks.com/disk-management/lvm-commands-tutorial-vgcreate-vgdisplay-vgscan/
[8]: https://kerneltalks.com/disk-management/lvm-commands-tutorial-lvcreate-lvdisplay-lvremove/
[9]: https://kerneltalks.com/disk-management/extend-file-system-online-lvm/
[10]: https://kerneltalks.com/config/understanding-etcfstab-file/

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[#]: collector: (lujun9972)
[#]: translator: ( )
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: subject: (12 open source tools for natural language processing)
[#]: via: (https://opensource.com/article/19/3/natural-language-processing-tools)
[#]: author: (Dan Barker (Community Moderator) https://opensource.com/users/barkerd427)
12 open source tools for natural language processing
======
Take a look at a dozen options for your next NLP application.
![Chat bubbles][1]
Natural language processing (NLP), the technology that powers all the chatbots, voice assistants, predictive text, and other speech/text applications that permeate our lives, has evolved significantly in the last few years. There are a wide variety of open source NLP tools out there, so I decided to survey the landscape to help you plan your next voice- or text-based application.
For this review, I focused on tools that use languages I'm familiar with, even though I'm not familiar with all the tools. (I didn't find a great selection of tools in the languages I'm not familiar with anyway.) That said, I excluded tools in three languages I am familiar with, for various reasons.
The most obvious language I didn't include might be R, but most of the libraries I found hadn't been updated in over a year. That doesn't always mean they aren't being maintained well, but I think they should be getting updates more often to compete with other tools in the same space. I also chose languages and tools that are most likely to be used in production scenarios (rather than academia and research), and I have mostly used R as a research and discovery tool.
I was also surprised to see that the Scala libraries are fairly stagnant. It has been a couple of years since I last used Scala, when it was pretty popular. Most of the libraries haven't been updated since that time—or they've only had a few updates.
Finally, I excluded C++. This is mostly because it's been many years since I last wrote in C++, and the organizations I've worked in have not used C++ for NLP or any data science work.
### Python tools
#### Natural Language Toolkit (NLTK)
It would be easy to argue that [Natural Language Toolkit (NLTK)][2] is the most full-featured tool of the ones I surveyed. It implements pretty much any component of NLP you would need, like classification, tokenization, stemming, tagging, parsing, and semantic reasoning. And there's often more than one implementation for each, so you can choose the exact algorithm or methodology you'd like to use. It also supports many languages. However, it represents all data in the form of strings, which is fine for simple constructs but makes it hard to use some advanced functionality. The documentation is also quite dense, but there is a lot of it, as well as [a great book][3]. The library is also a bit slow compared to other tools. Overall, this is a great toolkit for experimentation, exploration, and applications that need a particular combination of algorithms.
#### SpaCy
[SpaCy][4] is probably the main competitor to NLTK. It is faster in most cases, but it only has a single implementation for each NLP component. Also, it represents everything as an object rather than a string, which simplifies the interface for building applications. This also helps it integrate with many other frameworks and data science tools, so you can do more once you have a better understanding of your text data. However, SpaCy doesn't support as many languages as NLTK. It does have a simple interface with a simplified set of choices and great documentation, as well as multiple neural models for various components of language processing and analysis. Overall, this is a great tool for new applications that need to be performant in production and don't require a specific algorithm.
#### TextBlob
[TextBlob][5] is kind of an extension of NLTK. You can access many of NLTK's functions in a simplified manner through TextBlob, and TextBlob also includes functionality from the Pattern library. If you're just starting out, this might be a good tool to use while learning, and it can be used in production for applications that don't need to be overly performant. Overall, TextBlob is used all over the place and is great for smaller projects.
#### Textacy
This tool may have the best name of any library I've ever used. Say "[Textacy][6]" a few times while emphasizing the "ex" and drawing out the "cy." Not only is it great to say, but it's also a great tool. It uses SpaCy for its core NLP functionality, but it handles a lot of the work before and after the processing. If you were planning to use SpaCy, you might as well use Textacy so you can easily bring in many types of data without having to write extra helper code.
#### PyTorch-NLP
[PyTorch-NLP][7] has been out for just a little over a year, but it has already gained a tremendous community. It is a great tool for rapid prototyping. It's also updated often with the latest research, and top companies and researchers have released many other tools to do all sorts of amazing processing, like image transformations. Overall, PyTorch is targeted at researchers, but it can also be used for prototypes and initial production workloads with the most advanced algorithms available. The libraries being created on top of it might also be worth looking into.
### Node tools
#### Retext
[Retext][8] is part of the [unified collective][9]. Unified is an interface that allows multiple tools and plugins to integrate and work together effectively. Retext is one of three syntaxes used by the unified tool; the others are Remark for markdown and Rehype for HTML. This is a very interesting idea, and I'm excited to see this community grow. Retext doesn't expose a lot of its underlying techniques, but instead uses plugins to achieve the results you might be aiming for with NLP. It's easy to do things like checking spelling, fixing typography, detecting sentiment, or making sure text is readable with simple plugins. Overall, this is an excellent tool and community if you just need to get something done without having to understand everything in the underlying process.
#### Compromise
[Compromise][10] certainly isn't the most sophisticated tool. If you're looking for the most advanced algorithms or the most complete system, this probably isn't the right tool for you. However, if you want a performant tool that has a wide breadth of features and can function on the client side, you should take a look at Compromise. Overall, its name is accurate in that the creators compromised on functionality and accuracy by focusing on a small package with much more specific functionality that benefits from the user understanding more of the context surrounding the usage.
#### Natural
[Natural][11] includes most functions you might expect in a general NLP library. It is mostly focused on English, but some other languages have been contributed, and the community is open to additional contributions. It supports tokenizing, stemming, classification, phonetics, term frequency–inverse document frequency, WordNet, string similarity, and some inflections. It might be most comparable to NLTK, in that it tries to include everything in one package, but it is easier to use and isn't necessarily focused around research. Overall, this is a pretty full library, but it is still in active development and may require additional knowledge of underlying implementations to be fully effective.
#### Nlp.js
[Nlp.js][12] is built on top of several other NLP libraries, including Franc and Brain.js. It provides a nice interface into many components of NLP, like classification, sentiment analysis, stemming, named entity recognition, and natural language generation. It also supports quite a few languages, which is helpful if you plan to work in something other than English. Overall, this is a great general tool with a simplified interface into several other great tools. This will likely take you a long way in your applications before you need something more powerful or more flexible.
### Java tools
#### OpenNLP
[OpenNLP][13] is hosted by the Apache Foundation, so it's easy to integrate it into other Apache projects, like Apache Flink, Apache NiFi, and Apache Spark. It is a general NLP tool that covers all the common processing components of NLP, and it can be used from the command line or within an application as a library. It also has wide support for multiple languages. Overall, OpenNLP is a powerful tool with a lot of features and ready for production workloads if you're using Java.
#### StanfordNLP
[Stanford CoreNLP][14] is a set of tools that provides statistical NLP, deep learning NLP, and rule-based NLP functionality. Many other programming language bindings have been created so this tool can be used outside of Java. It is a very powerful tool created by an elite research institution, but it may not be the best thing for production workloads. This tool is dual-licensed with a special license for commercial purposes. Overall, this is a great tool for research and experimentation, but it may incur additional costs in a production system. The Python implementation might also interest many readers more than the Java version. Also, one of the best Machine Learning courses is taught by a Stanford professor on Coursera. [Check it out][15] along with other great resources.
#### CogCompNLP
[CogCompNLP][16], developed by the University of Illinois, also has a Python library with similar functionality. It can be used to process text, either locally or on remote systems, which can remove a tremendous burden from your local device. It provides processing functions such as tokenization, part-of-speech tagging, chunking, named-entity tagging, lemmatization, dependency and constituency parsing, and semantic role labeling. Overall, this is a great tool for research, and it has a lot of components that you can explore. I'm not sure it's great for production workloads, but it's worth trying if you plan to use Java.
* * *
What are your favorite open source tools and libraries for NLP? Please share in the comments—especially if there's one I didn't include.
--------------------------------------------------------------------------------
via: https://opensource.com/article/19/3/natural-language-processing-tools
作者：[Dan Barker (Community Moderator)][a]
选题：[lujun9972][b]
译者：[译者ID](https://github.com/译者ID)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://opensource.com/users/barkerd427
[b]: https://github.com/lujun9972
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/talk_chat_communication_team.png?itok=CYfZ_gE7 (Chat bubbles)
[2]: http://www.nltk.org/
[3]: http://www.nltk.org/book_1ed/
[4]: https://spacy.io/
[5]: https://textblob.readthedocs.io/en/dev/
[6]: https://readthedocs.org/projects/textacy/
[7]: https://pytorchnlp.readthedocs.io/en/latest/
[8]: https://www.npmjs.com/package/retext
[9]: https://unified.js.org/
[10]: https://www.npmjs.com/package/compromise
[11]: https://www.npmjs.com/package/natural
[12]: https://www.npmjs.com/package/node-nlp
[13]: https://opennlp.apache.org/
[14]: https://stanfordnlp.github.io/CoreNLP/
[15]: https://opensource.com/article/19/2/learn-data-science-ai
[16]: https://github.com/CogComp/cogcomp-nlp

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[#]: collector: (lujun9972)
[#]: translator: ( )
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: subject: (Easy means easy to debug)
[#]: via: (https://arp242.net/weblog/easy.html)
[#]: author: (Martin Tournoij https://arp242.net/)
What does it mean for a framework, library, or tool to be “easy”? There are many possible definitions one could use, but my definition is usually that it’s easy to debug. I often see people advertise a particular program, framework, library, file format, or something else as easy because “look with how little effort I can do task X, this is so easy!” That’s great, but an incomplete picture.
You only write software once, but will almost always go through several debugging cycles. With debugging cycle I don’t mean “there is a bug in the code you need to fix”, but rather “I need to look at this code to fix the bug”. To debug code, you need to understand it, so “easy to debug” by extension means “easy to understand”.
Abstractions which make something easier to write often come at the cost of make things harder to understand. Sometimes this is a good trade-off, but often it’s not. In general I will happily spend a little but more effort writing something now if that makes things easier to understand and debug later on, as it’s often a net time-saver.
Simplicity isn’t the only thing that makes programs easier to debug, but it is probably the most important. Good documentation helps too, but unfortunately good documentation is uncommon (note that quality is not measured by word count!)
This is not exactly a novel insight; from the 1974 The Elements of Programming Style by Brian W. Kernighan and P. J. Plauger:
> Everyone knows that debugging is twice as hard as writing a program in the first place. So if you’re as clever as you can be when you write it, how will you ever debug it?
A lot of stuff I see seems to be written “as clever as can be” and is consequently hard to debug. I’ll list a few examples of this pattern below. It’s not my intention to argue that any of these things are bad per se, I just want to highlight the trade-offs in “easy to use” vs. “easy to debug”.
* When I tried running [Let’s Encrypt][1] a few years ago it required running a daemon as root(!) to automatically rewrite nginx files. I looked at the source a bit to understand how it worked and it was all pretty complex, so I was “let’s not” and opted to just pay €10 to the CA mafia, as not much can go wrong with putting a file in /etc/nginx/, whereas a lot can go wrong with complex Python daemons running as root.
(I don’t know the current state/options for Let’s Encrypt; at a quick glance there may be better/alternative ACME clients that suck less now.)
* Some people claim that systemd is easier than SysV init.d scripts because it’s easier to write systemd unit files than it is to write shell scripts. In particular, this is the argument Lennart Poettering used in his [systemd myths][2] post (point 5).
I think is completely missing the point. I agree with Poettering that shell scripts are hard – [I wrote an entire post about that][3] – but by making the interface easier doesn’t mean the entire system becomes easier. Look at [this issue][4] I encountered and [the fix][5] for it. Does that look easy to you?
* Many JavaScript frameworks I’ve used can be hard to fully understand. Clever state keeping logic is great and all, until that state won’t work as you expect, and then you better hope there’s a Stack Overflow post or GitHub issue to help you out.
* Docker is great, right up to the point you get:
```
ERROR: for elasticsearch Cannot start service elasticsearch:
oci runtime error: container_linux.go:247: starting container process caused "process_linux.go:258:
applying cgroup configuration for process caused \"failed to write 898 to cgroup.procs: write
/sys/fs/cgroup/cpu,cpuacct/docker/b13312efc203e518e3864fc3f9d00b4561168ebd4d9aad590cc56da610b8dd0e/cgroup.procs:
invalid argument\""
```
or
```
ERROR: for elasticsearch Cannot start service elasticsearch: EOF
```
And … now what?
* Many testing libraries can make things harder to debug. Ruby’s rspec is a good example where I’ve occasionally used the library wrong by accident and had to spend quite a long time figuring out what exactly went wrong (as the errors it gave me were very confusing!)
I wrote a bit more about that in my [Testing isn’t everything][6] post.
* ORM libraries can make database queries a lot easier, at the cost of making things a lot harder to understand once you want to solve a problem.
--------------------------------------------------------------------------------
via: https://arp242.net/weblog/easy.html
作者：[Martin Tournoij][a]
选题：[lujun9972][b]
译者：[译者ID](https://github.com/译者ID)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://arp242.net/
[b]: https://github.com/lujun9972
[1]: https://en.wikipedia.org/wiki/Let%27s_Encrypt
[2]: http://0pointer.de/blog/projects/the-biggest-myths.html
[3]: https://arp242.net/weblog/shell-scripting-trap.html
[4]: https://unix.stackexchange.com/q/185495/33645
[5]: https://cgit.freedesktop.org/systemd/systemd/commit/?id=6e392c9c45643d106673c6643ac8bf4e65da13c1
[6]: /weblog/testing.html
[7]: mailto:martin@arp242.net
[8]: https://github.com/Carpetsmoker/arp242.net/issues/new

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[#]: collector: (lujun9972)
[#]: translator: ( )
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: subject: (How to Install OpenLDAP on Ubuntu Server 18.04)
[#]: via: (https://www.linux.com/blog/2019/3/how-install-openldap-ubuntu-server-1804)
[#]: author: (Jack Wallen https://www.linux.com/users/jlwallen)
How to Install OpenLDAP on Ubuntu Server 18.04
======
![OpenLDAP][1]
In part one of this short tutorial series, Jack Wallen explains how to install OpenLDAP.
[Creative Commons Zero][2]
The Lightweight Directory Access Protocol (LDAP) allows for the querying and modification of an X.500-based directory service. In other words, LDAP is used over a Local Area Network (LAN) to manage and access a distributed directory service. LDAPs primary purpose is to provide a set of records in a hierarchical structure. What can you do with those records? The best use-case is for user validation/authentication against desktops. If both server and client are set up properly, you can have all your Linux desktops authenticating against your LDAP server. This makes for a great single point of entry so that you can better manage (and control) user accounts.
The most popular iteration of LDAP for Linux is [OpenLDAP][3]. OpenLDAP is a free, open-source implementation of the Lightweight Directory Access Protocol, and makes it incredibly easy to get your LDAP server up and running.
In this three-part series, I’ll be walking you through the steps of:
1. Installing OpenLDAP server.
2. Installing the web-based LDAP Account Manager.
3. Configuring Linux desktops, such that they can communicate with your LDAP server.
In the end, all of your Linux desktop machines (that have been configured properly) will be able to authenticate against a centralized location, which means you (as the administrator) have much more control over the management of users on your network.
In this first piece, I’ll be demonstrating the installation and configuration of OpenLDAP on Ubuntu Server 18.04. All you will need to make this work is a running instance of Ubuntu Server 18.04 and a user account with sudo privileges.
Let’s get to work.
### Update/Upgrade
The first thing you’ll want to do is update and upgrade your server. Do note, if the kernel gets updated, the server will need to be rebooted (unless you have Live Patch, or a similar service running). Because of this, run the update/upgrade at a time when the server can be rebooted.
To update and upgrade Ubuntu, log into your server and run the following commands:
```
sudo apt-get update
sudo apt-get upgrade -y
```
When the upgrade completes, reboot the server (if necessary), and get ready to install and configure OpenLDAP.
### Installing OpenLDAP
Since we’ll be using OpenLDAP as our LDAP server software, it can be installed from the standard repository. To install the necessary pieces, log into your Ubuntu Server and issue the following command:
### sudo apt-get instal slapd ldap-utils -y
During the installation, you’ll be first asked to create an administrator password for the LDAP directory. Type and verify that password (Figure 1).
![password][4]
Figure 1: Creating an administrator password for LDAP.
[Used with permission][5]
Configuring LDAP
With the installation of the components complete, it’s time to configure LDAP. Fortunately, there’s a handy tool we can use to make this happen. From the terminal window, issue the command:
```
sudo dpkg-reconfigure slapd
```
In the first window, hit Enter to select No and continue on. In the second window of the configuration tool (Figure 2), you must type the DNS domain name for your server. This will serve as the base DN (the point from where a server will search for users) for your LDAP directory. In my example, I’ve used example.com (you’ll want to change this to fit your needs).
![domain name][6]
Figure 2: Configuring the domain name for LDAP.
[Used with permission][5]
In the next window, type your Organizational name (ie the name of your company or department). You will then be prompted to (once again) create an administrator password (you can use the same one as you did during the installation). Once you’ve taken care of that, you’ll be asked the following questions:
* Database backend to use - select **MDB**.
* Do you want the database to be removed with slapd is purged? - Select **No.**
* Move old database? - Select **Yes.**
OpenLDAP is now ready for data.
### Adding Initial Data
Now that OpenLDAP is installed and running, it’s time to populate the directory with a bit of initial data. In the second piece of this series, we’ll be installing a web-based GUI that makes it much easier to handle this task, but it’s always good to know how to add data the manual way.
One of the best ways to add data to the LDAP directory is via text file, which can then be imported in with the __ldapadd__ command. Create a new file with the command:
```
nano ldap_data.ldif
```
In that file, paste the following contents:
```
dn: ou=People,dc=example,dc=com
objectClass: organizationalUnit
ou: People
dn: ou=Groups,dc=EXAMPLE,dc=COM
objectClass: organizationalUnit
ou: Groups
dn: cn=DEPARTMENT,ou=Groups,dc=EXAMPLE,dc=COM
objectClass: posixGroup
cn: SUBGROUP
gidNumber: 5000
dn: uid=USER,ou=People,dc=EXAMPLE,dc=COM
objectClass: inetOrgPerson
objectClass: posixAccount
objectClass: shadowAccount
uid: USER
sn: LASTNAME
givenName: FIRSTNAME
cn: FULLNAME
displayName: DISPLAYNAME
uidNumber: 10000
gidNumber: 5000
userPassword: PASSWORD
gecos: FULLNAME
loginShell: /bin/bash
homeDirectory: USERDIRECTORY
```
In the above file, every entry in all caps needs to be modified to fit your company needs. Once you’ve modified the above file, save and close it with the [Ctrl]+[x] key combination.
To add the data from the file to the LDAP directory, issue the command:
```
ldapadd -x -D cn=admin,dc=EXAMPLE,dc=COM -W -f ldap_data.ldif
```
Remember to alter the dc entries (EXAMPLE and COM) in the above command to match your domain name. After running the command, you will be prompted for the LDAP admin password. When you successfully authentication to the LDAP server, the data will be added. You can then ensure the data is there, by running a search like so:
```
ldapsearch -x -LLL -b dc=EXAMPLE,dc=COM 'uid=USER' cn gidNumber
```
Where EXAMPLE and COM is your domain name and USER is the user to search for. The command should report the entry you searched for (Figure 3).
![search][7]
Figure 3: Our search was successful.
[Used with permission][5]
Now that you have your first entry into your LDAP directory, you can edit the above file to create even more. Or, you can wait until the next entry into the series (installing LDAP Account Manager) and take care of the process with the web-based GUI. Either way, you’re one step closer to having LDAP authentication on your network.
--------------------------------------------------------------------------------
via: https://www.linux.com/blog/2019/3/how-install-openldap-ubuntu-server-1804
作者：[Jack Wallen][a]
选题：[lujun9972][b]
译者：[译者ID](https://github.com/译者ID)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://www.linux.com/users/jlwallen
[b]: https://github.com/lujun9972
[1]: https://www.linux.com/sites/lcom/files/styles/rendered_file/public/ldap.png?itok=r9viT8n6 (OpenLDAP)
[2]: /LICENSES/CATEGORY/CREATIVE-COMMONS-ZERO
[3]: https://www.openldap.org/
[4]: https://www.linux.com/sites/lcom/files/styles/rendered_file/public/ldap_1.jpg?itok=vbWScztB (password)
[5]: /LICENSES/CATEGORY/USED-PERMISSION
[6]: https://www.linux.com/sites/lcom/files/styles/rendered_file/public/ldap_2.jpg?itok=10CSCm6Z (domain name)
[7]: https://www.linux.com/sites/lcom/files/styles/rendered_file/public/ldap_3.jpg?itok=df2Y65Dv (search)

