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published/20191007 Using the Java Persistence API.md
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published/20191007 Using the Java Persistence API.md
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@ -0,0 +1,265 @@
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[#]: collector: (lujun9972)
|
||||
[#]: translator: (runningwater)
|
||||
[#]: reviewer: (wxy)
|
||||
[#]: publisher: (wxy)
|
||||
[#]: url: (https://linux.cn/article-11717-1.html)
|
||||
[#]: subject: (Using the Java Persistence API)
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||||
[#]: via: (https://opensource.com/article/19/10/using-java-persistence-api)
|
||||
[#]: author: (Stephon Brown https://opensource.com/users/stephb)
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|
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使用 Java 持久化 API
|
||||
======
|
||||
|
||||
> 我们通过为自行车商店构建示例应用程序来学习如何使用 JPA。
|
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|
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|
||||
|
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对应用开发者来说，<ruby>Java 持久化 API<rt>Java Persistence API</rt></ruby>（JPA）是一项重要的 java 功能，需要透彻理解。它为 Java 开发人员定义了如何将对象的方法调用转换为访问、持久化及管理存储在 NoSQL 和关系型数据库中的数据的方案。
|
||||
|
||||
本文通过构建自行车借贷服务的教程示例来详细研究 JPA。此示例会使用 Spring Boot 框架、MongoDB 数据库（[已经不开源][2]）和 Maven 包管理来构建一个大型应用程序，并且构建一个创建、读取、更新和删除（CRUD）层。这儿我选择 NetBeans 11 作为我的 IDE。
|
||||
|
||||
此教程仅从开源的角度来介绍 Java 持久化 API 的工作原理，不涉及其作为工具的使用说明。这全是关于编写应用程序模式的学习，但对于理解具体的软件实现也很益处。可以从我的 [GitHub 仓库][3]来获取相关代码。
|
||||
|
||||
### Java: 不仅仅是“豆子”
|
||||
|
||||
Java 是一门面向对象的编程语言，自 1996 年发布第一版 Java 开发工具（JDK）起，已经变化了很多很多。要了解其各种发展及其虚拟机本身就是一堂历史课。简而言之，和 Linux 内核很相似，自发布以来，该语言已经向多个方向分支发展。有对社区免费的标准版本、有针对企业的企业版本及由多家供应商提供的开源替代品。主要版本每六个月发布一次，其功能往往差异很大，所以确认选用版本前得先做些研究。
|
||||
|
||||
总而言之，Java 的历史很悠久。本教程重点介绍 Java 11 的开源实现 [JDK 11][4]。因其是仍然有效的长期支持版本之一。
|
||||
|
||||
* **Spring Boot** 是由 Pivotal 公司开发的大型 Spring 框架的一个模块。Spring 是 Java 开发中一个非常流行的框架。它支持各种框架和配置，也为 WEB 应用程序及安全提供了保障。Spring Boot 为快速构建各种类型的 Java 项目提供了基本的配置。本教程使用 Spring Boot 来快速编写控制台应用程序并针对数据库编写测试用例。
|
||||
* **Maven** 是由 Apache 开发的项目/包管理工具。Maven 通过 `POM.xml` 文件来管理包及其依赖项。如果你使用过 NPM 的话，可能会非常熟悉包管理器的功能。此外 Maven 也用来进行项目构建及生成功能报告。
|
||||
* **Lombok** 是一个库，它通过在对象文件里面添加注解来自动创建 getters/setters 方法。像 C# 这些语言已经实现了此功能，Lombok 只是把此功能引入 Java 语言而已。
|
||||
* **NetBeans** 是一款很流行的开源 IDE，专门用于 Java 开发。它的许多工具都随着 Java SE 和 EE 的版本更新而更新。
|
||||
|
||||
我们会用这组工具为一个虚构自行车商店创建一个简单的应用程序。会实现对 `Customer` 和 `Bike` 对象集合的的插入操作。
|
||||
|
||||
### 酿造完美
|
||||
|
||||
导航到 [Spring Initializr][5] 页面。该网站可以生成基于 Spring Boot 和其依赖项的基本项目。选择以下选项：
|
||||
|
||||
1. **项目：** Maven 工程
|
||||
2. **语言：** Java
|
||||
3. **Spring Boot：** 2.1.8（或最稳定版本）
|
||||
4. **项目元数据：** 无论你使用什么名字，其命名约定都是像 `com.stephb` 这样的。
|
||||
* 你可以保留 Artifact 名字为 “Demo”。
|
||||
5. **依赖项：** 添加：
|
||||
* Spring Data MongoDB
|
||||
* Lombok
|
||||
|
||||
点击 **下载**，然后用你的 IDE（例如 NetBeans） 打开此新项目。
|
||||
|
||||
#### 模型层概要
|
||||
|
||||
在项目里面，<ruby>模型<rt>model</rt></ruby>代表从数据库里取出的信息的具体对象。我们关注两个对象：`Customer` 和 `Bike`。首先，在 `src` 目录创建 `dto` 目录；然后，创建两个名为 `Customer.java` 和 `Bike.java` 的 Java 类对象文件。其结构如下示：
|
||||
|
||||
```Java
|
||||
package com.stephb.JavaMongo.dto;
|
||||
|
||||
import lombok.Getter;
|
||||
import lombok.Setter;
|
||||
import org.springframework.data.annotation.Id;
|
||||
|
||||
/**
|
||||
*
|
||||
* @author stephon
|
||||
*/
|
||||
@Getter @Setter
|
||||
public class Customer {
|
||||
|
||||
private @Id String id;
|
||||
private String emailAddress;
|
||||
private String firstName;
|
||||
private String lastName;
|
||||
private String address;
|
||||
|
||||
}
|
||||
```
|
||||
|
||||
*Customer.Java*
|
||||
|
||||
```Java
|
||||
package com.stephb.JavaMongo.dto;
|
||||
|
||||
import lombok.Getter;
|
||||
import lombok.Setter;
|
||||
import org.springframework.data.annotation.Id;
|
||||
|
||||
/**
|
||||
*
|
||||
* @author stephon
|
||||
*/
|
||||
@Getter @Setter
|
||||
public class Bike {
|
||||
private @Id String id;
|
||||
private String modelNumber;
|
||||
private String color;
|
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private String description;
|
||||
|
||||
@Override
|
||||
public String toString() {
|
||||
return "This bike model is " + this.modelNumber + " is the color " + this.color + " and is " + description;
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
*Bike.java*
|
||||
|
||||
如你所见，对象中使用 Lombok 注解来为定义的<ruby>属性<rt>properties</rt></ruby>/<ruby>特性<rt>attributes</rt></ruby>生成 getters/setters 方法。如果你不想对该类的所有特性都生成 getters/setters 方法，可以在属性上专门定义这些注解。这两个类会变成容器，里面携带有数据，无论在何处想显示信息都可以使用。
|
||||
|
||||
#### 配置数据库
|
||||
|
||||
我使用 [Mongo Docker][7] 容器来进行此次测试。如果你的系统上已经安装了 MongoDB，则不必运行 Docker 实例。你也可以登录其官网，选择系统信息，然后按照安装说明来安装 MongoDB。
|
||||
|
||||
安装后，就可以使用命令行、GUI（例如 MongoDB Compass）或用于连接数据源的 IDE 驱动程序来与新的 MongoDB 服务器进行交互。到目前为止，可以开始定义数据层了，用来拉取、转换和持久化数据。需要设置数据库访问属性，请导航到程序中的 `applications.properties` 文件，然后添加如下内容：
|
||||
|
||||
```
|
||||
spring.data.mongodb.host=localhost
|
||||
spring.data.mongodb.port=27017
|
||||
spring.data.mongodb.database=BikeStore
|
||||
```
|
||||
|
||||
#### 定义数据访问对象/数据访问层
|
||||
|
||||
<ruby>数据访问层<rt>data access layer</rt></ruby>（DAL）中的<ruby>数据访问对象<rt>data access objects</rt></ruby>（DAO）定义了与数据库中的数据的交互过程。令人惊叹的就是在使用 `spring-boot-starter` 后，查询数据库的大部分工作已经完成。
|
||||
|
||||
让我们从 `Customer` DAO 开始。在 `src` 下的新目录 `dao` 中创建一个接口文件，然后再创建一个名为 `CustomerRepository.java` 的 Java 类文件，其内容如下示：
|
||||
|
||||
```
|
||||
package com.stephb.JavaMongo.dao;
|
||||
|
||||
import com.stephb.JavaMongo.dto.Customer;
|
||||
import java.util.List;
|
||||
import org.springframework.data.mongodb.repository.MongoRepository;
|
||||
|
||||
/**
|
||||
*
|
||||
* @author stephon
|
||||
*/
|
||||
public interface CustomerRepository extends MongoRepository<Customer, String>{
|
||||
@Override
|
||||
public List<Customer> findAll();
|
||||
public List<Customer> findByFirstName(String firstName);
|
||||
public List<Customer> findByLastName(String lastName);
|
||||
}
|
||||
```
|
||||
|
||||
这个类是一个接口，扩展或继承于 `MongoRepository` 类，而 `MongoRepository` 类依赖于 DTO （`Customer.java`）和一个字符串，它们用来实现自定义函数查询功能。因为你已继承自此类，所以你可以访问许多方法函数，这些函数允许持久化和查询对象，而无需实现或引用自己定义的方法函数。例如，在实例化 `CustomerRepository` 对象后，你就可以直接使用 `Save` 函数。如果你需要扩展更多的功能，也可以重写这些函数。我创建了一些自定义查询来搜索我的集合，这些集合对象是我自定义的元素。
|
||||
|
||||
`Bike` 对象也有一个存储源负责与数据库交互。与 `CustomerRepository` 的实现非常类似。其实现如下所示：
|
||||
|
||||
```
|
||||
package com.stephb.JavaMongo.dao;
|
||||
|
||||
import com.stephb.JavaMongo.dto.Bike;
|
||||
import java.util.List;
|
||||
import org.springframework.data.mongodb.repository.MongoRepository;
|
||||
|
||||
/**
|
||||
*
|
||||
* @author stephon
|
||||
*/
|
||||
public interface BikeRepository extends MongoRepository<Bike,String>{
|
||||
public Bike findByModelNumber(String modelNumber);
|
||||
@Override
|
||||
public List<Bike> findAll();
|
||||
public List<Bike> findByColor(String color);
|
||||
}
|
||||
```
|
||||
|
||||
#### 运行程序
|
||||
|
||||
现在，你已经有了一种结构化数据的方式，可以对数据进行提取、转换和持久化，然后运行这个程序。
|
||||
|
||||
找到 `Application.java` 文件（有可能不是此名称，具体取决于你的应用程序名称，但都会包含有 “application” ）。在定义此类的地方，在后面加上 `implements CommandLineRunner`。这将允许你实现 `run` 方法来创建命令行应用程序。重写 `CommandLineRunner` 接口提供的 `run` 方法，并包含如下内容用来测试 `BikeRepository` ：
|
||||
|
||||
```
|
||||
package com.stephb.JavaMongo;
|
||||
|
||||
import com.stephb.JavaMongo.dao.BikeRepository;
|
||||
import com.stephb.JavaMongo.dao.CustomerRepository;
|
||||
import com.stephb.JavaMongo.dto.Bike;
|
||||
import java.util.Scanner;
|
||||
import org.springframework.beans.factory.annotation.Autowired;
|
||||
import org.springframework.boot.CommandLineRunner;
|
||||
import org.springframework.boot.SpringApplication;
|
||||
import org.springframework.boot.autoconfigure.SpringBootApplication;
|
||||
|
||||
|
||||
@SpringBootApplication
|
||||
public class JavaMongoApplication implements CommandLineRunner {
|
||||
@Autowired
|
||||
private BikeRepository bikeRepo;
|
||||
private CustomerRepository custRepo;
|
||||
|
||||
public static void main(String[] args) {
|
||||
SpringApplication.run(JavaMongoApplication.class, args);
|
||||
}
|
||||
@Override
|
||||
public void run(String... args) throws Exception {
|
||||
Scanner scan = new Scanner(System.in);
|
||||
String response = "";
|
||||
boolean running = true;
|
||||
while(running){
|
||||
System.out.println("What would you like to create? \n C: The Customer \n B: Bike? \n X:Close");
|
||||
response = scan.nextLine();
|
||||
if ("B".equals(response.toUpperCase())) {
|
||||
String[] bikeInformation = new String[3];
|
||||
System.out.println("Enter the information for the Bike");
|
||||
System.out.println("Model Number");
|
||||
bikeInformation[0] = scan.nextLine();
|
||||
System.out.println("Color");
|
||||
bikeInformation[1] = scan.nextLine();
|
||||
System.out.println("Description");
|
||||
bikeInformation[2] = scan.nextLine();
|
||||
|
||||
Bike bike = new Bike();
|
||||
bike.setModelNumber(bikeInformation[0]);
|
||||
bike.setColor(bikeInformation[1]);
|
||||
bike.setDescription(bikeInformation[2]);
|
||||
|
||||
bike = bikeRepo.save(bike);
|
||||
System.out.println(bike.toString());
|
||||
|
||||
|
||||
} else if ("X".equals(response.toUpperCase())) {
|
||||
System.out.println("Bye");
|
||||
running = false;
|
||||
} else {
|
||||
System.out.println("Sorry nothing else works right now!");
|
||||
}
|
||||
}
|
||||
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
其中的 `@Autowired` 注解会自动依赖注入 `BikeRepository` 和 `CustomerRepository` Bean。我们将使用这些类来从数据库持久化和采集数据。
|
||||
|
||||
已经好了。你已经创建了一个命令行应用程序。该应用程序连接到数据库，并且能够以最少的代码执行 CRUD 操作
|
||||
|
||||
### 结论
|
||||
|
||||
从诸如对象和类之类的编程语言概念转换为用于在数据库中存储、检索或更改数据的调用对于构建应用程序至关重要。Java 持久化 API（JPA）正是为 Java 开发人员解决这一难题的重要工具。你正在使用 Java 操纵哪些数据库呢？请在评论中分享。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/19/10/using-java-persistence-api
|
||||
|
||||
作者：[Stephon Brown][a]
|
||||
选题：[lujun9972][b]
|
||||
译者：[runningwater](https://github.com/runningwater)
|
||||
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/stephb
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/java-coffee-beans.jpg?itok=3hkjX5We (Coffee beans)
|
||||
[2]: https://www.techrepublic.com/article/mongodb-ceo-tells-hard-truths-about-commercial-open-source/
|
||||
[3]: https://github.com/StephonBrown/SpringMongoJava
|
||||
[4]: https://openjdk.java.net/projects/jdk/11/
|
||||
[5]: https://start.spring.io/
|
||||
[6]: http://www.google.com/search?hl=en&q=allinurl%3Adocs.oracle.com+javase+docs+api+string
|
||||
[7]: https://hub.docker.com/_/mongo
|
||||
[8]: http://www.google.com/search?hl=en&q=allinurl%3Adocs.oracle.com+javase+docs+api+exception
|
||||
[9]: http://www.google.com/search?hl=en&q=allinurl%3Adocs.oracle.com+javase+docs+api+system
|
||||
336
published/20191023 How to program with Bash- Loops.md
Normal file
336
published/20191023 How to program with Bash- Loops.md
Normal file
@ -0,0 +1,336 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: (lxbwolf)
|
||||
[#]: reviewer: (wxy)
|
||||
[#]: publisher: (wxy)
|
||||
[#]: url: (https://linux.cn/article-11714-1.html)
|
||||
[#]: subject: (How to program with Bash: Loops)
|
||||
[#]: via: (https://opensource.com/article/19/10/programming-bash-loops)
|
||||
[#]: author: (David Both https://opensource.com/users/dboth)
|
||||
|
||||
怎样用 Bash 编程：循环
|
||||
======
|
||||
|
||||
> 本文是 Bash 编程系列三篇中的最后一篇，来学习使用循环执行迭代的操作。
|
||||
|
||||
|
||||
|
||||
Bash 是一种强大的用于命令行和 shell 脚本的编程语言。本系列的三部分都是基于我的三集 [Linux 自学课程][2] 写的，探索怎么用 CLI 进行 bash 编程。
|
||||
|
||||
本系列的 [第一篇文章][3] 讨论了 bash 编程的一些简单命令行操作，如使用变量和控制操作符。[第二篇文章][4] 探讨了文件、字符串、数字等类型和各种各样在执行流中提供控制逻辑的的逻辑运算符，还有 bash 中不同种类的扩展。本文是第三篇（也是最后一篇），意在考察在各种迭代的操作中使用循环以及怎么合理控制循环。
|
||||
|
||||
### 循环
|
||||
|
||||
我使用过的所有编程语言都至少有两种循环结构来用来执行重复的操作。我经常使用 `for` 循环，然而我发现 `while` 和 `until` 循环也很有用处。
|
||||
|
||||
#### for 循环
|
||||
|
||||
我的理解是，在 bash 中实现的 `for` 命令比大部分语言灵活，因为它可以处理非数字的值；与之形成对比的是，诸如标准 C 语言的 `for` 循环只能处理数字类型的值。
|
||||
|
||||
Bash 版的 `for` 命令基本的结构很简单：
|
||||
|
||||
```
|
||||
for Var in list1 ; do list2 ; done
|
||||
```
|
||||
|
||||
解释一下：“对于 `list1` 中的每一个值，把 `$Var` 设置为那个值，使用该值执行 `list2` 中的程序语句；`list1` 中的值都执行完后，整个循环结束，退出循环。” `list1` 中的值可以是一个简单的显式字符串值，也可以是一个命令执行后的结果（`` 包含其内的命令执行的结果，本系列第二篇文章中有描述）。我经常使用这种结构。
|
||||
|
||||
要测试它，确认 `~/testdir` 仍然是当前的工作目录（PWD）。删除目录下所有东西，来看下这个显式写出值列表的 `for` 循环的简单的示例。这个列表混合了字母和数字 — 但是不要忘了，在 bash 中所有的变量都是字符串或者可以被当成字符串来处理。
|
||||
|
||||
```
|
||||
[student@studentvm1 testdir]$ rm *
|
||||
[student@studentvm1 testdir]$ for I in a b c d 1 2 3 4 ; do echo $I ; done
|
||||
a
|
||||
b
|
||||
c
|
||||
d
|
||||
1
|
||||
2
|
||||
3
|
||||
4
|
||||
```
|
||||
|
||||
给变量赋予更有意义的名字，变成前面版本的进阶版：
|
||||
|
||||
```
|
||||
[student@studentvm1 testdir]$ for Dept in "Human Resources" Sales Finance "Information Technology" Engineering Administration Research ; do echo "Department $Dept" ; done
|
||||
Department Human Resources
|
||||
Department Sales
|
||||
Department Finance
|
||||
Department Information Technology
|
||||
Department Engineering
|
||||
Department Administration
|
||||
Department Research
|
||||
```
|
||||
|
||||
创建几个目录（创建时显示一些处理信息）：
|
||||
|
||||
```
|
||||
[student@studentvm1 testdir]$ for Dept in "Human Resources" Sales Finance "Information Technology" Engineering Administration Research ; do echo "Working on Department $Dept" ; mkdir "$Dept" ; done
|
||||
Working on Department Human Resources
|
||||
Working on Department Sales
|
||||
Working on Department Finance
|
||||
Working on Department Information Technology
|
||||
Working on Department Engineering
|
||||
Working on Department Administration
|
||||
Working on Department Research
|
||||
[student@studentvm1 testdir]$ ll
|
||||
total 28
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:45 Administration
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:45 Engineering
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:45 Finance
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:45 'Human Resources'
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:45 'Information Technology'
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:45 Research
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:45 Sales
|
||||
```
|
||||
|
||||
在 `mkdir` 语句中 `$Dept` 变量必须用引号包裹起来；否则名字中间有空格（如 `Information Technology`）会被当做两个独立的目录处理。我一直信奉的一条实践规则：所有的文件和目录都应该为一个单词（中间没有空格）。虽然大部分现代的操作系统可以处理名字中间有空格的情况，但是系统管理员需要花费额外的精力去确保脚本和 CLI 程序能正确处理这些特例。（即使它们很烦人，也务必考虑它们，因为你永远不知道将拥有哪些文件。）
|
||||
|
||||
再次删除 `~/testdir` 下的所有东西 — 再运行一次下面的命令：
|
||||
|
||||
```
|
||||
[student@studentvm1 testdir]$ rm -rf * ; ll
|
||||
total 0
|
||||
[student@studentvm1 testdir]$ for Dept in Human-Resources Sales Finance Information-Technology Engineering Administration Research ; do echo "Working on Department $Dept" ; mkdir "$Dept" ; done
|
||||
Working on Department Human-Resources
|
||||
Working on Department Sales
|
||||
Working on Department Finance
|
||||
Working on Department Information-Technology
|
||||
Working on Department Engineering
|
||||
Working on Department Administration
|
||||
Working on Department Research
|
||||
[student@studentvm1 testdir]$ ll
|
||||
total 28
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:52 Administration
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:52 Engineering
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:52 Finance
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:52 Human-Resources
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:52 Information-Technology
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:52 Research
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:52 Sales
|
||||
```
|
||||
|
||||
假设现在有个需求，需要列出一台 Linux 机器上所有的 RPM 包并对每个包附上简短的描述。我为北卡罗来纳州工作的时候，曾经遇到过这种需求。由于当时开源尚未得到州政府的“批准”，而且我只在台式机上使用 Linux，对技术一窍不通的老板（PHB）需要我列出我计算机上安装的所有软件，以便他们可以“批准”一个特例。
|
||||
|
||||
你怎么实现它？有一种方法是，已知 `rpm –qa` 命令提供了 RPM 包的完整描述，包括了白痴老板想要的东西：软件名称和概要描述。
|
||||
|
||||
让我们一步步执行出最后的结果。首先，列出所有的 RPM 包：
|
||||
|
||||
```
|
||||
[student@studentvm1 testdir]$ rpm -qa
|
||||
perl-HTTP-Message-6.18-3.fc29.noarch
|
||||
perl-IO-1.39-427.fc29.x86_64
|
||||
perl-Math-Complex-1.59-429.fc29.noarch
|
||||
lua-5.3.5-2.fc29.x86_64
|
||||
java-11-openjdk-headless-11.0.ea.28-2.fc29.x86_64
|
||||
util-linux-2.32.1-1.fc29.x86_64
|
||||
libreport-fedora-2.9.7-1.fc29.x86_64
|
||||
rpcbind-1.2.5-0.fc29.x86_64
|
||||
libsss_sudo-2.0.0-5.fc29.x86_64
|
||||
libfontenc-1.1.3-9.fc29.x86_64
|
||||
<snip>
|
||||
```
|
||||
|
||||
用 `sort` 和 `uniq` 命令对列表进行排序和打印去重后的结果（有些已安装的 RPM 包具有相同的名字）：
|
||||
|
||||
|
||||
```
|
||||
[student@studentvm1 testdir]$ rpm -qa | sort | uniq
|
||||
a2ps-4.14-39.fc29.x86_64
|
||||
aajohan-comfortaa-fonts-3.001-3.fc29.noarch
|
||||
abattis-cantarell-fonts-0.111-1.fc29.noarch
|
||||
abiword-3.0.2-13.fc29.x86_64
|
||||
abrt-2.11.0-1.fc29.x86_64
|
||||
abrt-addon-ccpp-2.11.0-1.fc29.x86_64
|
||||
abrt-addon-coredump-helper-2.11.0-1.fc29.x86_64
|
||||
abrt-addon-kerneloops-2.11.0-1.fc29.x86_64
|
||||
abrt-addon-pstoreoops-2.11.0-1.fc29.x86_64
|
||||
abrt-addon-vmcore-2.11.0-1.fc29.x86_64
|
||||
<snip>
|
||||
```
|
||||
|
||||
以上命令得到了想要的 RPM 列表，因此你可以把这个列表作为一个循环的输入信息，循环最终会打印每个 RPM 包的详细信息：
|
||||
|
||||
```
|
||||
[student@studentvm1 testdir]$ for RPM in `rpm -qa | sort | uniq` ; do rpm -qi $RPM ; done
|
||||
```
|
||||
|
||||
这段代码产出了多余的信息。当循环结束后，下一步就是提取出白痴老板需要的信息。因此，添加一个 `egrep` 命令用来搜索匹配 `^Name` 或 `^Summary` 的行。脱字符（`^`）表示行首，整个命令表示显示所有以 Name 或 Summary 开头的行。
|
||||
|
||||
```
|
||||
[student@studentvm1 testdir]$ for RPM in `rpm -qa | sort | uniq` ; do rpm -qi $RPM ; done | egrep -i "^Name|^Summary"
|
||||
Name : a2ps
|
||||
Summary : Converts text and other types of files to PostScript
|
||||
Name : aajohan-comfortaa-fonts
|
||||
Summary : Modern style true type font
|
||||
Name : abattis-cantarell-fonts
|
||||
Summary : Humanist sans serif font
|
||||
Name : abiword
|
||||
Summary : Word processing program
|
||||
Name : abrt
|
||||
Summary : Automatic bug detection and reporting tool
|
||||
<snip>
|
||||
```
|
||||
|
||||
在上面的命令中你可以试试用 `grep` 代替 `egrep` ，你会发现用 `grep` 不能得到正确的结果。你也可以通过管道把命令结果用 `less` 过滤器来查看。最终命令像这样：
|
||||
|
||||
```
|
||||
[student@studentvm1 testdir]$ for RPM in `rpm -qa | sort | uniq` ; do rpm -qi $RPM ; done | egrep -i "^Name|^Summary" > RPM-summary.txt
|
||||
```
|
||||
|
||||
这个命令行程序用到了管道、重定向和 `for` 循环，这些全都在一行中。它把你的 CLI 程序的结果重定向到了一个文件，这个文件可以在邮件中使用或在其他地方作为输入使用。
|
||||
|
||||
这个一次一步构建程序的过程让你能看到每步的结果，以此来确保整个程序以你期望的流程进行且输出你想要的结果。
|
||||
|
||||
白痴老板最终收到了超过 1900 个不同的 RPM 包的清单，我严重怀疑根本就没人读过这个列表。我给了他们想要的东西，没有从他们嘴里听到过任何关于 RPM 包的信息。
|
||||
|
||||
### 其他循环
|
||||
|
||||
Bash 中还有两种其他类型的循环结构：`while` 和 `until` 结构，两者在语法和功能上都类似。这些循环结构的基础语法很简单：
|
||||
|
||||
```
|
||||
while [ expression ] ; do list ; done
|
||||
```
|
||||
|
||||
逻辑解释：表达式（`expression`）结果为 true 时，执行程序语句 `list`。表达式结果为 false 时，退出循环。
|
||||
|
||||
```
|
||||
until [ expression ] ; do list ; done
|
||||
```
|
||||
|
||||
逻辑解释：执行程序语句 `list`，直到表达式的结果为 true。当表达式结果为 true 时，退出循环。
|
||||
|
||||
#### While 循环
|
||||
|
||||
`while` 循环用于当逻辑表达式结果为 true 时执行一系列程序语句。假设你的 PWD 仍是 `~/testdir`。
|
||||
|
||||
最简单的 `while` 循环形式是这个会一直运行下去的循环。下面格式的条件语句永远以 `true` 作为返回。你也可以用简单的 `1` 代替 `true`，结果一样，但是这解释了 true 表达式的用法。
|
||||
|
||||
```
|
||||
[student@studentvm1 testdir]$ X=0 ; while [ true ] ; do echo $X ; X=$((X+1)) ; done | head
|
||||
0
|
||||
1
|
||||
2
|
||||
3
|
||||
4
|
||||
5
|
||||
6
|
||||
7
|
||||
8
|
||||
9
|
||||
[student@studentvm1 testdir]$
|
||||
```
|
||||
|
||||
既然你已经学了 CLI 的各部分知识，那就让它变得更有用处。首先，为了防止变量 `$X` 在前面的程序或 CLI 命令执行后有遗留的值，设置 `$X` 的值为 0。然后，因为逻辑表达式 `[ true ]` 的结果永远是 1，即 true，在 `do` 和 `done` 中间的程序指令列表会一直执行 — 或者直到你按下 `Ctrl+C` 抑或发送一个 2 号信号给程序。那些程序指令是算数扩展，用来打印变量 `$X` 当前的值并加 1.