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[#]: collector: (lujun9972)
[#]: translator: (Amanda0212)
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: subject: (lawyer The MIT License, Line by Line)
[#]: via: (https://writing.kemitchell.com/2016/09/21/MIT-License-Line-by-Line.html)
[#]: author: (Kyle E. Mitchell https://kemitchell.com/)
MIT许可证的“精华”
======
### MIT许可证的“精华”
[MIT许可证][1] 是最流行的开源软件许可证，请阅读下面的内容。
#### 阅读许可证
如果你参与了开源软件的开发，然而你还没有花时间从头开始阅读尽管只有171个单词的许可证，你现在就需要这么做，尤其是如果许可证不是你的日常生活。记住任何看起来不对劲或不清楚的事情，然后继续思考。我将重复上下文和评论的每一个字，按块和顺序。但重要的是你要做到心中有数。
> MIT 许可证
>
> 版权(c)<年份><版权持有人>
>
> 现免费准许任何人取得本软件及相关文件档案（"软件"）的副本，以便不受限制地处理该软件，包括不受限制地使用、复制、修改，合并、公布、分发、转授许可证和/或出售软件副本的权利，并允许向其提供软件的人这样做，但须符合下列条件：
>
> 在软件和软件的所有副本中都必须包含版权声明和许可声明。
>
> 该软件是"原封不动地"提供的，没有任何明示或默示的保证，包括但不限于适销性、适合某一特定目的和不侵权的保证。在任何情况下，作者或版权所有人都不应对因下列原因引起的任何索赔、损害或其他责任负责，与软件或软件中的使用或其他交易有关的。
许可证由五个部分组成，在逻辑组成上像下面这样：
* **页眉**
* **许可证所有权** : “MIT执照”
* **版权公告** : “版权 (c) …”
* **许可证授予** : “特此批准 …”
* **授予范围** : “… 在软件方面的处理 …”
* **条件** : “… 服从于 …”
* **归属和通知** : “以上...应包含...在内”
* **保修免责声明** : “该软件“原封不动地”提供...”
* **赔偿责任限制** : “在任何情况下....”
我们开始了：
#### 写在前面
##### 许可证所有权
> 麻省理工许可证（MIT）
“麻省理工许可证”并不是一个单一的许可证，而是包含来自于麻省理工学院为发布而准备的语言的一系列许可证表格。这些年来，无论是对于使用它的原始项目都经历了许多变化，还是作为其他项目的模型。fedora项目保持了一种[mit许可证陈列室的种类][2]，在简单文本中保留了微小的变化，如甲醛中的解剖标本，追踪着一种没有规律的进化。
幸运的是，[开源计划][3]和[数据交换软件包][4]组已经将通用的MIT式许可证表格标准化为“mit许可证”。而OSI则将SPDX的标准化[字符串识别符][5]用于普通的开源许可证，“MIT”明确指向标准化的表格“MIT许可证”。
即使在“许可证”文件中包含“MIT许可证”或“SPDX：MIT”，负责任的评论者为了确定仍然会对文本和标准表单进行比较。尽管各种自称为“麻省理工许可证”的许可证表格只在细节上有所不同，但所谓的“麻省理工许可证”的宽松已经诱使一些作者添加了令人讨厌的“定制”。典型的可怕的的例子就是[JSON许可证][6]，一个MIT-family许可证加上“软件应该用于正途的，而不是邪恶的...”这种事情可能是“非常克罗克福德”。这绝对是一个痛苦的事情。可能是律师们开的一个玩笑，但他们一路笑到最后。
这个故事的寓意是：“麻省理工许可证”本身是模棱两可的。人们或许对你的意思有清晰的理解，但是你只会通过将标准的MIT许可证表格的文本复制到你的项目中来节省所有人的时间，包括你自己。如果您使用元数据，如包管理器元数据文件中的“许可证”属性来指定“MIT”许可证，请确保您的“许可证”文件和任何头注使用标准窗体文本。而这些都可以[自动化][7]。
##### 版权公告
> 版权(c)<年份><版权持有人>
直到1976年的版权法，美国版权法要求采取具体行动以确保创作作品的版权，称为“手续”。如果你没有遵循这些手续，你起诉他人未经授权使用你的作品的权利是有限的，但这种权利基本丧失。其中一种形式是“通知”：在你的作品上做标记，或者在声明过后让市场知道你拥有版权。 © 是标记有版权作品的标准符号，以发出版权通知。ascii字符集没有 © 符号，但是“版权（c）”得到了这种权利。
1976年“执行”了伯尔尼国际公约的许多要求版权法却取消了保护版权的手续。至少在美国，版权拥有者仍然需要在起诉侵权行为之前登记他们的版权作品，但如果他们在侵权行为开始前登记，也许会造成更高的损害。然而，现实中许多人在提起诉讼之前登记了版权。你不会因为只是没有在版权上张贴通知、注册、向国会图书馆发送副本等行为而失去版权。
即使版权公告不再像过去那样绝对必要，但它们仍然很有用。说明作品创作的年份和版权持有者，使人们对作品的版权何时到期有某种感觉，从而使作品进入公共领域。作者的身份也很有用：美国法律对个人和“公司”两种身份的作者的版权计算方法不同。尤其是在商业上，即使许可条款给予非常慷慨的许可，公司也有必要对使用已知竞争对手的软件三思而后行。如果你希望别人看到你的作品，并希望从你那里获得许可，版权公告就可以很好裁决归属问题。
至于“版权持有人”：并不是所有的标准格式许可证都有地方写出来。近期的许可证表格，如[apache 2.0][8]和[gpl 3.0][9]，发布“许可证”文本，这些文本本应逐字复制，与头注和单独的文件其他地方，以表明谁拥有版权，并正在给予许可证。这些做法有意无意地阻止了对"标准"文本的更改，还使自动许可证认证更加可靠。
MIT许可证是机构为发布代码而编写的语言。对于机构发布，只有一个明确的“版权持有人”，即机构发布代码。其他一些机构用他们自己的名字代替了“MIT”，最终形成了我们现在的通用格式。这个过程重复了这个时代的其他短形式的机构许可证，值得注意的是加州大学伯克利分校的[原四条款BSD许可证][10]，现在用于[三条款][11]和[二条款][12]的变体，以及互联网系统联盟（MIT的一种变体）的（ISC许可证）。
在所有情况下，机构都将自己列为版权所有人，以依赖版权所有权规则，称为"[受雇作品][14]"规则，这就给了雇主和客户一些版权，他们的雇员和承包商代表他们做的工作。这些规则通常不适用于自愿提交代码的分布式合作者。这给项目管理者基金会带来了一个问题，比如apache基金会和日食基金会，这些基金会接受了来自更多样化的捐助者群体的捐助。到目前为止，通常的基础方法是使用一种房屋许可证，该许可证规定只有一个版权持有人——[Apache 2.0][8]和[EPL 1.0][15]——由出资人许可证协议支持——[apache clas][16]并且[clas][17]——从贡献者那里收集权利。在像GPL这样的“版权许可”下，在一个地方收集版权所有权更加重要，因为它依赖于版权所有人强制执行许可条件以促进软件自由值。
如今，只有很少的任何机构或企业管理者的项目在使用MIT式的许可证条款。SPDX和OSI通过规范MIT和ISC等不涉及特定实体或机构版权持有人的许可证形式，帮助了这些案例的使用。有了这些表格，项目作者的普遍做法是在很早表格的版权通知时就填写他们自己的名字，也许会在这里或那里增加一年的时间。至少根据美国版权法，由此产生的版权通知并没有给出一个完整的情况。
软件的原拥有者保留对其作品的所有权。但是，尽管MIT式的许可条款赋予了其他人在软件上进行开发和更改的权利，创造了法律所称的“衍生作品”，但它们并没有赋予原始作者在他人贡献中的版权所有权。相反，每个贡献者都拥有以现有代码为起点的作品的版权。
这些项目中的大多数也对接受贡献者许可协议的想法有所保留，更不用说签署版权转让了。这其实很好理解。尽管假定一些较新的开源开发者对github“自动”发送退出请求，根据项目的现有许可条款授权分配贡献，但美国法律不承认这样的规则。默认的是强有力的版权保护，而不是许可许可。
更新：GitHub后来改变了它在整个网站的服务条款，包括试图翻转这个默认，至少在GitHub.com。我已经写了一些关于这个发展的想法，不是所有的都是积极的，在[另一个帖子][19]。
为填补具有法律效力的且有充分文件证明的捐款权利授予与完全没有书面记录之间的空白，一些项目采用了[开发商原产地证书][20]，一个标准的语句贡献者暗示在他们的Git提交中使用“签名关闭”元数据标签。在臭名昭著的SCO诉讼事件之后，Linux内核开发人员为Linux内核开发了原产地证书，该诉讼指控Linux的代码块来自于SCO拥有的UNIX源代码。作为一种创建文件线索的手段，显示每一行Linux代码的贡献者，开发人员原产地证书的功能很好。虽然开发人员的原产地证书不是许可证，但它确实提供了大量的证据，证明提交代码的人希望项目分发他们的代码，并让其他人在内核的现有许可条款下使用。内核还维护一个机器可读的“信用”文件，列出具有名称、关联、贡献区域和其他元数据的贡献者。我已经做了[一些][实验][22]将这种方法应用于不使用内核开发流程的项目。
#### 许可授权
> 现免费准许任何人取得本软件及相关文件档案（"软件"）的副本.
按照猜测，麻省理工执照的重点是执照。一般而言，许可是一个人或一个法律规定的实体----"许可人"----允许另一人----"被许可人"----做法律本来允许他们起诉的事情。MIT执照承诺不起诉。
法律有时会将许可证与承诺颁发许可证区分开来。如果有人违背了给他发许可证的承诺，你也许可以控告他违反了承诺，但你可能没有得到许可证。"在此"是律师们无法摆脱的时髦的古语之一。它在这里用来显示许可证文本本身给出了许可证，而不仅仅是一个许可证的承诺。这是合法的[IIFE][23]。
虽然许多许可证给予许可的具体命名的许可证，麻省理工学院许可证则是一个“公共许可证”。公共许可证给予广大公众许可。这是开放源码许可的三大理念之一。MIT许可证通过向“获得该软件副本的任何人”颁发许可证来捕捉这一想法。正如我们将在后面看到的，若获得这个许可证也有一个条件，以确保其他人也会知道他们的许可。
在美国式的法律文件中，用大写的引号（一个“定义”）来表示术语的标准方法。当法院在文件的其他地方看到一个定义明确、资本化的术语时，大写的引号将会很可靠地回顾定义的术语。
##### 授予范围
> 不受限制的软件处理
麻省理工许可证中最重要的七个词就是从被许可人的观点来看。其关键的法律问题是被起诉侵犯版权和被起诉侵犯专利。版权法和专利法都没有使用“处理”作为术语，它在法庭上没有具体的含义。因此，对许可人与被许可人之间的争议作出裁决的任何法院都会询问该措词所指的当事人的含义和理解。法院将会看到的是，该描述是不详细的和开放式的。这给了被许可人一个强有力的论据——在许可人没有允许被许可人对软件做特定的事情时反对许可人的任何主张，即使在许可的时候，这一想法都没有出现。
> 包括在不受限制的情况下使用、复制、修改、合并、公布、分发、转授许可证和/或出售软件副本的权利，以及允许软件给予者这样做的权利。
没有哪篇法律文章是完美的，“在根本上完全解决”，或者明确无误的。要小心那些装模作样的人。这是麻省理工执照中最不完美的部分。有三个主要问题：
首先，"包括不受限制"是一种法律上的反模式。它产生了各种理解：
* “包括，不受限制”
* “包括，在不限制上述一般性的情况下”
* “包括，但不局限于”
* 很多很多毫无意义的措辞变化
所有这些都有共同的目标，但都没能真正地实现。从根本上说，它们的创始人也在尝试从中得到好处。在MIT许可证中，这意味着引入“软件交易”，其具体示例是“使用、复制、修改”等等，而不是暗示被许可人的行为必须类似于给出的“交易”的示例。问题是，如果你最终需要一个法庭来审查和解释许可证的条款，法庭则看作找出那些争论的语言的含义。法院不能“忽略”示例决定什么是“交易”，，即使你告诉它。也是较短的。
第二，作为“处理”的例子给出的动词是一个大杂烩。有些在版权法或专利法下有特定的含义，有些却没有：
*使用出现在[美国法典第35章，第271(a)条][24]，专利法的清单中，列出了专利所有人可以因未经许可而起诉他人的行为。
*复制出现在《版权法》（美国法典第17编第106条）[25]中，列出了版权所有人可以因未经许可而起诉他人的行为
*修改不出现在版权或专利法规中。它可能最接近版权法规下的“准备衍生作品”，但也可能涉及改进或其他衍生发明。
*合并没有出现在版权或专利法规中。“合并”在版权上有特定的含义，但这显然不是这里的本意。相反，法院可能根据其在业界的含义来理解“合并”，如“合并代码”。
*出版不出现在版权或专利法规中。由于“软件”是发布的内容，它可能最接近于[版权法规][25]下的“发布”。法律也涵盖了“公开”表演和展示作品的权利，但这些权利只适用于特定类型的有版权的作品，如戏剧、录音和电影。
*散布出现在[版权法规][25]中。
*次级许可是知识产权法的总称。转牌权是指利用给予他人自己的执照做一些有权利做的事情的权利。MIT许可证的转行权在开源许可证中是不常见的。每个人只要拿到软件及其许可条款的副本，就可以直接从所有者那里得到许可，这就是Heather Meeker所说的“直接授权”方法。任何可能通过麻省理工许可证获得次级许可证的人，很可能最终会得到一份许可证副本，告诉他们自己也有直接许可证。
*出售的副本是一个混合物。它接近[专利法规][24]中的"要约销售"和"销售"，却指的是版权概念中的"副本"。在版权方面，它似乎接近“发行”，但[版权法规][25]没有提到出售。
*允许向软件提供者这样做，"次级许可"似乎是多余的并且也是不必要的，因为人们得到的副本也获得了直接许可证。
最后，由于法律、工业、一般知识产权和一般用途条款的混淆，目前还不清楚麻省理工学院的许可证是否包括专利许可证。一般的语言“处理”和一些例子动词，特别是“使用”，指向专利许可，尽管是一个非常不清楚的。许可证来自版权持有人，他对软件中的发明可能有也可能没有专利权，以及大多数示例动词和"软件"本身的定义，所有这些都强烈指向版权许可证.更近期的许可开放源码许可证，如[apache 2.0][8]，涉及单独和具体的版权、专利甚至商标。
##### 许可证的三个条件
> 须符合以下条件：
总有人能符合MIT的三个条件！
如果你不遵守麻省理工的许可条件，你就得不到许可。因此，如果不按条件所说的做，至少在理论上，你会面临一场诉讼，很可能是一场版权诉讼。
利用软件的价值来激励被许可人遵守条件，即使被许可人没有为许可支付任何费用，是开源许可的第二个伟大想法。最后一个，在MIT许可证中没有，建立在许可证条件的基础上：“版权”许可证，像[GNU通用公共许可证][9]使用利益来控制那些进行更改的人去许可和分发他们的更改版本。
##### 公告条件
> 上述版权通知和许可通知应包含在软件的副本的绝大部分内容中。
如果你给某人软件的副本，你需要包括许可证文本和任何版权通知。这有几个关键目的：
1.通知他人他们有许可使用该软件的公共许可证。这是直接授权模式的一个关键部分，即每个用户直接从版权持有人那里获得许可证。
2.让他们知道谁是软件的参与者，使得他们能够接受检验。
3.确保免责声明和赔偿责任限制（下一步）伴随软件。每个得到副本的人也应该得到一份这些许可人保护的副本。
没有源代码的情况下，没有什么可以阻止您付费获得副本，甚至是编译形式的副本。但是当你这样做的时候，你不能假装MIT的代码是你自己的专有代码，或者是在其他许可证下提供的代码。领取者得了解他们在"公共许可证"下的权利。
坦率地说，这一条件很难去遵守。几乎每个开源许可证都有这样的“归属”条件。系统和已安装软件的制造商通常都明白，他们需要为自己的每个版本编写一个通知文件或“许可证信息”，并为库和组件提供许可证文本的副本。项目管理基金会在传授这些做法方面发挥了重要作用。但总体而言，网络开发者并没有得到这份备忘录。这不能用缺少工具来解释——有大量的工具——或者是来自npm和其他存储库的软件包的高度模块化性质——它们统一地将许可证信息的元数据格式标准化。所有好的JavaScript迷你机都有用于保存许可证标题注释的命令行标记。其他工具将从包装箱树连接“许可证”文件。实在没有理由去遗忘这一条件。
##### 保护免责声明
> 该软件是"原封不动地"提供的，没有任何明示或默示的保证，包括但不限于适销性、适合某一特定目的和不侵权的保证。
美国几乎每个州都颁布了统一商业法典，这是一个规范商业交易的法律范本。加州大学洛杉矶分校（UCC）的第2条则规定了货物销售合同，从旧汽车的购进到工业化学品的大规模运输，再到制造工厂。
加州大学洛杉矶分销关于销售合同的某些规则是强制性的。不管那些买卖他们喜欢与否这些规则总是适用的。而其他的只是“默认”。除非买卖双方以书面形式选择不参与，否则UCC暗示他们希望在UCC的文本中找到他们交易的基准规则。在默认规则中，隐含着“保证”，或卖方向买方承诺所售货物的质量和可用性。
对于像MIT许可证这样的公共许可证到底是合同（许可人和被许可人之间可执行的协议）还是仅仅只是许可证（只有一种方式，但可能附带条件），存在着很大的争论。而关于软件是否算作“商品”的争论则较少，这触发了UCC的规则。许可证持有者之间没有关于赔偿责任的争论：他们不想因为大量的钱财而被起诉，如果他们赠送的软件是免费、则会引起一些麻烦。这与“默认保证”的三个默认规则正好相反：
1.[UCC第2-314][26]条对"适销性"的默认保证是"货物"或者软件应至少具有平均质量，包装和适当的标签，适合他们的用途。这个保证只适用于提供软件的人是软件的“商人”，这意味着他们从事软件交易，并坚持自己在软件方面很熟练。
2.[UCC第2-315][27]条中关于"适合某一特定目的"的默认保证，在卖方知道买方因为某一用途而购买软件时，默认保护是有用的。因此，货物必须"合适"。
3.“不侵权”的默认保证不是合同约定的一部分，而是一般合同法的共同特征。如果买方收到的货物侵犯了他人的知识产权，该默认承诺保护买方。如果MIT许可下的软件实际上不属于试图授权它的软件，或者它属于其他人拥有的专利，就不会去保护买方。
UCC[章节 2-316(3)][28]条要求选择或"排除"关于适销性和适合某一特定目的的隐含保证的语言非常一目了然。而“显眼”则意味着书写或格式化的目的是为了引起人们对其本身的注意，这与微观的细微印刷相反，其目的是为了避开不谨慎的消费者。州法律可能对不侵权的免责声明规定类似的吸引注意力的要求。
长期以来，律师们一直被一种错觉所困扰，认为用“全盖”写任何东西都符合明显的要求，然而这确实假的。法院已经批判了这一标准，因为它太假了，而且大多数人都同意全上限的做法更多的是为了阻止阅读，而不是强迫阅读。尽管如此，大多数开源许可证的格式都将其保证免责声明设置为全上限，部分原因是这是唯一明显的方法，可以使其在纯文本“许可证”文件中脱颖而出。我宁愿用星号或其他的ASCII艺术，但那已经很久了。
##### 限制
> 在任何情况下，作者或版权持有人均不对因下列原因而引起的任何索赔、损害或其他责任承担任何责任或是与软件或者软件中的使用或其他交易有关的责任。
MIT许可证允许“免费”使用软件，但法律并不认为获得免费许可证的人会在事情出了差错时放弃起诉的权利，而应归咎于许可人。“赔偿责任限制”，通常与“损害赔偿排除”结合在一起，就像保证不起诉一样，很像许可证。但这些是对许可人免受被许可人诉讼的保护。
一般来说，法院谨慎地解读赔偿责任和损害赔偿排除的限制，因为它们可以将巨大的风险从一方转移到另一方。为了保护社区的重大利益，他们“严格解释”限制责任的语言让人们能够纠正在法庭上犯下的错误，在可能的情况下对照受其保护的语言来解读。限制赔偿责任必须是明确的，才能成立。尤其是在“消费者”合同和其他情况下，那些放弃起诉权的人缺乏技巧或议价能力，法院有时拒绝尊重那些言外之意。律师们由于这个原因可能也由于纯粹的习惯而倾向于限制给予赔偿责任。
只要稍微钻低一点，“赔偿责任限额”就是被许可人可以起诉的金额的上限。在开源许可证中，这个限制总是没有钱的——0美元，“不负责任”。相比之下，在商业许可证中，尽管它通常是经过协商的而决定出为过去12个月期间支付的许可证费用的倍数。
"排除"部分具体列出了各类法律索赔以及许可人不能使用造成损害赔偿的理由。和许多法律形式一样，MIT执照提到了“合同”行为中的违约行为和“侵权行为”。侵权行为规则是防止不小心或恶意伤害他人的一般规则。如果你发短信的时候在路上撞上了某人，你就犯下了侵权行为。如果你的公司出售的耳机有问题，让人耳朵发麻，那么你的公司就犯下了侵权行为。如果合同没有明确排除侵权索赔，法院有时会在合同中阅读排除语，以防止只发生合同索赔。为了更好地衡量这种排除部分，麻省理工的执照上写着“或者其他”，仅仅是不同寻常的法律主张。
"产生于、或与之有关"这句话是法律起草人固有的、焦虑的不安全感的反复出现的症状。重点是任何与软件有关的诉讼都在限制和排除范围之内。在偶然的机会，一些东西可以"产生"，但不是"产生"，或"联系"，不必介意它在形式上的三种的说法。出现在不同地方的同一个词语或许都是不同意思，假设一个专业起草人不会使用不同的词语在一排的意思相同的事情则不必介意，在实践中，如果法院对一开始就不满意想这个限制，那么他们就会非常愿意仔细地解读范围触发因素。但我离题了。同样的语言出现在数百万份合同中或许理解都不一样。
#### 总结
这些俏皮话虽然有点像碎碎念，但MIT许可证却是法律上的经典。MIT许可证是有用的。虽然MIT式的许可证非常出色但它绝不是解决所有软件ip弊病的灵丹妙药，尤其是早于它几十年出现的软件专利的祸害。实现了用最低限度的谨慎的法律工具组合来扭转麻烦的版权、销售和合同法的默认规则这个狭隘的目标。在更大的计算环境中，它的生命周期是惊人的。MIT许可证的有效期已经超过了它所授权的绝大多数软件。我们只能猜测，当它最终对那些自己请不起律师的人失去好感时，它将提供多少几十年忠实的法律服务。
我们已经看到了我们今天所知的MIT许可证是一套具体的、标准化的术语，最终给机构特有的、随意变化的混乱带来了秩序。
我们已经看到了它是如何为学术、标准、商业和基金会机构的知识产权管理实践提供归属和版权通知的依据。
我们已经看到了MIT许可证是如何向所有人免费授予软件许可的，但我们必须遵守保护许可人免受担保和赔偿责任的条件。
我们已经看到，尽管有一些不是很精准的词和修饰，但这一百七十一个词已经足够严谨，能够通过一个密集的知识产权和合同为开源软件开辟新的道路。
我非常感谢所有愿意花时间来阅读这篇长文的人，让我知道他们认为它有用，并帮助改进它。和往常一样，我欢迎您通过[电子邮件][29], [推特][30], 和 [GitHub][31].发表评论。
若是想阅读更多的内容或者找到其他许可证的概要，比如GNU公共许可证或者Apache 2.0许可证。无论你有什么关于这方面的兴趣，我都衷心推荐以下的书：
* Andrew M. St. Laurent’s [Understanding Open Source & Free Software Licensing][32], from O’Reilly.
我是这本书开始入门的，虽然它有点过时，但它的方法也最接近上面使用的逐行方法。O’Reilly 已经在网上提供了它。
* Heather Meeker’s [Open (Source) for Business][34]
在我看来，目前为止，关于GNU公共许可证和版权写的比较好的已经有很多了。这本书涵盖了许可证的历史、发展、以及兼容性和合规性。这是我借给客户的书，考虑或处理GPL。
* Larry Rosen’s [Open Source Licensing][35], from Prentice Hall.
这是很棒的一本书，也[在线][36]免费的。这是对程序员关于从零开始的开源许可和相关法律的最好的介绍。虽然这一点也有点过时了，但是在一些具体的细节中拉里对许可证的分类法和对开源商业模式的简洁总结是经得起时间考验的。
所有的这些教育都对作为开源授权律师的我至关重要。他们的作者是我这行的英雄。强烈推荐阅读！-- K.E.M
我在[创意共享许可4.0版本][37]授权这篇文章.
--------------------------------------------------------------------------------
via: https://writing.kemitchell.com/2016/09/21/MIT-License-Line-by-Line.html
作者：[Kyle E. Mitchell][a]
选题：[lujun9972][b]
译者：[Amanda0212](https://github.com/Amanda0212)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://kemitchell.com/
[b]: https://github.com/lujun9972
[1]: http://spdx.org/licenses/MIT
[2]: https://fedoraproject.org/wiki/Licensing:MIT?rd=Licensing/MIT
[3]: https://opensource.org
[4]: https://spdx.org
[5]: http://spdx.org/licenses/
[6]: https://spdx.org/licenses/JSON
[7]: https://www.npmjs.com/package/licensor
[8]: https://www.apache.org/licenses/LICENSE-2.0
[9]: https://www.gnu.org/licenses/gpl-3.0.en.html
[10]: http://spdx.org/licenses/BSD-4-Clause
[11]: https://spdx.org/licenses/BSD-3-Clause
[12]: https://spdx.org/licenses/BSD-2-Clause
[13]: http://www.isc.org/downloads/software-support-policy/isc-license/
[14]: http://worksmadeforhire.com/
[15]: https://www.eclipse.org/legal/epl-v10.html
[16]: https://www.apache.org/licenses/#clas
[17]: https://wiki.eclipse.org/ECA
[18]: https://en.wikipedia.org/wiki/Feist_Publications,_Inc.,_v._Rural_Telephone_Service_Co.
[19]: https://writing.kemitchell.com/2017/02/16/Against-Legislating-the-Nonobvious.html
[20]: http://developercertificate.org/
[21]: https://github.com/berneout/berneout-pledge
[22]: https://github.com/berneout/authors-certificate
[23]: https://en.wikipedia.org/wiki/Immediately-invoked_function_expression
[24]: https://www.govinfo.gov/app/details/USCODE-2017-title35/USCODE-2017-title35-partIII-chap28-sec271
[25]: https://www.govinfo.gov/app/details/USCODE-2017-title17/USCODE-2017-title17-chap1-sec106
[26]: https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?sectionNum=2314.&lawCode=COM
[27]: https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?sectionNum=2315.&lawCode=COM
[28]: https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?sectionNum=2316.&lawCode=COM
[29]: mailto:kyle@kemitchell.com
[30]: https://twitter.com/kemitchell
[31]: https://github.com/kemitchell/writing/tree/master/_posts/2016-09-21-MIT-License-Line-by-Line.md
[32]: https://lccn.loc.gov/2006281092
[33]: http://www.oreilly.com/openbook/osfreesoft/book/
[34]: https://www.amazon.com/dp/1511617772
[35]: https://lccn.loc.gov/2004050558
[36]: http://www.rosenlaw.com/oslbook.htm
[37]: https://creativecommons.org/licenses/by-sa/4.0/legalcode