|
||||
|
||||
《[系统管理员的 Linux 哲学][5]》的信条之一是追求优雅，实现优雅的一种方式就是简化。你可以用操作符 `++` 来简化这个程序。在第一个例子中，变量当前的值被打印出来，然后变量的值增加了。可以在变量后加一个 `++` 来表示这个逻辑：
|
||||
|
||||
```
|
||||
[student@studentvm1 ~]$ X=0 ; while [ true ] ; do echo $((X++)) ; done | head
|
||||
0
|
||||
1
|
||||
2
|
||||
3
|
||||
4
|
||||
5
|
||||
6
|
||||
7
|
||||
8
|
||||
9
|
||||
```
|
||||
|
||||
现在删掉程序最后的 `| head` 再运行一次。
|
||||
|
||||
在下面这个版本中，变量在值被打印之前就自增了。这是通过在变量之前添加 `++` 操作符实现的。你能看出区别吗？
|
||||
|
||||
```
|
||||
[student@studentvm1 ~]$ X=0 ; while [ true ] ; do echo $((++X)) ; done | head
|
||||
1
|
||||
2
|
||||
3
|
||||
4
|
||||
5
|
||||
6
|
||||
7
|
||||
8
|
||||
9
|
||||
```
|
||||
|
||||
你已经把打印变量的值和自增简化到了一条语句。类似 `++` 操作符，也有 `--` 操作符。
|
||||
|
||||
你需要一个在循环到某个特定数字时终止循环的方法。把 true 表达式换成一个数字比较表达式来实现它。这里有一个循环到 5 终止的程序。在下面的示例代码中，你可以看到 `-le` 是 “小于或等于” 的数字逻辑操作符。整个语句的意思：只要 `$X` 的值小于或等于 5，循环就一直运行。当 `$X` 增加到 6 时，循环终止。
|
||||
|
||||
```
|
||||
[student@studentvm1 ~]$ X=0 ; while [ $X -le 5 ] ; do echo $((X++)) ; done
|
||||
0
|
||||
1
|
||||
2
|
||||
3
|
||||
4
|
||||
5
|
||||
[student@studentvm1 ~]$
|
||||
```
|
||||
|
||||
#### Until 循环
|
||||
|
||||
`until` 命令非常像 `while` 命令。不同之处是，它直到逻辑表达式的值是 `true` 之前，会一直循环。看一下这种结构最简单的格式：
|
||||
|
||||
```
|
||||
[student@studentvm1 ~]$ X=0 ; until false ; do echo $((X++)) ; done | head
|
||||
0
|
||||
1
|
||||
2
|
||||
3
|
||||
4
|
||||
5
|
||||
6
|
||||
7
|
||||
8
|
||||
9
|
||||
[student@studentvm1 ~]$
|
||||
```
|
||||
|
||||
它用一个逻辑比较表达式来计数到一个特定的值：
|
||||
|
||||
```
|
||||
[student@studentvm1 ~]$ X=0 ; until [ $X -eq 5 ] ; do echo $((X++)) ; done
|
||||
0
|
||||
1
|
||||
2
|
||||
3
|
||||
4
|
||||
[student@studentvm1 ~]$ X=0 ; until [ $X -eq 5 ] ; do echo $((++X)) ; done
|
||||
1
|
||||
2
|
||||
3
|
||||
4
|
||||
5
|
||||
[student@studentvm1 ~]$
|
||||
```
|
||||
|
||||
### 总结
|
||||
|
||||
本系列探讨了构建 Bash 命令行程序和 shell 脚本的很多强大的工具。但是这仅仅是你能用 Bash 做的很多有意思的事中的冰山一角，接下来就看你的了。
|
||||
|
||||
我发现学习 Bash 编程最好的方法就是实践。找一个需要多个 Bash 命令的简单项目然后写一个 CLI 程序。系统管理员们要做很多适合 CLI 编程的工作，因此我确信你很容易能找到自动化的任务。
|
||||
|
||||
很多年前，尽管我对其他的 Shell 语言和 Perl 很熟悉，但还是决定用 Bash 做所有系统管理员的自动化任务。我发现，有时稍微搜索一下，我可以用 Bash 实现我需要的所有事情。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/19/10/programming-bash-loops
|
||||
|
||||
作者：[David Both][a]
|
||||
选题：[lujun9972][b]
|
||||
译者：[lxbwolf](https://github.com/lxbwolf)
|
||||
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/dboth
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/fail_progress_cycle_momentum_arrow.png?itok=q-ZFa_Eh (arrows cycle symbol for failing faster)
|
||||
[2]: http://www.both.org/?page_id=1183
|
||||
[3]: https://linux.cn/article-11552-1.html
|
||||
[4]: https://linux.cn/article-11687-1.html
|
||||
[5]: https://www.apress.com/us/book/9781484237298
|
||||
@ -1,8 +1,8 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: (geekpi)
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: reviewer: (wxy)
|
||||
[#]: publisher: (wxy)
|
||||
[#]: url: (https://linux.cn/article-11716-1.html)
|
||||
[#]: subject: (Create virtual machines with Cockpit in Fedora)
|
||||
[#]: via: (https://fedoramagazine.org/create-virtual-machines-with-cockpit-in-fedora/)
|
||||
[#]: author: (Karlis KavacisPaul W. Frields https://fedoramagazine.org/author/karlisk/https://fedoramagazine.org/author/pfrields/)
|
||||
@ -12,19 +12,19 @@
|
||||
|
||||
![][1]
|
||||
|
||||
本文向你展示如何在 Fedora 31 上使用安装 Cockpit 所需软件来创建和管理虚拟机。Cockpit 是一个[交互式管理界面][2]，可让你在任何受支持的 Web 浏览器上访问和管理系统。随着 [virt-manager 正逐渐废弃][3]，用户被鼓励使用 Cockpit 来替换它。
|
||||
本文向你展示如何在 Fedora 31 上使用安装 Cockpit 所需软件来创建和管理虚拟机。Cockpit 是一个[交互式管理界面][2]，可让你在任何受支持的 Web 浏览器上访问和管理系统。随着 [virt-manager 逐渐被废弃][3]，鼓励用户使用 Cockpit 来替换它。
|
||||
|
||||
Cockpit 是一个积极开发的项目，它有许多扩展其工作的插件。例如，其中一个是 “Machines”，它与 libvirtd 交互并允许用户创建和管理虚拟机。
|
||||
Cockpit 是一个正在活跃开发的项目，它有许多扩展其工作的插件。例如，其中一个是 “Machines”，它与 libvirtd 交互并允许用户创建和管理虚拟机。
|
||||
|
||||
### 安装软件
|
||||
|
||||
先决所需软件是 _libvirt _、_ cockpit_ 和 _cockpit-machines_。要将它们安装在 Fedora 31 上，请在终端[使用 sudo][4] 运行以下命令：
|
||||
先决所需软件是 `libvirt`、`cockpit` 和 `cockpit-machines`。要将它们安装在 Fedora 31 上，请在终端[使用 sudo][4] 运行以下命令：
|
||||
|
||||
```
|
||||
$ sudo dnf install libvirt cockpit cockpit-machines
|
||||
```
|
||||
|
||||
Cockpit 也在 “Headless Management” 软件包组中。该组对于仅通过网络访问的基于 Fedora 的服务器很有用。在这里，请使用以下命令进行安装：
|
||||
Cockpit 也在 “Headless Management” 软件包组中。该软件组对于仅通过网络访问的基于 Fedora 的服务器很有用。在这里，请使用以下命令进行安装：
|
||||
|
||||
```
|
||||
$ sudo dnf groupinstall "Headless Management"
|
||||
@ -32,7 +32,7 @@ $ sudo dnf groupinstall "Headless Management"
|
||||
|
||||
### 设置 Cockpit 服务
|
||||
|
||||
安装了必要的软件包后，就该启用服务了。 _libvirtd_ 服务运行虚拟机，而 Cockpit 有一个激活的套接字服务，可让你访问 Web GUI：
|
||||
安装了必要的软件包后，就该启用服务了。`libvirtd` 服务运行虚拟机，而 Cockpit 有一个激活的套接字服务，可让你访问 Web GUI：
|
||||
|
||||
```
|
||||
$ sudo systemctl enable libvirtd --now
|
||||
@ -59,35 +59,31 @@ $ sudo systemctl status cockpit.socket
|
||||
|
||||
使用系统的用户名和密码登录界面。你还可以选择是否允许在此会话中将密码用于管理任务。
|
||||
|
||||
选择 _Virtual Machines_，然后选择_ Create VM_ 来创建一台新的虚拟机。控制台为你提供几个选项：
|
||||
选择 “Virtual Machines”，然后选择 “Create VM” 来创建一台新的虚拟机。控制台为你提供几个选项：
|
||||
|
||||
* 使用 Cockpit 的内置库下载操作系统
|
||||
* 使用系统上已下载的安装媒体
|
||||
* 指向系统安装树的 URL
|
||||
* 通过 [PXE][5] 协议通过网络引导媒体
|
||||
|
||||
|
||||
|
||||
输入所有必要的参数。然后选择 _Create_ 启动新虚拟机。
|
||||
输入所有必要的参数。然后选择 “Create” 启动新虚拟机。
|
||||
|
||||
此时，将出现一个图形控制台。大多数现代 Web 浏览器都允许你使用键盘和鼠标与 VM 控制台进行交互。现在，你可以完成安装并使用新的 VM，就像[过去通过 virt-manager][6] 一样。
|
||||
|
||||
* * *
|
||||
|
||||
_照片由 [Miguel Teixeira][7] 发布于 [Flickr][8]（CC BY-SA 2.0）_
|
||||
*照片由 [Miguel Teixeira][7] 发布于 [Flickr][8]（CC BY-SA 2.0）*
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://fedoramagazine.org/create-virtual-machines-with-cockpit-in-fedora/
|
||||
|
||||
作者：[Karlis KavacisPaul W. Frields][a]
|
||||
作者：[Karlis Kavacis][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
|
||||
|
||||
[a]: https://fedoramagazine.org/author/karlisk/https://fedoramagazine.org/author/pfrields/
|
||||
[a]: https://fedoramagazine.org/author/karlisk/
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://fedoramagazine.org/wp-content/uploads/2019/11/create-vm-cockpit-816x345.jpg
|
||||
[2]: https://cockpit-project.org/
|
||||
@ -0,0 +1,112 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (Darktable 3 Released With GUI Rework and New Features)
|
||||
[#]: via: (https://itsfoss.com/darktable-3-release/)
|
||||
[#]: author: (Abhishek Prakash https://itsfoss.com/author/abhishek/)
|
||||
|
||||
Darktable 3 Released With GUI Rework and New Features
|
||||
======
|
||||
|
||||
Here’s the Christmas gift for the photography enthusiasts. Darktable 3.0 has just released.
|
||||
|
||||
[Darktable][1] is one of the [best applications for editing RAW images on Linux][2]. You can consider it as a [free and open source alternative to Adobe Lightroom][3].
|
||||
|
||||
Darktable 3 is a major new release with tons of feature improvements and a complete rework of the user interface. The GUI is now completely controlled by GTK+ CSS rules, which makes the whole GUI themable. There are eight themes available by default.
|
||||
|
||||
With the help of over 3000 commits and 553 pull requests, the new release has fixed 66 bugs and added many new features.
|
||||
|
||||
Let’s see what features this new release brings.
|
||||
|
||||
### New features in Darktable 3.0
|
||||
|
||||
![Darktable 3.0 Screenshot][4]
|
||||
|
||||
Here are the highlighted new features:
|
||||
|
||||
* Reworked UI
|
||||
* A new module for handling 3D RGB Lut transformations
|
||||
* Many improvements to the ‘denoise (profiled)’ module
|
||||
* A new ‘culling’ mode and timeline view added
|
||||
* Many improvements to the ‘denoise (profiled)’ module
|
||||
* New tone equalizer’ basic and filmic RGB modules
|
||||
* Better 4K/5K display support
|
||||
* Undo/redo support for more operations
|
||||
* Many code optimizations for CPU and SSE paths
|
||||
* Support for exporting to Google Photos
|
||||
* More camera support, white balance presets, and noise profiles
|
||||
* Plenty of bug fixes and feature improvements
|
||||
|
||||
|
||||
|
||||
You can read about all the changes in the [release notes on GitHub][5].
|
||||
|
||||
### Installing Darktable 3.0 on Linux
|
||||
|
||||
Let’s see how to get the latest Darktable release.
|
||||
|
||||
#### Installing Darktable 3.0 on Ubuntu-based distributions
|
||||
|
||||
Darktable is available in Ubuntu but you won’t get the latest release immediately. For the LTS version, it may take months before you have this version update.
|
||||
|
||||
Worry not! Darktable provides its [own PPA][6] to install the latest release on Ubuntu-based distributions.
|
||||
|
||||
Unfortuntaley, That Darktable PPA has not been updated with the new release.
|
||||
|
||||
Worry not (again)! Thanks to our friend [Ji M of Ubuntu Handbook][7], we have an unofficial PPA for easily installing Darktable 3.0 on Ubuntu and other Ubuntu based distributions.
|
||||
|
||||
Open a terminal and use these commands one by one:
|
||||
|
||||
```
|
||||
sudo add-apt-repository ppa:ubuntuhandbook1/darktable
|
||||
sudo apt update
|
||||
sudo apt install darktable
|
||||
```
|
||||
|
||||
#### Uninstall Darktable 3
|
||||
|
||||
To remove Darktable installed via this PPA, you can first uninstall the application:
|
||||
|
||||
```
|
||||
sudo apt remove darktable
|
||||
```
|
||||
|
||||
And then [remove the PPA][8] as well:
|
||||
|
||||
```
|
||||
sudo add-apt-repository -r ppa:ubuntuhandbook1/darktable
|
||||
```
|
||||
|
||||
#### Installing Darktable on other Linux distributions
|
||||
|
||||
You may wait for your distribution to provide this new release through the software manager.
|
||||
|
||||
You may also download the tarball or the entire source code from the GitHub release page (it’s at the bottom of the page).
|
||||
|
||||
[Download Darktable 3.0][5]
|
||||
|
||||
With Darktable 3, you can edit your holiday pictures better :)
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://itsfoss.com/darktable-3-release/
|
||||
|
||||
作者：[Abhishek Prakash][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://itsfoss.com/author/abhishek/
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://www.darktable.org/
|
||||
[2]: https://itsfoss.com/raw-image-tools-linux/
|
||||
[3]: https://itsfoss.com/open-source-photoshop-alternatives/
|
||||
[4]: https://i1.wp.com/itsfoss.com/wp-content/uploads/2019/12/darktable_3_screenshot.jpg?ssl=1
|
||||
[5]: https://github.com/darktable-org/darktable/releases/tag/release-3.0.0
|
||||
[6]: https://launchpad.net/~pmjdebruijn/+archive/ubuntu/darktable-release
|
||||
[7]: http://ubuntuhandbook.org/index.php/2019/12/install-darktable-3-0-0-ubuntu-18-04-19-10/
|
||||
[8]: https://itsfoss.com/how-to-remove-or-delete-ppas-quick-tip/
|
||||
@ -0,0 +1,63 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (How to run a business with open source: Top reads)
|
||||
[#]: via: (https://opensource.com/article/19/12/business-open-source)
|
||||
[#]: author: (Jim Hall https://opensource.com/users/jim-hall)
|
||||
|
||||
How to run a business with open source: Top reads
|
||||
======
|
||||
Open source software is open for business, as evidenced in the these top
|
||||
5 articles from 2019.
|
||||
![Open for business][1]
|
||||
|
||||
Open source is ready to get to work, and in 2019, Opensource.com had many great articles about how organizations have adopted open source software or open methods to drive their business. As open source matures, we've seen open source not just replace proprietary software, but create entirely new business models.
|
||||
|
||||
Check out this list of five outstanding articles from Opensource.com in 2019 about running a business with open source.
|
||||
|
||||
### Get your business up and running with these open source tools
|
||||
|
||||
In [_Get your business up and running with these open source tools_][2], I explain: "Yes, you really can operate a business using open source software." In this article, I review the key open source software tools that I use to run my company, including Inkscape, GIMP, LibreOffice, and Scribus.
|
||||
|
||||
### What's your favorite open source BI software?
|
||||
|
||||
As Lauren Maffeo explains in _[What's your favorite open source BI software?][3]_ "Open source business intelligence (BI) software helps users upload, visualize, and make decisions based on data that is pulled from several sources... BI involves turning data into insights that help your business make better decisions... Before choosing which open source BI tool to adopt, it's worth weighing the pros and cons of each tool against your business needs." The article's accompanying poll asks readers whether they prefer Pentaho, Logz.io, Cluvio, Qlikview, Sisense, or another BI application. Answer the poll to let us know which is your favorite and to see what other readers say.
|
||||
|
||||
### Scrum vs. kanban: Which agile framework is better?
|
||||
|
||||
Because scrum and kanban both fall under the agile framework umbrella, many people confuse them or think they're the same thing. There are differences, however. In [_Scrum vs. kanban: Which agile framework is better?_][4] Taz Brown explains the differences between scrum and kanban and helps you decide which one may be best for your team.
|
||||
|
||||
### What is Small Scale Scrum?
|
||||
|
||||
"Agile is fast becoming a mainstream way industries act, behave, and work as they look to improve efficiency, minimize costs, and empower staff. Most software developers naturally think, act, and work this way, and alignment towards agile software methodologies has gathered pace in recent years," write Agnieszka Gancarczyk and Leigh Griffin in [_What is Small Scale Scrum?_][5] In this article, they explain how the scrum agile methodology can help small teams work more efficiently.
|
||||
|
||||
### What does DevOps mean to you?
|
||||
|
||||
In *[What does DevOps mean to you?][6] *Girish Managoli offers one answer to this article's headline: "DevOps is a process of software development focusing on communication and collaboration to facilitate rapid application and product deployment." But there are a range of opinions and expectations around DevOps. To help explain DevOps and how to leverage it in organizations, Girish interviewed six experts to break down DevOps and the key practices and philosophies in making DevOps work for you.
|
||||
|
||||
### Open source is open for business
|
||||
|
||||
As open source plays an increasingly important role in business, there's more to learn about the topic. What do you want to know about it in 2020? Please share your ideas for articles in the comments—or even share your own experiences with running a business on open source software by [writing an article for Opensource.com][7].