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Chaosnet 简史
===
如果你输入 `dig` 命令对 `google.com` 进行 DNS 查询，你会得到如下答复：
```
$ dig google.com
; <<>> DiG 9.10.6 <<>> google.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 27120
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;google.com. IN A
;; ANSWER SECTION:
google.com. 194 IN A 216.58.192.206
;; Query time: 23 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Fri Sep 21 16:14:48 CDT 2018
;; MSG SIZE rcvd: 55
```
这个输出一部分描述了你的问题（“ `google.com` 的 IP 地址是什么？），另一部分则详细解析了你收到的回答。在<ruby>答案区段<rb>ANSWER SECTION</rb></ruby>里，`dig` 为我们创造了一个包含五个字段的记录。从左数第四个字段 `A` 定义了这个记录的类型 —— 这是一个地址记录。在 `A` 的右边，第五个字段告知我们 `google.com` 的 `IP` 地址是 `216.58.192.206`。第二个字段，`194` 则代表这个记录的缓存时间是 194 秒。
那么， `IN` 字段告诉了我们什么呢？令人尴尬的是，在很长的一段时间里，我都认为这是一个介词。那时候我认为 DNS 记录大概是表达了“在 `A` 记录里，`google.com` 的 `IP` 地址是 `216.58.192.206`。”后来我才知道 `IN` 是“internet”的简写。`IN` 这一个部分告诉了我们这个记录分属的类别。
那么，除了“internet”之外，DNS 记录还会有什么别的类别吗？这究竟意味着什么？你怎么去搜寻一个不位于 internet 上的地址？看起来 `IN` 是唯一一个可能填写进这个字段的答案。而且的确，如果你尝试去获得除了 `IN` 之外的，关于 `google.com` 的记录的话，DNS 服务器通常不能给出恰当的回应。但凡事总有意外，以下就是我们尝试向 `8.8.8.8`（谷歌公共 DNS 服务器）询问在 `HS` 类别里 `google.com` 的 IP 地址。我们得到了状态为 `SERVFAIL` 的回复。
```
$ dig -c HS google.com
; <<>> DiG 9.10.6 <<>> -c HS google.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 31517
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;google.com. HS A
;; Query time: 34 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Tue Sep 25 14:48:10 CDT 2018
;; MSG SIZE rcvd: 39
```
所以说，除了 `IN` 以外的类别不能被服务器广泛支持，但它们的确是存在的。除了 `IN` 之外，DNS 记录还有 `HS`（我们刚刚看到的）和 `CH` 这两个类别。`HS` 类是为一个叫做 [Hesiod][1] 的系统预留的，它可以利用 DNS 来存储并让用户访问一些文本资料。它通常在本地环境中作为 [LDAP][2] 的替代品使用。而 `CH` 这个类别，则是为 Chaosnet 技术预留的。
如今，大家都在使用 TCP/IP 协议族。这两种协议（还有 UDP）是绝大部分电脑远程连接采用的协议。不过我觉得，从互联网的垃圾堆里翻出了一个布满灰尘，绝迹已久，被人们遗忘的系统，也是一件令人愉悦的事情。那么，Chaosnet 是什么？为什么它像恐龙一样，走上了毁灭的道路呢？
### 在 MIT 的机房里
Chaosnet 是在 1970 年代，由 MIT 人工智能实验室的研究员们研发的。它是一个宏伟目标的一部分 —— 设计并制造一个能比其他电脑更高效率运行 Lisp 代码的机器。
Lisp 是 MIT 教授 John McCarthy 的造物，他亦是人工智能领域的先驱者。在 1960 年发布的[一篇论文][3]中，他首次描述了 Lisp 这个语言。在 1962 年，Lisp 的编译器和解释器诞生了。Lisp 拥有非常多的新特性。这些特性在现在看来是每一门编程语言不可或缺的一部分。它是第一门拥有垃圾回收器，REPL 和支持的动态类型的语言。在人工智能领域工作的程序员们都十分喜爱这门语言，比如说 —— 大名鼎鼎的 [SHRDLU][4] 就是用它写的。这个程序允许人们使用自然语言，向机器下达挪动玩具方块这样的命令。
Lisp 的缺点是它太慢了。跟其他语言相比，Lisp 需要使用两倍的时间来执行相同的操作。因为 Lisp 在运行中仍会检查变量类型，这一操作通常都是在编译过程中完成的。在 IBM 7090 上，它的垃圾回收器也需要长达一秒钟的时间来执行。这个问题急需解决，因为 AI 研究者们试图搭建类似 SHRDLU 的应用。他们需要程序与使用者进行实时互动。因此，在 1970 年代的晚期，MIT 人工智能研究所的研究员们决定去建造一个能更高效运行 Lisp 的机器来解决这个问题。这些“Lisp 机器”们拥有更大的存储和更小的指令集，更加适合 Lisp。类型检查由专门的回路完成，因此在 Lisp 运行速度的提升上达成了质的飞跃。跟那时流行的计算机系统不同，这些机器并不支持分时，整台电脑的资源都用来运行一个单独的 Lisp 程序。每一个用户都会得到单独的 CPU。Lisp 机器研发小组在一个备忘录里提到，这些功能是如何让 Lisp 运行变得更简单的：
>Lisp 机器是个人电脑。它支持个人编程，这意味着处理器和内存并不是分时多工的，每个人都能得到单属于自己的处理器和内存。这个私人运算系统由许多处理器组成，每个处理器都有它们自己的内存和虚拟内存。当一个用户登陆时，他就会被分配一个处理器，在他的登陆期间这个处理器是独属于他的。当他登出，这个处理器就会重新可用，等待被分配给下一个用户。通过采取这种方法，当前用户就不用和其他用户竞争内存的使用，他经常使用的信息也能保存在核心里，因此把信息调出所需要的时间也大大缩短了。这个 Lisp 机器解决了分时 Lisp 机器里产生的问题。
这个 Lisp 机器跟我们认知的现代个人电脑由很大的不同。开发小组希望今后用户不用直接面对 Lisp 机器，而是面对终端。那些终端会与位于别处的 Lisp 机器进行连接。虽然每个用户都有自己专属的处理器，但那些处理器在工作时会发出很大的噪音，因此它们最好是位于机房，而不是放在本应安静的办公室里。这些处理器会共享一个文件系统，然后通过一个“完全分布式控制”的高速本地网络访问设备，例如打印机。这个网络的名字就是 Chaosnet。
Chaosnet 既是硬件标准也是软件的协议。它的硬件标准与以太网类似，事实上软件协议也是运行在以太网之上的。这个软件协议在网络层和传输层之间交互，它并不像 TCP/IP，一直控制着本地网络。Lisp 机器开发小组的一个成员， David Moon 写的备忘录中提到，Chaosnet “目前并不打算为低速链接，噪链，多路径，长距离链接做特别的优化。”他们专注于打造一个在小型网络里表现极佳的协议。
因为 Chaosnet 连接在 Lisp 处理器和文件系统之间，所以速度十分重要。网络延迟会严重拖慢一些像打开文本文档这种简单操作的速度，为了提高速度，Chaosnet 结合了在<ruby><rb>Network Control Program</rb>网络控制程序</ruby>中使用的一些改进方法，随后的 Arpanet 项目中也使用了这些方法。根据 Moon 说过的“为了突破速率瓶颈，很有必要采纳新的设计。目前来看，瓶颈在于由多个链接分享控制链接，而且在下一个信息发送之前，我们需要知道本次信息已经送达。”Chaosnet 协议簇的 ACK 包跟当今 TCP 的差不多，它减少了 1/3 到一半的需要传输的包的数量。
因为绝大多数 Lisp 机器使用较短的单线进行连接，所以 Chaosnet 可以使用较为简单的路径算法。Moon 在 Chaosnet 路径的发展规划中写道“预计要适配的网络架构十分简单，并没有包含多少路径，而且每个节点之间的距离很短。所以我认为没有必要进行复杂的方案设计。”因为 Chaosnet 采用的算法十分简单，所以部署它也很容易。与之对比明显，Arpanet 网络控制项目的内容一半与部署有关。
Chaosnet 的另一个特性是，它的地址只有 16 bit，是 IPv4 地址的一半。所以这也意味着 Chaosnet 只能在局域网里工作。Chaosnet 也不会去使用端口号；当一个进程试图连接另一个机器上的其他进程时，需要首先初始化连接，获取一个特定的“连接名称”。这个连接名称一般是某个特定服务的名字。比方说，一个主机试图使用 `TELNET` 作为连接名称，连接另一个主机。我认为它的工作方式在实践中类似于 TCP，因为有些非常著名的服务也会拥有连接名称，比如运行在 80 端口上的 `HTTP` 服务。
在 1986 年，[RFC 973][5] 通过了将 Chaosnet DNS 类别加入域名解析系统的决议。它替代了一个早先出现的类别`CSNET` 。`CSNET` 是为了支持一个名叫计算机科学网络而被制造出来的协议。我并不知道为什么 Chaosnet 能被域名解析系统另眼相待。很多别的协议也有资格加入 DNS，但是却被忽略了。比如说 Xerox’s 网络协议，在域名解析系统的创办人之一 Paul Mockapetris 提到，在他原本的构想里这个协议应该被包括在 DNS 里。但是它并没有被加入。Chaosnet 被加入的原因大概是因为 Arpanet 项目的早期工作，有很多都在剑桥的 Bolt， Beranek 和 Newman 学院。因此研究人员和 MIT 大多有紧密的联系。在这一小撮致力于发展计算机网络人中，Chaosnet 这个协议应该较为有名。
Chaosnet 随着 Lisp 机器的衰落渐渐变得不那么流行。尽管在一小段时间内 Lisp 机器有商业应用 —— Symbolics 和 Lisp Machines Inc 在 80 年代售卖了这些机器。但它们很快被更便宜的微型计算机替代。这些计算机没有特殊制造的回路，但也可以快速运行 Lisp。Chaosnet 被制造出来的目的之一是解决一些 Apernet 协议的原始设计缺陷，但现在 TCP/IP 协议族同样能够解决这些问题了。
### 壳中幽灵
非常不幸的是，在互联网中留存的关于 Chaosnet 的资料不多。RFC 675 —— TCP/IP 的初稿于 1974 年发布，而Chasnet 于 1975 年开始开发。但 TCP/IP 最终征服了整个互联网世界，Chaosnet 则被宣布技术性死亡。尽管 Chaosnet 有可能影响了接下来 TCP/IP 的发展，可我并没有找到能够支持这个猜测的证据。
唯一一个可见的 Chaosnet 残留就是 DNS 的 `CH` 类。这个事实让我着迷。`CH` 类别是那被遗忘的幽魂 —— 在 TCP/IP 广泛部署存在的，Chaosnet 协议的最后栖身之地。至少对于我来说，这件事情是十分让人激动。它告诉我关于 Chaosnet 的最后一丝痕迹，仍然藏在我们日常使用的网络基础架构之中。DNS 的 `CH` 类别是有趣的数码考古学遗迹。但它同时也是活生生的标识，提醒着我们互联网尚未完全诞生，TCP/IP 不是唯一一个能够让计算机们交流的协议。“万维网”也远远不是我们这全球交流系统所能有的，最酷的名字。
如果你喜欢这篇文章，欢迎订阅 [RSS feed][7] 来查看最新更新。
过往文章
> RSS 是如何诞生的？ 它当时为何盛极一时，但现在鲜为人知？
>
> — TwoBitHistory (@TwoBitHistory) [September 17, 2018][8]
--------------------------------------------------------------------------------
via: https://twobithistory.org/2018/09/30/chaosnet.html
作者：[Two-Bit History][a]
选题：[lujun9972][b]
译者：[acyanbird](https://github.com/acyanbird)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://twobithistory.org
[b]: https://github.com/lujun9972
[1]: https://en.wikipedia.org/wiki/Hesiod_(name_service)
[2]: https://en.wikipedia.org/wiki/Lightweight_Directory_Access_Protocol
[3]: http://www-formal.stanford.edu/jmc/recursive.pdf
[4]: https://en.wikipedia.org/wiki/SHRDLU
[5]: https://tools.ietf.org/html/rfc973
[6]: https://twitter.com/TwoBitHistory
[7]: https://twobithistory.org/feed.xml
[8]: https://twitter.com/TwoBitHistory/status/1041485204802756608?ref_src=twsrc%5Etfw