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/19/12/business-open-source
|
||||
|
||||
作者：[Jim Hall][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/jim-hall
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/BUSINESS_openseries.png?itok=rCtTDz5G (Open for business)
|
||||
[2]: https://opensource.com/article/19/9/business-creators-open-source-tools
|
||||
[3]: https://opensource.com/article/19/8/favorite-open-source-bi-software
|
||||
[4]: https://opensource.com/article/19/8/scrum-vs-kanban
|
||||
[5]: https://opensource.com/article/19/1/what-small-scale-scrum
|
||||
[6]: https://opensource.com/article/19/1/what-does-devops-mean-you
|
||||
[7]: https://opensource.com/how-submit-article
|
||||
@ -1,3 +1,4 @@
|
||||
chenmu-kk is translating.
|
||||
How the four components of a distributed tracing system work together
|
||||
======
|
||||
|
||||
|
||||
@ -1,5 +1,5 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: translator: (chen-ni)
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
@ -144,7 +144,7 @@ via: https://opensource.com/article/19/7/how-make-old-computer-useful-again
|
||||
|
||||
作者：[Howard Fosdick][a]
|
||||
选题：[lujun9972][b]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
译者：[译者ID](https://github.com/chen-ni)
|
||||
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
|
||||
|
||||
@ -1,124 +0,0 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: (chen-ni)
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (How tracking pixels work)
|
||||
[#]: via: (https://jvns.ca/blog/how-tracking-pixels-work/)
|
||||
[#]: author: (Julia Evans https://jvns.ca/)
|
||||
|
||||
How tracking pixels work
|
||||
======
|
||||
|
||||
I spent some time talking to a reporter yesterday about how advertisers track people on the internet. We had a really fun time looking at Firefox’s developer tools together (I’m not an internet privacy expert, but I do know how to use the network tab in developer tools!) and I learned a few things about how tracking pixels actually work in practice!
|
||||
|
||||
### the question: how does Facebook know that you went to Old Navy?
|
||||
|
||||
I often hear about this slightly creepy internet experience: you’re looking at a product online, and a day later see an ad for the same boots or whatever that you were looking at. This is called “retargeting”, but how does it actually work exactly in practice?
|
||||
|
||||
In this post we’ll experiment a bit and see exactly how Facebook can know what products you’ve looked at online! I’m using Facebook as an example in this blog post just because it’s easy to find websites with Facebook tracking pixels on them but of course almost every internet advertising company does this kind of tracking.
|
||||
|
||||
### the setup: allow third party trackers, turn off my adblocker
|
||||
|
||||
I use Firefox, and by default Firefox blocks a lot of this kind of tracking. So I needed to modify my Firefox privacy settings to get this tracking to work.
|
||||
|
||||
I changed my privacy settings from the default ([screenshot][1]) to a custom setting that allows third-party trackers ([screenshot][2]). I also disabled some privacy extensions I usually have running.
|
||||
|
||||
### tracking pixels: it’s not the gif, it’s the query parameters
|
||||
|
||||
A tracking pixel is a 1x1 gif that sites use to track you. By itself, obviously a tiny 1x1 gif doesn’t do too much. So how do tracking pixels track you? 2 ways:
|
||||
|
||||
1. Sites use the **query parameters** in the tracking pixel to add extra information like the URL of the page you’re visiting. So instead of just requesting `https://www.facebook.com/tr/` (which is a 44-byte 1x1 gif), it’ll request `https://www.facebook.com/tr/?the_website_you're_on`. (email marketers use similar tricks to figure out if you’ve opened an email, by giving the tracking pixel a unique URL)
|
||||
2. Sites send **cookies** with the tracking pixel so that they can tell that the person who visited oldnavy.com is the same as the person who’s using Facebook on the same computer.
|
||||
|
||||
|
||||
|
||||
### the Facebook tracking pixel on Old Navy’s website
|
||||
|
||||
To test this out, I went to look at a product on the Old Navy site with the URL [https://oldnavy.gap.com/browse/product.do?pid=504753002&cid=1125694&pcid=1135640&vid=1&grid=pds_0_109_1][3] (a “Soft-Brushed Plaid Topcoat for Men”).
|
||||
|
||||
When I did that, the Javascript running on that page (presumably [this code][4]) sent a request to facebook.com that looks like this in Developer tools: (I censored most of the cookie values because some of them are my login cookies :) )
|
||||
|
||||
![][5]
|
||||
|
||||
Let’s break down what’s happening:
|
||||
|
||||
1. My browser sends a request to ` https://www.facebook.com/tr/?id=937725046402747&ev=PageView&dl=https%3A%2F%2Foldnavy.gap.com%2Fbrowse%2Fproduct.do%3Fpid%3D504753002%26cid%3D1125694%26pcid%3Dxxxxxx0%26vid%3D1%26grid%3Dpds_0_109_1%23pdp-page-content&rl=https%3A%2F%2Foldnavy.gap.com%2Fbrowse%2Fcategory.do%3Fcid%3D1135640%26mlink%3D5155%2Cm_mts_a&if=false&ts=1576684838096&sw=1920&sh=1080&v=2.9.15&r=stable&a=tmtealium&ec=0&o=30&fbp=fb.1.1576684798512.1946041422&it=15xxxxxxxxxx4&coo=false&rqm=GET`
|
||||
2. With that request, it sends a cookie called `fr` which is set to `10oGXEcKfGekg67iy.AWVdJq5MG3VLYaNjz4MTNRaU1zg.Bd-kxt.KU.F36.0.0.Bd-kx6.` (which I guess is my Facebook ad tracking ID)
|
||||
|
||||
|
||||
|
||||
So the three most notable things that are being sent in the tracking pixel query string are:
|
||||
|
||||
* the page I visited: [https://oldnavy.gap.com/browse/product.do?pid=504753002&cid=1125694&pcid=1135640&vid=1&grid=pds_0_109_1#pdp-page-content][6]
|
||||
* the page that referred me to that page: [https://oldnavy.gap.com/browse/category.do?cid=1135640&mlink=5155,m_mts_a][7]
|
||||
* an identifier cookie for me: `10oGXEcKfGekg67iy.AWVdJq5MG3VLYaNjz4MTNRaU1zg.Bd-kxt.KU.F36.0.0.Bd-kx6.`
|
||||
|
||||
|
||||
|
||||
### now let’s visit Facebook!
|
||||
|
||||
Next, let’s visit Facebook, where I’m logged in. What cookies is my browser sending Facebook?
|
||||
|
||||
Unsurprisingly, it’s the same `fr` cookie from before: `10oGXEcKfGekg67iy.AWVdJq5MG3VLYaNjz4MTNRaU1zg.Bd-kxt.KU.F36.0.0.Bd-kx6.`. So Facebook now definitely knows that I (Julia Evans, the person with this Facebook account) visited the Old Navy website a couple of minutes ago and looked at a “Soft-Brushed Plaid Topcoat for Men”, because they can use that identifier to match up the data.
|
||||
|
||||
### these cookies are third-party cookies
|
||||
|
||||
The `fr` cookie that Facebook is using to track what websites I go to is called a “third party cookie”, because Old Navy’s website is using it to identify me to a third party (facebook.com). This is different from first-party cookies, which are used to keep you logged in.
|
||||
|
||||
Safari and Firefox both block many third-party cookies by default (which is why I had to change Firefox’s privacy settings to get this experiment to work), and as of today Chrome doesn’t (presumably because Chrome is owned by an ad company).
|
||||
|
||||
### sites have lots of tracking pixels
|
||||
|
||||
Like I expected, sites have **lots** of tracking pixels. For example, wrangler.com loaded 19 different tracking pixels in my browser from a bunch of different domains. The tracking pixels on wrangler.com came from: `ct.pinterest.com`, `af.monetate.net`, `csm.va.us.criteo.net`, `google-analytics.com`, `dpm.demdex.net`, `google.ca`, `a.tribalfusion.com`, `data.photorank.me`, `stats.g.doubleclick.net`, `vfcorp.dl.sc.omtrdc.net`, `ib.adnxs.com`, `idsync.rlcdn.com`, `p.brsrvr.com`, and `adservice.google.com`.
|
||||
|
||||
For most of these trackers, Firefox helpfully pointed out that it would have blocked them if I was using the standard Firefox privacy settings:
|
||||
|
||||
![][8]
|
||||
|
||||
### why browsers matter
|
||||
|
||||
The reason browsers matter so much is that your browser has the final word on what information it sends about you to which websites. The Javascript on the Old Navy’s website can ask your browser to send tracking information about you to Facebook, but your browser doesn’t have to do it! It can decide “oh yeah, I know that facebook.com/tr/ is a tracking pixel, I don’t want my users to be tracked, I’m just not going to send that request”.
|
||||
|
||||
And it can make that behaviour configurable by changing browser settings or installing browser extensions, which is why there are lots of privacy extensions.
|
||||
|
||||
### it’s fun to see how this works!
|
||||
|
||||
I think it’s fun to see how cookies / tracking pixels are used to track you in practice, even if it’s kinda creepy! I sort of knew how this worked before but I’d never actually looked at the cookies on a tracking pixel myself or what kind of information it was sending in its query parameters exactly.
|
||||
|
||||
And if you know how it works, it’s a easier to figure out how to be tracked less!
|
||||
|
||||
### what can you do?
|
||||
|
||||
I do a few small things to get tracked on the internet a little less:
|
||||
|
||||
* install an adblocker (like ublock origin or something), which will block a lot of tracker domains
|
||||
* use Firefox/Safari instead of Chrome (which have stronger default privacy settings right now)
|
||||
* use the [Facebook Container][9] Firefox extension, which takes extra steps to specifically prevent Facebook from tracking you
|
||||
|
||||
|
||||
|
||||
There are still lots of other ways to be tracked on the internet (especially when using mobile apps where you don’t have the same kind of control as with your browser), but I like understanding how this one method of tracking works and think it’s nice to be tracked a little bit less.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://jvns.ca/blog/how-tracking-pixels-work/
|
||||
|
||||
作者：[Julia Evans][a]
|
||||
选题：[lujun9972][b]
|
||||
译者：[译者ID](https://github.com/chen-ni)
|
||||
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://jvns.ca/
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://jvns.ca/images/trackers.png
|
||||
[2]: https://jvns.ca/images/firefox-insecure-settings.png
|
||||
[3]: https://oldnavy.gap.com/browse/product.do?pid=504753002&cid=1125694&pcid=1135640&vid=1&grid=pds_0_109_1
|
||||
[4]: https://developers.facebook.com/docs/facebook-pixel/implementation/
|
||||
[5]: https://jvns.ca/images/fb-old-navy.png
|
||||
[6]: https://oldnavy.gap.com/browse/product.do?pid=504753002&cid=1125694&pcid=1135640&vid=1&grid=pds_0_109_1#pdp-page-content
|
||||
[7]: https://oldnavy.gap.com/browse/category.do?cid=1135640&mlink=5155,m_mts_a
|
||||
[8]: https://jvns.ca/images/firefox-helpful.png
|
||||
[9]: https://addons.mozilla.org/en-CA/firefox/addon/facebook-container/
|
||||
@ -1,72 +0,0 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: (geekpi)
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (Customize your Linux desktop with KDE Plasma)
|
||||
[#]: via: (https://opensource.com/article/19/12/linux-kde-plasma)
|
||||
[#]: author: (Seth Kenlon https://opensource.com/users/seth)
|
||||
|
||||
Customize your Linux desktop with KDE Plasma
|
||||
======
|
||||
This article is part of a special series of 24 days of Linux desktops.
|
||||
If you think there's no such thing as too much opportunity to customize
|
||||
your desktop, KDE Plasma may be for you.
|
||||
![5 pengiuns floating on iceburg][1]
|
||||
|
||||
The Plasma desktop by the KDE community is a pinnacle among open source desktops. KDE got into the Linux desktop market early, but since its foundational Qt toolkit did not have a fully open license at the time, the [GNOME][2] desktop was created. Since then, Qt has become open source, and KDE (and its derivatives, like the [Trinity desktop][3]) has thrived.
|
||||
|
||||
You may find the KDE desktop in your distribution's software repository, or you can download and install a distribution that ships KDE as its default. Before you install, be aware that KDE provides a full, integrated, and robust desktop experience, so several KDE applications are installed along with it. If you're already running a different desktop, you will find yourself with redundant applications (two PDF readers, several media players, two or more file managers, and so on). If you just want to try the KDE desktop without committing to it, you can install a KDE-based distribution in a virtual machine, such as [GNOME Boxes][4], or you can try a bootable OS like [Porteus][5].
|
||||
|
||||
### KDE desktop tour
|
||||
|
||||
The [KDE Plasma][6] desktop is relatively boring at first glance—but in a comforting way. It's got the industry-standard layout: pop-up application menu in the bottom-left corner, taskbar in the middle, system tray on the right. It's exactly what you'd expect from a standard household or business computer.
|
||||
|
||||
![KDE Plasma desktop][7]
|
||||
|
||||
What sets KDE apart, though, is that you can change nearly anything you want. The Qt toolkit can be taken apart and rearranged in some surprising ways, meaning you can essentially design your own desktop using KDE's parts as your foundation. The settings available for how your desktop behaves are vast, too. KDE can act as a standard desktop, a tiling window manager, and anything in between. You can create your own window rules by window class, role, type, title, or any combination thereof, so if you want specific applications to behave differently than everything else, you can create an exception to global settings.
|
||||
|
||||
Furthermore, there's a rich collection of widgets to enable you to customize the way you interface with your desktop. There's a GNOME-like full-screen application launcher, a Unity-like dock launcher and icons-only taskbar, and a traditional taskbar. You can create and place panels on any edge of the screen you want.
|
||||
|
||||
![A slightly customized KDE desktop][8]
|
||||
|
||||
There's so much customization, in fact, that one of the most common critiques of KDE is that it's _too customizable_, so keep in mind that customization is optional. You can use the Plasma desktop in its default configuration, and change things gradually and only as you feel necessary. What matters most about Plasma desktop configuration options isn't their number, but that they're discoverable and intuitive, either in the System Settings application or with a right-click.
|
||||
|
||||
The fact is, on KDE, there's almost never just one way to accomplish any given task, and its users see that as its greatest strength. There's no implied workflow in KDE, only a default. And all defaults can be changed, until everything you need to do with your desktop is second-nature.
|
||||
|
||||
### Consistency and integration
|
||||
|
||||
The KDE community prides itself on consistency and integration, made possible through great developer and community management and the KDE libraries. The developers of KDE aren't just developers of a desktop. They provide a [stunning collection of applications][9], each of them created with KDE libs that extend and standardize common Qt widgets. It's no accident that after using KDE for a few months, whether you open [DigiKam][10] for photo management or Kmail to check email or KTorrent to grab the latest ISO or Dolphin to manage files, your muscle memory takes you where you need to go in the UI before you consciously think about it.
|
||||
|
||||
![KDE on Porteus][11]
|
||||
|
||||
### Try KDE
|
||||
|
||||
KDE has something for everyone. Use its default settings for a smooth, plain-vanilla desktop experience, or customize it to make it your own. It's a stable, attractive, and robust desktop environment that probably has everything you need for whatever you want to do on Linux.
|
||||
|
||||
KDE originally stood for Kool Desktop Environment, but is now known by many as the K Desktop...
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/19/12/linux-kde-plasma
|
||||
|
||||
作者：[Seth Kenlon][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/seth
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/rh_003499_01_linux31x_cc.png?itok=Pvim4U-B (5 pengiuns floating on iceburg)
|
||||
[2]: https://opensource.com/article/19/12/gnome-linux-desktop
|
||||
[3]: https://opensource.com/article/19/12/linux-trinity-desktop-environment-tde
|
||||
[4]: https://opensource.com/article/19/5/getting-started-gnome-boxes-virtualization
|
||||
[5]: https://opensource.com/article/19/6/linux-distros-to-try
|
||||
[6]: https://kde.org/plasma-desktop
|
||||
[7]: https://opensource.com/sites/default/files/uploads/advent-kde-presskit.jpg (KDE Plasma desktop)
|
||||
[8]: https://opensource.com/sites/default/files/uploads/advent-kde-dock.jpg (A slightly customized KDE desktop)
|
||||
[9]: https://kde.org/applications/
|
||||
[10]: https://opensource.com/life/16/5/how-use-digikam-photo-management
|
||||
[11]: https://opensource.com/sites/default/files/uploads/advent-kde.jpg (KDE on Porteus)
|
||||
@ -1,66 +0,0 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: (HankChow)
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (Why your Python code needs to be beautiful and explicit)
|
||||
[#]: via: (https://opensource.com/article/19/12/zen-python-beauty-clarity)
|
||||
[#]: author: (Moshe Zadka https://opensource.com/users/moshez)
|
||||
|
||||
Why your Python code needs to be beautiful and explicit
|
||||
======
|
||||
Welcome to Pythonukkah, a special series about the Zen of Python. On the
|
||||
first day, we celebrate the first two principles: beauty and
|
||||
explicitness.
|
||||
![Searching for code][1]
|
||||
|
||||
Python contributor Tim Peters introduced us to the [Zen of Python][2] in 1999. Twenty years later, its 19 guiding principles continue to be relevant within the community. We start our Pythonukkah celebration—like Hanukkah, a festival of lights—with the first two principles in the Zen of Python: on beauty and explicitness.
|
||||
|
||||
> "Hanukkah is the Festival of Lights,
|
||||
> Instead of one day of presents, we get eight crazy nights."
|
||||
> —Adam Sandler, [_The Hanukkah Song_][3]
|
||||
|
||||
### Beautiful is better than ugly.
|
||||
|
||||
It was in _[Structure and Interpretation of Computer Programs][4]_ (_SICP_) that the point was made: "Programs must be written for people to read and only incidentally for machines to execute." Machines do not care about beauty, but people do.
|
||||
|
||||
A beautiful program is one that is enjoyable to read. This means first that it is consistent. Tools like [Black][5], [flake8][6], and [Pylint][7] are great for making sure things are reasonable on a surface layer.
|
||||
|
||||
But even more important, only humans can judge what humans find beautiful. Code reviews and a collaborative approach to writing code are the only realistic way to build beautiful code. Listening to other people is an important skill in software development.
|
||||
|
||||
Finally, all the tools and processes are moot if the _will_ is not there. Without an appreciation for the importance of beauty, there will never be an emphasis on writing beautiful code.
|
||||
|
||||
This is why this is the first principle: it is a way of making "beauty" a value in the Python community. It immediately answers: "Do we _really_ care about beauty?" We do.
|
||||
|
||||
### Explicit is better than implicit.
|
||||
|
||||
We humans celebrate light and fear the dark. Light helps us make sense of vague images. In the same way, programming with more explicitness helps us make sense of abstract ideas. It is often tempting to make things implicit.
|
||||
|
||||
"Why is **self** explicitly there as the first parameter of methods?"
|
||||
|
||||
There are many technical explanations, but all of them are wrong. It is almost a Python programmer's rite of passage to write a metaclass that makes explicitly listing **self** unnecessary. (If you have never done this before, do so; it makes a great metaclass learning exercise!)
|
||||
|
||||
The reason **self** is explicit is not because the Python core developers did not want to make a metaclass like that the "default" metaclass. The reason it is explicit is because there is one less special case to teach: the first argument is _explicit_.
|
||||
|
||||
Even when Python does allow non-explicit things, such as context variables, we must always ask: Are we sure we need them? Could we not just pass arguments explicitly? Sometimes, for many reasons, this is not feasible. But prioritizing explicitness means, at the least, asking the question and estimating the effort.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/19/12/zen-python-beauty-clarity
|
||||
|
||||
作者：[Moshe Zadka][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/moshez
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/search_find_code_python_programming.png?itok=ynSL8XRV (Searching for code)
|
||||
[2]: https://www.python.org/dev/peps/pep-0020/
|
||||
[3]: https://en.wikipedia.org/wiki/The_Chanukah_Song
|
||||
[4]: https://en.wikipedia.org/wiki/Structure_and_Interpretation_of_Computer_Programs
|
||||
[5]: https://opensource.com/article/19/5/python-black
|
||||
[6]: https://opensource.com/article/19/5/python-flake8
|
||||
[7]: https://opensource.com/article/19/10/python-pylint-introduction
|
||||
@ -0,0 +1,95 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (Chill out with the Linux Equinox Desktop Environment)
|
||||
[#]: via: (https://opensource.com/article/19/12/ede-linux-desktop)
|
||||
[#]: author: (Seth Kenlon https://opensource.com/users/seth)
|
||||
|
||||
Chill out with the Linux Equinox Desktop Environment
|
||||
======
|
||||
This article is part of a special series of 24 days of Linux desktops.
|
||||
EDE is not the most glamorous, minimal, nor efficient desktop. But its
|
||||
soft, muted tones are calming, its familiarity soothing, and its icon
|
||||
theme fun.
|
||||
![Linux penguin at the north pole beside an igloo][1]
|
||||
|
||||
I haven't used the Fast Light Toolkit ([FLTK][2]) for anything serious yet, but I'm a fan of the C++ GUI toolkit that's pretty simple to learn and (in my experience) reliable even across updates. When I found out that there was a desktop environment built with FLTK, I was eager to try it—and I was quickly glad I did. The [Equinox Desktop Environment (EDE)][3] is a fast and simple desktop written in C++ and FLTK for Unix desktops. It uses common desktop conventions, so it looks and feels familiar right away, and after only a few days of using it, I found its simplicity provides a minimal elegance that I enjoy.
|
||||
|
||||
![EDE desktop][4]
|
||||
|
||||
### Installing EDE
|
||||
|
||||
You are likely to find EDE included in your distribution's software repository, but you can also find it in its [SourceForge repository][5]. If you're already running a different desktop, it's safe to install EDE on the same system because it brings along just a few extra applications, which are specific to EDE so they won't get in your way on other desktops.
|
||||
|
||||
EDE is only the desktop, and it uses the [Pekwm][6] window manager to handle layout.
|
||||
|
||||
After installing EDE, log out of your current desktop session so you can log into your new one. By default, your session manager (KDM, GDM, LightDM, or XDM, depending on your setup) will continue to log you into your previous desktop, so you must override that before logging in.
|
||||
|
||||
With GDM:
|
||||
|
||||
![][7]
|
||||
|
||||
With SDDM:
|
||||
|
||||
![][8]
|
||||
|
||||
When EDE first boots, you might be prompted to confirm some startup tasks. On my Slackware workstation, KDE had marked some services as startup tasks (such as the HPLIP print monitor and a Bluetooth daemon), and EDE imported them with just one confirmation box.
|
||||
|
||||
![Importing desktop services in EDE][9]
|
||||
|
||||
After setting it up once, you won't need to do it again.
|
||||
|
||||
### EDE desktop tour
|
||||
|
||||
EDE's layout is exactly what most people expect from a desktop: application menu on the left, taskbar in the middle, system tray on the right. It's the standard off-the-shelf layout that confuses nobody; this is a desktop that's safe to install on a Linux computer and hand over, with confidence, to someone who's never used Linux in their life. They'll fall right into this desktop with a soft and gentle landing.
|
||||
|
||||
You can bring up a small desktop menu with a right-click. This allows you to make an application launcher on the desktop, create a folder, and set some theme options.
|
||||
|
||||
The panel at the bottom of the screen is retractable, so you can work full-screen if you prefer. Click the clock in the bottom-right of the screen to bring up a calendar and time-zone settings.
|
||||
|
||||
EDE has a small Configuration Place application that provides access to a few simple preferences:
|
||||
|
||||
* Background and icon settings
|
||||
* Screensaver settings
|
||||
* Time and clock
|
||||
* System bell
|
||||
* Keyboard
|
||||
* Preferred applications
|
||||
|
||||
|
||||
|
||||
![EDE Configuration Place][10]
|
||||
|
||||
There's not much more to EDE. There's no file manager, no text editor, or paint program, or game of solitaire. You must bring anything you want to run on your desktop. That means you get to pick and choose from the wide array of Linux applications and use whatever you love the most.
|
||||
|
||||
### EDE as a statement
|
||||
|
||||
I found the simplicity of EDE oddly comforting, at least as a kind of "holiday" desktop; it's a nice place to visit. It's not the most glamorous desktop available, nor the most minimal, nor the most efficient. But its soft, muted tones are calming, its familiarity soothing, and its icon theme fun and exuberant. EDE is a desktop that's proud of its slow and steady pace.
|
||||
|
||||
If you're in the mood to put your feet up and enjoy a clean and pleasant interface, try EDE.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/19/12/ede-linux-desktop
|
||||
|
||||
作者：[Seth Kenlon][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/seth
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/penguin.igloo_.png?itok=K92O7H6b (Linux penguin at the north pole beside an igloo)
|
||||
[2]: https://www.fltk.org/
|
||||
[3]: https://sourceforge.net/projects/ede/
|
||||
[4]: https://opensource.com/sites/default/files/uploads/advent-ede.jpg (EDE desktop)
|
||||
[5]: http://ede.sf.net
|
||||
[6]: https://opensource.com/article/19/12/pekwm-linux-desktop
|
||||
[7]: https://opensource.com/sites/default/files/advent-gdm_2.jpg
|
||||
[8]: https://opensource.com/sites/default/files/advent-kdm_1.jpg
|
||||
[9]: https://opensource.com/sites/default/files/uploads/advent-ede-init.jpg (Importing desktop services in EDE)
|
||||
[10]: https://opensource.com/sites/default/files/uploads/advent-ede-conf.jpg (EDE Configuration Place)
|
||||
@ -0,0 +1,72 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (Top articles for learning Python in 2020)
|
||||
[#]: via: (https://opensource.com/article/19/12/learn-python)
|
||||
[#]: author: (Matthew Broberg https://opensource.com/users/mbbroberg)
|
||||
|
||||
Top articles for learning Python in 2020
|
||||
======
|
||||
No matter where you are in your Python programming journey,
|
||||
Opensource.com's top Python articles from 2019 will help you along the
|
||||
way.
|
||||
![Hands on a keyboard with a Python book ][1]
|
||||
|
||||
Python had a big year in 2019. According to popular resources like [GitHub][2] and [Stack Overflow][3], it's trending as the second most popular language in the world.
|
||||
|
||||
> "Python, the fastest-growing major programming language, has risen in the ranks of programming languages in our survey yet again, edging out Java this year and standing as the second most loved language (behind Rust)."
|
||||
> — [Stack Overflow Insights][3]
|
||||
|
||||
Similarly, Python grew in readership on Opensource.com by leaps and bounds. Here are the top Python articles from 2019, grouped by topic, for your perusal.
|
||||
|
||||
### Why choose Python?
|
||||
|
||||
There are many languages out there, so what makes Python such a destination? If the most-read articles tell us anything, it's that people enjoy its flexibility. There are [multiple paradigms][4] that are accessible to Python developers, as Jigyasa Grover explains, including the popular [object-oriented programming][5] Seth Kenlon's tutorial shows.
|
||||
|
||||
If you're a long-time user and looking for advanced examples of why Python is a perfect language, Moshe Zadka covers his [top 5 reasons for loving Python][6]. If that's not enough, you can also use it play around with powerful tools without a lot of code, like in Parul Pandey's tutorial on [image manipulation][7].
|
||||
|
||||
### Configuring Python
|
||||
|
||||
As Python's popularity continues to rise, more people are starting with the language than ever before. Many of those first-timers are doing so on the Mac operating system and are using a [guide to setting up Python 3][8] that Moshe and I wrote.
|
||||
|
||||
After installing Python, decisions on where to write your code come next. There are many options when it comes to text editors and integrated development environments (IDEs), but readers appear to favor graphical options, as Stephan Avenwedde's article about [Pythonic][9] and my article on [JupyterLab][10] were the most read articles on that topic in 2019.
|
||||
|
||||
On the path to getting confident with the language, developers will have to face the multitude of options available for how to manage versions of the language and project dependencies. Luckily, László Kiss Kollár's article makes [managing Python packages][11] a bit simpler.
|
||||
|
||||
When you're ready to configure an IDE with all of the features you'll want to make the most of the language, be sure to give the [opinionated linter Black][12] a try, as Moshe explains, to keep your code clean.
|
||||
|
||||
### Wrapping up
|
||||
|
||||
No matter where you are in your path to enjoying Python programming, the top Python articles from 2019 are here to help you along the way. I can't wrap this up without at least one acknowledgment of the importance of testing, and Moshe offers another well-read article [on tox][13] for that purpose.