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[#]:collector:(lujun9972)
[#]:translator:(lujun9972)
[#]:reviewer:()
[#]:publisher:()
[#]:url:()
[#]:subject:(IRCvsIRL:HowtorunagoodIRCmeeting)
[#]:via:(https://opensource。com/article/19/2/irc-vs-irl-meetings)
[#]:author:(Ben Cotton https://opensource。com/users/bcotton)
IRC vs IRL: 如何召开一个良好的 IRC 会议
======
若你遵守这些最佳实践，InternetRelayChat 会议可以很好滴推进项目进展。
！[](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/BUSINESS_community_1.png?itok=rT7EdN2m)
开展任何形式的会议都是门艺术。很多人已经学会了开展面对面会议和电话会议，但是 [InternetRelayChat][1](IRC) 会议因其特殊的性质有别于"现实 (inreallife)"(IRL) 会议。本文将会分享 IRC 这种会议形式的优势和劣势以及帮你更有效地领导 IRC 会议的小技巧。
为什么是 IRC? 虽说现在有大量的实时聊天工具可供选择，[IRC 依然是开源项目的基石 ][2]。若你的项目使用其他沟通工具，也不要紧。这里大多数的建议都适用于同步的文本聊天机制，只需要进行一些微调。
### IRC 会议的挑战
与面对面会议相比，IRC 会议会遇到一些挑战。你应该直到一个人结束谈话到下一个人开始谈话之间的间隙吧？在 IRC 中这更糟糕，因为人们需要输入他们的所想。这比说话要更慢，—而且不像谈话一样—你不知道别人什么时候在组织消息。主持人在要求回复或转到下一主题前必须等待很长一段时间。而想要发言的人需要先插入一个简短的信息(例如，一个句号)来让主持人知道(他需要发言)。
IRC 会议还缺少其他方法中能够获得的那些元数据。你无法通过文本了解面部表情和语调。这意味着你必须小心你的措辞。
而且 IRC 会议很容易让人分心。至少在面对面会议中，当某人正在看搞笑的猫咪图片时，你可以看到他面带笑容而且在不合时宜的时候发出笑声。在 IRC 中，除非他们不小心粘贴了错误的短信，否者甚至都没有同伴的压力来让他们假装专注。你甚至可以同时参加多个 IRC 会议。我就这么做过，但如果你需要积极参与这些会议，那就很危险了。
### IRC 会议的优势
IRC 会议也有某些独一无二的优势。IRC 是一个非常轻资源的媒介。它并不怎么消耗带宽和 CPU。这降低了参与的门槛，这对贫困这和正在路上的人都是有利的。对于志愿者来说，这意味着他们可以在工作日参加会议。同时它也意味着参与者无需寻找一个安静的地方来让他们沟通而不打扰到周围的人。
借助会议机器人，IRC 可以立即生成会议记录。在 Fedora 中，我们使用 Zodbot，Debian 的 [Meetbot][3] 的一个实例，来记录会议并提供交互。会议结束后，会议记录和完整的日志立即可供社区使用。这减少了开展会议的管理开销。
### 这跟普通会议类似，但有所不同
通过 IRC 或其他基于文本的媒介进行会议意味着以稍微不同寻常的方式来看待会议。虽然它缺少一些更高带宽沟通模式的有点，但它也有自己的有点。开展 IRC 会议可以让你有机会开发出各种规则，而这些规则有助于你开展各种类型的会议。
与任何会议一样，IRC 会议最好有明确的日程和目的。一个好的会议主持者知道什么时候让谈话继续下去以及什么时候将话题拉回来。并没有什么硬性规定—这是一门艺术。但 IRC 在这方面有一个优势。通过这是频道主题为会议的当前主题，人们可以看到他们应该谈论的内容。
如果你的项目尚未实施过同步会议，你应该考虑一下。对于项目成员分布在不同时区的项目，找到一个大家都认可的时间来组织会议很难。你不能把会议作为你唯一的协调方式。但他们可以是项目工作的重要组成部分。
--------------------------------------------------------------------------------
via: https://opensource.com/article/19/2/irc-vs-irl-meetings
作者：[Ben Cotton][a]
选题：[lujun9972][b]
译者：[lujun9972](https://github.com/lujun9972)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://opensource.com/users/bcotton
[b]: https://github.com/lujun9972
[1]: https://en.wikipedia.org/wiki/Internet_Relay_Chat
[2]: https://opensource.com/article/16/6/getting-started-irc
[3]: https://wiki.debian.org/MeetBot

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10款你可以通过Wine在Linux上玩的游戏
======
![](https://www.maketecheasier.com/assets/uploads/2017/09/wine-games-feat.jpg)
Linux _确实_ 能玩游戏，而且还能玩不少游戏。独立游戏在 Linux 平台上蓬勃发展，顶级的独立游戏也常常会在发售首日便发布 Linux 版本。然而，3A 游戏大作的开发者们却常常忽略 Linux，所以你不会很快就能玩上身边朋友们口中正火的那些游戏。
但情况还没有糟透。Wine —— 一个能使 Windows 应用在类似 Linux, BSD 和 OS X 上运行的兼容层，在支持的游戏数量和性能表现上都取得了巨大进步。很多游戏大作都可以在 Wine 的支持下运行。你不能完全释放本机性能，但还是可以跑起来游戏，运行也还算流畅，当然这也要取决与你的系统配置。下面我们来盘点一下这些可能会令你大吃一惊的可以通过 Wine 在 Linux 上玩的游戏。
### 10. 魔兽世界
![World of Warcraft Wine][1]
这款经典的 MMORPG 之王仍旧坚挺并保持活力。虽然这不是一款以画面见长的游戏，但想要开到全画质也需要费一些功夫。魔兽世界已经在 Wine 的支持下运行了很多年。到了最新资料片发布时，魔兽世界为它的 Mac 版本提供了 OpenGL 支持，使得游戏也可以很轻松地在 Linux 下运行。这已经不再是个问题了。
你需要通过 DX9 来运行游戏并从 [Gallium Nine][2] 补丁来获得一些性能提升，不过你也可以放心大胆地在 Linux 中下副本了。
### 9. 上古卷轴 5：天际
![Skyrim Wine][3]
上古卷轴 5 已经不是款新游戏了，但它的 mod 社区依旧活跃。如果你的 Linux 系统有足够资源的话，你可以很轻松地加上很多很多 mod。需要记住的是 Wine 运行时要比游戏占用更多的系统资源，所以使用 mod 时也要考虑这一点。
### 8. 星际争霸 II
![StarCraft II Wine][4]
星际争霸 II 是成为市场上最受欢迎的 RTS 游戏之一，并且在 Wine 下运作良好。它实际上也是 Wine 下表现最好的游戏之一。
考虑到这款游戏本身的竞技性，你当然希望游戏能够流畅地运行。不过不用担心，只要你的硬件够用就绝对没问题。
这是一个你可以从 “staging” 补丁获益的例子，所以在你设置游戏时请继续使用它们。
### 7. 辐射3 / 辐射：新维加斯
![Fallout 3 Wine][5]
在你提问之前，辐射 4 已经很快就准备就绪，也许就在你正读这篇文章的时候就可以玩了。就目前而言，辐射 3 和 辐射：新维加斯都能在有无 mod 的情况下良好运行。这些游戏在 Wine 下运行地非常好，甚至还能加载大量 mod 来保持游戏的新鲜性和趣味性。在辐射 4 获得全面支持前玩这些旧作也不算是个很大的妥协。
### 6. Doom (2016)
![Doom Wine][6]
Doom（毁灭战士）是过去几年中最刺激的射击游戏之一。在 Wine 支持下并加载 “staging” 补丁可以流畅地运行最新版本。单人模式和多人模式都有很棒的游戏体验，而且也不需要花费大量时间来配置 Wine 和调整设置。所以你想在 Linux 上体验 3A 级射击游戏的话，不妨尝试一下 Doom 。
### 5. 激战 2
![Guild Wars 2 Wine][7]
激战 2 是一款无月卡(买断制)的融合了多人和迷宫探险元素的游戏。它在市场上很受欢迎，并自称在游戏中有着很多创新。你同样可以通过 Wine 在 Linux 上玩到这款游戏。
激战 2 也不算一款很老的 MMO 游戏。它试图以图像表现来保持现代风格，并具有着相当高分辨率的纹理和视觉效果。所有这些特点都能在 Wine 下顺利运行。
### 4. 英雄联盟
![League Of Legends Wine][8]
在 MOBA 游戏的世界中有两个强者：DoTA2 和英雄联盟。Valve 已经将 DoTA2 移植到 Linux 上很久了，但玩家们却从没在 Linux 上玩过英雄联盟。如果你是 Linux 的使用者并热衷英雄联盟，你还是可以通过 Wine 来玩这款你最爱的 MOBA 游戏。
英雄联盟是个很有趣的例子。它的游戏本身运行良好，但安装程序却会因为需要 Adobe Air 而中断。一些安装程序脚本例如 Lutris 和 PlayOnLinux 能帮你通过这一步骤。一旦安装完毕，你就可以毫无困难地运行游戏，甚至在激烈的战况中依旧畅快玩耍。
### 3. 炉石传说
![HearthStone Wine][9]
炉石传说是一款流行且令人上瘾的免费卡牌游戏，你可在各种平台上来一局......除了 Linux。不过别担心，在 Wine 中你可以轻松玩到这款游戏。炉石并不大，所以即使在最低配置的系统里也都能玩，这是个好消息。不过由于它的竞技性所以还是要对游戏性能有一定要求。
玩炉石不需要任何特殊配置和补丁，直接开玩！
### 2. 巫师3
![Witcher 3 Wine][10]
你不是唯一一个对在这份榜单中看到了巫师 3 而感到吃惊的人。在最新版 “stage” 补丁的支持下，你终于可以在 Linux 中体验这款游戏了。尽管最初承诺会有原生版本，但 Linux 玩家还是等了很久才迎来了巫师系列的第三部。
不过最好不要指望一切都能完美运行。巫师 3 _刚刚_ 得到支持，有些内容可能还不会达到预期。也就是说，如果你只能用 Liux 来玩游戏，并且愿意处理一些问题。那么你也可以享受到这款完美游戏带来的初体验了。
### 1. 守望先锋
![Overwatch Wine][11]
最后，让我们来谈谈 Linux 玩家心中的另一个“白鲸”。很多人认为守望先锋会像大多数暴雪游戏一样，在发售当日就能在 Wine 上获得支持。不过情况非常不同，因为守望先锋只支持 DX11，这也正是 Wine 面临的一个痛点。
守望先锋目前还不能拥有最佳性能表现，但是你还是可以通过装有特殊补丁的 Wine 和包括“staging”在内的一系列定制补丁包来运行游戏。这也说明了 Linux 玩家们真的很渴望游玩这款游戏，以至于自己开发了一套补丁来为它提供支持。
这份榜单当然会遗漏一些其他游戏。大多数是由于受欢迎程度或只能从 Wine 中得到有限的支持。其他暴雪游戏，如“风暴英雄”和“暗黑破坏神 3”也能很好地运行，但这样来写就会使暴雪游戏霸占这份榜单，这不是我们想突出的重点。
如果你正打算玩以上任一款游戏，请使用 Wine 的 [Gallium Nine versions][2] 版本并装载“staging”补丁，否则游戏可能无法正常运行。“staging”中装载的最新补丁和提升要比正式的 Wine 发行版提供的内容要早很多，使用它会令你在性能上处于领先地位。
说到进步，Wine 目前在对 DirectX11 的支持有了很大进步。对于 Windows 玩家这可能不算什么，但对于 Linux 玩家来说绝对算是一件大事。大多数游戏新作支持 DX11 和 DX12，而最新版本的 Wine 仍只是支持 DX9。有了 DX11 的支持，Wine 将会让很多过去无法在 Linux 上玩的游戏运行起来。所以，定期查看你最喜欢的 Windows 游戏是否也可以开始在 Wine 上运行，你可能会非常惊喜。
--------------------------------------------------------------------------------
via: https://www.maketecheasier.com/games-play-on-linux-with-wine/
作者：[Nick Congleton][a]
译者：[Modrisco](https://github.com/Modrisco)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]:https://www.maketecheasier.com/author/nickcongleton/
[1]:https://www.maketecheasier.com/assets/uploads/2017/09/wow.jpg (World of Warcraft Wine)
[2]:https://www.maketecheasier.com/install-wine-gallium-nine-linux
[3]:https://www.maketecheasier.com/assets/uploads/2017/09/skyrim.jpg (Skyrim Wine)
[4]:https://www.maketecheasier.com/assets/uploads/2017/09/sc2.jpg (StarCraft II Wine)
[5]:https://www.maketecheasier.com/assets/uploads/2017/09/Fallout_3.jpg (Fallout 3 Wine)
[6]:https://www.maketecheasier.com/assets/uploads/2017/09/doom.jpg (Doom Wine)
[7]:https://www.maketecheasier.com/assets/uploads/2017/09/gw2.jpg (Guild Wars 2 Wine)
[8]:https://www.maketecheasier.com/assets/uploads/2017/09/League_of_legends.jpg (League Of Legends Wine)
[9]:https://www.maketecheasier.com/assets/uploads/2017/09/HearthStone.jpg (HearthStone Wine)
[10]:https://www.maketecheasier.com/assets/uploads/2017/09/witcher3.jpg (Witcher 3 Wine)
[11]:https://www.maketecheasier.com/assets/uploads/2017/09/Overwatch.jpg (Overwatch Wine)