|
||||
|
||||
Thank you to all the authors who wrote for Opensource.com in 2019! If you're just learning to program in Python, let us know in the comments what you want to know. And, if you're a seasoned veteran, consider sharing your tips and tricks with us by [writing an article][14] about your favorite Python topic.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/19/12/learn-python
|
||||
|
||||
作者：[Matthew Broberg][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/mbbroberg
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/python-programming-code-keyboard.png?itok=fxiSpmnd (Hands on a keyboard with a Python book )
|
||||
[2]: https://octoverse.github.com/#top-languages
|
||||
[3]: https://insights.stackoverflow.com/survey/2019
|
||||
[4]: https://opensource.com/article/19/10/python-programming-paradigms
|
||||
[5]: https://opensource.com/article/19/7/get-modular-python-classes
|
||||
[6]: https://opensource.com/article/19/10/why-love-python
|
||||
[7]: https://opensource.com/article/19/3/python-image-manipulation-tools
|
||||
[8]: https://opensource.com/article/19/5/python-3-default-mac
|
||||
[9]: https://opensource.com/article/19/5/graphically-programming-pythonic
|
||||
[10]: https://opensource.com/article/19/5/jupyterlab-python-developers-magic
|
||||
[11]: https://opensource.com/article/19/4/managing-python-packages
|
||||
[12]: https://opensource.com/article/19/5/python-black
|
||||
[13]: https://opensource.com/article/19/5/python-tox
|
||||
[14]: https://opensource.com/how-submit-article
|
||||
@ -0,0 +1,87 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (Why your Python code should be flat and sparse)
|
||||
[#]: via: (https://opensource.com/article/19/12/zen-python-flat-sparse)
|
||||
[#]: author: (Moshe Zadka https://opensource.com/users/moshez)
|
||||
|
||||
Why your Python code should be flat and sparse
|
||||
======
|
||||
This is part of a special series about the Zen of Python focusing on the
|
||||
fifth and sixth principles: flatness and sparseness.
|
||||
![Digital creative of a browser on the internet][1]
|
||||
|
||||
The [Zen of Python][2] is called that for a reason. It was never supposed to provide easy-to-follow guidelines for programming. The rules are specified tersely and are designed to engage the reader in deep thought.
|
||||
|
||||
In order to properly appreciate the Zen of Python, you must read it and then meditate upon the meanings. If the Zen was designed to be a set of clear rules, it would be a fault that it has rules that contradict each other. However, as a tool to help you meditate on the best solution, contradictions are powerful.
|
||||
|
||||
### Flat is better than nested.
|
||||
|
||||
Nowhere is the pressure to be "flat" more obvious than in Python's strong insistence on indentation. Other languages will often introduce an implementation that "cheats" on the nested structure by reducing indentation requirements. To appreciate this point, let's take a look at JavaScript.
|
||||
|
||||
JavaScript is natively async, which means that programmers write code in JavaScript using a lot of callbacks.
|
||||
|
||||
|
||||
```
|
||||
a(function(resultsFromA) {
|
||||
b(resultsFromA, function(resultsfromB) {
|
||||
c(resultsFromC, function(resultsFromC) {
|
||||
console.log(resultsFromC)
|
||||
}
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
Ignoring the code, observe the pattern and the way indentation leads to a right-most point. This distinctive "arrow" shape is tough on the eye to quickly walk through the code, so it's seen as undesirable and even nicknamed "callback hell." However, in JavaScript, it is possible to "cheat" and not have indentation reflect nesting.
|
||||
|
||||
|
||||
```
|
||||
a(function(resultsFromA) {
|
||||
b(resultsFromA,
|
||||
function(resultsfromB) {
|
||||
c(resultsFromC,
|
||||
function(resultsFromC) {
|
||||
console.log(resultsFromC)
|
||||
}}}
|
||||
```
|
||||
|
||||
Python affords no such options to cheat: every nesting level in the program must be reflected in the indentation level. So deep nesting in Python _looks_ deeply nested. That makes "callback hell" was a worse problem in Python than in JavaScript: nesting callbacks mean indenting with no options to "cheat" with braces.
|
||||
|
||||
This challenge, in combination with the Zen principle, has led to an elegant solution by a library I worked on. In the [Twisted][3] framework, we came up with the _deferred_ abstraction, which would later inspire the popular JavaScript _promise_ abstraction. In this way, Python's unwavering commitment to clear code forces Python developers to discover new, powerful abstractions.
|
||||
|
||||
|
||||
```
|
||||
future_value = future_result()
|
||||
future_value.addCallback(a)
|
||||
future_value.addCallback(b)
|
||||
future_value.addCallback(c)
|
||||
```
|
||||
|
||||
(This might look familiar to modern JavaScript programmers: Promises were heavily influenced by Twisted's deferreds.)
|
||||
|
||||
### Sparse is better than dense.
|
||||
|
||||
The easiest way to make something less dense is to introduce nesting. This habit is why the principle of sparseness follows the previous one: after we have reduced nesting as much as possible, we are often left with _dense_ code or data structures. Density, in this sense, is jamming too much information into a small amount of code, making it difficult to decipher when something goes wrong.
|
||||
|
||||
Reducing that denseness requires creative thinking, and there are no simple solutions. The Zen of Python does not offer simple solutions. All it offers are ways to find what can be improved in the code, without always giving guidance for "how."
|
||||
|
||||
Take a walk. Take a shower. Smell the flowers. Sit in a lotus position and think hard, until finally, inspiration strikes. When you are finally enlightened, it is time to write the code.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/19/12/zen-python-flat-sparse
|
||||
|
||||
作者：[Moshe Zadka][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/moshez
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/browser_web_internet_website.png?itok=g5B_Bw62 (Digital creative of a browser on the internet)
|
||||
[2]: https://www.python.org/dev/peps/pep-0020/
|
||||
[3]: https://twistedmatrix.com/trac/
|
||||
@ -0,0 +1,97 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (12 open source resources for kids and young adults)
|
||||
[#]: via: (https://opensource.com/article/19/12/kids-students-education)
|
||||
[#]: author: (Don Watkins https://opensource.com/users/don-watkins)
|
||||
|
||||
12 open source resources for kids and young adults
|
||||
======
|
||||
Explore new technologies with Opensource.com's top 12 articles from 2019
|
||||
about learning an open source technology.
|
||||
![Person reading a book and digital copy][1]
|
||||
|
||||
Are you looking to challenge your children (or even yourself) to learn new things about open source technologies? Whether you're in elementary school, high school, or college, or even a parent or teacher, Opensource.com has some great reading about open source technologies suitable for the younger generation. Here are our top 12 articles from 2019 on open source for students (and those who love them).
|
||||
|
||||
### Hacking math education with Python
|
||||
|
||||
As a student, I had difficulty with the abstraction of mathematics. Traditional classroom instruction didn't work for me. Peter Farrell has another approach for learners who are challenged by conventional mathematics instruction. His unique approach, which teaches math using Python, resonated with me when I interviewed him about how he is [_Hacking math education with Python_][2].
|
||||
|
||||
### 5 open source tools for teaching young children to read
|
||||
|
||||
No doubt, you have seen how easy it is for children to master today's electronic devices—but what about traditional literacy? Are today's children getting the foundation in reading, writing, and arithmetic that they need to be successful? Laura Janusek's [_5 open source tools for teaching young children to read_][3] may help. She says, "Access to literary environments has been shown to impact literacy and attitudes towards reading. Why not strive to create a digital literacy environment for our kids by filling our devices with educational technologies, just like our shelves are filled with books?"
|
||||
|
||||
### What programming language would you teach a kid first?
|
||||
|
||||
Coding has become a hot area for schools and parents. Opinions abound on the best computer language to teach and when to begin teaching it. Lauren Pritchett celebrated Ada Lovelace Day 2019 by exploring [_What programming language would you teach kids first?_][4] Be sure to take the accompanying poll, too.
|
||||
|
||||
### Getting started with the BBC Microbit
|
||||
|
||||
Learning to code should be fun, and one of the ways to ensure a great early experience is by using an inexpensive open hardware board. In [_Getting started with the BBC Microbit_][5], I provide step-by-step directions and some code examples so your child can learn to program with MicroPython.
|
||||
|
||||
### Introducing kids to computational thinking with Python
|
||||
|
||||
Coding can be the key that lifts children out of poverty and empowers them to gain new skills, confidence, and the knowledge necessary to break free from socioeconomic disadvantages. In [_Introducing kids to computational thinking with Python_][6], I interviewed librarian Qumisha Goss, who is leveraging the power of Python to transform children's lives in Detroit.
|
||||
|
||||
### A dozen ways to learn Python
|
||||
|
||||
Do you know someone who really wants to learn to Python but is looking for the right hook to get started? Removing abstraction has been key to my best learning experiences, and I share some of the resources I've found in [_A dozen ways to learn Python_][7]. They will start you on your journey to Python proficiency and sustain your learning over the long haul.
|
||||
|
||||
### 100 ways to learn Python and R for data science
|
||||
|
||||
Many people want to learn data science but are drowning in the deluge of information available online, leaving them confused about where to find the best book, tutorial, or other learning resources. Where would you turn to learn the skills necessary to play a role in this rapidly growing field? Chris Englehardt, Dorris Scott, and Annu Singh share their suggestions in [_100 ways to learn Python and_ _R for data science_][8].
|
||||
|
||||
### How a trip to China inspired Endless OS and teaching kids to hack
|
||||
|
||||
I've long been interested in inexpensive, Linux-based computers that help children around the world learn how to code. One of these is Endless' Hack, a low-cost laptop, and an accompanying series of video games designed to get kids coding and become creative problem solvers while they're having fun. In 2019, I got to interview Endless' founder Matt Dalio, where he shares [_How a trip to China inspired Endless OS and teaching kids to hack_][9].
|
||||
|
||||
### How to use the internet to learn IT skills
|
||||
|
||||
Looking to do something meaningful in the new year? How about helping a few young people take their first steps in an IT career? You can follow the lead of David Clinton, a systems administrator, teacher, and writer, who shares [_How to use the internet to learn IT skills_][10]. Giving students access to open source tools and letting them explore and iterate creates a rich learning experience, he explains.
|
||||
|
||||
### Digital divide? How the Asian Penguins share Linux at Minnesota charter school
|
||||
|
||||
Stu Keroff is an educator who has turned his passion for Linux and open source into a school–community outreach program that serves a large number of immigrant families in Minnesota. He is a husband, father, teacher, speaker, and advocate for Linux in K-12 education and a winner of the [2016 Opensource.com Readers Choice Award][11]. In [_Digital divide? How the Asian Penguins share Linux at Minnesota charter school_][12], Stu shares his Linux-powered solution to expand digital literacy in his community.
|
||||
|
||||
### 13 books for picking up new tech in 2019
|
||||
|
||||
If you (or someone you know) learn best by reading, my [_13 books for picking up new tech in 2019_][13] may help you discover a new skill that piques your curiosity. The list includes books on everything from Python to Linux to developing games on a Raspberry Pi.
|
||||
|
||||
### 11 surprising ways you use Linux every day
|
||||
|
||||
If you, like me, wonder what powers all the electronic gadgets that power our day-to-day lives today, read my article on [_11 surprising ways you use Linux every day_][14]. You might be amazed at how much we depend on open source to get us through our days.
|
||||
|
||||
### A lifetime of learning
|
||||
|
||||
What would you like to know to help the children in your life expand their tech knowledge and skills? Please share your ideas in the comments, or even consider sharing your own experiences with Opensource.com readers by [submitting an article][15] about your favorite open source education topic.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/19/12/kids-students-education
|
||||
|
||||
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/sites/default/files/styles/image-full-size/public/lead-images/read_book_guide_tutorial_teacher_student_apaper.png?itok=_GOufk6N (Person reading a book and digital copy)
|
||||
[2]: https://opensource.com/article/19/1/hacking-math
|
||||
[3]: https://opensource.com/article/19/4/early-literacy-tools
|
||||
[4]: https://opensource.com/article/19/10/first-programming-language-kids
|
||||
[5]: https://opensource.com/article/19/8/getting-started-bbc-microbit
|
||||
[6]: https://opensource.com/article/19/2/break-down-stereotypes-python
|
||||
[7]: https://opensource.com/article/19/8/dozen-ways-learn-python
|
||||
[8]: https://opensource.com/article/19/5/learn-python-r-data-science
|
||||
[9]: https://opensource.com/article/19/6/endless-digital-literacy
|
||||
[10]: https://opensource.com/article/19/5/it-skills-internet
|
||||
[11]: https://opensource.com/community/16/2/winners-2016-community-awards
|
||||
[12]: https://opensource.com/article/19/2/asian-penguins-close-digital-divide
|
||||
[13]: https://opensource.com/article/19/1/tech-books-new-skils
|
||||
[14]: https://opensource.com/article/19/8/everyday-tech-runs-linux
|
||||
[15]: https://opensource.com/how-submit-article
|
||||
84
sources/tech/20191225 5 security tips from Santa.md
Normal file
84
sources/tech/20191225 5 security tips from Santa.md
Normal file
@ -0,0 +1,84 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (5 security tips from Santa)
|
||||
[#]: via: (https://opensource.com/article/19/12/security-tips)
|
||||
[#]: author: (Mike Bursell https://opensource.com/users/mikecamel)
|
||||
|
||||
5 security tips from Santa
|
||||
======
|
||||
Stay off Santa's (and your employer's) naughty list by following this
|
||||
list of useful security tips and practices.
|
||||
![Security monster][1]
|
||||
|
||||
If you're reading this in 2019, it's almost Christmas (as celebrated according to the Western Christian calendar), and, like all children and IT professionals, it's time to write your letter to Santa/St. Nick/Father Christmas. Don't forget: those who have been good get nice presents and those who haven't get coal. Coal is _not_ a clean-burning fuel, and with climate change well and truly upon us,[1][2] you don't want to be going for the latter option.
|
||||
|
||||
Think back to all of the good security practices you've adopted over the past 11 or so months. And then think back to all of the bad security practices you've adopted when you should have been doing the _right_ thing. Oh, dear. It's not looking good for you, is it?
|
||||
|
||||
Here's the good news, though: because Santa is a benevolent soul, there's time to make amends (unless you're reading this after Christmas[2][3]). Here's a list of useful security tips and practices that Santa follows and therefore are bound to put you on his "good" side.
|
||||
|
||||
### 1\. Use a password manager
|
||||
|
||||
Santa is very careful with his passwords. Here's a little secret: from time to time, rather than have his elves handcraft every little present, he sources his gifts from other parties. I'm not suggesting that he pays market rates (he's ordering in bulk, and he has a very, very good credit rating), but he uses lots of different suppliers, and he's aware that not all of them take security as seriously as he does. He doesn't want all his account logins to be leaked if one of his suppliers is hacked, so he uses separate passwords for each account. Now, Santa, being Santa, could remember all of these details if he wanted to—and even generate unique passwords that meet all the relevant complexity requirements for each site—but he uses an open source [password manager][4] for safety and for succession planning.[3][5]
|
||||
|
||||
### 2\. Manage personal information properly
|
||||
|
||||
You may work for a large company, organisation, or government, and you may think you have lots of customers and associated data, but consider Santa. He manages (or has managed) names, birth dates, addresses, hobbies, shoe sizes, colour preferences, and other personal data for literally every person on Earth. That's an awful lot of sensitive data, and it needs to be protected. When people grow too old for presents from Santa,[4][6] he needs to delete their data securely. In fact, Santa may well be the archetypal [GDPR][7] data controller, and he needs to be very careful who and what can access the data that he holds. Of course, he encrypts all the data and is very careful about key management. He's also very aware of the dangers associated with cold boot attacks (given the average temperature around his residence), so he ensures data is properly wiped before shutdown.
|
||||
|
||||
### 3\. Measure and mitigate risk
|
||||
|
||||
Santa knows all about [risk][8]. He has complex systems for ordering, fulfillment, travel planning, logistics, and delivery that are the envy of most of the world. He understands what impact failure in any part of the supply chain can have on his customers: mainly children and IT professionals. He quantifies risk, recalculating it on a regular basis to ensure that he is up to date with possible vulnerabilities and ready with mitigations.
|
||||
|
||||
### 4\. Patch frequently but carefully
|
||||
|
||||
Santa absolutely cannot afford for his systems to go down, particularly around his most busy period. He has established processes to ensure that the [concerns of security are balanced with the needs of the business][9].[5][10] He knows that sometimes business continuity must take priority, and on other occasions, the impact of a security breach would be so major that patches just _have_ to be applied. He tells people what he wants and listens to their views, taking them into account where he can. In other words, he embraces open management, delegating decisions where possible to the people who are best positioned to make the call, and only intervenes when asked for an executive decision or when exceptions arise. Santa is a _very_ enlightened manager.
|
||||
|
||||
### 5\. Embrace diversity
|
||||
|
||||
One of the useful consequences of running a global operation is that Santa values diversity. Old or young (at heart); male, female, or gender-neutral; neurotypical or neurodiverse; of any culture, sexuality, race, ability, creed, or nose colour, Santa takes into account his stakeholders and their views on what might go wrong. What a fantastic set of viewpoints Santa has available to him! And he's surprisingly hip to the opportunities for security practices that a wide and [diverse set of opinions and experiences][11] can bring[6][12] not to mention the multiple [positive impacts][13] on his organisation.
|
||||
|
||||
### Summary
|
||||
|
||||
Here's my advice: Be like Santa, and adopt at least some of his security practices. You'll have a much better opportunity of getting onto his good side, and that's going to go down well—not just with him, but also with your employer, who is just certain to give you a nice bonus, right? And if not, well, it's not too late to write that letter directly to Santa himself.
|
||||
|
||||
* * *
|
||||
|
||||
1. If you have a problem with this statement, then either you need to find another article, or you're reading this in the far future where all our climate problems have been solved. I hope.
|
||||
2. Or you dwell in one of those cultures where Santa visits quite early in December.
|
||||
3. A high-flying goose in the face can do terrible damage to a fast-moving reindeer, and if the sleigh were to crash, what then...?
|
||||
4. Not me!
|
||||
5. Santa doesn't refer to it as a "business," but he's happy for us to call it that, so we can model our own experience on his. He's nice like that.
|
||||
6. Though Santa would never use the phrase "hip to the opportunities." He's way too cool for that.
|
||||
|
||||
|
||||
|
||||
Download the free All Things Open interview series eBook Jessica McKellar is an entrepreneur,...
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/19/12/security-tips
|
||||
|
||||
作者：[Mike Bursell][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/mikecamel
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/security_password_chaos_engineer_monster.png?itok=J31aRccu (Security monster)
|
||||
[2]: tmp.PgLkHLx1Uz#1
|
||||
[3]: tmp.PgLkHLx1Uz#2
|
||||
[4]: https://opensource.com/article/18/4/3-password-managers-linux-command-line
|
||||
[5]: tmp.PgLkHLx1Uz#3
|
||||
[6]: tmp.PgLkHLx1Uz#4
|
||||
[7]: https://opensource.com/article/18/1/being-open-about-data-privacy
|
||||
[8]: http://aliceevebob.com/2019/03/12/dont-talk-security-talk-risk/
|
||||
[9]: http://aliceevebob.com/2017/10/17/stop-reading-start-patching/
|
||||
[10]: tmp.PgLkHLx1Uz#5
|
||||
[11]: http://aliceevebob.com/2017/08/08/diversity-in-it-security-not-just-a-canine-issue/
|
||||
[12]: tmp.PgLkHLx1Uz#6
|
||||
[13]: https://opensource.com/article/19/11/diversity-and-inclusion-strategies
|
||||
@ -0,0 +1,149 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (Khadas VIM3L: An Open Source HTPC Device)
|
||||
[#]: via: (https://itsfoss.com/vim3l/)
|
||||
[#]: author: (Community https://itsfoss.com/author/itsfoss/)
|
||||
|
||||
Khadas VIM3L: An Open Source HTPC Device
|
||||
======
|
||||
|
||||
If you’ve read our list of [Raspberry Pi alternatives][1], you might have come across VIM by Khadas.
|
||||
|
||||
China-based [Khadas][2] is becoming increasingly popular for its single board computers (SCB). Apart from the generic do-it-yourself (DIY) VIM series, Khadas also has [Tone boards][3] that can be utilized for DJing and [Edge][4] boards for AI and other related projects.
|
||||
|
||||
As discussed in [Raspberry Pi projects][5], one of the most popular use of a single board computer is to use it as a media center. You can turn your TV in more than just a smart TV (without being monitored) and play local music, videos, pictures and even games on your TV. You can also watch streaming services through these media center.
|
||||
|
||||
You can always configure VIm (or any other SCB) as a media center. It’s a good DIY exercise but not everyone would like it.
|
||||
|
||||
This is why Khadas has introduced [VIM3L][6] which is a ready to use media center device based on VIM 3. In this article, we’ll have a look at this device and see how to set it up.
|
||||
|
||||
### VIM 3L specifications
|
||||
|
||||
One of the strong point of Khadas is its emphasis on open source. All their source code, including [U-Boot][7], mainline Linux and Android is available on [their GitHub repository][8].
|
||||
|
||||
VIM3L comes with [CoreELEC][9] operating system. CoreELEC is a custom Linux distribution that comes with software like [Kodi][10] and its add-ons to give you a complete HTPC (home theatre PC) experience.
|
||||
|
||||
![][11]
|
||||
|
||||
You are not restricted to CoreELEC though. You can get the barebon version of VIM 3L and use Android or install your a Linux distribution of your choice.
|
||||
|
||||
* Amlogic S905D3 SoC with quad-core Cortex-A55 CPU clocked at 1.9GHz
|
||||
* 16GB eMMC
|
||||
* 2GB RAM
|
||||
* 2x WiFi antennas
|
||||
* PCIe 2.0 and M.2 NVMe SSD support
|
||||
* HDMI port
|
||||
* Dolby Audio
|
||||
|
||||
|
||||
|
||||
The HTPC version costs slightly more than the bare board but it consists of some additional hardware along with CoreELEC operating system:
|
||||
|
||||
* Transparent DIY case
|
||||
* Metal DIY case
|
||||
* Heatsink
|
||||
* IR Remote
|
||||
|
||||
|
||||
|
||||
![VIM3L HTPC Kit][12]
|
||||
|
||||
VIM3L is capable of running 4K video at 75 fps. It also includes TrustZone based security for DRM video streaming. Both Android and CoreELEC are capable of [OTA updates][13].
|
||||
|
||||
[VIM3L HTPC version costs $89.99][14] and the bare board (with Android) costs $69.99. It’s FOSS readers can _**get $6 off with itsfossfuns coupon code**_ that can be used at the checkout page of Khadas shop.
|
||||
|
||||
[Khadas VIM3 Series][15]
|
||||
|
||||
You may opt for the free shipping option but it will take 2-3 weeks for the device to reach you from China. You can pay $20 extra for an express DHL shipping. The shipping options are available at checkout. I think you might have to pay custom tax depending on your country’s rules so ordering one from Amazon would be better in such a case but you won’t get the It’s FOSS special discount on Amazon.
|
||||
|
||||
Now that you are aware of the specifications, let me show you how to set it up and how was my experience with it.
|
||||
|
||||
_The amazon links in this article are affiliate links. Please read our [affiliate policy][16]._
|
||||
|
||||
### Setting up VIM3L and using it as home theatre PC
|
||||
|
||||
Initially, when you start VIM3L, a window appears on the screen which consists of a series of questions and options. Everything you choose determines the initial state of its operation. In each case, however, you can modify your options from the settings menu. Better not to rush through the settings, since the multitude of options you have at startup seem to turn the VIM3L into a superpower device.
|
||||
|
||||
![Setting up proxy network][17]
|
||||
|
||||
The addition of the proxy connectivity in the internet settings is a welcome option. As a enthusiast of user privacy, I enabled it to connect through the [Tor network][18]. The choice is of course yours.
|
||||
|
||||
![Peripheral devices][19]
|
||||
|
||||
You can modify how many and which peripheral devices you have on that device. For example, in addition to the handheld control, you can mount a keyboard or even a console controller. Correct! A console controller that will allow you to play games.
|
||||
|
||||
![Option to save logs][20]
|
||||
|
||||
An important addition is the log storage option. With this, the users can consult the logs in case of an event of an error or malfunction. This could help in troubleshooting the issue.
|
||||
|
||||
![Plenty of add-ons][21]
|
||||
|
||||
On the left, a user can see options such as music, videos, radio, photos, games and many other options that we would like to take some time to cover.
|
||||
|
||||
Add-ons further extends the capabilities of your HTPC. Here, you can find music libraries, documentaries, games, open-source software and more. The software includes various graphics, audio, and video editors, simulators etc.
|
||||
|
||||
You have the freedom to choose whether you want to download them through 3rd party repositories, or from the environment of the accessory. Also, if you try to install software, you will most likely notice that along with the program, appropriate libraries and software are also installed. As you can see, this is not an accessory from scratch, but an accessory that is ready to cope with its users’ choices.
|
||||
|
||||
VIM3L has different configuration profile consisting of a standard, intermediate, expert profile. As you climb into difficulty, your choices are multiplied, giving you total freedom.
|
||||
|
||||
### Thoughts on VIM3L
|
||||
|
||||
![][22]
|
||||
|
||||
I liked VIM3L for what it offers. This is not to say that it is a perfect device.
|
||||
|
||||
I found that some point, the controller is not fully accurate in signal transmission. As a result, after pressing a button twice, the signal is sent later and there is a quick change of screen. Maybe the controller I received was faulty.
|
||||
|
||||
In conclusion, I would like to say that it’s not an expensive device and the feature it offers are good enough to provide you with entertainment, fun, productivity, and creativity. Most importantly, the software it offers are free and open source.
|
||||
|
||||
If you like what you see here, you can either order it from [its own shop that ships from China][6] or get it from [Amazon][23].
|
||||
|
||||
Preview | Product | Price |
|
||||
---|---|---|---
|
||||
![Khadas Amlogic S905D3 VIM3L HTPC Kit][24] ![Khadas Amlogic S905D3 VIM3L HTPC Kit][24] | [Khadas Amlogic S905D3 VIM3L HTPC Kit][25] | $89.99[][26] | [Buy on Amazon][27]
|
||||
|
||||
Have you used VIM3L or any other pre-built media center device? Or do you prefer making your own HTPC? Do share your views.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://itsfoss.com/vim3l/
|
||||
|
||||
作者：[Community][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://itsfoss.com/author/itsfoss/
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://itsfoss.com/raspberry-pi-alternatives/
|
||||
[2]: https://www.khadas.com/
|
||||
[3]: https://www.amazon.com/dp/B07K6GQNH3?tag=chmod7mediate-20&linkCode=ogi&th=1&psc=1 (Tone boards)
|
||||
[4]: https://www.khadas.com/edge
|
||||
[5]: https://itsfoss.com/raspberry-pi-projects/
|
||||
[6]: https://www.khadas.com/vim3l
|
||||
[7]: https://www.denx.de/wiki/U-Boot
|
||||
[8]: https://github.com/khadas
|
||||
[9]: https://coreelec.org/
|
||||
[10]: https://itsfoss.com/install-kodi-ubuntu/
|
||||
[11]: https://i1.wp.com/itsfoss.com/wp-content/uploads/2019/12/VIM3L_OS_Freedom_graphic.jpg?ssl=1
|
||||
[12]: https://i0.wp.com/itsfoss.com/wp-content/uploads/2019/12/VIM3L-Htpc-Kit.jpg?ssl=1
|
||||
[13]: https://source.android.com/devices/tech/ota
|
||||
[14]: https://www.amazon.com/dp/B081H66D7Q?tag=chmod7mediate-20&linkCode=ogi&th=1&psc=1 (VIM3L HTPC version costs $89.99)
|
||||
[15]: https://www.khadas.com/shop-vim3
|
||||
[16]: https://itsfoss.com/affiliate-policy/
|
||||
[17]: https://i0.wp.com/itsfoss.com/wp-content/uploads/2019/12/khadas_vim3l_3.jpg?ssl=1
|
||||
[18]: https://itsfoss.com/tor-guide/
|
||||
[19]: https://i1.wp.com/itsfoss.com/wp-content/uploads/2019/12/khadas_vim3l_2.jpg?ssl=1
|
||||
[20]: https://i1.wp.com/itsfoss.com/wp-content/uploads/2019/12/khadas_vim3l_4.jpg?ssl=1
|
||||
[21]: https://i0.wp.com/itsfoss.com/wp-content/uploads/2019/12/khadas_vim3l_1.jpg?ssl=1
|
||||
[22]: https://i1.wp.com/itsfoss.com/wp-content/uploads/2019/12/VIM3L.jpg?ssl=1
|
||||
[23]: https://www.amazon.com/dp/B081H66D7Q?tag=chmod7mediate-20&linkCode=ogi&th=1&psc=1 (Amazon)
|
||||
[24]: https://i0.wp.com/m.media-amazon.com/images/I/41YC-mlA2PL._SL160_.jpg?ssl=1
|
||||
[25]: https://www.amazon.com/dp/B081H66D7Q?tag=chmod7mediate-20&linkCode=ogi&th=1&psc=1 (Khadas Amlogic S905D3 VIM3L HTPC Kit)
|
||||
[26]: https://www.amazon.com/gp/prime/?tag=chmod7mediate-20 (Amazon Prime)
|
||||
[27]: https://www.amazon.com/dp/B081H66D7Q?tag=chmod7mediate-20&linkCode=ogi&th=1&psc=1 (Buy on Amazon)
|
||||
@ -0,0 +1,61 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (Making trade-offs when writing Python code)
|
||||
[#]: via: (https://opensource.com/article/19/12/zen-python-trade-offs)
|
||||
[#]: author: (Moshe Zadka https://opensource.com/users/moshez)
|
||||
|
||||
Making trade-offs when writing Python code
|
||||
======
|
||||
This is part of a special series about the Zen of Python focusing on the
|
||||
seventh, eighth, and ninth principles: readability, special cases, and
|
||||
practicality.
|
||||
![Brick wall between two people, a developer and an operations manager][1]
|
||||
|
||||
Software development is a discipline rife with trade-offs. For every choice, there is an equally defensible but opposite choice. Make a method private? You're encouraging copy-paste. Make a method public? You're committing prematurely to an interface.
|
||||
|
||||
Software developers make hard choices every minute. While all the principles in the [Zen of Python][2] cover trade-offs to some extent, the following principles take the hardest, coldest look at some trade-offs.
|
||||
|
||||
### Readability counts.
|
||||
|
||||
In some sense, this middle principle is indeed the center of the entire Zen of Python. The Zen is not about writing efficient programs. It is not even about writing robust programs, for the most part. It is about writing programs that _other people can read_.
|
||||
|
||||
Reading code, by its nature, happens after the code has been added to the system. Often, it happens long after. Neglecting readability is the easiest choice since it does not hurt right now. Whatever the reason for adding new code—a painful bug or a highly requested feature—it does hurt. Right now.
|
||||
|
||||
In the face of immense pressure to throw readability to the side and just "solve the problem," the Zen of Python reminds us: readability counts. Writing the code so it can be read is a form of compassion for yourself and others.
|
||||
|
||||
### Special cases aren't special enough to break the rules.
|
||||
|
||||
There is always an excuse. This bug is particularly painful; let's not worry about simplicity. This feature is particularly urgent; let's not worry about beauty. The domain rules covering this case are particularly hairy; let's not worry about nesting levels.
|
||||
|
||||
Once we allow special pleading, the dam wall breaks, and there are no more principles; things devolve into a Mad Max dystopia with every programmer for themselves, trying to find the best excuses.
|
||||
|
||||
Discipline requires commitment. It is only when things are hard, when there is a strong temptation, that a software developer is tested. There is always a valid excuse to break the rules, and that's why the rules must be kept the rules. Discipline is the art of saying no to exceptions. No amount of explanation can change that.
|
||||
|
||||
### Although, practicality beats purity.
|
||||
|
||||
> "If you think only of hitting, springing, striking, or touching the enemy, you will not be able actually to cut him."
|
||||
> — Miyamoto Musashi, _[The Book of Water][3]_
|
||||
|
||||
Ultimately, software development is a practical discipline. Its goal is to solve real problems, faced by real people. Practicality beats purity: above all else, we must _solve the problem_. If we think only about readability, simplicity, or beauty, we will not be able to actually _solve the problem_.
|
||||
|
||||
As Musashi suggested, the primary goal of every code change should be to _solve a problem_. The problem must be foremost in our minds. If we waver from it and think only of the Zen of Python, we have failed the Zen of Python. This is another one of those contradictions inherent in the Zen of Python.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/19/12/zen-python-trade-offs
|
||||
|
||||
作者：[Moshe Zadka][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/moshez
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/devops_confusion_wall_questions.png?itok=zLS7K2JG (Brick wall between two people, a developer and an operations manager)
|
||||
[2]: https://www.python.org/dev/peps/pep-0020/
|
||||
[3]: https://en.wikipedia.org/wiki/The_Book_of_Five_Rings#The_Book_of_Water
|
||||
@ -0,0 +1,86 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (10 Linux command tutorials for beginners and experts)
|
||||
[#]: via: (https://opensource.com/article/19/12/linux-commands)
|
||||
[#]: author: (Moshe Zadka https://opensource.com/users/moshez)
|
||||
|
||||
10 Linux command tutorials for beginners and experts
|
||||
======
|
||||
Learn how to make Linux do what you need it to do in Opensource.com's
|
||||
top 10 articles about Linux commands from 2019.
|
||||
![Penguin driving a car with a yellow background][1]
|
||||
|
||||
Using Linux _well_ means understanding what commands are available and what they're capable of doing for you. We have covered a lot of them on Opensource.com during 2019, and here are 10 favorites from the bunch.
|
||||
|
||||
### Using the force at the Linux command line
|
||||
|
||||
The Force has a light side and a dark side. Properly understanding that is crucial to true mastery. In his article [_Using the force at the Linux command line_][2], Alan Formy-Duval explains the **-f** option (also known as **\--force**) for several popular and sometimes dangerous commands.
|
||||
|
||||
### Intro to the Linux useradd command
|
||||
|
||||
Sharing accounts is a bad idea. Instead, give separate accounts to different people (and even different roles) with the quintessential **useradd** command. Part of his venerable series on basic Linux administration, Alan Formy-Duval provides an [_Intro to the Linux useradd command_][3], and, as usual, he explains it in _plain English_ so that both new and experienced admins can understand it.
|
||||
|
||||
### Linux commands to display your hardware information
|
||||
|
||||
What's _inside_ the box? Sometimes it's useful to inspect your hardware without using a screwdriver. In [_Linux commands to display your hardware information_][4], Howard Fosdick provides both popular and obscure commands to help you dig deep into the computer you're using, the computer you're testing at the store before buying, or the computer you're trying to repair.
|
||||
|
||||
### How to encrypt files with gocryptfs on Linux
|
||||
|
||||
Our files hold lots of private data, from social security numbers to personal letters to loved ones. In [_How to encrypt files with gocryptfs on Linux_][5], Brian "Bex" Exelbierd explains how to keep *private *what's meant to be private. As a bonus, he demonstrates encrypting files in a way that has little to no impact on your existing workflow. This isn't a complex PGP-style puzzle of key management and background key agents; this is quick, seamless, and secure file encryption.
|
||||
|
||||
### How to use advanced rsync for large Linux backups
|
||||
|
||||
In the New Year, many people will resolve to be more diligent about making backups. Alan Formy-Duval must have made that resolution years ago, because in [_How to use advanced rsync for large Linux backups_][6], he displays remarkable familiarity with the file synchronization command. You might not remember all the syntax right away, but the idea is to read and process the options, construct your backup command, and then automate it. That's the smart way to use **rsync**, and it's the _only_ way to do backups reliably.
|
||||
|
||||
### Using more to view text files at the Linux command line
|
||||
|
||||
In Scott Nesbitt's article [_Using more to view text files at the Linux command line_][7], the good old default pager **more** finally gets the spotlight. Many people install and use **less**, because it's more flexible than **more**. However, with more and more systems being implemented in the sparsest of containers, the luxury of fancy new tools like **less** or **most** sometimes just doesn't exist. Knowing and using **more** is simple, it's a common default, and it's the production system's debugging tool of last resort.
|
||||
|
||||
### What you probably didn't know about sudo
|
||||
|
||||
The **sudo** command is famous to a fault. People know the **sudo** term, and most of us believe we know what it does. And we're a little bit correct, but as Peter Czanik reveals in his article [_What you probably didn't know about sudo_][8], there's a lot more to the command than just "Simon says." Like that classic childhood game, the **sudo** command is powerful and also prone to silly mistakes—only with greater potential for horrible consequences. This is one game you do not want to lose!
|
||||
|
||||
### How to program with Bash: Syntax and tools
|
||||
|
||||
If you're a Linux, BSD, or Mac (and lately, Windows) user, you may have used the Bash shell interactively. It's a great shell for quick, one-off commands, which is why so many Linux users love to use it as their primary user interface. However, Bash is much more than just a command prompt. It's also a programming language, and if you're already using Bash commands, then the path to automation has never been more straightforward. Learn all about it in David Both's excellent [_How to program with Bash: Syntax and tools_][9].
|
||||
|
||||
### Master the Linux ls command
|
||||
|
||||
The **ls** command is one of those commands that merits a two-letter name; one-letter commands are an optimization for slow terminals where each letter causes a significant delay and also a nice bonus for lazy typists. Seth Kenlon explains how you can [_Master the Linux ls command_][10] and he does so with his usual clarity and pragmatism. Most significantly, in a system where "everything is a file," being able to list the files is crucial.
|
||||
|
||||
### Getting started with the Linux cat command
|
||||
|
||||
The **cat** command (short for con_cat_enate) is deceptively simple. Whether you use it to quickly see the contents of a file or to pipe the contents to another command, you may not be using **cat** to its full potential. Alan Formy-Duval's elucidating [_Getting started with the Linux cat command_][11] offers new ideas to take advantage of a command that lets you open a file without feeling like you've opened it. As a bonus, learn all about **zcat** so you can decompress files without all the trouble of decompression! It's a small and simple thing, but _this_ is what makes Linux great.
|
||||
|
||||
### Continue the journey
|
||||
|
||||
Don't let Opensource.com's 10 best articles about Linux commands of 2019 be the end of your journey. There's much more to discover about Linux and its versatile prompt, so stay tuned in 2020 for more insights. And, if there's a Linux command you want us to know about, please tell us about it in the comments, or share your knowledge with Opensource.com readers by [submitting an article][12] about your favorite Linux command.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/19/12/linux-commands
|
||||
|
||||
作者：[Moshe Zadka][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/moshez
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/car-penguin-drive-linux-yellow.png?itok=twWGlYAc (Penguin driving a car with a yellow background)
|
||||
[2]: https://opensource.com/article/19/5/may-the-force-linux
|
||||
[3]: https://opensource.com/article/19/10/linux-useradd-command
|
||||
[4]: https://opensource.com/article/19/9/linux-commands-hardware-information
|
||||
[5]: https://opensource.com/article/19/8/how-encrypt-files-gocryptfs
|
||||
[6]: https://opensource.com/article/19/5/advanced-rsync
|
||||
[7]: https://opensource.com/article/19/1/more-text-files-linux
|
||||
[8]: https://opensource.com/article/19/10/know-about-sudo
|
||||
[9]: https://opensource.com/article/19/10/programming-bash-syntax-tools
|
||||
[10]: https://opensource.com/article/19/7/master-ls-command
|
||||
[11]: https://opensource.com/article/19/2/getting-started-cat-command
|
||||
[12]: https://opensource.com/how-submit-article
|
||||
@ -0,0 +1,123 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (10 articles to become more data science savvy)
|
||||
[#]: via: (https://opensource.com/article/19/12/data-science-resources)
|
||||
[#]: author: (Lauren Maffeo https://opensource.com/users/lmaffeo)
|
||||
|
||||
10 articles to become more data science savvy
|
||||
======
|
||||
Boost your data science game in 2020 with Opensource.com's top 10
|
||||
most-read articles on the topic from 2019.
|
||||
![Open data brain][1]
|
||||
|
||||
When LinkedIn released its third annual [Emerging Jobs report][2], engineers everywhere said, "Amen." More than half the list consists of engineering roles, with new fields like robotics appearing for the first time.
|
||||
|
||||
But data science had a strong showing as well. The role shows 37% annual growth, topping that aspect of the Emerging Jobs list for the third year in a row.
|
||||
|
||||
Looking at the core skills a data scientist needs—including R, Python, and Apache Spark—it's easy to find overlaps with open source. So, we're not surprised that data science was one of the most popular topics at Opensource.com in 2019.
|
||||
|
||||
We saw a need for knowledge about diverse data science topics. And our community of authors delivered answers.
|
||||
|
||||
For your reading pleasure, we've listed the top 10 data science articles of 2019. We define "top" as the data science articles that were published in 2019 and earned the most page views, starting with the most popular.
|
||||
|
||||
Whether you want to use Kubernetes for batch jobs or query 10 years' worth of GitHub data, these articles will boost your data science game in 2020.
|
||||
|
||||
### Why data scientists love Kubernetes
|
||||
|
||||
Kubernetes is having more than a moment. That's due in no small part to its versatility. You might already know that Kubernetes helps software developers and system operators deploy applications in Linux containers. But did you know how helpful it can be for data science as well?
|
||||
|
||||
In [_Why data scientists love Kubernetes_][3], our most popular data science article in 2019, William Benton and Sophie Watson share how Kubernetes supports the data science workflow. From repeatable batch jobs to debugging ML models, this article shares several ways for data scientists to leverage Kubernetes.
|
||||
|
||||
### How to use Spark SQL: A hands-on tutorial
|
||||
|
||||
Wondering how to use a cloud service for big data analytics? [_How to use Spark SQL: A hands-on tutorial_][4] uses Spark DataFrames to show how to use relational databases at scale. DJ Sarkar uses a real-world dataset to walk readers through the process of using Spark SQL.
|
||||
|
||||
Rich with screenshots and code, Sarkar's tutorial is the ideal sequel to [his first piece][5] on this subject. He shares several ways that you can use Spark to manage structured data obtained from flat files or databases.
|
||||
|
||||
### 9 resources for data science projects
|
||||
|
||||
The growth of data science in open source—from machine learning to neural networks—has left many engineers wanting to learn more. In [_9 resources for data science projects_][6], Dan Barker shares the books, tools, and online courses he thinks are a must for any engineer who wants to get started.
|
||||
|
||||
Barker is especially keen on Cathy O'Neil's book [_Weapons of Math Destruction_][7], which shares how bias creeps into data and how you can stop it. He also shares a range of websites for newbies to explore.
|
||||
|
||||
### Getting started with data science using Python
|
||||
|
||||
Alongside the rise of data science techniques, Python has seen a meteoric rise. It's now one of the most popular programming languages. When used with libraries like pandas and Seaborn, Python is an ideal entry to data science.
|
||||
|
||||
In [_Getting started with data science using Python_][8], a follow-up to his [intro to Python][9] article, Seth Kenlon shares how to create a Python virtual environment; install pandas and NumPy; create a sample dataset; and much more. This article is an especially good read if you want to learn more about data visualization.
|
||||
|
||||
### How to analyze log data with Python and Apache Spark
|
||||
|
||||
Like many articles in our top 10 list, [_How to analyze log data with Python and Apache Spark_][10] is a sequel to [an earlier article][11] on using Python and Apache Spark to wrangle data. Once you've learned how to put your data into a clean, structured format, DJ Sarkar offers this piece to help you analyze that data.
|
||||
|
||||
Whether you want to see the top 10 error endpoints or content size statistics, Sarkar shows you how to analyze several types of log data in your [DataFrame][12]. The data that he uses isn't "big data" from a size or volume standpoint. But these techniques can scale for use with larger datasets.
|
||||
|
||||
### How to wrangle log data with Python and Apache Spark
|
||||
|
||||
[_How to wrangle log data with Python and Apache Spark_][11], DJ Sarkar's prequel to his piece on analyzing log data, also made our top 10 list. It's no surprise since most organizations use a range of systems and infrastructure that run constantly. Data logs are an ideal way to make sure that everything keeps working effectively.
|
||||
|
||||
In this tutorial, Sarkar shows how to use Apache Spark on real-world production logs from NASA. He walks through the process of using Spark to do log analytics at scale on semi-structured log data. This ranges from setting up dependencies to data wrangling.
|
||||
|
||||
### Querying 10 years of GitHub data with GHTorrent and Libraries.io
|
||||
|
||||
Did you know that you can use Kibana or the Elasticsearch API to turn Amazon S3 object-storage data into a searchable Elasticsearch-type cluster? Likewise, did you know about the project that aims to build an offline version of all data available through GitHub APIs?
|
||||
|
||||
In [_Querying 10 years of GitHub data with GHTorrent and Libraries.io_][13], Pete Cheslock explores how to access and query GHTorrent data. You can do it using several formats, including CSV and Google Big Query. Cheslock uses the latter to search indexed GHTorrent data to learn which software languages, licenses, and rates of growth are most popular for GitHub projects.
|
||||
|
||||
### Predicting NFL play outcomes with Python and data science
|
||||
|
||||
Want to increase your machine learning skills in Python? With the NFL playoff season upon us, it's a great time to read [_Predicting NFL play outcomes with Python and data science_][14], which shares some data science tips to predict plays.
|
||||
|
||||
Christa Hayes shows how to spot weird values, predict downs and play types, make regression plots, and train models. Once you've read her article on [how to format data for training][15], this one is the ideal next step.
|
||||
|
||||
### Analyzing the Stack Overflow Survey with Python and Pandas
|
||||
|
||||
Stack Overflow's annual developer survey is a tech behemoth. Nearly 90,000 developers took this year's 20-minute survey and left a lot of data in their wake.
|
||||
|
||||
To find certain results, Moshe Zadka used the pandas library to search the survey's [anonymized results][16]. If you want to filter Stack Overflow's dataset for certain details (like seeing how many developers use certain languages or contribute to open source projects), Moshe's [_Analyzing the Stack Overflow Survey with Python and Pandas_][17] tutorial shows you how.
|
||||
|
||||
### 4 Python tools for getting started with astronomy
|
||||
|
||||
For readers with their heads in the clouds, NumFOCUS republished some of its blog posts on Opensource.com this year. In [_4 Python tools for getting started with astronomy_][18], Dr. Gina Helfrich shares how you can get involved in astronomy.
|
||||
|
||||
Intimidated? Don't be: Dr. Helfrich says Python packages are so advanced that building data-reduction scripts is much easier than ever before. If you want to play with astronomy imaging datasets, this piece will steer you in the right direction.
|
||||
|
||||
### What do you want to know about data science?
|
||||
|
||||
Data science is an exciting field with countless things to explore. If there's something you want to know about data science, please tell us about it in the comments so we can try to cover it in 2020. Or, if you are so inclined, please share your knowledge with Opensource.com readers by [submitting an article][19] about your favorite data science topic.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/19/12/data-science-resources
|
||||
|
||||
作者：[Lauren Maffeo][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/lmaffeo
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/osdc_520x292_opendata_0613mm.png?itok=UIjD_jhK (Open data brain)
|
||||
[2]: https://business.linkedin.com/content/dam/me/business/en-us/talent-solutions/emerging-jobs-report/Emerging_Jobs_Report_U.S._FINAL.pdf
|
||||
[3]: https://opensource.com/article/19/1/why-data-scientists-love-kubernetes
|
||||
[4]: https://opensource.com/article/19/3/apache-spark-and-dataframes-tutorial
|
||||
[5]: https://opensource.com/article/19/3/sql-scale-apache-spark-sql-and-dataframes
|
||||
[6]: https://opensource.com/article/19/2/learn-data-science-ai
|
||||
[7]: https://www.amazon.com/Weapons-Math-Destruction-Increases-Inequality/dp/0553418815
|
||||
[8]: https://opensource.com/article/19/9/get-started-data-science-python
|
||||
[9]: https://opensource.com/article/17/10/python-101
|
||||
[10]: https://opensource.com/article/19/5/visualize-log-data-apache-spark
|
||||
[11]: https://opensource.com/article/19/5/log-data-apache-spark
|
||||
[12]: https://pandas.pydata.org/pandas-docs/stable/getting_started/dsintro.html#dataframe
|
||||
[13]: https://opensource.com/article/19/5/chaossearch-github-ghtorrent
|
||||
[14]: https://opensource.com/article/19/10/predicting-nfl-plays-python
|
||||
[15]: https://opensource.com/article/19/10/formatting-nfl-data-python
|
||||
[16]: https://insights.stackoverflow.com/survey
|
||||
[17]: https://opensource.com/article/19/9/stack-overflow-survey-python-pandas
|
||||
[18]: https://opensource.com/article/19/10/python-astronomy-open-data
|
||||
[19]: https://opensource.com/how-submit-article
|
||||
@ -0,0 +1,56 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (How the Zen of Python handles errors)
|
||||
[#]: via: (https://opensource.com/article/19/12/zen-python-errors)
|
||||
[#]: author: (Moshe Zadka https://opensource.com/users/moshez)
|
||||
|
||||
How the Zen of Python handles errors
|
||||
======
|
||||
This is part of a special series about the Zen of Python focusing on the
|
||||
10th and 11th principles: on the silence (or not) of errors.
|
||||
![a checklist for a team][1]
|
||||
|
||||
Handling "exceptional conditions" is one of the most debated issues in programming. That could be because the stakes are high: mishandled error values can bring down even the largest systems. Since "exception conditions," by nature, are the least tested but occur with unpleasant frequency, correctly handling them can often distinguish a system that horror stories are told about to a system that "just works."
|
||||
|
||||
From Java's **checked** exceptions through Erlang's fault isolation to Haskell's **Maybe**, different languages have remarkably different attitudes to error handling.
|
||||
|
||||
The [Zen][2] offers Python's meditation on the topic.
|
||||
|
||||
### Errors should never pass silently…
|
||||
|
||||
Before the Zen of Python was a twinkle in Tim Peters' eye, before Wikipedia became informally known as "wiki," the first WikiWiki site, [C2][3], existed as a trove of programming guidelines. These are principles that mostly came out of a [Smalltalk][4] programming community. Smalltalk's ideas influenced many object-oriented languages, Python included.
|
||||
|
||||
The C2 wiki defines the Samurai Principle: "return victorious, or not at all." In Pythonic terms, it encourages eschewing sentinel values, such as returning **None** or **-1** to indicate an inability to complete the task, in favor of raising exceptions. A **None** is silent: it looks like a value and can be put in a variable and passed around. Sometimes, it is even a _valid_ return value.