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[#]: collector: (lujun9972)
[#]: translator: (GraveAccent)
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: subject: (JSON vs XML vs TOML vs CSON vs YAML)
[#]: via: (https://www.zionandzion.com/json-vs-xml-vs-toml-vs-cson-vs-yaml/)
[#]: author: (Tim Anderson https://www.zionandzion.com)
JSON vs XML vs TOML vs CSON vs YAML
======
### 一段超级严肃的关于样本序列化的集合、子集和超集的文字
我是开发者。我读代码。我写代码。我写会写代码的代码。我写会写供其它代码读的代码的代码。这些都非常火星语，但是有其美妙之处。然而，最后一点，写会写供其它代码读的代码的代码，可以很快变得比这段文字更费解。有很多方法可以做到这一点。一种不那么复杂而且开发者社区最爱的方式是数据序列化。对于那些不了解我刚刚向你抛的时髦词的人，数据序列化是从一个系统获取一些信息，将其转换为其它系统可以读取的格式，然后将其传递给其它系统的过程。
虽然[数据序列化格式][1]多到可以埋葬哈利法塔，但它们大多分为两类：
* 易于人类读写，
* 易于机器读写。
很难两全其美，因为人类喜欢让我们更具表现力的松散类型和灵活格式标准，而机器倾向于被确切告知一切事情不带疑惑和细节缺失，并且认为“严格规范”是他们最爱的 Ben & Jerry's 口味。
由于我是一名 web 开发者而且我们是一个创建网站的代理商，我们将坚持使用 web 系统可以理解或不需要太多努力就能理解以及对人类可读性特别有用的特殊格式：XML，JSON，TOML，CSON以及 YAML。每个都有各自的优缺点和适当的用例。
### 事实最先
回到互联网的早期，[一些非常聪明的家伙][2]决定整合一种标准语言，即每个系统都能理解，创造性地将其命名为标准通用标记语言（简称SGML）。SGML 非常灵活，发布者也很好地定义了它。他成为了 XML，SVG 和 HTML 等语言之父。所有这三个都符合 SGML 规范，可是它们都是规则更严格、灵活性更少的子集。
最终，人们开始看到大量非常小、简洁、易读且易于生成的数据，这些数据可以在系统之间以程序的方式共享，而开销很小。大约在那个时候，JSON 诞生了并且能够满足所有的需求。反过来，其它语言开始出现以处理更多的专业用例，如 CSON，TOML 和 YAML。
### XML: 不行了
最初，XML语言非常灵活且易于编写，但它的缺点是冗长，人类难以阅读，计算机非常难以读取，并且有很多语法对于传达信息并不是完全必要的。
今天，它在 web 上的数据序列化目的已经消失了。除非你在编写 HTML 或者 SVG，否则你不太能在许多其它地方看到XML。一些过时的系统今天仍在使用它，但是用它传递数据往往太重了。
我已经可以听到 XML 老人开始在他们的石碑上乱写为什么 XML 是了不起的，所以我将提供一个小的附录：XML可以很容易地由系统和人读写。然而，真的，我的意思是荒谬，很难创建一个可以将其读入规范的系统。这是一个简单美观的 XML 示例：
```
<book id="bk101">
<author>Gambardella, Matthew</author>
<title>XML Developer's Guide</title>
<genre>Computer</genre>
<price>44.95</price>
<publish_date>2000-10-01</publish_date>
<description>An in-depth look at creating applications
with XML.</description>
</book>
```
太棒了。易于阅读，推理，编写和编码的可以读写的系统。但请考虑这个例子：
```
<!DOCTYPE r [ <!ENTITY y "a]>b"> ]>
<r>
<a b="&y;>" />
<![CDATA[[a>b <a>b <a]]>
<?x <a> <!-- <b> ?> c --> d
</r>
```
这上面是 100% 有效的 XML。不可能阅读、理解或推理。编写可以使用和理解这个的代码将花费至少36头的头发和248磅咖啡。我们没有那么多时间或咖啡，而且我们大多数老人现在都是秃头。所以，让它活在我们的记忆里，就像 [css hacks][3]，[internet explorer][4] 和[真空管][5]那样。
### JSON: 并列聚会
好吧，我们都同意了。XML = 差劲。那么，什么是好的替代品？JavaScript 对象表示法，简称 JSON。JSON（读起来像 Jason 这个名字） 是 Brendan Eich 发明的，并且被 [JavaScript 的荷兰叔叔][6] Douglas Crockford 推广。它现在几乎用在任何地方。这种格式很容易由人和机器编写，相当容易用规范中的严格规则[解析][7]，并且灵活-允许深层嵌套数据，所有原始数据类型和集合如数组和对象的解释。JSON 成为了将数据从一个系统传输到另一个系统的事实标准。几乎所有语言都有内置读写它的功能。
JSON语法很简单。 方括号表示数组，花括号表示记录，由冒号分隔两个值表示属性（或“键”）在左边，值在右边。所有键必须用双引号括起来：
```
{
"books": [
{
"id": "bk102",
"author": "Crockford, Douglas",
"title": "JavaScript: The Good Parts",
"genre": "Computer",
"price": 29.99,
"publish_date": "2008-05-01",
"description": "Unearthing the Excellence in JavaScript"
}
]
}
```
这对你来说应该是完全合理的。它简洁明了，并且从 XML 中删除了大量额外废话以传达相同数量的信息。JSON 现在是王道，本文剩下的部分会介绍其它语言格式，这些格式只不过是煮沸了的 JSON，尝试让其更简洁或更易读，可结构还是非常相似的。
### TOML: 缩短到彻底的利他主义
TOML（Tom 的显而易见最低限度语言）允许快速简洁地定义深层嵌套的数据结构。名字中的名字是指发明者 [Tom Preston Werner][8]，他是一位活跃于我们行业的创造者和软件开发人员。与 JSON 相比，语法有点尴尬，更类似 [ini 文件][9]。这不是一个糟糕的语法，但是需要一些时间适应。
```
[[books]]
id = 'bk101'
author = 'Crockford, Douglas'
title = 'JavaScript: The Good Parts'
genre = 'Computer'
price = 29.99
publish_date = 2008-05-01T00:00:00+00:00
description = 'Unearthing the Excellence in JavaScript'
```
TOML 中集成了一些很棒的功能，例如多行字符串，保留字符的自动转义，日期，时间，整数，浮点数，科学记数法和“表扩展”等数据类型。最后一点是特别的，是TOML如此简洁的原因：
```
[a.b.c]
d = 'Hello'
e = 'World'
```
以上扩展到以下内容：
```
{
"a": {
"b": {
"c": {
"d": "Hello"
"e": "World"
}
}
}
}
```
使用TOML，你可以肯定在时间和文件长度上会节省不少。很少有系统使用它或非常类似的东西作为配置，这是它最大的缺点。根本没有很多语言或库可以用来解释 TOML。
### CSON: 特定系统所包含的简单样本
首先，有两个 CSON 规范。 一个代表 CoffeeScript Object Notation，另一个代表 Cursive Script Object Notation。后者不经常使用，所以我们不会关注它。我们只关注 CoffeeScript。
[CSON][10] 会介绍一点。首先，我们来谈谈 CoffeeScript。[CoffeeScript][11] 是一种通过运行编译器生成 JavaScript 的语言。它允许你以更加简洁的语法编写 JavaScript 并[转译][12]成实际的 JavaScript，然后你可以在你的 web 应用程序中使用它。CoffeeScript 通过删除 JavaScript 中必需的许多额外语法，使编写 JavaScript 变得更容易。CoffeeScript 摆脱的一个大问题是花括号 - 不需要他们。同样，CSON 是没有大括号的 JSON。它依赖于缩进来确定数据的层次结构。CSON 非常易于读写，并且通常比 JSON 需要更少的代码行，因为没有括号。
CSON 还提供一些 JSON 不提供的额外细节。多行字符串非常容易编写，你可以通过使用 hash 符号开始一行来输入[注释][13]，并且不需要用逗号分隔键值对。
```
books: [
id: 'bk102'
author: 'Crockford, Douglas'
title: 'JavaScript: The Good Parts'
genre: 'Computer'
price: 29.99
publish_date: '2008-05-01'
description: 'Unearthing the Excellence in JavaScript'
]
```
这是 CSON 的重大问题。它是 **CoffeScript** 对象表示法。也就是说你用 CoffeeScript 解析/标记化/lex/转译或其它方式使用 CSON。CoffeeScript 是读取数据的系统。如果数据序列化的目的是允许数据从一个系统传递到另一个系统，这里我们有一个只能由单个系统读取的数据序列化格式，这使得它与防火的火柴、防水的海绵或者叉勺恼人的脆弱分叉处一样有用。
如果其它系统采用这种格式，它在开发者世界中可能非常有用。到目前为止这整体上没有发生，所以在 PHP 或 JAVA 等替代语言中使用它是不行的。
### YAML:年轻人的呼喊
开发人员感到高兴，因为 YAML 来自[一个 Python 的贡献者][14]。YAML 具有与 CSON 相同的功能集和类似的语法，一系列新功能，以及几乎所有 web 编程语言都可用的解析器。它还有一些额外的功能，如循环引用，软包装，多行键，类型转换标签，二进制数据，对象合并和[集合映射][15]。它具有令人难以置信的良好的可读性和可写性，并且是 JSON 的超集，因此你可以在 YAML 中使用完全合格的 JSON 语法并且一切正常工作。你几乎从不需要引号，它可以解释大多数基本数据类型（字符串，整数，浮点数，布尔值等）。
```
books:
- id: bk102
author: Crockford, Douglas
title: 'JavaScript: The Good Parts'
genre: Computer
price: 29.99
publish_date: !!str 2008-05-01
description: Unearthing the Excellence in JavaScript
```
业界的年轻人正在迅速采用 YAML 作为他们首选的数据序列化和系统配置格式。他们这样做很机智。YAML 有像 CSON 一样简洁带来的所有好处，有 JSON 在数据类型解释方面的所有功能。YAML 像加拿大人容易相处一样容易阅读。
YAML 有两个问题，对我而言，第一个是大问题。在撰写本文时，YAML 解析器尚未内置于多种语言，因此你需要使用第三方库或扩展来为你选择的语言解析 .yaml 文件。这不是什么大问题，可似乎大多数为 YAML 创建解析器的开发人员都选择随机将“附加功能”放入解析器中。有些允许[标记化][16]，有些允许[链引用][17]，有些甚至允许内联计算。这一切都很好（某种意义上），除了这些功能都不是规范的一部分，因此很难在其他语言的其他解析器中找到。这导致系统锁定，你最终遇到了与 CSON 相同的问题。如果你使用仅在一个解析器中找到的功能，则其他解析器将无法解释输入。大多数这些功能都是无意义的，不属于数据集，而是属于你的应用程序逻辑，因此最好简单地忽略它们和编写符合规范的 YAML。
第二个问题是很少有解析器完全实现规范。所有的基本要素都在那里，但是很难找到一些更复杂和更新的东西，比如软包装，文档标记和首选语言的循环引用。我还没有看到对这些东西的刚需，所以希望它们不让你很失望。考虑到上述情况，我倾向于保持 [1.1 规范][18] 中呈现的更成熟的功能集，避免在 [1.2 规范][19] 中找到的新东西。然而，编程是一个不断发展的怪兽，所以当你读完这篇文章时，你或许可以使用 1.2 规范。
### 最终哲学
这是最后一段话。每个序列化语言都应该以其用例的标准评价。当涉及机器的可读性时，有些是蜜蜂的膝盖。对于人类可读性，有些是猫的喵喵声，有些只是镀金的粪便。以下是最终细分：如果你要编写供其他代码阅读的代码，请使用 YAML。如果你正在编写能写供其他代码读取的代码的代码，请使用 JSON。最后，如果你正在编写将代码转译为供其他代码读取的代码的代码，请重新考虑你的人生选择。
--------------------------------------------------------------------------------
via: https://www.zionandzion.com/json-vs-xml-vs-toml-vs-cson-vs-yaml/
作者：[Tim Anderson][a]
选题：[lujun9972][b]
译者：[译者ID](https://github.com/GraveAccent)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://www.zionandzion.com
[b]: https://github.com/lujun9972
[1]: https://en.wikipedia.org/wiki/Comparison_of_data_serialization_formats
[2]: https://en.wikipedia.org/wiki/Standard_Generalized_Markup_Language#History
[3]: https://www.quirksmode.org/css/csshacks.html
[4]: http://www.ie6death.com/
[5]: https://en.wikipedia.org/wiki/Vacuum_tube
[6]: https://twitter.com/BrendanEich/status/773403975865470976
[7]: https://en.wikipedia.org/wiki/Parsing#Parser
[8]: https://en.wikipedia.org/wiki/Tom_Preston-Werner
[9]: https://en.wikipedia.org/wiki/INI_file
[10]: https://github.com/bevry/cson#what-is-cson
[11]: http://coffeescript.org/
[12]: https://en.wikipedia.org/wiki/Source-to-source_compiler
[13]: https://en.wikipedia.org/wiki/Comment_(computer_programming)
[14]: http://clarkevans.com/
[15]: http://exploringjs.com/es6/ch_maps-sets.html
[16]: https://www.tutorialspoint.com/compiler_design/compiler_design_lexical_analysis.htm
[17]: https://en.wikipedia.org/wiki/Fluent_interface
[18]: http://yaml.org/spec/1.1/current.html
[19]: http://www.yaml.org/spec/1.2/spec.html

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Python ChatOps 库: Opsdroid 和 Errbot
======
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/idea_innovation_mobile_phone.png?itok=RqVtvxkd)
这篇文章由笔者和 [Lacey Williams Henschel][1] 共同编写。
ChatOps 是基于会话导向而进行的开发。它的想法是你可以编写能够对聊天窗口中的某些输入进行回复的可执行代码。作为一个开发者，你能够用 ChatOps 从 Slack 合并拉取请求，自动从收到的 Facebook 消息中给某人分配支持票或者通过 IRC 检查开发状态。
在 Python 世界，最为广泛使用的 ChatOps 库是 Opsdroid 和 Errbot。在这个月的 Python 专栏，让我们一起聊聊使用它们是怎样的体验，它们各自适用于什么方面以及如何着手使用它们。
### Opsdroid
[Opsdroid][2] 是一个相对年轻的（始于 2016）Python 开源聊天机器人库。它有着良好的开发文档，不错的教程并且包含能够帮助你对接流行的聊天服务的插件。
#### 它内建了什么
库本身并没有自带所有你需要上手的东西，但这是故意的。轻量级的框架鼓励你去运用它现存的连接器（Opsdroid 所谓的帮你接入聊天服务的插件）或者去编写你自己的，但是它并不会因自带你所不需要的的连接器而自贬身价。你可以轻松使用现有的 Opsdroid 连接器来接入：
+ 命令行
+ Cisco Spark
+ Facebook
+ GitHub
+ Matrix
+ Slack
+ Telegram
+ Twitter
+ Websockets
Opsdroid 引用使聊天机器人能够展现它们的技能的函数。这些技能其实是 `异步` Python 函数并使用 Opsdroid 叫做“匹配器”的匹配装饰器。你可以设置你的 Opsdroid 项目，来使用同样从你设置文件所在的代码基地来的技能。你也可以从外面的公共或私人仓库调用这些技能。
你同样可以激活一些现存的 Opsdroid 技能包括 [seen][3]，它会告诉你什么时候一个特定用户被聊天机器人所看到以及 [weather][4]，会将天气报告给用户。
最后，Opdroid 允许你使用现存的数据库模块设置数据库。现在 Opdroid 支持的数据库包括：
+ Mongo
+ Redis
+ SQLite
你可以在你的 Opdroid 项目中的 `configuration.yaml` 文件设置数据库、技能和连接器。
#### Opsdroid 的优势
**Docker 支持：**从一开始 Opsdroid 就打算在 Docker 中良好运行。Docker 指导是它 [安装文档][5] 中的一部分。使用 Opsdroid 和 Docker Copmose 也很简单：将 Opsdroid 设置成一种服务，当你运行 `docker-compose up` 时，你的 Opsdroid 服务将会开启你的聊天机器人也将就绪。
```
version: "3"
services:
  opsdroid:
    container_name: opsdroid
    build:
      context: .
      dockerfile: Dockerfile
```
**丰富的连接器：** Opsdroid 支持九种从外部接入像 Slack 和 Github 等服务的连接器。你所要做的一切就是在你的设置文件中激活那些连接器然后把必须的口令或者 API 密匙传过去。比如为了激活 Opsdroid 以在一个叫做 `#updates` 的 Slack 频道发帖，你需要将以下代码加入你设置文件的 `connectors` 部分：
```
- name: slack
    api-token: "this-is-my-token"
    default-room: "#updates"
```
在设置 Opsdroid 以接入 Slack 之前你需要[添加一个机器人用户][6]。
如果你需要接入一个 Opsdroid 不支持的服务，在[文档][7]里有有添加你自己的连接器的教程。
**相当不错的文档：** 特别是对于一个在积极开发中的新兴库来说，Opsdroid 的文档十分有帮助。这些文档包括一篇带你创建几个不同的基本技能的[教程][8]。Opsdroid 在[技能][9]，[连接器][7]，[数据库][10]，以及[匹配器][11]方面的文档也十分清晰。
**自然语言处理：**它所支持的技能和连接器的仓库为它的技能提供了富有帮助的示范代码。它同样提供了几个包括 [Dialogflow][12]，[luis.ai][13]，[Recast.AI][14] 以及 [wit.ai][15] 的 NLP API。
#### 对 Opsdroid 可能的考虑
Opsdroid 对它的一部分连接器还没有激活全部的特性。比如说，Slack API 允许你向你的消息添加颜色柱，图片以及其他的“附件”。Opsdroid Slack 连接器并没有激活“附件”特性，所以如果那些特性对你来说很重要的话，你需要编写一个自定义的 Slack 连接器。如果连接器缺少一个你需要的特性，Opsdroid 将欢迎你的[贡献][16]。文档中可以使用更多的例子，特别是对于预料到的使用场景。
#### 示例用法
`hello/__init__.py`
```
from opsdroid.matchers import match_regex
import random
@match_regex(r'hi|hello|hey|hallo')
async def hello(opsdroid, config, message):
    text = random.choice(["Hi {}", "Hello {}", "Hey {}"]).format(message.user)
    await message.respond(text)
```
`configuration.yaml`
```
connectors:
  - name: websocket
skills:
  - name: hello
    repo: "https://github.com/<user_id>/hello-skill"
```
### Errbot
[Errbot][17] 是一个功能齐全的开源聊天机器人。Errbot 发行于2012年并且拥有人们从一个成熟的项目能期待的一切，包括良好的文档，优秀的教程以及许多帮你连入现存的流行聊天服务的插件。
#### 它内建了什么
不像采用了一个较轻量级途径的 Opsdroid，Errbot 安全地自带了你需要创建一个自定义机器人的一切东西。
Errbot 包括了对于本地 XMPP， IRC， Slack， Hipchat 以及 Telegram 服务的支持。它通过社区支持的后端列出了另外十种服务。
#### Errbot 的优势
**良好的文档：** Errbot 的文档成熟易读。
**动态插件架构：** Errbot 允许你通过和聊天机器人交谈安全安装，卸载，更新，激活以及禁用插件。这使得开发和添加特性十分简便。感谢 Errbot 的颗粒性授权系统，出于安全意识这所有的一切都可以被锁闭。
当某个人输入 `!help`，Errbot 使用你的插件文档字符串来为可获取的命令生成文档，这使得了解每行命令的作用更加简便。
**內建的管理和安全特性：** Errbot 允许你限制拥有管理员权限甚至细粒度访问控制用户列表。比如说你可以限制特定用户或房间访问特定命令。
**额外的插件框架：** Errbot 支持钩子，回调，子命令，webhook，轮询以及其它[多得多的特性][18]。如果那些还不够，你甚至可以编写[动态插件][19]。当你需要基于在远程服务器上什么命令可以获取来激活聊天命令时，这个特性十分有用。
**自带测试框架：** Errbot 支持 [pytest][20] 同时也自带一些能使测试插件变的可能且简便的有用设施。它“[测试你的插件][21]”的文档出于深思熟虑并提供足够的资料让你上手。
#### 对 Errbot 可能的考虑
**首先 !：** 默认情况下，Errbot 命令发出时以一个惊叹号打头（`!help` 以及 `!hello`）。一些人可能会喜欢这样，但是另一些人可能认为这让人烦恼。谢天谢地，这很容易关掉。
**插件元数据** 首先，Errbot 的 [Hello World][22] 插件示例看上去易于使用。然而我无法加载我的插件直到我进一步阅读了教程并发现我还需要一个 `.plug` 文档，一个 Errbot 用来加载插件的文档。这可能比较吹毛求疵了，但是在我深挖文档之前，这对我来说都不是显而易见的。
### 示例用法
`hello.py`
```
import random
from errbot import BotPlugin, botcmd
class Hello(BotPlugin):
    @botcmd
    def hello(self, msg, args):
        text = random.choice(["Hi {}", "Hello {}", "Hey {}"]).format(message.user)
        return text
```
`hello.plug`
```
[Core]
Name = Hello
Module = hello
[Python]
Version = 2+
[Documentation]
Description = Example "Hello" plugin
```
你用过 Errbot 或 Opsdroid 吗？如果用过请留下关于你对于这些工具印象的留言。
--------------------------------------------------------------------------------
via: https://opensource.com/article/18/3/python-chatops-libraries-opsdroid-and-errbot
作者：[Jeff Triplett][a]
译者：[tomjlw](https://github.com/tomjlw)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]:https://opensource.com/users/laceynwilliams
[1]:https://opensource.com/users/laceynwilliams
[2]:https://opsdroid.github.io/
[3]:https://github.com/opsdroid/skill-seen
[4]:https://github.com/opsdroid/skill-weather
[5]:https://opsdroid.readthedocs.io/en/stable/#docker
[6]:https://api.slack.com/bot-users
[7]:https://opsdroid.readthedocs.io/en/stable/extending/connectors/
[8]:https://opsdroid.readthedocs.io/en/stable/tutorials/introduction/
[9]:https://opsdroid.readthedocs.io/en/stable/extending/skills/
[10]:https://opsdroid.readthedocs.io/en/stable/extending/databases/
[11]:https://opsdroid.readthedocs.io/en/stable/matchers/overview/
[12]:https://opsdroid.readthedocs.io/en/stable/matchers/dialogflow/
[13]:https://opsdroid.readthedocs.io/en/stable/matchers/luis.ai/
[14]:https://opsdroid.readthedocs.io/en/stable/matchers/recast.ai/
[15]:https://opsdroid.readthedocs.io/en/stable/matchers/wit.ai/
[16]:https://opsdroid.readthedocs.io/en/stable/contributing/
[17]:http://errbot.io/en/latest/
[18]:http://errbot.io/en/latest/features.html#extensive-plugin-framework
[19]:http://errbot.io/en/latest/user_guide/plugin_development/dynaplugs.html
[20]:http://pytest.org/
[21]:http://errbot.io/en/latest/user_guide/plugin_development/testing.html
[22]:http://errbot.io/en/latest/index.html#simple-to-build-upon