|
||||
|
||||
The principle here is that if a function cannot accomplish its contract, it should "fail loudly": raise an exception. The raised exception will never look like a possible value. It will skip past the **returned_value = call_to_function(parameter)** line and go up the stack, potentially crashing the program.
|
||||
|
||||
A crash is straightforward to debug: there is a stack trace indicating the problem as well as the call stack. The failure might mean that a necessary condition for the program was not met, and human intervention is needed. It might mean that the program's logic is faulty. In either case, the loud failure is better than a hidden, "missing" value, infecting the program's valid data with **None**, until it is used somewhere and an error message says "**None does not have method split**," which you probably already knew.
|
||||
|
||||
### Unless explicitly silenced.
|
||||
|
||||
Exceptions sometimes need to be explicitly caught. We might anticipate some of the lines in a file are misformatted and want to handle those in a special way, maybe by putting them in a "lines to be looked at by a human" file, instead of crashing the entire program.
|
||||
|
||||
Python allows us to catch exceptions with **except**. This means errors can be _explicitly_ silenced. This explicitness means that the **except** line is visible in code reviews. It makes sense to question why this is the right place to silence, and potentially recover from, the exception. It makes sense to ask if we are catching too many exceptions or too few.
|
||||
|
||||
Because this is all explicit, it is possible for someone to read the code and understand which exceptional conditions are recoverable.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/19/12/zen-python-errors
|
||||
|
||||
作者：[Moshe Zadka][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/moshez
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/checklist_hands_team_collaboration.png?itok=u82QepPk (a checklist for a team)
|
||||
[2]: https://www.python.org/dev/peps/pep-0020/
|
||||
[3]: https://wiki.c2.com/
|
||||
[4]: https://en.wikipedia.org/wiki/Smalltalk
|
||||
@ -0,0 +1,72 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (Top 10 Raspberry Pi articles of 2019)
|
||||
[#]: via: (https://opensource.com/article/19/12/raspberry-pi-2019)
|
||||
[#]: author: (Joshua Allen Holm https://opensource.com/users/holmja)
|
||||
|
||||
Top 10 Raspberry Pi articles of 2019
|
||||
======
|
||||
Take a look back at the year in Raspberry Pi and get excited for what's
|
||||
to come in 2020.
|
||||
![Raspberries with pi symbol overlay][1]
|
||||
|
||||
Since its introduction, the Raspberry Pi has been one of the hottest topics on Opensource.com. This trend continued in 2019 with an impressive list of over 30 articles about various Raspberry Pi projects. The top 10 articles are covered below, but if you are a true Raspberry Pi aficionado, I encourage you to check out out our entire selection of [Raspberry Pi articles][2].
|
||||
|
||||
1. _[Turn a Raspberry Pi 3B+ into a PriTunl VPN][3]_ by Stephen Bancroft demonstrates how to set up a PriTunl virtual private networking (VPN) on a Raspberry Pi 3B+. There are several sticky points about the process that Bancroft helpfully and clearly explains. Following his instructions, you can easily turn a Raspberry Pi into a VPN server.
|
||||
|
||||
2. In _[Let’s get physical: How to use GPIO pins on the Raspberry Pi][4]_, Anderson Silva provides a brief introduction to using the GPIO pins on a Raspberry Pi. The article is full of links to other resources, including some of Silva’s other pieces, for those who want to dig deeper into the topic.
|
||||
|
||||
3. Sam Bocetta’s article _[How to use your Raspberry Pi as a VPN server][5]_, demonstrates how to install and configure PiVPN on a Raspberry Pi to create a VPN server. The article covers every aspect of the installation and configuration process, so if the reader has followed all the instructions provided, they will end up with their own Raspberry Pi-powered VPN.
|
||||
|
||||
4. _[Program the real world using Rust on Raspberry Pi][6]_ by Rahul Thakoor explores how to use the Rust programming language on the Raspberry Pi. By adding **rust_gpiozero** to a Rust project, it is possible to write code in Rust that can interact with buttons, servos, and other hardware connected to a Raspberry Pi. This article shows you how to get started.
|
||||
|
||||
5. Ben Nuttall, Raspberry Pi community manager, proclaims _[Raspberry Pi 4 is here!][7]_ in this article covering the release of the Raspberry Pi 4. The Raspberry Pi 4 features many improvements over previous Raspberry Pi models, and Nuttall walks through them in detail. From the new hardware features to the software updates in the updated release of Raspbian, this article brings you up to speed on what the Raspberry Pi 4 brings to the Raspberry Pi ecosystem.
|
||||
|
||||
6. _[How to build a WiFi picture frame with a Raspberry Pi][8]_ by Manuel Dewald shows you how to create a WiFi-connected digital picture frame using a Raspberry Pi 3. This step-by-step tutorial provides all the instructions needed to configure the software, but if you want to make a fancy case for your digital picture frame, that part is up to you.
|
||||
|
||||
7. Anderson Silva’s _[How to boot up a new Raspberry Pi][9]_ explains what you need to do to boot an operating system on a Raspberry Pi. This article primarily provides an overview of NOOBS (New Out Of Box Software) and contains links to the official Raspberry Pi website for the most up-to-date installation instructions.
|
||||
|
||||
8. _[How to build a mobile particulate matter sensor with a Raspberry Pi][10]_ by Stephan Tetzel illustrates how to build a sensor that can monitor your air quality using a Raspberry Pi, a small LCD display, and an inexpensive sensor. The particulate matter sensor you create can be used anywhere when paired with a power bank.
|
||||
|
||||
9. _[3 popular programming languages you can learn with Raspberry Pi][11]_ by Anderson Silva looks at programming Python, Java, and JavaScript on the Raspberry Pi. The Thonny IDE for Python and the BlueJ IDE for Java are briefly covered. The article also encourages users who are interested in other programming languages with the assurance that "there’s a high likelihood that you can use your Raspberry Pi to compile or interpret any language of choice, including C, C++, PHP, and Ruby."
|
||||
|
||||
10. Take a trip down memory lane by _[Resurrecting the Amiga on the Raspberry Pi][12]_ with this guide by Sarah Thornton. Using the instructions provided, you can experience the Amiga again on a Raspberry Pi or several other devices. Thornton even provides a helpful set of links for those interested in learning more about the history of the Amiga.
|
||||
|
||||
|
||||
|
||||
|
||||
I hope these articles encourage you to explore the possibilities of the Raspberry Pi. Maybe they have even inspired you to [share your own Raspberry Pi story][13] with us? Your story could end up on this list next year!
|
||||
|
||||
In this month's Raspberry Pi column, Ben Nuttall introduces readers to five projects that you might...
|
||||
|
||||
Owning a little cloud has a lot of benefits and can save you over $100 per month. In this step-by-...
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/19/12/raspberry-pi-2019
|
||||
|
||||
作者：[Joshua Allen Holm][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/holmja
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/life-raspberrypi_0.png?itok=Kczz87J2 (Raspberries with pi symbol overlay)
|
||||
[2]: https://opensource.com/tags/raspberry-pi
|
||||
[3]: https://opensource.com/article/19/1/pritunl-vpn-raspberry-pi
|
||||
[4]: https://opensource.com/article/19/3/gpio-pins-raspberry-pi
|
||||
[5]: https://opensource.com/article/19/6/raspberry-pi-vpn-server
|
||||
[6]: https://opensource.com/article/19/3/physical-computing-rust-raspberry-pi
|
||||
[7]: https://opensource.com/article/19/6/raspberry-pi-4
|
||||
[8]: https://opensource.com/article/19/2/wifi-picture-frame-raspberry-pi
|
||||
[9]: https://opensource.com/article/19/3/how-boot-new-raspberry-pi
|
||||
[10]: https://opensource.com/article/19/3/mobile-particulate-matter-sensor
|
||||
[11]: https://opensource.com/article/19/3/programming-languages-raspberry-pi
|
||||
[12]: https://opensource.com/article/19/3/amiga-raspberry-pi
|
||||
[13]: https://opensource.com/how-submit-article
|
||||
@ -0,0 +1,120 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (Explained! Why Your Distribution Still Using an ‘Outdated’ Linux Kernel?)
|
||||
[#]: via: (https://itsfoss.com/why-distros-use-old-kernel/)
|
||||
[#]: author: (Abhishek Prakash https://itsfoss.com/author/abhishek/)
|
||||
|
||||
Explained! Why Your Distribution Still Using an ‘Outdated’ Linux Kernel?
|
||||
======
|
||||
|
||||
[Check your Linux kernel version][1]. Chances are that you’ll find that the kernel version your system is using has already reached end of life (EOL) as listed on Linux Kernel website.
|
||||
|
||||
End of life means a software won’t get bug fixes and support anymore.
|
||||
|
||||
That poses some valid questions. Why is my Linux distribution using a kernel that has reached end of life? Is this not a security risk? Is my system safe?
|
||||
|
||||
Let me explain all these questions in this article.
|
||||
|
||||
Summary
|
||||
|
||||
The upstream kernel support and the your distribution’s kernel support are two different things.
|
||||
|
||||
For example, Linux kernel 4.15 might have reached end of life (as per the official Linux kernel website) but Ubuntu 18.04 LTS release will use it and maintain it till April 2023 by backporting security patches and bug fixes.
|
||||
|
||||
### Checking Linux kernel version and finding its end of life status
|
||||
|
||||
Let’s first check the Linux kernel version on your system:
|
||||
|
||||
```
|
||||
uname -r
|
||||
```
|
||||
|
||||
I am using Ubuntu 18.04 here and it shows the Linux kernel version like this:
|
||||
|
||||
```
|
||||
[email protected]:~$ uname -r
|
||||
5.0.0-37-generic
|
||||
```
|
||||
|
||||
Now, you may go to the official Linux kernel website and see what Linux kernels are still being supported. It’s displayed on the homepage itself.
|
||||
|
||||
[Linux Kernel Official Website][2]
|
||||
|
||||
You should see a status like this:
|
||||
|
||||
![Linux Kernel Status][3]
|
||||
|
||||
If you don’t see a kernel version listed on the homepage of kernel website, it means that specific version has reached end of life.
|
||||
|
||||
As you can see, kernel 5.0 is not listed here. It indicates that this kernel version is not being supported anymore. Actually, it [reached end of life in June 2019][4].
|
||||
|
||||
The life cycle of a Linux kernel doesn’t follow a set pattern, unfortunately. It’s NOT like a regular kernel stable release will be supported for X months and a long term support(LTS) kernel will be supported for Y years.
|
||||
|
||||
Based on the demand and requirements, there could be several LTS kernel versions with different EOL. You can find them along with their projected EOL on [this page][5].
|
||||
|
||||
Now comes the big question. Why is Ubuntu providing kernel 5.0 if the Linux kernel website shows that it has reached its end of life?
|
||||
|
||||
### Your distribution uses an EOL Linux kernel but that’s Okay!
|
||||
|
||||
![][6]
|
||||
|
||||
Have you ever wondered why Ubuntu/Debian/Fedora etc are called Linux distributions? It’s because they ‘distribute’ the Linux kernel.
|
||||
|
||||
They have their own modification of the Linux kernel, they add the GUI elements (desktop environment, display server etc) and software and they make it available to their users.
|
||||
|
||||
In the typical workflow, a Linux distribution will choose a kernel to provide to its users. And then it will hold on to this kernel for months or years even after the kernel has reached end of life.
|
||||
|
||||
How is it safe then? It’s because the _**distribution maintains the kernel by backporting all the important fixes to its kernel**_.
|
||||
|
||||
In other words, your Linux distribution makes sure that your Linux kernel is patched well and has all the bug fixes and important new features backported to it. There will be thousands of changes on top of the ‘old outdated Linux kernel’.
|
||||
|
||||
When the Linux kernel website says that a certain kernel version has reached EOL, it means that the core Linux kernel maintainers are not going to update/patch that kernel version anymore.
|
||||
|
||||
But at the same time, the developers at Debian/Ubuntu or other distributions work to keep the same old version alive by bringing the relevant changes from the newer kernel versions (being maintained by the core kernel team) to your distribution’s old kernel.
|
||||
|
||||
Bottom line is that even if it seems like your distribution is using an outdated Linux kernel, it is actually being well maintained and not really outdated.
|
||||
|
||||
### Should you use the latest stable kernel version?
|
||||
|
||||
![][7]
|
||||
|
||||
A new stable Linux kernel version is released every 2-3 months. And this makes many users wonder who they can get their hands on that new shiny thing.
|
||||
|
||||
To be frank, you should not do that unless you have a pretty good reason for it. Your distribution doesn’t provide it to you. You cannot just use ‘_sudo apt give-me-the-latest-stable-kernel_‘.
|
||||
|
||||
Now, manually [installing the mainline Linux kernel version][8] could be a challenge in itself. Even if you manage to install it, it is now up to you to make sure that this kernel is updated every time there is a bug fix. And when this new kernel reaches end of life, it becomes your responsibility to upgrade to the newer kernel version. It won’t be handled with apt upgrade like regular [Ubuntu updates][9].
|
||||
|
||||
You should also keep in mind that your distribution also has drivers and patches which you may not be able to use if you switch to the mainline kernel.
|
||||
|
||||
As [Greg Kroah-Hartman][10] puts it, “_**the best kernel you can use is one that someone else supports**_“. And who can be better at this job then your Linux distribution!
|
||||
|
||||
I hope you have a better understanding on this topic and you won’t panic the next time you find out that the kernel version your system is using has reached end of life.
|
||||
|
||||
I welcome your questions and suggestions. Please feel free to use the comment section.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://itsfoss.com/why-distros-use-old-kernel/
|
||||
|
||||
作者：[Abhishek Prakash][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://itsfoss.com/author/abhishek/
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://itsfoss.com/find-which-kernel-version-is-running-in-ubuntu/
|
||||
[2]: https://www.kernel.org/
|
||||
[3]: https://i0.wp.com/itsfoss.com/wp-content/uploads/2019/12/linux-kernel-status.jpg?ssl=1
|
||||
[4]: http://lkml.iu.edu/hypermail/linux/kernel/1906.0/02354.html
|
||||
[5]: https://www.kernel.org/category/releases.html
|
||||
[6]: https://i0.wp.com/itsfoss.com/wp-content/uploads/2019/12/Keep_Calm_and_Trust_Your_Distribution.png?ssl=1
|
||||
[7]: https://i0.wp.com/itsfoss.com/wp-content/uploads/2019/12/using_latest_kernel.png?ssl=1
|
||||
[8]: https://wiki.ubuntu.com/Kernel/MainlineBuilds
|
||||
[9]: https://itsfoss.com/update-ubuntu/
|
||||
[10]: https://en.wikipedia.org/wiki/Greg_Kroah-Hartman
|
||||
@ -1,272 +0,0 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: (runningwater)
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (Using the Java Persistence API)
|
||||
[#]: via: (https://opensource.com/article/19/10/using-java-persistence-api)
|
||||
[#]: author: (Stephon Brown https://opensource.com/users/stephb)
|
||||
|
||||
使用 Java 持久化 API
|
||||
======
|
||||
我们通过为自行车商店构建示例应用程序来学习如何使用 JPA。
|
||||
![Coffee beans][1]
|
||||
|
||||
对应用开发者来说，Java 持久化 API （JPA）是一项重要的技能，需要透彻理解。它为 Java 开发人员定义了如何将对象的方法调用转换为访问、持久化及管理 NoSQL 和关系型数据库数据存储的问题的方案。
|
||||
|
||||
本文通过构建自行车借贷服务的教程示例来详细研究 JPA。此示例会使用 Spring Boot 框架、MongoDB 数据库（[已经不开源][2]）和 Maven 包管理来构建一个大型应用程序，并且创建一个创建、读取、更新和删除(CRUD) 层。这儿我选择 NetBeans 11 作为我的 IDE。
|
||||
|
||||
此教程仅从开源的角度来介绍 Java 持久化的工作原理，不涉及其作为工具的使用说明。这全是关于编写应用程序模式的学习，但对于理解具体的软件实现也很益处。可以从我的[ GitHub 源仓库][3] 来获取相关代码。
|
||||
|
||||
### Java: 不仅仅是 'beans'
|
||||
|
||||
Java 是一门面向对象的编程语言，自 1996 年发布第一版 Java 开发工具（JDK）起，已经变化了很多很多。要了解其特性和其虚拟机本身就是个很长的历史。简而言之，和 Linux 内核很相似，自发布以来，该语言已经向多个方向分支发展。有对社区免费的标准版本、有针对企业的企业版本及由多家供应商提供的开源替代品。主要版本每六个月发布一次，其功能往往差异很大，所以确认选用版本前得先做些研究。
|
||||
|
||||
总而言之，Java 的历史很悠久。本教程重点介绍 Java 11 的开源实现 [JDK 11][4]。因其是扔然有效的长期支持版本之一。
|
||||
|
||||
* **Spring Boot: ** Spring Boot 是由 Pivotal 公司开发大型 Spring 框架的一个模块。Spring 是 Java 开发中一个非常流行的框架。它支持各种框架和配置，也支持 WEB 应用程序及提供了应用安全保障功能。Spring Boot 为快速启动项目集成了基本的配置。本教程使用 Spring Boot 来快速编写控制台应用程序并针对数据库编写测试用例。
|
||||
* **Maven:** Maven 是由 Apache 开发的项目/包管理工具。Maven 通过 `POM.xml` 文件来管理包及其依赖项。如果你们使用过 NPM 的话，可能会非常熟悉包管理器的功能。此外 Maven 也用来进行项目构建及生成功能报告。
|
||||
* **Lombok:** Lombok 是一个库，它通过在对象文件里面添加注解来自动创建 getters/setters 方法。像 C# 这些语言已经实现了此功能，Lombok 只是把此功能引入 Java 语言而已。
|
||||
* **NetBeans: ** NetBeans 是一款很流行的开源 IDE，专门用于 Java 开发。它的许多工具都随着 Java SE 和 EE 的版本更新而更新。