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[#]: collector: "lujun9972"
[#]: translator: "MZqk"
[#]: reviewer: " "
[#]: publisher: " "
[#]: url: " "
[#]: subject: "What does DevOps mean to you?"
[#]: via: "https://opensource.com/article/19/1/what-does-devops-mean-you"
[#]: author: "Girish Managoli https://opensource.com/users/gammay"
DevOps 对你意味着什么？
======
6 位专家对 DevOps 的实现、实践关键和哲学分解。
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/innovation_lightbulb_gears_devops_ansible.png?itok=TSbmp3_M)
如果你问 10 个人关于 DevOps 的问题，你会得到 12 个答案。这是对于 DevOps 意见和期望多样性的结果，更不用说它在实践中的差异。
为了解读 DevOps 的悖论，我们找到了最了解它的人 - 这个行业的顶尖从业者。这些人熟悉 DevOps，了解技术的来龙去脉，并且已经有了多年 DevOps 实践。他们的观点应该能鼓励、刺激和激发您对 DevOps 的想法。
### DevOps 对你意味着什么？
让我们从基本原理开始。我们不能只在教科书上寻找答案，而应该需要知道专家们怎么说。
简而言之，专家们说的是关于 DevOps 的原则、实践和工具。
IBM 数字企业集团 DevOps 商业平台领导者 [Ann Marie Fred][1]，说，“对于我来说，DevOps 是一套实践的原则，旨在使团队在设计，开发，交付和操作软件方面有更好的效率。”
根据红帽资深 DevOps 布道者 [Daniel Oh][2]，“ 通常来说，DevOps 促使企业基于当前的 IT 流程和工具之上发展与开发相关的应用程序 、IT 运营和安全协议。”
Tactec Strategic Solutions 的创始人 [Brent Reed][3]，就持续改进利益相关者进行了会谈。“DevOps 对我来说意味着一种工作方式，包括一种思维方式，允许持续改进运营绩效，逐渐使其成熟为组织提升绩效，从而让利益相关者高兴。”
许多专家也强调 DevOps 文化。Ann Marie 说，“这也关于持续改进和学习的问题。它涉及的是人和文化，以及工具和技术。”
美国保监会 (NAIC) 首席架构师兼 DevOps 领导者 [Dan Barker][4]，“DevOps 主要是关于文化…它将几个独立的领域聚集在一起，如精益生产、[合适文化 ][5] 和持续的学习。我认为文化是最关键和最难执行的。”
Atos 的 DevOps 负责人 [Chris Baynham-Hughes][6]，说，“[DevOps] 实践是通过组织内的文化、流程和工具的发展而被采用的。重点是文化变革，DevOps 文化借鉴的关键是协作、试验、快速反馈和持续改进。”
云架构师 [Geoff Purdy][7]，谈论敏捷和反馈，“缩短和放大反馈回路。我们希望团队在几分钟内而不是几周内获得反馈。”
但在最后，Daniel 通过解释开源和开源文化是如何让他以简单快捷的方式实现目标来强调这点，“在推动 DevOps 中，最重要的事情应该是开源文化而不是具体的工具或复杂的解决方案。”
### 你认为哪些 DevOps 实践有效？
“选择一个自动化配置，对我的团队来说非常有效。”
专家列举的那些最佳实践是普遍存在的，但又各不相同。
Ann Marie 表示：“一些十分强大灵活的项目管理[实践]，能在职能、独立的小组之间打破壁垒；全自动化持续部署，蓝/绿部署实现零时间停机状态；开发人员设置自己的监控和警告，无缝自我修复，自动化的安全性与合规性。”
Chris 说，“特别的突破是倾情合作；持续改成；开放的领导；缩短业务时长；从垂直孤岛转向横向，跨功能的产品团队。工作透明化，相互影响，Mobius 循环，缩短反馈回路，自动化（环境上的 CI/CD）。”
Brent 支持“发展学习文化，包括 TTD[ 测试驱动开发]和 BDD[ 行为驱动开发]捕获事件，并通过持续集成和持续交付从设计、构建和测试到实施在生产环境上一系列事件的自动化。测试采用故障优先的方法，能够自动化集成和交付流程，并在整个生命周期中包含快速反馈。”
Geoff 强调自动化配置。“选择一个自动化配置，对我的团队来说非常有效。更具体地说从版本控制代码库中自动配置。”
Dan uses fun。“ 我们做了很多不同的事情来建立 DevOps 文化。我们举办 ‘Lunch & Learns”’，提供免费的食物来鼓励大家一起学习。我们买书，分组学习。”
### 你如何激励你的团队实现 DevOps 这个目标？
```
"庆祝你所取得的进步。"
```
Daniel 强调“自动化的问题就是为了减少 DevOps 计划中来自多个团队的异议，您应该鼓励您的团队提高开发、测试与 IT 运营的自动化能力，以及新的流程和程序。例如，Linux 容器是实现 DevOps 自动化功能的关键工具。”
Geoff 很是赞同，“机械化的劳作，你有讨厌现在做的任务吗？很棒。如果可能的话，让它们消失。不行，那就让他们自动化。它能使工作不会变得太枯燥，因为工作总是在变化。”
Dan，Ann Marie 和 Brent 强调团队的执行力。
Dan 说，“在 NAIC，我们有个很好的奖励系统来鼓励特定的行为。我们有多个级别的奖项，其中两个奖项可以任何人颁布给某人。我们也会颁奖给完成重要任务的团队，但我们通常只奖励给个人贡献者。”
Ann Marie 表示，“我所在地区的团队最大的动力是看见其他人成功。我们每周都会彼此播放一次，其中一部分是分享我们从尝试新工具或实践中学到的东西。团队热衷于他们现在做的事情，并愿意帮助其他人开始，相信更多的团队很快也会加入进来。”
Brent 表示赞同。“让每个人学习，并掌握基础知识同样至关重要。。。。。。我喜欢从评估什么能帮助团队实现目标[以及]产品负责人和用户需要提供的内容入手。”
Chris 推荐采用双管齐下的方法。“每周运行可以实现的小目标，并且[在这]可以看到他们正在运做的功能工作之外的进展，庆祝你所取得的进步。”
### DevOps 和敏捷开发如何协同工作？
```
“DevOps ！= 敏捷。其次 敏捷 ！=Scrum流程”
```
这是一个重要的问题，因为 DevOps 和敏捷开发都是现代软件开发的基石。
DevOps 是一个软件开发的过程，专注与沟通与协作，以促进快速部署应用程序和产品。而敏捷开发是一种开发方法，涉及持续开发，连续迭代和连续测试，以实现可预测和可交付的成果质量。
那么，它们又有怎样的联系？让我们去问问专家吧。
在 Brent 来看，“DevOps！= 敏捷。其次 敏捷！=Scrum 流程。。。敏捷工具和工作方式——支撑着 DevOps 策略和目标——它们是如此融合在一起的。”
Chris 说，“对我而言敏捷是 DevOps 的一个基本组件。当然，我们可以讨论如何在非敏捷开发环境中采用 DevOps 文化，但最终表明，提高软件设计方式的灵活性是采用 DevOps 成熟读的一个关键指标。”
Dan 将 DevOps 与更伟大的[敏捷宣言 ][8] 联系起来。“我在谈到敏捷时总会引用敏捷宣言来设置基准，而有许多实现中并不关注宣言。当您阅读宣言时，您会发现它确实从开发的角度描述了 DevOps。因此，将敏捷融入 DevOps 文化非常容易，因为敏捷关注于沟通、协作、变化的灵活性以及快速地投入生产。”
Geoff 认为 “DevOps 是敏捷实施的众多实现之一。敏捷本质上是一套原则，而 DevOps 则是体现这些原则的文化、流程和工具链。”
Ann Marie 简洁说明，“敏捷是 DevOps 的先决条件。DevOps 使敏捷变得更加有效。”
### DevOps 是否受益于开源？
```
”开源做得好，需要DevOps文化。“
```
这个问题得到了所有参与者的热烈肯定，然后解释了他们看到的好处。
Ann Marie 说，”我们站在巨人的肩膀上，在已有的基础之上发展。拉取请求和代码评审的开源模式，对 DevOps 团队维护软件很有效果。“
Chris” 毫无疑问“地赞同 DevOps 受益于开源。”从设计和工具方面（例如，Ansible），到流程和人员方面，通分享行业内的故事和开源社区的领导。“
Geoff 提到一个好处是”基层的采纳“。没有人需要签署购买或申请免费（如免费啤酒）的软件。团队发现了满足他们需求的工具，可以自行（自由的）进行修改。[然后]在它之上构建，并为更大的社区提供更好的功能。如此往复。
开源已经向 DevOps 展示着”就像开源软件开发者那样做，采用更好的方式来来克服新的变化 “，Daniel 说。
Brent 同意道 ”DevOps 从开源中获益良多。一种方法是使用这些工具来理解它们是如何加速 DevOps 的目标和策略；在自动化、自动伸缩、虚拟化和容器化等关键方面对开发人员和操作人员进行培训，如果不引入使 DevOps 更加容易的技术支持，就很难实现这些特性。”
Dan 指出了 DevOps 和开源之间的双向共生关系，“做好开源需要 DevOps 文化。大多数开源项目都具有非常开放的沟通结构，很少有不透明的地方。对于 Devops 实践者来说，这实际上是一个很好的学习机会，可以让他们了解到可能需要将什么引入自己的组织中。此外能够使用来自社区与组织类似的工具来鼓励自己的文化成长。我喜欢用 GitLab 作为这种共生关系的一个例子。当我把 GitLab 带入一家公司时，我们得到了一个很棒的工具，但我们真正购买的是他们独特的文化，通过我们与他们的互动以及我们的贡献带来了巨大价值。他们的工具也可以为 Devops 组织提供更多东西，而他们的文化已经在我介绍它给的公司中引起了他们的敬畏。”
现在我们的 DevOps 专家已经参与进来了，请在评论中分享您对 DevOps 的理解，以及向我们提出其其他问题。
--------------------------------------------------------------------------------
via: https://opensource.com/article/19/1/what-does-devops-mean-you
作者：[Girish Managoli][a]
选题：[lujun9972][b]
译者：[MZqk](https://github.com/MZqk)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://opensource.com/users/gammay
[b]: https://github.com/lujun9972
[1]: https://twitter.com/DukeAMO
[2]: https://twitter.com/danieloh30?lang=en
[3]: https://twitter.com/brentareed
[4]: https://twitter.com/barkerd427
[5]: https://psnet.ahrq.gov/resources/resource/1582
[6]: https://twitter.com/onlychrisbh?lang=en
[7]: https://twitter.com/geoff_purdy
[8]: https://agilemanifesto.org/

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[#]: collector: "lujun9972"
[#]: translator: "sanfusu "
[#]: reviewer: " "
[#]: publisher: " "
[#]: url: " "
[#]: subject: "Blockchain 2.0: An Introduction [Part 1]"
[#]: via: "https://www.ostechnix.com/blockchain-2-0-an-introduction/"
[#]: author: "EDITOR https://www.ostechnix.com/author/editor/"
# 区块链 2.0: 一份介绍 [Part 1]
![](https://www.ostechnix.com/wp-content/uploads/2019/03/blockchain-introduction-720x340.png)
### 区块链 2.0 - 下一个计算范式
**区块链**现在被认为是一种转型技术，它将为人们使用互联网的方式带来革新。本系列文章将探讨即将到来的基于区块链 2.0 的技术和应用。不同的涉众对它表现出的极大兴趣证明了区块链的存在。
对于任何打算使用互联网做任何事情的人来说，了解它是什么以及它是如何工作的都是至关重要的。即使你所做的只是盯着 Instagram 上朋友们的早餐照片，或者寻找下一个最好的视频片段，你也需要知道这项技术能对这些提供什么样的帮助。
尽管区块链的基本概念早在上世纪 90 年代就被学术界提及，但它之所以成为网民热词，要归功于诸如**比特币**和 **Ethers** 等支付平台的崛起。
比特币最初是一种去中心化的数字货币。它的出现意味着你基本上可以通过互联网进行完全匿名，安全可靠的支付。不过，在比特币这个简单的金融令牌系统背后，是区块链。您可以将比特币技术或任何加密货币看作是 3 层结构。区块链基础技术包括验证、记录和确认交易，在这个基础之上是协议，本质上来讲是一个规则或在线礼仪，用来尊重、记录和确认交易，当然，最重要的是通常被称作比特币的加密货币令牌。一旦记录了协议相关的事务，区块链就会生成令牌。
虽然大多数人只看到了最顶层，即代表比特币真正含义的硬币或代币，但很少有人敢于深入了解，在区块链基金会的帮助下，金融交易只是众多此类可能性中的一种。目前正在探讨这些可能性，以产生和开发所有去中心化交易方式的新标准。
在最基本的层次上，区块链可以被认为是一个包含所有记录和交易的账簿。这实际上意味着区块链理论上可以处理所有类型的记录。未来这方面的发展可能会导致各种硬资产(如房地产契约、实物钥匙等)和软无形资产(如身份记录、专利、商标、预约等)被编码为数字资产，通过区块链进行保护和转让。
对于不熟悉区块链的人来说，区块链上的事务本质上被认为是无偏见的永久记录。这是可能的，因为协议中内置了**共识系统**。所有交易均由系统参与者确认、审核和记录，在比特币加密货币平台中，该角色由**矿商**和交易所负责。这可能因平台而异，也可能因区块链到区块链而异。根据定义，构建该平台的协议栈应该是开放源码的，并且对任何具有技术能力的人都是免费的。与目前互联网上运行的许多其他平台不同，该系统内置了透明度。
一旦事务被记录并编码到区块链中，它们就会被看穿。参与者有义务按照他们最初打算执行的方式履行他们的交易和合同。除非最初的条款禁止执行，否则执行本身将由平台自动处理，因为它是硬编码的。区块链平台对于试图篡改记录、记录的持久性等方面的恢复能力，在因特网上是闻所未闻的。当这项技术的支持者们宣称其日益重要的意义时，这种能力是经常被提及的附加信任层。
这些特性并不是最近发现的隐藏的平台潜力，而是从一开始就被设想出来的。公报中，**Satoshi Nakamoto（中本聪）**，传说中的比特币创造者，**“我花了数年的时间来构造一个用来支撑巨大的各种可能事务类型的设计……如果比特币能够流行起来，这些都是我们未来要探索的……但是他们从设计之初，就要确保他们以后可能性。”**。结合这样一个事实，即这些特性被设计并融入到已经存在的协议中。关键的想法是，去中性化的事务分类账(如区块链的功能)可以用于传输、部署和执行各种形式的契约。
领先机构目前正在探索重新发明股票、养老金和衍生品等金融工具的可能性，而世界各国政府更关注区块链的防篡改和永久性保存记录的潜力。该平台的支持者声称，一旦开发达到一个关键的门槛，从你的酒店钥匙卡到版权和专利，那时起，一切都将通过区块链记录和实现。
**Ledra Capital**在[**这个**][1]页面上编译并维护了几乎完整的项目和细节列表，这些项目和细节理论上可以通过区块链模型实现。想要真正意识到区块链对我们生活的影响有多大是一项艰巨的任务，但看看这个清单就会重申这么做的重要性。
现在，上面提到的所有官僚和商业用途可能会让你相信，这样的技术只会出现在政府和大型私营企业领域。然而，事实远非如此。鉴于该系统的巨大潜力使其对此类用途具有吸引力，区块链还具有其他可能性和特性。还有一些与该技术相关的更复杂的概念，如**DApps**、**DAOs**、**DACs**、**DASs**等，本系列文章将深入讨论这些概念。
基本上，开发正在如火如荼地进行，任何人都还没有来得及对基于区块链的系统的定义、标准和功能进行评论，以便进行更广泛的推广，但是这种可能性及其即将产生的影响无疑是存在的。甚至有人谈到基于区块链的智能手机和选举期间的投票。
这只是一个简短的鸟瞰平台的能力。我们将通过一系列这样详细的帖子和文章来研究这些不同的可能性。关注[**本系列的下一篇文章**][2]，它将探索区块链是如何革新交易和契约的。
---
via: https://www.ostechnix.com/blockchain-2-0-an-introduction/
作者：[EDITOR][a]
选题：[lujun9972][b]
译者：[sanfusu](https://github.com/sanfusu)
校对：[校对者 ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux 中国](https://linux.cn/) 荣誉推出
[a]: https://www.ostechnix.com/author/editor/
[b]: https://github.com/lujun9972
[1]: http://ledracapital.com/blog/2014/3/11/bitcoin-series-24-the-mega-master-blockchain-list
[2]: https://www.ostechnix.com/blockchain-2-0-revolutionizing-the-financial-system/