|
||||
|
||||
|
||||
|
||||
我们会这组工具来创建一个简单的虚构自行车商店应用程序。会实现对 "Customer" 和 "Bike" 对象集合的的插入操作。
|
||||
|
||||
### 酿造完美
|
||||
|
||||
导航到 [Spring Initializr][5] 页面。该网站可以生成基于 Spring Boot 和其依赖项的基本项目。选择以下选项：
|
||||
|
||||
1. **项目:** Maven 工程
|
||||
2. **语言:** Java
|
||||
3. **Spring Boot:** 2.1.8 (或最稳定版本)
|
||||
4. **项目元数据:** 无论你使用什么名字，其命名约定都是像 **com.stephb** 这样的。
|
||||
* 你可以保留 Artifact 名字为 “Demo”。
|
||||
5. **依赖项:** 添加:
|
||||
* Spring Data MongoDB
|
||||
* Lombok
|
||||
|
||||
|
||||
|
||||
点击 **下载**，然后用你的 IDE（例如 NetBeans） 打开此新项目。
|
||||
|
||||
#### 模型层(Model)概要
|
||||
|
||||
项目里面，模型代表从数据库里取出的信息的具体对象。我们关注两个对象：**Customer** 和 **Bike**。首先，在 **src** 目录创建 **dto** 目录；然后，创建两个名为 **Customer.java** 和 **Bike.java** 的 Java 类对象文件。其结构如下示：
|
||||
|
||||
**Customer.Java**
|
||||
|
||||
|
||||
```
|
||||
1 package com.stephb.JavaMongo.dto;
|
||||
2
|
||||
3 import lombok.Getter;
|
||||
4 import lombok.Setter;
|
||||
5 import org.springframework.data.annotation.Id;
|
||||
6
|
||||
7 /**
|
||||
8 *
|
||||
9 * @author stephon
|
||||
10 */
|
||||
11 @Getter @Setter
|
||||
12 public class Customer {
|
||||
13
|
||||
14 private @Id String id;
|
||||
15 private String emailAddress;
|
||||
16 private String firstName;
|
||||
17 private String lastName;
|
||||
18 private String address;
|
||||
19
|
||||
20 }
|
||||
```
|
||||
|
||||
**Bike.java**
|
||||
|
||||
|
||||
```Java
|
||||
1 package com.stephb.JavaMongo.dto;
|
||||
2
|
||||
3 import lombok.Getter;
|
||||
4 import lombok.Setter;
|
||||
5 import org.springframework.data.annotation.Id;
|
||||
6
|
||||
7 /**
|
||||
8 *
|
||||
9 * @author stephon
|
||||
10 */
|
||||
11 @Getter @Setter
|
||||
12 public class Bike {
|
||||
13 private @Id String id;
|
||||
14 private String modelNumber;
|
||||
15 private String color;
|
||||
16 private String description;
|
||||
17
|
||||
18 @Override
|
||||
19 public String toString() {
|
||||
20 return "This bike model is " + this.modelNumber + " is the color " + this.color + " and is " + description;
|
||||
21 }
|
||||
22 }
|
||||
```
|
||||
|
||||
如你所见，对象中使用 Lombok 注解来为定义的属性(特性)生成 getters/setters 方法。如果你不想对所有属于都生成 getters/setters 方法，可以在属性上定义这些注解。这两个类会变成容器，里面携带有数据，无论在何处想显示信息都可以使用。
|
||||
|
||||
#### 配置数据库
|
||||
|
||||
我使用 [Mongo Docker][7] 容器来进行此次测试。如果你的系统上已经安装了 MongoDB，则不必运行 Docker 实例。你也可以登陆其官网，然后按照安装说明，选择系统信息来安装 MongoDB。
|
||||
|
||||
安装后，就可以使用命令行、GUI（例如 MongoDB Compass）或用于连接数据源的 IDE 驱动程序来与新的 MongoDB 服务进行交互。到目前为止，可以开始定义数据层了，用来拉取、转换和持久化数据。需要设置数据库访问属性，请导航到程序中的 **applications.properties** 文件，然后添加如下内容：
|
||||
|
||||
|
||||
```
|
||||
1 spring.data.mongodb.host=localhost
|
||||
2 spring.data.mongodb.port=27017
|
||||
3 spring.data.mongodb.database=BikeStore
|
||||
```
|
||||
|
||||
#### 定义数据访问对象(数据)层
|
||||
|
||||
数据访问层（DAL）中的数据访问对象（DAO）定义了与数据库中的数据的交互过程。令人惊叹的就是在使用 **spring-boot-starter** 后，查询数据库的大部分工作已经完成。
|
||||
|
||||
让我们从 **Customer** DAO 开始。在 **src** 下的新目录 **dao** 中创建一个接口文件，然后再创建一个名为 **CustomerRepository.java** 的 Java 类文件，其内容如下示：
|
||||
|
||||
|
||||
```
|
||||
1 package com.stephb.JavaMongo.dao;
|
||||
2
|
||||
3 import com.stephb.JavaMongo.dto.Customer;
|
||||
4 import java.util.List;
|
||||
5 import org.springframework.data.mongodb.repository.MongoRepository;
|
||||
6
|
||||
7 /**
|
||||
8 *
|
||||
9 * @author stephon
|
||||
10 */
|
||||
11 public interface CustomerRepository extends MongoRepository<Customer, String>{
|
||||
12 @Override
|
||||
13 public ListStringCustomer> findAll();
|
||||
14 public List<Customer> findByFirstName(String firstName);
|
||||
15 public List<Customer> findByLastName(String lastName);
|
||||
16 }
|
||||
```
|
||||
|
||||
这个类是一个接口，扩展或继承于 **MongoRepository** 类，而 MongoRepository 类依赖于 DTO （**Customer.java**）和一个字符串，它们用来实现自定义函数查询功能。因为您已继承自此类，所以您可以访问许多方法函数，这些函数允许持久化和查询对象，而无需实现或引用自己定义的方法函数。例如，在实例化 **CustomerRepository** 对象后，你就可以直接使用 **Save** 功能。如果你需要扩展更多的功能，也可以重写这些方法。我创建了一些自定义查询来搜索我的集合，这些集合对象是我自定义的元素。
|
||||
|
||||
**Bike** 对象也有一个存储源负责与数据库交互。与 **CustomerRepository** 的实现非常类似。其实现如下所示：
|
||||
|
||||
```
|
||||
1 package com.stephb.JavaMongo.dao;
|
||||
2
|
||||
3 import com.stephb.JavaMongo.dto.Bike;
|
||||
4 import java.util.List;
|
||||
5 import org.springframework.data.mongodb.repository.MongoRepository;
|
||||
6
|
||||
7 /**
|
||||
8 *
|
||||
9 * @author stephon
|
||||
10 */
|
||||
11 public interface BikeRepository extends MongoRepository<Bike,String>{
|
||||
12 public Bike findByModelNumber(String modelNumber);
|
||||
13 @Override
|
||||
14 public List<Bike> findAll();
|
||||
15 public List<Bike> findByColor(String color);
|
||||
16 }
|
||||
```
|
||||
|
||||
#### 运行程序
|
||||
|
||||
现在，你已经有了一种结构化数据的方式，可以对数据进行提取、转换和持久化，然后运行这个程序。
|
||||
|
||||
找到 **Application.java** 文件（有可能不是此名称，具体取决于你的应用程序名称，但都会包含有 “application” ）。在定义此类的地方，在后面加上 **CommandLineRunner 的实现**。这将允许你实现 **run** 方法来创建命令行应用程序。重写 **CommandLineRunner** 接口提供的 **run** 方法，并包含如下内容用来测试 **BikeRepository** ：
|
||||
|
||||
|
||||
```
|
||||
1 package com.stephb.JavaMongo;
|
||||
2
|
||||
3 import com.stephb.JavaMongo.dao.BikeRepository;
|
||||
4 import com.stephb.JavaMongo.dao.CustomerRepository;
|
||||
5 import com.stephb.JavaMongo.dto.Bike;
|
||||
6 import java.util.Scanner;
|
||||
7 import org.springframework.beans.factory.annotation.Autowired;
|
||||
8 import org.springframework.boot.CommandLineRunner;
|
||||
9 import org.springframework.boot.SpringApplication;
|
||||
10 import org.springframework.boot.autoconfigure.SpringBootApplication;
|
||||
11
|
||||
12
|
||||
13 @SpringBootApplication
|
||||
14 public class JavaMongoApplication implements CommandLineRunner {
|
||||
15 @Autowired
|
||||
16 private BikeRepository bikeRepo;
|
||||
17 private CustomerRepository custRepo;
|
||||
18
|
||||
19 public static void main(String[] args) {
|
||||
20 SpringApplication.run(JavaMongoApplication.class, args);
|
||||
21 }
|
||||
22 @Override
|
||||
23 public void run(String... args) throws [Exception] {
|
||||
24 Scanner scan = new Scanner(System.in);
|
||||
25 String response = "";
|
||||
26 boolean running = true;
|
||||
27 while(running){
|
||||
28 System.out.println("What would you like to create? \n C: The Customer \n B: Bike? \n X:Close");
|
||||
29 response = scan.nextLine();
|
||||
30 if ("B".equals(response.toUpperCase())) {
|
||||
31 String[] bikeInformation = new String;
|
||||
32 System.out.println("Enter the information for the Bike");
|
||||
33 System.out.println("Model Number");
|
||||
34 bikeInformation[0] = scan.nextLine();
|
||||
35 System.out.println("Color");
|
||||
36 bikeInformation[1] = scan.nextLine();
|
||||
37 System.out.println("Description");
|
||||
38 bikeInformation[2] = scan.nextLine();
|
||||
39
|
||||
40 Bike bike = new Bike();
|
||||
41 bike.setModelNumber(bikeInformation[0]);
|
||||
42 bike.setColor(bikeInformation[1]);
|
||||
43 bike.setDescription(bikeInformation[2]);
|
||||
44
|
||||
45 bike = bikeRepo.save(bike);
|
||||
46 System.out.println(bike.toString());
|
||||
47
|
||||
48
|
||||
49 } else if ("X".equals(response.toUpperCase())) {
|
||||
50 System.out.println("Bye");
|
||||
51 running = false;
|
||||
52 } else {
|
||||
53 System.out.println("Sorry nothing else works right now!");
|
||||
54 }
|
||||
55 }
|
||||
56
|
||||
57 }
|
||||
58 }
|
||||
```
|
||||
|
||||
其中的 **@Autowired** 注解会自动依赖注入 **BikeRepository** 和 **CustomerRepository** Bean。我们将使用这些类来从数据库持久化和采集数据。
|
||||
|
||||
已经好了。你已经创建了一个命令行应用程序。该应用程序连接到数据库，并且能够以最少的代码执行 CRUD 操作
|
||||
|
||||
### 结论
|
||||
|
||||
从诸如对象和类之类的编程语言概念转换为用于在数据库中存储、检索或更改数据的调用对于构建应用程序至关重要。Java 持久化 API （JPA）正是为 Java 开发人员解决这一难题的重要工具。 你正在使用 Java 操纵哪些数据库呢？ 请在评论中分享。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/19/10/using-java-persistence-api
|
||||
|
||||
作者：[Stephon Brown][a]
|
||||
选题：[lujun9972][b]
|
||||
译者：[runningwater](https://github.com/runningwater)
|
||||
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/stephb
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/java-coffee-beans.jpg?itok=3hkjX5We (Coffee beans)
|
||||
[2]: https://www.techrepublic.com/article/mongodb-ceo-tells-hard-truths-about-commercial-open-source/
|
||||
[3]: https://github.com/StephonBrown/SpringMongoJava
|
||||
[4]: https://openjdk.java.net/projects/jdk/11/
|
||||
[5]: https://start.spring.io/
|
||||
[6]: http://www.google.com/search?hl=en&q=allinurl%3Adocs.oracle.com+javase+docs+api+string
|
||||
[7]: https://hub.docker.com/_/mongo
|
||||
[8]: http://www.google.com/search?hl=en&q=allinurl%3Adocs.oracle.com+javase+docs+api+exception
|
||||
[9]: http://www.google.com/search?hl=en&q=allinurl%3Adocs.oracle.com+javase+docs+api+system
|
||||
@ -1,337 +0,0 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: (lxbwolf)
|
||||
[#]: reviewer: (wxy)
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (How to program with Bash: Loops)
|
||||
[#]: via: (https://opensource.com/article/19/10/programming-bash-loops)
|
||||
[#]: author: (David Both https://opensource.com/users/dboth)
|
||||
|
||||
Bash 编程教程之循环
|
||||
======
|
||||
本文是 bash 编程系列（3 部分）的最后一篇，来学习使用循环执行迭代的操作。
|
||||
![arrows cycle symbol for failing faster][1]
|
||||
|
||||
Bash 是一种强大的用于命令行和 shell 脚本里的编程语言。本系列的三部分都是基于我的 [Linux 自学课程三卷][2] 写的，探索怎么用 CLI（command-line interface）进行 bash 编程。本系列的 [第一篇文章][3] 讨论了 bash 编程的一些简单命令行操作，如使用变量和控制操作符。[第二篇文章][4] 探讨了文件、字符串、数字等类型和各种各样在执行流中提供控制逻辑的的逻辑运算符，还有 bash 中不同种类的扩展。本文是第三篇（也是最后一篇），意在考察在各种迭代的操作中使用循环以及怎么合理控制循环。
|
||||
|
||||
### 循环
|
||||
|
||||
我使用过的所有编程语言都有很多种循环结构来用来执行重复的操作。我经常使用 for 循环，然而我发现 while 和 until 循环也很有用处。
|
||||
|
||||
#### for 循环
|
||||
|
||||
我的理解是，**for** 命令在 bash 中的实现比大部分语言灵活，因为它可以处理非数字的值；与之形成对比的是，诸如标准 C 语言的 **for** 循环只能处理数字类型的值。
|
||||
|
||||
Bash 版的 **for** 命令基本的结构很简单：
|
||||
|
||||
|
||||
```
|
||||
`for Var in list1 ; do list2 ; done`
|
||||
```
|
||||
|
||||
解释一下：“对于 list1 中的每一个值，把 **$Var** 设置为那个值，使用该值执行 list2 中的程序语句；list1 中的值都执行完后，整个循环结束，退出循环。” list1 中的值可以是一个简单的显式字符串值，也可以是一个命令执行后的结果（译注：**\` \`** 包含的命令执行的结果，本系列第二篇文章中有描述）。我经常使用这种结构。
|
||||
|
||||
确认 **~/testdir** 仍然是当前的工作目录（PWD）。删除目录下所有东西，来看下这个显式写出值列表的 **for** 循环的简单的示例。这个列表中的值是字母值 — 但是不要忘了，在 bash 中所有的变量都是 string 或者可以被当成 string 来处理。
|
||||
|
||||
|
||||
```
|
||||
[student@studentvm1 testdir]$ rm *
|
||||
[student@studentvm1 testdir]$ for I in a b c d 1 2 3 4 ; do echo $I ; done
|
||||
a
|
||||
b
|
||||
c
|
||||
d
|
||||
1
|
||||
2
|
||||
3
|
||||
4
|
||||
```
|
||||
|
||||
给变量赋予更有意义的名字，变成前面版本的进阶版：
|
||||
|
||||
|
||||
```
|
||||
[student@studentvm1 testdir]$ for Dept in "Human Resources" Sales Finance "Information Technology" Engineering Administration Research ; do echo "Department $Dept" ; done
|
||||
Department Human Resources
|
||||
Department Sales
|
||||
Department Finance
|
||||
Department Information Technology
|
||||
Department Engineering
|
||||
Department Administration
|
||||
Department Research
|
||||
```
|
||||
|
||||
创建几个目录（创建时显示一些处理信息）：
|
||||
|
||||
|
||||
```
|
||||
[student@studentvm1 testdir]$ for Dept in "Human Resources" Sales Finance "Information Technology" Engineering Administration Research ; do echo "Working on Department $Dept" ; mkdir "$Dept" ; done
|
||||
Working on Department Human Resources
|
||||
Working on Department Sales
|
||||
Working on Department Finance
|
||||
Working on Department Information Technology
|
||||
Working on Department Engineering
|
||||
Working on Department Administration
|
||||
Working on Department Research
|
||||
[student@studentvm1 testdir]$ ll
|
||||
total 28
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:45 Administration
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:45 Engineering
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:45 Finance
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:45 'Human Resources'
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:45 'Information Technology'
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:45 Research
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:45 Sales
|
||||
```
|
||||
|
||||
在 **mkdir** 语句中 **$Dept** 变量必须用引号包裹起来；否则名字中间有空格（如 `Information Technology`）会被当做两个独立的目录处理。我一直信奉的一条实践规则：所有的文件和目录都应该为一个单词（中间没有空格）。虽然大部分现代的操作系统可以处理名字中间有空格的情况，但是系统管理员需要花费额外的精力去确保脚本和 CLI 程序能正确处理这些特例。（尽管你因为不知道将要处理什么样的文件而烦恼，但是脚本和 CLI 应该已经把这些特例考虑在内了。）
|
||||
|
||||
再次删除 **~/testdir** 下的所有东西 — 再运行一次下面的命令：
|
||||
|
||||
|
||||
```
|
||||
[student@studentvm1 testdir]$ rm -rf * ; ll
|
||||
total 0
|
||||
[student@studentvm1 testdir]$ for Dept in Human-Resources Sales Finance Information-Technology Engineering Administration Research ; do echo "Working on Department $Dept" ; mkdir "$Dept" ; done
|
||||
Working on Department Human-Resources
|
||||
Working on Department Sales
|
||||
Working on Department Finance
|
||||
Working on Department Information-Technology
|
||||
Working on Department Engineering
|
||||
Working on Department Administration
|
||||
Working on Department Research
|
||||
[student@studentvm1 testdir]$ ll
|
||||
total 28
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:52 Administration
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:52 Engineering
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:52 Finance
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:52 Human-Resources
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:52 Information-Technology
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:52 Research
|
||||
drwxrwxr-x 2 student student 4096 Apr 8 15:52 Sales
|
||||
```
|
||||
|
||||
假设现在有个需求，需要列出一台 Linux 机器上所有的 RPM 包并对每个包附上简短的描述。我为North Carolina 州工作的时候，曾经遇到过这种需求。由于当时州代理处不允许使用开源的工具，而且我对 Linux 不够熟悉，对技术一窍不通的老板（PHB）需要我列出我计算机上安装的所有软件，这样他们就可以“查看“计算机上有没有安装异常的软件了。
|
||||
|
||||
你怎么实现它？有一种方法是，已知 **rpm –qa** 命令提供了 RPM 包的完整描述，包括 PHB 想要的东西：软件名称和概要描述。一步步执行出最后的结果。首先，列出所有的 RPM 包：
|
||||
|
||||
|
||||
```
|
||||
[student@studentvm1 testdir]$ rpm -qa
|
||||
perl-HTTP-Message-6.18-3.fc29.noarch
|
||||
perl-IO-1.39-427.fc29.x86_64
|
||||
perl-Math-Complex-1.59-429.fc29.noarch
|
||||
lua-5.3.5-2.fc29.x86_64
|
||||
java-11-openjdk-headless-11.0.ea.28-2.fc29.x86_64
|
||||
util-linux-2.32.1-1.fc29.x86_64
|
||||
libreport-fedora-2.9.7-1.fc29.x86_64
|
||||
rpcbind-1.2.5-0.fc29.x86_64
|
||||
libsss_sudo-2.0.0-5.fc29.x86_64
|
||||
libfontenc-1.1.3-9.fc29.x86_64
|
||||
<snip>
|
||||
```
|
||||
|
||||
用 **sort** 和 **uniq** 命令对列表进行排序和打印去重后的结果（有些已安装的 RPM 包具有相同的名字：）
|
||||
|
||||
|
||||
```
|
||||
[student@studentvm1 testdir]$ rpm -qa | sort | uniq
|
||||
a2ps-4.14-39.fc29.x86_64
|
||||
aajohan-comfortaa-fonts-3.001-3.fc29.noarch
|
||||
abattis-cantarell-fonts-0.111-1.fc29.noarch
|
||||
abiword-3.0.2-13.fc29.x86_64
|
||||
abrt-2.11.0-1.fc29.x86_64
|
||||
abrt-addon-ccpp-2.11.0-1.fc29.x86_64
|
||||
abrt-addon-coredump-helper-2.11.0-1.fc29.x86_64
|
||||
abrt-addon-kerneloops-2.11.0-1.fc29.x86_64
|
||||
abrt-addon-pstoreoops-2.11.0-1.fc29.x86_64
|
||||
abrt-addon-vmcore-2.11.0-1.fc29.x86_64
|
||||
<snip>
|
||||
```
|
||||
|
||||
以上命令得到了想要的 RPM 列表，因此你可以把这个列表作为一个循环的输入信息，循环最终会打印每个 RPM 包的详细信息：
|
||||
|
||||
|
||||
```
|
||||
[student@studentvm1 testdir]$ for RPM in `rpm -qa | sort | uniq` ; do rpm -qi $RPM ; done
|
||||
```
|
||||
|
||||
这段代码产出了多余的信息。当循环结束后， 下一步就是提取出 PHB 需要的信息。因此，添加一个 **egrep** 命令用来搜索匹配 **^Name** 或 **^Summary** 的行。脱字符（^）表示行首，整个命令表示显示所有以 Name 或 Summary 开头的行。
|
||||
|
||||
|
||||
```
|
||||
[student@studentvm1 testdir]$ for RPM in `rpm -qa | sort | uniq` ; do rpm -qi $RPM ; done | egrep -i "^Name|^Summary"
|
||||
Name : a2ps
|
||||
Summary : Converts text and other types of files to PostScript
|
||||
Name : aajohan-comfortaa-fonts
|
||||
Summary : Modern style true type font
|
||||
Name : abattis-cantarell-fonts
|
||||
Summary : Humanist sans serif font
|
||||
Name : abiword
|
||||
Summary : Word processing program
|
||||
Name : abrt
|
||||
Summary : Automatic bug detection and reporting tool
|
||||
<snip>
|
||||
```
|
||||
|
||||
在上面的命令中你可以试试用 **grep** 代替 **egrep** ，你会发现用 **grep** 不能得到正确的结果。你可以通过管道把命令结果用 **less** 过滤下。最终命令像这样：
|
||||
|
||||
|
||||
```
|
||||
[student@studentvm1 testdir]$ for RPM in `rpm -qa | sort | uniq` ; do rpm -qi $RPM ; done | egrep -i "^Name|^Summary" > RPM-summary.txt
|
||||
```
|
||||
|
||||
这个命令行程序在同一行中用到了管道、重定向和 **for** 循环。它把你 CLI 程序的结果重定向到了一个文件，这个文件可以在邮件中使用或在其他地方作为输入使用。这个一次一步构建程序的过程让你能看到每步的结果，以此来确保整个程序以你期望的流程进行且输出你想要的结果。
|
||||
|
||||
PHB 最终收到了超过 1900 个独立 RPM 包的清单，我严重怀疑根本就没人去读它。我给了他们想要的东西，没有从他们嘴里听到过任何关于 RPM 包的信息。
|
||||
|
||||
### 其他循环
|
||||
|
||||
Bash 中还有两种其他类型的循环结构：**while** 和 **until** 结构，两者在语法和功能上都类似。这些循环结构的基础语法很简单：
|
||||
|
||||
|
||||
```
|
||||
while [ expression ] ; do list ; done
|
||||
```
|
||||
|
||||
逻辑解释：表达式（expression）结果为 true 时，执行程序语句 `list`。表达式结果为 false 时，退出循环。
|
||||
|
||||
|
||||
```
|
||||
until [ expression ] ; do list ; done
|
||||
```
|
||||
|
||||
逻辑解释：直到表达式的结果为 true，执行程序语句 `list`。当表达式结果为 true 时，退出循环。
|
||||
|
||||
#### While 循环
|
||||
|
||||
**while** 循环用于当逻辑表达式结果为 true 时执行一系列程序语句。假设你的 PWD 仍是 **~/testdir** 。最简单的 **while** 循环会一直运行下去。下面格式的条件语句永远以 `true` 作为返回。你也可以用简单的 `1` 代替 `true` — 结果一样 — 但是这解释了 true 表达式的用法。
|
||||
|
||||
|
||||
```
|
||||
[student@studentvm1 testdir]$ X=0 ; while [ true ] ; do echo $X ; X=$((X+1)) ; done | head
|
||||
0
|
||||
1
|
||||
2
|
||||
3
|
||||
4
|
||||
5
|
||||
6
|
||||
7
|
||||
8
|
||||
9
|
||||
[student@studentvm1 testdir]$
|
||||
```
|
||||
|
||||
既然你已经学了 CLI 的各部分知识，那就让它变得更有用处。首先，为了防止变量 **$X** 在前面的程序或 CLI 命令执行后有遗留的值，设置 **$X** 的值为 0。然后，因为逻辑表达式 **[ true ]** 的结果永远是 1，即 true，在 **do** 和 **done** 中间的程序指令列表会一直执行 — 或者直到你按下 **Ctrl+C** 抑或发送一个 `signal 2` 给程序。那些程序指令是算法扩展，用来打印变量 **$X** 当前的值并加 1.