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[#]:collector:(lujun9972)
[#]:translator:(lujun9972)
[#]:reviewer:()
[#]:publisher:()
[#]:url:()
[#]:subject:(ManageYourMirrorswithArchLinuxMirrorlistManager)
[#]:via:(https://itsfoss。com/archlinux-mirrorlist-manager)
[#]:author:(JohnPaulhttps://itsfoss.com/author/john/)
使用 Arch Linux Mirrorlist Manager 管理你的镜像
======
**Arch Linux Mirrorlist Manager 时一个简单的图形化程序，它让你可以方便地管理 ArchLinux 中的镜像。**
对于 Linux 用户来说，保持好的镜像列表非常重要。今天我们来介绍一个用来管理 Arch 镜像列表的应用程序。
！[Arch Linux Mirrorlist Manager][1]
Arch Linux Mirrorlist Manager
### 什么是镜像？
至新手，Linux 操作系统有赖于分布全球的的一系列服务器。这些服务器包含了特定发行版的所有可用的软件包的相同副本。这就是为什么它们被称为“镜像”。
这些服务器的最终目标时让每个国家都有多个镜像。这样就能让当地的用户可以快速升级系统。然而，这并不绝对。有时别国的镜像反而更快。
### Arch Linux Mirrorlist Manager 让在 ArchLinux 中管理镜像更简单
！[Arch Linux Mirrorlist Manager][2]
主界面
在 Arch 中[管理并对有效镜像进行排序 ][3] 不是个简单的事情。它需要用到很长的命令。还好，有人想出了一个解决方案。
去年，[RizwanHasan][4] 用 Python 编写了一个名为 [Arch Linux Mirrorlist Manager][5] 的 Qt 应用程序。你可能对 Rizwan 这个名字感到眼熟，因为这不是第一次我们在本站介绍他做的玩意了。一年多前，我介绍过一个名为 [MagpieOS][6] 的基于 Arch 的新 Linux 发行版就是 Rizwan 创造的。我想 Rizwan 创造 MagpieOS 的经历激励了他创建了这个程序。
Arch Linux Mirrorlist Manager 的功能并不多。它让你根据回应速度对镜像进行排序，并可以根据数量和国家进行过滤。
也就是说，若你在德国，你可以限制只保留在位于德国的最快的 3 个镜像。
### 安装 Arch Linux Mirrorlist Manager
```
它仅适用于 Arch Linux 用户
注意! ArchLinux Mirrorlist Manager 只能应用于Arch linux发行版. 不要在其他基于Arch的发行版中使用它,除非你能确定该发行版使用的是Arch镜像. 否则, 你将会遇到我在Manjaro中遇到的问题(在下面章节解释).
```
```
Manjaro的镜像管理器替代者
当使用类Arch的系统时, 我选择了Manjaro. 在开始本文之前, 我在Manjaro及其上安装了 ArchLinux Mirrorlist Manager. 它很快就对有效镜像进行了排序并保存到我的镜像列表中.
然后我尝试进行系统更新却立即遇到了问题. 当 ArchLinux Mirrorlist Manager 对我系统使用的镜像进行排序时, 它使用普通的Arch镜像替换了我的 Manjaro 镜像. (Manjaro 基于Arch, 但却有着自己的镜像,这是因为开发团队会在推送软件包之前对所有这些软件包进行测试以保证不会出现系统崩溃的BUG.) 还好, Manjaro 论坛帮我修复了这个错误.
若你是 Manjaro 用户, 请不要重蹈我的覆辙. ArchLinux Mirrorlist Manager 仅适用于Arch以及使用Arch镜像的衍生版本.
幸运的是, manjaro有一个简单易用的终端程序来管理镜像列表. 那就是 [Pacman-mirrors][7]. 跟 ArchLinux Mirrorlist Manager 一样, 你可以根据回应速度进行排序. 只需要运行 `sudo pacman-mirrors --fasttrack` 即可. 若你像将结果局限在最快的5个镜像, 可以运行 `sudo pacman-mirrors --fasttrack 5`. 要像将结果局限在某个或某几个国家, 运行 `sudo pacman-mirrors --country Germany,Spain,Austria`. 你可以通过运行 `sudo pacman-mirrors --geoip` 来将结果局限在自己国家. 更多关于Pacman-mirrors的信息请参见 [Manjaro wiki][7].
运行Pacman-mirrors后, 你还需要运行 `sudo pacman -Syyu` 来同步软件包数据库并升级系统.
注意: Pacman-mirrors 仅仅适用于 **Manjaro**.
```
Arch Linux Mirrorlist Manager 包含在 [ArchUserRepository][8] 中。高级 Arch 用户可以直接从 [theGitHubpage][9] 下载 PKGBUILD。
### 对 Arch Linux Mirrorlist Manager 的最后思考
虽然 [Arch Linux Mirrorlist Manager][5] 对我不太有用，我很高兴有它的存在。这说明 Linux 用户正在努力让 Linux 更 n 加易于使用。正如我之前说过的，在 Arch 中管理镜像并不容易。Rizwan 的小工具可以让 Arch 对新手更加友好。
你有用过 Arch Linux Mirrorlist Manager 吗？你是怎么管理 Arch 镜像的？请在下面的评论告诉我。
如果你觉的本文有趣的话，请花点时间将它分享到社交媒体，HackerNews 或 [Reddit][10] 中去。
--------------------------------------------------------------------------------
via: https://itsfoss.com/archlinux-mirrorlist-manager
作者：[John Paul][a]
选题：[lujun9972][b]
译者：[lujun9972](https://github.com/lujun9972)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://itsfoss.com/author/john/
[b]: https://github.com/lujun9972
[1]: https://i2.wp.com/itsfoss.com/wp-content/uploads/2019/02/mirrorlist-manager2.png?ssl=1
[2]: https://i0.wp.com/itsfoss.com/wp-content/uploads/2019/02/mirrorlist-manager4.jpg?ssl=1
[3]: https://wiki.archlinux.org/index.php/Mirrors
[4]: https://github.com/Rizwan-Hasan
[5]: https://github.com/Rizwan-Hasan/ArchLinux-Mirrorlist-Manager
[6]: https://itsfoss.com/magpieos/
[7]: https://wiki.manjaro.org/index.php?title=Pacman-mirrors
[8]: https://aur.archlinux.org/packages/mirrorlist-manager
[9]: https://github.com/Rizwan-Hasan/MagpieOS-Packages/tree/master/ArchLinux-Mirrorlist-Manager
[10]: http://reddit.com/r/linuxusersgroup

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[#]: collector: (lujun9972)
[#]: translator: (sanfusu)
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: subject: (Blockchain 2.0: Revolutionizing The Financial System [Part 2])
[#]: via: (https://www.ostechnix.com/blockchain-2-0-revolutionizing-the-financial-system/)
[#]: author: (EDITOR https://www.ostechnix.com/author/editor/)
区块链2.0：金融体系改革[第2部分]
======
这是我们[**Blockchain 2.0**] [1]系列的第二部分。区块链可以改变个人和机构处理他们财务状况的方式。本文着眼于现有货币体系如何演变以及新的区块链系统如何为货币演变的下一个关键步骤带来改变。
两个关键思想将为本文奠定基础。 **PayPal** 在推出之时，其运营操作上具有革命性。该公司将收集，处理和确认大量的消费者数据，以促进各种在线交易，从而切实允许 eBay 等平台成长为可信赖的商业来源，并为全球数字支付系统奠定基准。其二，虽然是要强调的更为重要的关键思想，但却是一个存在性问题。我们都使用金钱或货币来满足我们的日常需求。一张 10 美元的账单可以让你从最喜欢的咖啡店买到一两杯咖啡，从而开始美好的一天。事实上，我们各方面都依赖于各自的国家货币。
当然，自从**易货系统**开始决定你的早餐是什么起，人类已经度过了漫长的时间。但是，货币到底是什么？谁或什么赋予它的价值？正如流行的谣言所说，去银行并给他们一美元钞票就可以获得货币“符号”所代表的真正价值吗？
大多数问题的答案都不存在。如果他们这样做，他们最多将是不可思议的模糊和主观。早在文明开始建立小城镇的那一天，本地货币被统治者认为合法是合法货币，并且几乎总是由那个社区中宝贵的东西组成。人们认为印第安人使用干胡椒进行交易，而古希腊人和罗马人则使用**盐**[1]交易。渐渐地，这些史前启蒙文明中的大部分都采用贵重金属和石头作为代​​币进行交易。金币，银饰和红宝石开始与“价值”同名。随着工业发展，人们开始印刷这些交易凭证，我们终于似乎看到了对纸币需求的呼吁。纸币可靠且廉价，只要国家为其用户所持纸币提供担保，纸币所代表的“价值”可以在需要时，由同等价值的黄金或硬通货作支撑，人们便乐于使用它们。但是，如果你仍然认为你现在持有的纸币具有相同的保证，那么您就错了。我们目前生活在一个几乎所有主要货币都在全球流通的时代，经济学家称之为**法定货币** [2]。缺少价值的纸片只能得到你所居住的国家的保证支持。法定货币的确切性质以及为什么它们可能是一个有缺陷的系统属于经济领域，我们目前不会涉及。
事实上，所有这一历史中与本篇文章相关的唯一的一点是，文明开始使用暗示或代表商品和服务贸易价值的代币，而不是非实际的易货系统。代币，当然，这也是加密货币背后的关键概念。他们没有任何固有的价值。它们的价值取决于采用该特定平台的人数，采用者对系统的信任，当然还有监管实体本身的背景（如果有监管实体的话）。 **比特币（BTC）**的高价格和市值并非巧合，它们是业内第一个加密货币并且有很多早期采用者。加密货币背后的最终真理使其如此重要而又具有如此难以理解的复杂性。这是“金钱”自然演变的下一步。有些人理解这一点，有些人仍然想到坚实的货币概念，其中“真正的”货币总是由某种内在价值支持。[3]虽然已经有无数关于这种困境的辩论和研究，但仍没有着眼于区块链的未来。
例如，**厄瓜多尔**在 2015 年成为头条新闻，因为它声称计划开发和发布**自己的国家加密货币** [4]。虽然官方尝试是为了援助和支持他们现有的货币体系。从那时起，其他国家及其监管机构已经或正在起草文件来控制加密货币的“流行病”，其中一些已经发布了框架，以创建区块链和加密开发的路线图。 **德国**被认为正在长期投资区块链项目，以简化其税收和金融系统[5]。发展中国家的银行正在加入一个名为银行链的体系中，用以合作创建**私有区块链**以提高他们的效率并优化其运营
现在，当我们将故事的两端结合在一起时，还记得在休闲历史课之前首次提到PayPal吗？专家们将比特币（BTC）的采用率与 PayPal 的采用率进行了比较。消费者最初有所犹豫，只有少数早期采用者准备好使用上述产品，但随后更广泛的采用逐渐成为类似平台的标杆态势。比特币（BTC）已经成为类似加密货币平台的基准，其主要硬币包括**以太坊（ETH）**和**波纹（XRP）** [6]。采用正在稳步增加，法律和监管框架也正在制定以支持它，积极的研究和开发也在进行中。与 PayPal 不同，专家认为，利用区块链技术为其数字基础设施提供加密货币和平台将很快成为标准规范而非个例。
尽管 2018 年加密货币价格的上涨可以被称为经济泡沫，但公司和政府仍在继续投资开发自己的区块链平台和金融代币。为了抵制和预防未来发生这样的事件，并同时同时继续在该领域投资，替代传统加密货币的**稳定币**已经开发成功。
金融巨头**摩根大通**推出了他们自己的企业就绪区块链解决方案，名为**Quorum**，用来处理被称为 **JPM Coin**[7]的稳定币。每个这样的 JPM 硬币都与 1 美元挂钩，其价值由母公司在支持法律框架下保证。像这样的平台使大型金融交易更容易通过互联网瞬间传输数百万或数十亿美元的音乐，而不必依赖 SWIFT 这样的传统银行系统，这些系统有着冗长的程序，而且本身已有数十年历史。
为了让区块链的细节可供所有人使用，以太坊平台允许第三方利用他们的区块链或从中派生以创建和管理他们自己对**区块链-协议-令牌**三元组的看法。该系统使用更少的基础工作量来推动更广泛的标准采纳。
区块链允许通过网络快速创建，记录和交易现有金融工具的数字版本，而无需第三方监控。该系统固有的安全性和安保特性使整个过程完全安全，并且不受欺诈和篡改的影响，这基本上是该部门需要第三方监控的唯一原因。政府和监管机构在金融服务和工具方面涉及的另一个领域是透明度和审计。通过区块链，银行和其他金融机构将能够维护完全透明，分层，几乎永久保存和防篡改的所有交易记录，使审计任务几乎无用。通过利用区块链，可以使当前金融系统和服务行业急需的发展和变化成为可能。分布式，防篡改，接近永久性存储和快速执行的平台对于银行家和政府监管机构来说都是非常有价值的，他们在这方面的投资似乎很有用[8]。
在本系列的下一篇文章中，我们将了解公司如何使用区块链来提供下一代金融服务。纵观在行业中创造涟漪的个别公司后，我们将探讨区块链下的经济未来会如何发展。
-------------------------------------------------- ------------------------------
通过：https：//www.ostechnix.com/blockchain-2-0-revolutionizing-the-financial-system/
作者：[EDITOR] [A]
选题：[lujun9972] [B]
译者：[sanfusu]（https://github.com/sanfusu）
校对：校对者ID]（https://github.com/校对者ID）
本文由[LCTT]（https://github.com/LCTT/TranslateProject）原创编译，[Linux中国]（https://linux.cn/）荣誉推出
[a]：https：//www.ostechnix.com/author/editor/
[b]：https：//github.com/lujun9972
[1]：https：//www.ostechnix.com/blockchain-2-0-an-introduction/

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[#]: via: (https://opensource.com/article/19/3/raspberry-pi-entertainment)
[#]: author: (Anderson Silva https://opensource.com/users/ansilva)
How to use your Raspberry Pi for entertainment
如何用树莓派来娱乐
======
Learn how to watch Netflix and listen to music on your Raspberry Pi, in the eighth article in our guide to getting started with Raspberry Pi.
在我们的树莓派使用入门的第八篇文章中，我们将学习如何使用树莓派观看 Netflix 上的影片和用它来听音乐。
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/video_editing_folder_music_wave_play.png?itok=-J9rs-My)
So far, this series has focused on more serious topics—how to [choose][1], [buy][2], [set up][3], and [update][4] your Raspberry Pi, and different things [kids][5] and [adults][6] can learn with it (including [Linux][7]). But now it's time to change up the subject and have some fun! Today we'll look at ways to use your Raspberry Pi for entertainment, and tomorrow we'll continue the fun with gaming.
到目前为止，本系列文章已经学习了很多话题 — 如何 [挑选][1]、[购买][2]、[设置][3]、和 [更新][4] 你的树莓派，以及 [儿童][5] 和 [成人][6] 如何使用它来做的不同的事情（包括学习 [Linux][7]）。今天我们换一个话题，将学习一些娱乐方面的内容！我们将学习如何使用树莓派来做一些娱乐方面的事情，明天我们继续这个话题，将用它来玩游戏。
### Watch TV and movies
### 观看电视和电影
You can use your Raspberry Pi and the [Open Source Media Center][8] (OSMC) to [watch Netflix][9]! The OSMC is a system based on the [Kodi][10] project that allows you to play back media from your local network, attached storage, and the internet. It's also known for having the best feature set and community among media center applications.
你可以使用你的树莓派和 [开源媒体中心][8] (OSMC) 去 [观看 Netflix][9]！OSMC 是一个基于 [Kodi][10] 项目的系统，你可以使用它来播放来自本地网络、附加存储、以及互联网上的多媒体。它因为良好的功能特性而在媒体播放应用界中拥有非常好的口碑。
NOOBS (which we talked about in the [third article][11] in this series) allows you to [install OSMC][12] on your Raspberry Pi as easily as possible. NOOBS also offers another media center system based on Kodi called [LibreELEC][13].
NOOBS（我们在本系列的 [第三篇文章][11] 中介绍过它）可以让你在你的树莓派中很容易地 [安装 OSMC][12]。在 NOOBS 中也提供了另外一个基于 Kodi 项目的媒体播放系统，它的名字叫 [LibreELEC][13]。
### Listen to music
### 听音乐
![](https://opensource.com/sites/default/files/uploads/raspberrypi_8_pimusicbox.png)
You can also stream music on your network via attached storage or services like Spotify on your Raspberry Pi with the [Pi Music Box][14] project. I [wrote about it][15] a while ago, but you can find newer instructions, including how to's and DIY projects, on the [Pi Music Box website][16].
你还可以让你的树莓派借助 [Pi Music Box][14] 项目通过网络来播放来自附加存储或像 Spotify 服务上的流媒体音乐。以前我 [写过关于这个主题的文章][15]，但是你可以在 [Pi Music Box 网站][16] 上找到最新的指导，包括如何使用和 DIY 项目。
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@ -32,7 +32,7 @@ via: https://opensource.com/article/19/3/raspberry-pi-entertainment
作者：[Anderson Silva][a]
选题：[lujun9972][b]
译者：[译者ID](https://github.com/译者ID)
译者：[qhwdw](https://github.com/qhwdw)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出

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[#]: translator: (geekpi)
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[#]: subject: (Emulators and Native Linux games on the Raspberry Pi)
[#]: via: (https://opensource.com/article/19/3/play-games-raspberry-pi)
[#]: author: (Anderson Silva https://opensource.com/users/ansilva)
树莓派上的模拟器和原生 Linux 游戏
======
树莓派是一个很棒的游戏平台。在我们的系列文章的第九篇中学习如何开始使用树莓派。
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/getting_started_with_minecraft_copy.png?itok=iz4RF7f8)
回到我们关于树莓派入门系列文章的[第五篇][1]，我提到 Minecraft 是一种教孩子们使用游戏平台进行编程的方法。作为一个不错的游戏平台，今天我们将讨论在树莓派上使用或者不使用模拟器来玩游戏的方式。
### 使用模拟器玩游戏
模拟器是一种能让你在树莓派上玩不同系统，不同年代游戏的软件。在如今众多的模拟器中，[RetroPi][2] 是树莓派中最受欢迎的。你可以用它来玩 Apple II、Amiga、Atari 2600、Commodore 64、Game Boy Advance 和[其他许多][3]游戏。
如果 RetroPi 听起来有趣，请阅读[这些说明][4]开始使用，玩得开心！
### 原生 Linux 游戏
树莓派的操作系统 Raspbian 上也有很多原生 Linux 游戏。“Make Use Of” 有一篇关于如何在树莓派上[玩 10 个老经典游戏][5]如 Doom 和 Nuke Dukem 3D 的文章。
你也可以将树莓派用作[游戏服务器][6]。例如，你可以在树莓派上安装 Terraria、Minecraft 和 QuakeWorld 服务器。
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via: https://opensource.com/article/19/3/play-games-raspberry-pi
作者：[Anderson Silva][a]
选题：[lujun9972][b]
译者：[geekpi](https://github.com/geekpi)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://opensource.com/users/ansilva
[b]: https://github.com/lujun9972
[1]: https://opensource.com/article/19/3/teach-kids-program-raspberry-pi
[2]: https://retropie.org.uk/
[3]: https://retropie.org.uk/about/systems
[4]: https://opensource.com/article/19/1/retropie
[5]: https://www.makeuseof.com/tag/classic-games-raspberry-pi-without-emulators/
[6]: https://www.makeuseof.com/tag/raspberry-pi-game-servers/

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[#]: collector: (lujun9972)
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[#]: subject: (Let's get physical: How to use GPIO pins on the Raspberry Pi)
[#]: via: (https://opensource.com/article/19/3/gpio-pins-raspberry-pi)
[#]: author: (Anderson Silva https://opensource.com/users/ansilva)
进入物理世界：如何使用树莓派的 GPIO 针脚
======
在树莓派使用入门的第十篇文章中，我们将学习如何使用 GPIO。
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/raspbery_pi_zero_wireless_hardware.jpg?itok=9YFzdxFQ)
到目前为止，本系列文章主要专注于树莓派的软件方面，而今天我们将学习硬件。在树莓派最初发布时，最让我感兴趣的主要特性之一就是它的 [通用输入输出][1]（GPIO）针脚。GPIO 可以让你的树莓派程序与连接到它上面的传感器、继电器、和其它类型的电子元件与物理世界来交互。
![](https://opensource.com/sites/default/files/uploads/raspberrypi_10_gpio-pins-pi2.jpg)
树莓派上的每个 GPIO 针脚要么有一个预定义的功能，要么被设计为通用的。另外，不同的树莓派型号要么 26 个，要么有 40 个 GPIO 针脚是你可以随意使用的。在维基百科上有一个 [关于每个针脚的非常详细的说明][2] 以及它的功能介绍。
你可以使用树莓派的 GPIO 针脚做更多的事情。关于它的 GPIO 的使用我写过一些文章，包括使用树莓派来控制节日彩灯的三篇文章（[第一篇][3]、 [第二篇][4]、和 [第三篇][5]），在这些文章中我通过使用开源程序让灯光随着音乐起舞。
树莓派社区在不同编程语言上创建不同的库方面做了非常好的一些工作，因此，你能够使用 [C][6]、[Python][7]、 [Scratch][8]、和其它语言与 GPIO 进行交互。
另外，如果你想在树莓派与物理世界交互方面获得更好的体验，你可以选用 [Raspberry Pi Sense Hat][9]，它是插入树莓派 GPIO 针脚上的一个很便宜的电路板，借助它你可以通过程序与 LED、驾驶杆、气压计、温度计、温度计、 陀螺仪、加速度计、以及磁力仪来交互。
--------------------------------------------------------------------------------
via: https://opensource.com/article/19/3/gpio-pins-raspberry-pi
作者：[Anderson Silva][a]
选题：[lujun9972][b]
译者：[qhwdw](https://github.com/qhwdw)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://opensource.com/users/ansilva
[b]: https://github.com/lujun9972
[1]: https://www.raspberrypi.org/documentation/usage/gpio/
[2]: https://en.wikipedia.org/wiki/Raspberry_Pi#General_purpose_input-output_(GPIO)_connector
[3]: https://opensource.com/life/15/2/music-light-show-with-raspberry-pi
[4]: https://opensource.com/life/15/12/ssh-your-christmas-tree-raspberry-pi
[5]: https://opensource.com/article/18/12/lightshowpi-raspberry-pi
[6]: https://www.bigmessowires.com/2018/05/26/raspberry-pi-gpio-programming-in-c/
[7]: https://www.raspberrypi.org/documentation/usage/gpio/python/README.md
[8]: https://www.raspberrypi.org/documentation/usage/gpio/scratch2/README.md
[9]: https://opensource.com/life/16/4/experimenting-raspberry-pi-sense-hat

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[#]: subject: (Learn about computer security with the Raspberry Pi and Kali Linux)
[#]: via: (https://opensource.com/article/19/3/computer-security-raspberry-pi)
[#]: author: (Anderson Silva https://opensource.com/users/ansilva)
通过树莓派和 kali Linux 学习计算机安全
======
树莓派是学习计算机安全的一个好方法。在我们入门系列的第 11 篇文章中会进行学习。
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/security_privacy_lock.png?itok=ZWjrpFzx)
是否有比保护你的计算机更热门的技术？一些专家会告诉你，没有绝对安全的系统。他们开玩笑说，如果你想要你的服务器或者应用程序真正的安全，就关掉你的服务器，从网络上断线，然后把它放在一个安全的地方。但问题是显而易见的：没人能用的应用程序或者服务器有什么用？
这是围绕安全的一个难题，我们如何才能在保证安全性的同时，让服务器或应用程序依然可用且有价值？我无论如何都不是一个安全专家，虽然我希望有一天我能是。考虑到这一点，对于你能用树莓派做什么，分享和这有关的想法来学习计算机安全，我认为是有意义的。
我会注意到，就像本系列中其他写给树莓派初学者的文章一样，我的目标不是深入研究，而是起个头，让你有兴趣去了解更多与这些主题相关的东西。
### Kali Linux
当我们谈到“做一些安全方面的事”的时候，出现在脑海中的一个 Linux 发行版就是 Kali Linux。kali Linux 的开发主要集中在调查取证和渗透测试方面。它有超过 600 个已经预先安装好了的渗透测试工具来测试你的计算机的安全性，以及取证模式，它可以防止自己接触到内部的硬盘驱动器或是被检查系统的交换空间。
![](https://opensource.com/sites/default/files/uploads/raspberrypi_11_kali.png)
就像 Raspbian 一样，Kali Linux 基于 Debian 的发行版，你可以在 kali 的主文档门户网页上找到将它安装在树莓派上的文档（译者注：截至到翻译时，该网页是这个：https://docs.kali.org/kali-on-arm/install-kali-linux-arm-raspberry-pi）。如果你已经在你的树莓派上安装了 Raspbian 或者是其他的 Linux 发行版。那么你装 Kali 应该是没问题的，Kali 的创造者甚至将培训、研讨会和职业认证整合到了一起，以此来帮助提升你在安全领域内的职业生涯。
### 其他的 Linux 发行版
大多数的标准 Linux 发行版，比如 Raspbian，Ubuntu 和 Fedora 这些，在它们的仓库里同样也有很多可用的安全工具。一些很棒的探测工具包括 Nmap，Wireshark，auditctl，和 SELinux。
### 项目
你可以在树莓派上运行很多其他的安全相关的项目，例如蜜罐，广告拦截器和 USB 清洁器。花些时间了解它们！
--------------------------------------------------------------------------------
via: https://opensource.com/article/19/3/computer-security-raspberry-pi
作者：[Anderson Silva][a]
选题：[lujun9972][b]
译者：[hopefully2333](https://github.com/hopefully2333)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://opensource.com/users/ansilva
[b]: https://github.com/lujun9972
[1]: https://www.kali.org/
[2]: https://en.wikipedia.org/wiki/Kali_Linux#Development
[3]: https://docs.kali.org/general-use/kali-linux-forensics-mode
[4]: https://docs.kali.org/kali-on-arm/install-kali-linux-arm-raspberry-pi
[5]: https://www.kali.org/penetration-testing-with-kali-linux/
[6]: https://linuxblog.darkduck.com/2019/02/9-best-linux-based-security-tools.html
[7]: https://nmap.org/
[8]: https://www.wireshark.org/
[9]: https://linux.die.net/man/8/auditctl
[10]: https://opensource.com/article/18/7/sysadmin-guide-selinux
[11]: https://trustfoundry.net/honeypi-easy-honeypot-raspberry-pi/
[12]: https://pi-hole.net/
[13]: https://www.circl.lu/projects/CIRCLean/

49
translated/tech/20190312 Do advanced math with Mathematica on the Raspberry Pi.md Normal file
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[#]: collector: (lujun9972)
[#]: translator: (geekpi)
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: subject: (Do advanced math with Mathematica on the Raspberry Pi)
[#]: via: (https://opensource.com/article/19/3/do-math-raspberry-pi)
[#]: author: (Anderson Silva https://opensource.com/users/ansilva)
在树莓派上使用 Mathematica 进行高级数学运算
======
Wolfram 将一个版本 Mathematica 捆绑到了 Raspbian 中。在我们关于树莓派入门系列的第 12 篇文章中学习如何使用它。
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/edu_math_formulas.png?itok=B59mYTG3)
在 90 年代中期，我进入了大学数学专业，即使我以计算机科学学位毕业，第二专业数学我已经上了足够的课程，但还有两门小课没有上。当时，我被介绍了 [Wolfram][2] 中一个名为[Mathematica][1] 的应用，我们可以将黑板上的许多代数和微分方程输入计算机。我每月花几个小时在实验室学习 Wolfram 语言并在 Mathematica 上解决积分等问题。
对于大学生来说 Mathematica 是闭源而且昂贵的，因此在差不多 20 年后，看到 Wolfram 将一个版本的 Mathematica 与 Raspbian 和 Raspberry Pi 捆绑在一起是一个惊喜。如果你决定使用另一个基于 Debian 的发行版，你可以从这里[下载][3]。请注意，此版本仅供非商业用途免费使用。
树莓派基金会的 [Mathematica 简介][4]页面介绍了一些基本概念，如变量和循环、解决一些数学问题、创建图形、做线性代数，甚至通过应用与 GPIO 引脚交互。
![](https://opensource.com/sites/default/files/uploads/raspberrypi_12_mathematica_batman-plot.png)
要深入了解 Mathematica，请查看 [Wolfram 语言文档][5]。如果你只是想解决一些基本的微积分问题，请[查看它的函数][6]部分。如果你想[绘制一些 2D 和 3D 图形][7]，请阅读链接的教程。
或者，如果你想在做数学运算时坚持使用开源工具，请查看命令行工具 **expr**、**factor** 和 **bc**。（记住使用 [**man** 命令][8] 阅读使用帮助）如果想画图，[Gnuplot][9] 是个不错的选择。
--------------------------------------------------------------------------------
via: https://opensource.com/article/19/3/do-math-raspberry-pi
作者：[Anderson Silva][a]
选题：[lujun9972][b]
译者：[geekpi](https://github.com/geekpi)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://opensource.com/users/ansilva
[b]: https://github.com/lujun9972
[1]: https://en.wikipedia.org/wiki/Wolfram_Mathematica
[2]: https://wolfram.com/
[3]: https://www.wolfram.com/raspberry-pi/
[4]: https://projects.raspberrypi.org/en/projects/getting-started-with-mathematica/
[5]: https://www.wolfram.com/language/
[6]: https://reference.wolfram.com/language/guide/Calculus.html
[7]: https://reference.wolfram.com/language/howto/PlotAGraph.html
[8]: https://opensource.com/article/19/3/learn-linux-raspberry-pi
[9]: http://gnuplot.info/

46
sources/tech/20190315 How To Navigate Inside A Directory-Folder In Linux Without CD Command.md → translated/tech/20190315 How To Navigate Inside A Directory-Folder In Linux Without CD Command.md
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[#]: collector: (lujun9972)
[#]: translator: ( )
[#]: translator: (geekpi)
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
@ -7,37 +7,37 @@
[#]: via: (https://www.2daygeek.com/navigate-switch-directory-without-using-cd-command-in-linux/)
[#]: author: (Magesh Maruthamuthu https://www.2daygeek.com/author/magesh/)
How To Navigate Inside A Directory/Folder In Linux Without CD Command?
如何在 Linux 中不使用 CD 命令进入目录/文件夹？
======
As everybody know that we can’t navigate inside a directory in Linux without CD command.
众所周知，如果没有 CD 命令，我们无法 Linux 中切换目录。
Yes that’s true but we have the Linux built-in command called `shopt` that help us to solve this issue.
这个没错，但我们有一个名为 `shopt` 的 Linux 内置命令能帮助我们解决这个问题。
[shopt][1] is a shell builtin command to set and unset various bash shell options, which is installed so, we no need to install it again.
[shopt][1] 是一个 shell 内置命令，用于设置和取消设置各种 bash shell 选项，由于它已安装，因此我们不需要再次安装它。
Yes we can navigate inside a directory without CD command after enabling this option.
是的，我们可以在启用此选项后，可以不使用 CD 命令切换目录。
We will show you, how to do this in this article. This is a small tweak but it’s very useful for newbies who all are moving from Windows to Linux.
我们将在本文中向你展示如何操作。这是一个小的调整，但对于那些从 Windows 迁移到 Linux 的新手来说非常有用。
This is not useful for Linux administrator because we won’t navigate to the directory without CD command, as we had a good practices on this.
这对 Linux 管理员没用，因为我们不会在没有 CD 命令的情况下切换到该目录，因为我们对此有一个很好的做法。
If you are trying to navigate a directory/folder in Linux without cd command, you will be getting the following error message. This is common in Linux.
如果你尝试在没有 cd 命令的情况下切换 Linux 的目录/文件夹，你将看到以下错误消息。这在 Linux 中很常见。
```
$ Documents/
bash: Documents/: Is a directory
```
To achieve this, we need to append the following values in a user `.bashrc` file.
为此，我们需要在用户 `.bashrc` 中追加以下值。
### What Is the .bashrc File?
### 什么是 .bashrc ？
The “.bashrc” file is a shell script which is run every time a user opens a new shell in interactive mode.
“.bashrc” 是一个 shell 脚本，每次用户以交互模式打开新 shell 时都会运行该脚本。
You can add any command in that file that you want to type at the command prompt.
你可以在该文件中添加要在命令提示符下输入的任何命令。
The .bashrc file itself contains a series of configurations for the terminal session. This includes setting up or enabling: colouring, completion, the shell history, command aliases and more.
.bashrc 文件本身包含终端会话的一系列配置。包括设置和启用：着色、补全，shell 历史，命令别名等。
```
$ vi ~/.bashrc
@ -45,13 +45,13 @@ $ vi ~/.bashrc
shopt -s autocd
```
Run the following command to make the changes to take effect.
运行以下命令使更改生效。
```
$ source ~/.bashrc
```
We have done all the configuration. Simple do the testing on this to confirm whether this working or not.
我们已完成所有配置。简单地对此进行测试以确认这是否有效。
```
$ Documents/
@ -68,12 +68,12 @@ $ pwd
```
![][3]
Yes, it’s working fine as expected.
是的，它正如预期的那样正常工作。
However, it’s working fine in `fish shell` without making any changes in the `.bashrc` file.
而且，它在 `fish shell` 中工作正常，而无需对 `.bashrc` 进行任何更改。
![][4]
If you would like to perform this action for temporarily then use the following commands (set/unset). This will go away when you reboot the system.
如果要暂时执行此操作，请使用以下命令（set/unset）。重启系统时，它将消失。
```
# shopt -s autocd
@ -87,7 +87,7 @@ autocd on
autocd off
```
shopt command is offering so many other options and if you want to verify those, run the following command.
shopt 命令提供了许多其他选项，如果要验证这些选项，请运行以下命令。
```
$ shopt
@ -146,9 +146,9 @@ sourcepath on
xpg_echo off
```
I had found few other utilities, that are help us to navigate a directory faster in Linux compared with cd command.
我找到了一些其他程序，它们可以帮助我们在 Linux 中比 cd 命令更快地切换目录。
Those are pushd, popd, up shell script and bd utility. We will cover these topics in the upcoming articles.
它们是 pushd、popd、up shell 脚本和 bd 工具。我们将在接下来的文章中介绍这些主题。
--------------------------------------------------------------------------------
@ -156,7 +156,7 @@ via: https://www.2daygeek.com/navigate-switch-directory-without-using-cd-command
作者：[Magesh Maruthamuthu][a]
选题：[lujun9972][b]
译者：[译者ID](https://github.com/译者ID)
译者：[geekpi](https://github.com/geekpi)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出