|
||||
|
||||
[系统管理员的 Linux 哲学][5] 的信条之一是追求优雅，实现优雅的一种方式就是简化。你可以用操作符 **++** 来简化这个程序。在第一个例子中，变量当前的值被打印出来，然后变量的值增加了。可以在变量后加一个 **++** 来表示这个逻辑：
|
||||
|
||||
|
||||
```
|
||||
[student@studentvm1 ~]$ X=0 ; while [ true ] ; do echo $((X++)) ; done | head
|
||||
0
|
||||
1
|
||||
2
|
||||
3
|
||||
4
|
||||
5
|
||||
6
|
||||
7
|
||||
8
|
||||
9
|
||||
```
|
||||
|
||||
现在删掉程序最后的 **| head** 再运行一次。在这个版本中，变量在值被打印之前就自增了。这是通过在变量之前添加 **++** 操作符实现的。你能看出区别吗？
|
||||
|
||||
|
||||
```
|
||||
[student@studentvm1 ~]$ X=0 ; while [ true ] ; do echo $((++X)) ; done | head
|
||||
1
|
||||
2
|
||||
3
|
||||
4
|
||||
5
|
||||
6
|
||||
7
|
||||
8
|
||||
9
|
||||
```
|
||||
|
||||
你已经把打印变量的值和自增简化到了一条语句。类似 **++** 操作符， 也有 **--** 操作符。你需要一个在循环到某个特定数字时终止循环的方法。把 true 表达式换成一个数字比较表达式来实现它。写一个循环到 5 终止的程序。在下面的示例代码中，你可以看到 **-le** 是 ”小于或等于“ 的数字逻辑操作符。整个语句的意思：只要 **$X** 的值小于或等于 5，循环就一直运行。当 **$X** 增加到 6时，循环终止。
|
||||
|
||||
|
||||
```
|
||||
[student@studentvm1 ~]$ X=0 ; while [ $X -le 5 ] ; do echo $((X++)) ; done
|
||||
0
|
||||
1
|
||||
2
|
||||
3
|
||||
4
|
||||
5
|
||||
[student@studentvm1 ~]$
|
||||
```
|
||||
|
||||
#### Until 循环
|
||||
|
||||
|
||||
|
||||
*until** 命令非常像 **while** 命令。不同之处是，它直到逻辑表达式的值是 `true` 之前，会一直循环。看一下这种结构最简单的格式：
|
||||
|
||||
|
||||
```
|
||||
[student@studentvm1 ~]$ X=0 ; until false ; do echo $((X++)) ; done | head
|
||||
0
|
||||
1
|
||||
2
|
||||
3
|
||||
4
|
||||
5
|
||||
6
|
||||
7
|
||||
8
|
||||
9
|
||||
[student@studentvm1 ~]$
|
||||
```
|
||||
|
||||
它用一个逻辑比较表达式来数到一个特定的值：
|
||||
|
||||
|
||||
```
|
||||
[student@studentvm1 ~]$ X=0 ; until [ $X -eq 5 ] ; do echo $((X++)) ; done
|
||||
0
|
||||
1
|
||||
2
|
||||
3
|
||||
4
|
||||
[student@studentvm1 ~]$ X=0 ; until [ $X -eq 5 ] ; do echo $((++X)) ; done
|
||||
1
|
||||
2
|
||||
3
|
||||
4
|
||||
5
|
||||
[student@studentvm1 ~]$
|
||||
```
|
||||
|
||||
### 总结：
|
||||
|
||||
本系列探讨了构建 bash 命令行程序和 shell 脚本的很多强大的工具。但是这仅仅是你能用 Bash 做的很多有意思的事中的冰山一角，接下来就看你的了。我发现学习 Bash 编程最好的方法就是实践。找一个需要多个 Bash 命令的简单项目然后写一个 CLI 程序。系统管理员们做了很多工作让任务变成 CLI 编程，因此我确信你很容易能找到自动化的任务。很多年前，尽管我对其他的 Shell 语言和 Perl 很熟悉，但还是决定用 Bash 做所有系统管理员的自动化任务。我发现 — 有时稍微搜索一下 — 我可以用 Bash 实现我需要的所有事情。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/19/10/programming-bash-loops
|
||||
|
||||
作者：[David Both][a]
|
||||
选题：[lujun9972][b]
|
||||
译者：[lxbwolf](https://github.com/lxbwolf)
|
||||
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/dboth
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/fail_progress_cycle_momentum_arrow.png?itok=q-ZFa_Eh (arrows cycle symbol for failing faster)
|
||||
[2]: http://www.both.org/?page_id=1183
|
||||
[3]: https://opensource.com/article/19/10/programming-bash-part-1
|
||||
[4]: https://opensource.com/article/19/10/programming-bash-part-2
|
||||
[5]: https://www.apress.com/us/book/9781484237298
|
||||
116
translated/tech/20191218 How tracking pixels work.md
Normal file
116
translated/tech/20191218 How tracking pixels work.md
Normal file
@ -0,0 +1,116 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: (chen-ni)
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (How tracking pixels work)
|
||||
[#]: via: (https://jvns.ca/blog/how-tracking-pixels-work/)
|
||||
[#]: author: (Julia Evans https://jvns.ca/)
|
||||
|
||||
追踪像素是如何工作的？
|
||||
======
|
||||
|
||||
昨天，我和一名记者谈到了一个问题：广告商是如何在互联网上对人们进行追踪的？我们津津有味地查看了 Firefox 的开发者工具（虽然我不是一个互联网隐私专家，但至少还会使用开发者工具中的“network”标签页），从中我终于弄明白追踪像素在实际中是如何工作的了。
|
||||
|
||||
### 问题：Facebook 怎么知道你逛了 Old Navy？
|
||||
|
||||
我时常听人们说起这种有些诡异的上网经历：你在线上浏览了一个商品，一天之后，竟然看到了同一款靴子（或者是别的什么你当时浏览的商品）的广告。这就是所谓的“再营销”，但它到底是如何实现的呢？
|
||||
|
||||
在本文中，我们来进行一个小实验，看看 Facebook 究竟是怎么知道你在线上浏览了什么商品的。这里使用 Facebook 作为示例，只是因为很容易找到投放了 Facebook 追踪像素的网站；其实，几乎所有互联网广告公司都会使用类似的追踪技术。
|
||||
|
||||
### 准备：允许第三方追踪器，同时关闭广告拦截器
|
||||
|
||||
我使用的浏览器是 Firefox，但是 Firefox 默认拦截了很多这种类型的追踪，所以需要修改 Firefox 的隐私设置，才能让这种追踪生效。
|
||||
|
||||
首先，我将隐私设置从默认设置（[截图][1]）修改为允许第三方追踪器的个性化设置（[截图][2]），然后禁用了一些平时运行的隐私保护扩展。
|
||||
|
||||
### 追踪像素：关键不在于 gif，而在于请求参数
|
||||
|
||||
追踪像素是网站用来追踪你的一个 1x1 大小的 gif。就其本身而言，一个小小的 1x1 gif 显然起不到什么作用。那么，追踪像素到底是如何进行追踪的？其中涉及两个方面：
|
||||
|
||||
1. 通过使用追踪像素上的**请求参数**，网站可以添加额外的信息，比如你正在访问的页面。这样一来，请求的就不是 `https://www.facebook.com/tr/`（这个链接是一个 44 字节大小的 1x1 gif），而是 `https://www.facebook.com/tr/?the_website_you're_on`。（邮件营销人员会使用类似的技巧，通过为追踪像素指定一个独特的 URL，弄清楚你是否打开了某一封邮件。）
|
||||
2. 在发送该请求的同时，还发送了相应的 cookie。这样一来广告商就可以知道，访问 oldnavy.com 的这个人和在同一台电脑上使用 Facebook 的是同一个人。
|
||||
|
||||
### Old Navy 网站上的 Facebook 追踪像素
|
||||
|
||||
为了对此进行验证，我在 Old Navy（GAP 旗下的一个服装品牌）网站上浏览了一个商品，相应的URL是 [https://oldnavy.gap.com/browse/product.do?pid=504753002&cid=1125694&pcid=1135640&vid=1&grid=pds_0_109_1][3]（这是一件“男款短绒格子花呢大衣”）。
|
||||
|
||||
在我浏览这个商品的同时，页面上运行的 Javascript（用的应该是[这段代码][4]）向 facebook.com 发送了一个请求。在开发者工具中，该请求看上去是这样的：（我屏蔽了大部分 cookie 值，因为其中有一些是我的登录 cookie）
|
||||
|
||||
![][5]
|
||||
|
||||
下面对其进行拆解分析：
|
||||
|
||||
1. 我的浏览器向 ` https://www.facebook.com/tr/?id=937725046402747&ev=PageView&dl=https%3A%2F%2Foldnavy.gap.com%2Fbrowse%2Fproduct.do%3Fpid%3D504753002%26cid%3D1125694%26pcid%3Dxxxxxx0%26vid%3D1%26grid%3Dpds_0_109_1%23pdp-page-content&rl=https%3A%2F%2Foldnavy.gap.com%2Fbrowse%2Fcategory.do%3Fcid%3D1135640%26mlink%3D5155%2Cm_mts_a&if=false&ts=1576684838096&sw=1920&sh=1080&v=2.9.15&r=stable&a=tmtealium&ec=0&o=30&fbp=fb.1.1576684798512.1946041422&it=15xxxxxxxxxx4&coo=false&rqm=GET` 发送了一个请求；
|
||||
2. 与该请求同时发送的，还有一个名为 `fr` 的 cookie，取值为 `10oGXEcKfGekg67iy.AWVdJq5MG3VLYaNjz4MTNRaU1zg.Bd-kxt.KU.F36.0.0.Bd-kx6.`（估计是我的 Facebook 广告追踪 ID）
|
||||
|
||||
在所发送的追踪像素查询字符串里，有三个值得注意的地方：
|
||||
|
||||
* 我当前访问的页面：[https://oldnavy.gap.com/browse/product.do?pid=504753002&cid=1125694&pcid=1135640&vid=1&grid=pds_0_109_1#pdp-page-content][6]
|
||||
* 引导我来到当前页面的上一级页面：[https://oldnavy.gap.com/browse/category.do?cid=1135640&mlink=5155,m_mts_a][7]；
|
||||
* 作为我的身份标识的 cookie：`10oGXEcKfGekg67iy.AWVdJq5MG3VLYaNjz4MTNRaU1zg.Bd-kxt.KU.F36.0.0.Bd-kx6.`
|
||||
|
||||
### 下面来逛逛 Facebook！
|
||||
|
||||
下面来逛逛 Facebook 吧。我之前已经登入了 Facebook，猜猜看，我的浏览器发送给 Facebook 的 cookie 是什么？
|
||||
|
||||
不出所料，正是之前见过的 `fr` cookie：`10oGXEcKfGekg67iy.AWVdJq5MG3VLYaNjz4MTNRaU1zg.Bd-kxt.KU.F36.0.0.Bd-kx6.`。Facebook 现在一定知道我（Julia Evans，这个 Facebook 账号所关联的人）在几分钟之前访问了 Old Navy 网站，并且浏览了“男款短绒格子花呢大衣”，因为他们可以使用这个 cookie 将数据串联起来。
|
||||
|
||||
### 这里涉及到的是第三方 cookie
|
||||
|
||||
Facebook 用来追踪我访问了哪些网站的 cookie，属于所谓的“第三方 cookie”，因为 Old Navy 的网站使用它为一个第三方（即 facebook.com）确认我的身份。这和用来维持登录状态的“第一方 cookie”有所不同。
|
||||
|
||||
Safari 和 Firefox 默认都会拦截许多第三方 cookie（所以需要更改 Firefox 的隐私设置，才能够进行这个实验），而 Chrome 目前并不进行拦截（很可能是因为 Chrome 的所有者正是一个广告公司）。
|
||||
|
||||
### 网站上的追踪像素有很多
|
||||
|
||||
如我所料，网站上的追踪像素有 **很多**。比如，wrangler.com 在我的浏览器里加载了来自不同域的 19 个不同的追踪像素。wrangler.com 上的追踪像素分别来自：`ct.pinterest.com`、`af.monetate.net`、`csm.va.us.criteo.net`、`google-analytics.com`、`dpm.demdex.net`、`google.ca`、`a.tribalfusion.com`、`data.photorank.me`、`stats.g.doubleclick.net`、`vfcorp.dl.sc.omtrdc.net`、`ib.adnxs.com`、`idsync.rlcdn.com`、`p.brsrvr.com`，以及`adservice.google.com`。
|
||||
|
||||
Firefox 贴心地指出，如果使用 Firefox 的标准隐私设置，其中的大部分追踪器都会被拦截：
|
||||
|
||||
![][8]
|
||||
|
||||
### 浏览器的重要性
|
||||
|
||||
浏览器之所以如此重要，是因为你的浏览器最终决定了发送你的什么信息、发送到哪些网站。Old Navy 网站上的 Javascript 可以请求你的浏览器向 Facebook 发送关于你的追踪信息，但浏览器可以拒绝执行。浏览器的决定可以是：“哈，我知道 facebook.com/tr/ 是一个追踪像素，我不想让我的用户被追踪，所以我不会发送这个请求”。
|
||||
|
||||
浏览器还可以允许用户对上述行为进行配置，方法包括更改浏览器设置，以及安装浏览器扩展（所以才会有如此多的隐私保护扩展）。
|
||||
|
||||
### 摸清其中原理，实为一件趣事
|
||||
|
||||
在我看来，弄清楚 cookie / 追踪像素是怎么用于对你进行追踪的，实在是一件趣事（尽管显得有点阴险）。我之前大概明白其中的道理，但是并没有亲自查看过追踪像素上的 cookie，也没有看过发送的查询参数上究竟包含什么样的信息。
|
||||
|
||||
当然，明白了其中的原理，也就更容易降低被追踪的概率了。
|
||||
|
||||
### 可以采取的措施
|
||||
|
||||
为了尽量避免在互联网上被追踪，我采取了几种简单的措施:
|
||||
|
||||
* 安装一个广告拦截器（比如 ublock origin 之类）。广告拦截器可以针对许多追踪器的域进行拦截。
|
||||
* 使用目前默认隐私保护强度更高的 Firefox/Safari，而不是 Chrome。
|
||||
* 使用 [Facebook Container][9] 这个 Firefox 扩展。该扩展针对 Facebook 进一步采取了防止追踪的措施。
|
||||
|
||||
虽然在互联网上被追踪的方式还有很多（尤其是在使用手机应用的时候，因为在这种情况下，你没有和像对浏览器一样的控制程度），但是能够理解这种追踪方法的工作原理，稍微减少一些被追踪的可能性，也总归是一件好事。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://jvns.ca/blog/how-tracking-pixels-work/
|
||||
|
||||
作者：[Julia Evans][a]
|
||||
选题：[lujun9972][b]
|
||||
译者：[译者ID](https://github.com/chen-ni)
|
||||
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://jvns.ca/
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://jvns.ca/images/trackers.png
|
||||
[2]: https://jvns.ca/images/firefox-insecure-settings.png
|
||||
[3]: https://oldnavy.gap.com/browse/product.do?pid=504753002&cid=1125694&pcid=1135640&vid=1&grid=pds_0_109_1
|
||||
[4]: https://developers.facebook.com/docs/facebook-pixel/implementation/
|
||||
[5]: https://jvns.ca/images/fb-old-navy.png
|
||||
[6]: https://oldnavy.gap.com/browse/product.do?pid=504753002&cid=1125694&pcid=1135640&vid=1&grid=pds_0_109_1#pdp-page-content
|
||||
[7]: https://oldnavy.gap.com/browse/category.do?cid=1135640&mlink=5155,m_mts_a
|
||||
[8]: https://jvns.ca/images/firefox-helpful.png
|
||||
[9]: https://addons.mozilla.org/en-CA/firefox/addon/facebook-container/
|
||||
@ -0,0 +1,70 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: (geekpi)
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (Customize your Linux desktop with KDE Plasma)
|
||||
[#]: via: (https://opensource.com/article/19/12/linux-kde-plasma)
|
||||
[#]: author: (Seth Kenlon https://opensource.com/users/seth)
|
||||
|
||||
使用 KDE Plasma 定制 Linux 桌面
|
||||
======
|
||||
本文是 24 天 Linux 桌面特别系列的一部分。如果你认为没有太多机会进行自定义桌面，KDE Plasma 可能适合你。
|
||||
![5 pengiuns floating on iceburg][1]
|
||||
|
||||
KDE 社区的 Plasma 桌面是开源桌面中的巅峰之作。KDE 很早就进入了 Linux 桌面市场，但是由于它的 基础 Qt 工具包当时没有完全开放的许可证，因此才有 [GNOME][2] 桌面。在此之后，Qt 开源了，并且 KDE（及其衍生产品，例如 [Trinity桌面][3]）开始蓬勃发展。
|
||||
|
||||
你可能会在发行版的软件仓库中找到 KDE 桌面，或者可以下载并安装将 KDE 作为默认桌面的发行版。在安装之前，请注意，KDE 提供了完整、集成且强大的桌面体验，因此会同时安装几个 KDE 应用。如果你已经在运行其他桌面，那么将发现有几个冗余的应用（两个 PDF 阅读器、多个媒体播放器、两个或多个文件管理器，等等）。如果你只想尝试而不是一直使用 KDE 桌面，那么可以在虚拟机，如[GNOME Boxes][4]中安装基于 KDE 的发行版，也可以尝试使用可引导的操作系统，例如 [Porteus][5]。
|
||||
|
||||
### KDE 桌面之旅
|
||||
|
||||
乍一看，[KDE Plasma][6] 桌面相对无聊，但让人感到舒适。它有行业标准的布局：左下角弹出应用菜单，中间是任务栏，右边是系统托盘。这正是你对标准家用或商用计算机的期望。
|
||||
|
||||
![KDE Plasma desktop][7]
|
||||
|
||||
但是，使 KDE 与众不同的是，你几乎可以更改任何想要的东西。Qt 工具包可以以令人惊讶的方式分割和重新排列，这意味着你实质上可以使用 KDE 的部件作为基础来设计自己的桌面。桌面行为的可用设置也很多。KDE 可以充当标准桌面，平铺窗口管理器以及两者之间的任意形式。你可以通过窗口类、角色、类型、标题或它们的任意组合来创建自己的窗口规则，因此，如果希望特定应用的行为不同于其他行为，那么可以创建全局设置的例外。
|
||||
|
||||
此外，它还有丰富的小部件集合，使你可以自定义与桌面交互的方式。它有一个类似 GNOME 的全屏应用启动器，一个类似 Unity 的 dock 启动器和仅有图标的任务栏，一个传统的任务栏。你可以在屏幕的任何边缘上创建和放置面板。
|
||||
|
||||
![A slightly customized KDE desktop][8]
|
||||
|
||||
实际上，它有太多的自定义项了，因此 KDE 最常见的批评之一是它的_太过可定制化_，所以请记住，自定义项是可选的。你可以在默认配置下使用 Plasma 桌面，并仅在你认为必要时逐步进行更改。Plasma 桌面配置选项最重要的不是它们的数目，而是它们容易发现和直观，它们都在系统设置应用或者右键单击中。
|
||||
|
||||
事实是，在 KDE 上，几乎绝不会只有一种方法可以完成任何给定的任务，并且它的用户将其视为其最大的优势。KDE 中没有隐含的工作流，只有默认的。并且可以更改所有默认设置，直到你需要桌面做的成为你的习惯。
|
||||
|
||||
### 一致性和集成
|
||||
|
||||
KDE 社区以一致性和集成为荣，出色的开发人员、社区管理以及 KDE 库使其成为可能。KDE 的开发人员不只是桌面开发人员。它们提供了[惊人的应用集合][9]，每个应用都使用 KDE 库创建，这些库扩展并标准化了常见的 Qt 小部件。使用 KDE 几个月后，无论是打开 [DigiKam][10] 进行照片管理，还是打开 Kmail 来检查电子邮件，还是打开 KTorrent 来获取最新的 ISO 或者使用 Dolphin 管理文件，你的肌肉记忆会在你思考之前直接带你进入对应 UI。
|
||||
|
||||
![KDE on Porteus][11]
|
||||
|
||||
### 尝试 KDE
|
||||
|
||||
KDE 适合所有人。使用其默认设置可获得流畅、原始的桌面体验，或对其进行自定义以使其成为自己专属。它是一个稳定、有吸引力且强大的桌面环境，可能有你想要在 Linux 完成要做的事的一切。
|
||||
|
||||
KDE 最初代表 Kool Desktop Environment，但现在被许多人称为 K Desktop。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/19/12/linux-kde-plasma
|
||||
|
||||
作者：[Seth Kenlon][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/seth
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/rh_003499_01_linux31x_cc.png?itok=Pvim4U-B (5 pengiuns floating on iceburg)
|
||||
[2]: https://opensource.com/article/19/12/gnome-linux-desktop
|
||||
[3]: https://opensource.com/article/19/12/linux-trinity-desktop-environment-tde
|
||||
[4]: https://opensource.com/article/19/5/getting-started-gnome-boxes-virtualization
|
||||
[5]: https://opensource.com/article/19/6/linux-distros-to-try
|
||||
[6]: https://kde.org/plasma-desktop
|
||||
[7]: https://opensource.com/sites/default/files/uploads/advent-kde-presskit.jpg (KDE Plasma desktop)
|
||||
[8]: https://opensource.com/sites/default/files/uploads/advent-kde-dock.jpg (A slightly customized KDE desktop)
|
||||
[9]: https://kde.org/applications/
|
||||
[10]: https://opensource.com/life/16/5/how-use-digikam-photo-management
|
||||
[11]: https://opensource.com/sites/default/files/uploads/advent-kde.jpg (KDE on Porteus)
|
||||
@ -0,0 +1,65 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: (HankChow)
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (Why your Python code needs to be beautiful and explicit)
|
||||
[#]: via: (https://opensource.com/article/19/12/zen-python-beauty-clarity)
|
||||
[#]: author: (Moshe Zadka https://opensource.com/users/moshez)
|
||||
|
||||
为什么 Python 代码要写得美观而明确
|
||||
======
|
||||
欢迎阅读“Python 光明节（Pythonukkah）”系列文章，这个系列文章将会讨论《Python 之禅》。我们首先来看《Python 之禅》里的前两个原则：美观与明确。
|
||||
![Searching for code][1]
|
||||
|
||||
早在 1999 年，Python 的贡献者之一，Tim Peters 就提出了《[Python 之禅][2]》，直到二十年后的今天，《Python 之禅》中的 19 条原则仍然对整个社区都产生着深远的影响。为此，我们举行了这一次的“Python 光明节”。首先，我们会讨论《Python 之禅》中的前两个原则：美观和明确。
|
||||
|
||||
> "Hanukkah is the Festival of Lights,
|
||||
> Instead of one day of presents, we get eight crazy nights."
|
||||
> —亚当·桑德勒, [光明节之歌][3]
|
||||
|
||||
### 美观胜于丑陋
|
||||
|
||||
著名的《[<ruby>计算机程序的构造和解释<rt>Structure and Interpretation of Computer Programs</rt></ruby>][4]》中有这么一句话：代码是写给人看的，只是恰好能让机器运行（Programs must be written for people to read and only incidentally for machines to execute.）。毕竟机器并不在乎代码的美观性，但人类在乎。
|
||||
|
||||
阅读美观的代码对人们来说是一种享受，这就要求在整套代码中保持一致的风格。使用诸如 [Black][5]、[flake8][6]、[Pylint][7] 这一类工具能够有效地接近这一个目标。
|
||||
|
||||
但实际上，只有人类自己才知道什么才是真正的美观。因此，代码审查和协同开发是其中的不二法门，同时，在开发过程中倾听别人的意见也是必不可少的。
|
||||
|
||||
最后，个人的主观能动性也很重要，否则一切工具和流程都会变得毫无意义。只有意识到美观的重要性，才能主动编写出美观的代码。
|
||||
|
||||
这就是为什么美观在众多原则当中排到了首位，它让“美”成为了 Python 社区的一种价值。如果有人要问，”我们真的在乎美吗？“社区会以代码给出肯定的答案。
|
||||
|
||||
### 明确胜于隐晦
|
||||
|
||||
人类会欢庆光明、惧怕黑暗，那是因为光能够让我们看到难以看清的事物。同样地，尽管有些时候我们会不自觉地把代码写得含糊不清，但明确地编写代码确实能够让我们理解很多抽象的概念。
|
||||
|
||||
“为什么类方法中要将 `self` 显式指定为第一个参数？”
|
||||
|
||||
这个问题已经是老生常谈了，但网络上很多流传已久的回答都是不准确的。在编写<ruby>元类<rt>metaclass</rt></ruby>时，显式指定 `self` 参数就显得毫无意义。如果你没有编写过元类，希望你可以尝试一下，这是很多 Python 程序员的必经之路。
|
||||
|
||||
显式指定 `self` 参数的原因并不是 Python 的设计者不想将这样的元类视为“默认”元类，而是因为第一个参数必须是显式的。
|
||||
|
||||
即使 Python 中确实允许非显式的情况存在（例如上下文变量），但我们还是应该提出疑问：某个东西是不是有存在的必要呢？如果非显式地传递参数会不会出现问题呢？有些时候，由于种种原因，这是会有问题的。总之，在写代码时一旦能够优先考虑到明确性，至少意味着能对不明确的地方提出疑问并对结果作出有效的估计。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/19/12/zen-python-beauty-clarity
|
||||
|
||||
作者：[Moshe Zadka][a]
|
||||
选题：[lujun9972][b]
|
||||
译者：[HankChow](https://github.com/HankChow)
|
||||
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/moshez
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/search_find_code_python_programming.png?itok=ynSL8XRV "Searching for code"
|
||||
[2]: https://www.python.org/dev/peps/pep-0020/
|
||||
[3]: https://en.wikipedia.org/wiki/The_Chanukah_Song
|
||||
[4]: https://en.wikipedia.org/wiki/Structure_and_Interpretation_of_Computer_Programs
|
||||
[5]: https://opensource.com/article/19/5/python-black
|
||||
[6]: https://opensource.com/article/19/5/python-flake8
|
||||
[7]: https://opensource.com/article/19/10/python-pylint-introduction
|
||||
|
||||
@ -0,0 +1,111 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: (wxy)
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (Unix is turning 50. What does that mean?)
|
||||
[#]: via: (https://www.networkworld.com/article/3511428/unix-is-turning-50-what-does-that-mean.html)
|
||||
[#]: author: (Sandra Henry-Stocker https://www.networkworld.com/author/Sandra-Henry_Stocker/)
|
||||
|
||||
Unix 即将迎来 50 岁
|
||||
======
|
||||
|
||||
Unix 时间（又称为“<ruby>纪元时间<rt>epoch time</rt></ruby>”）是自 1970 年 1 月 1 日以来经过的秒数。当 Unix 即将 50 岁时，让我们看一下让内核开发人员担心的地方。
|
||||
|
||||
[cbaquiran][1]
|
||||
|
||||
对于 Unix 而言，2020 年是重要的一年。在这一年年初，Unix 进入 50 岁。
|
||||
|
||||
尽管 Unix 的某些早期开发早于其“纪元”的正式开始，但 1970 年 1 月 1 日仍然是 POSIX 时间的零点，也是公认的 Unix 的万物之始。自那一刻算起，2020 年 1 月 1 日将是其 50 周年。
|
||||
|
||||
### Unix 时间与人类时间
|
||||
|
||||
就人类时间而言，50 年是很重要的。就 Unix 时间而言，50 年没有什么特别的。48.7 年同样重要。
|
||||
|
||||
Unix（包括 Linux）系统将日期/时间值存储为自 1970-01-01 00:00:00 UTC 以来经过的秒数（32 位二进制）。要确定自该时间以来经过了几秒钟，看看 Unix 时间值是什么样子，你可以发出如下命令：
|
||||
|
||||
```
|
||||
$ date +%s
|
||||
1576883876
|
||||
```
|
||||
|
||||
`％s` 参数告诉 `date` 命令将当前日期/时间显示为自 1970-01-01 开始以来的秒数。
|
||||
|
||||
### Unix 系统可以管理多少时间？
|
||||
|
||||
要了解 Unix 系统可以容纳多少时间，我们需要查看 32 位字段的容量。可以这样计算：
|
||||
|
||||
```
|
||||
$ echo '2^32' | bc
|
||||
4294967296
|
||||
```
|
||||
|
||||
但是，由于 Unix 需要容纳负数，因此它会为数字的符号保留一位，从而将其减少为：
|
||||
|
||||
```
|
||||
$ echo '2^31' | bc
|
||||
2147483648
|
||||
```
|
||||
|
||||
并且，由于 Unix 计数以 0 开头，这意味着我们有 2,147,483,648 个值，但最大的可能值为 2,147,483,647 个。Unix 日期/时间值不能超过该数字——就像汽车上的里程表可能不能超过 999,999 英里一样。加 1 该值就变为了 -2147483648。（LCTT 译注：此处原文描述有误，已修改。在达到最大值之后，即 2018/1/19 03:14:07，下 1 秒导致符号位变为 1，其余 31 位为 0，即 -2147483648，时间变为 1901/12/13 20:45:52，这就是 Y2K38 问题。）
|
||||
|
||||
### 一年有多少秒？
|
||||
|
||||
大多数年份的秒数可以这样计算：每天的小时数乘以每小时的分钟数乘以每分钟的秒数乘以一年中的天数：
|
||||
|
||||
```
|
||||
$ expr 24 \* 60 \* 60 \* 365
|
||||
31536000
|
||||
```
|
||||
|
||||
在闰年，我们再增加一天：
|
||||
|
||||
```
|
||||
$ expr 24 \* 60 \* 60 \* 366
|
||||
31622400
|
||||
```
|
||||
|
||||
### Unix 将如何庆祝其 50 岁生日？
|
||||
|
||||
2020 年 1 月 1 日中午 12:00 是纪元时间的 1577836800。这个计算有些棘手，但主要是因为我们必须适应闰年。自该纪元开始以来，我们经历了 12 个闰年，从 1972 年开始，到上一个闰年是 2016 年。而且，当我们达到 2020 年时，我们将有 38 个常规年份。
|
||||
|
||||
这是使用 `expr` 命令进行的计算，以计算这 50 年的秒数：
|
||||
|
||||
```
|
||||
$ expr 24 \* 60 \* 60 \* 365 \* 38 + 24 \* 60 \* 60 \* 366 \* 12
|
||||
1577836800
|
||||
```
|
||||
|
||||
前半部分是计算 38 个非闰年的秒数。然后，我们加上闰年的 366 天的类似计算。或者，你可以使用前面介绍的每年秒数，然后执行以下操作：
|
||||
|
||||
```
|
||||
$ expr 31536000 \* 38 + 31622400 \* 12
|
||||
1577836800
|
||||
```
|
||||
|
||||
这种跟踪日期和时间的方式使 Unix 系统完全不受 Y2K 恐慌的影响，1999 年末人们开始担心进入 2000 年会对计算机系统造成严重破坏。但是实际遇到的问题比人们担心的少得多。实际上，只有以两位数格式存储年份的应用程序才会将年份变为 00，以表示时间倒退。尽管如此，许多应用程序开发人员还是做了很多额外的繁琐工作，以确保 2000 年到来时，他们的系统不会出现严重问题。
|
||||
|
||||
### Unix 时间何时会遇到问题？
|
||||
|
||||
在 2038 年之前，Unix 系统不会遇到 Y2K 类型的问题，直到如上所述存储的日期将超过其 32 位空间分配。但这距离现在已经只有 18 年了，内核开发人员已经在研究如何避免灾难。但现在开始恐慌还为时过早。
|
||||
|
||||
2038 年的问题有时称为 Y2K38 问题。我们必须在 2038 年 1 月 19 日星期二之前解决这个问题。如果问题到时候仍未解决，则该日期之后的系统可能会认为是 1901 年。解决该问题的一种方法是切换为日期/时间信息的 64 位表示形式。有些人认为，即使那样，也会有比听起来更复杂的问题。无论如何，恐慌还为时过早。并且，与此同时，也许在新年前夜演唱了《Auld Lang Syne》之后，你可以向 Unix 唱《生日快乐》歌了。Unix 50 岁了，这仍然是大事。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://www.networkworld.com/article/3511428/unix-is-turning-50-what-does-that-mean.html
|
||||
|
||||
作者：[Sandra Henry-Stocker][a]
|
||||
选题：[lujun9972][b]
|
||||
译者：[wxy](https://github.com/wxy)
|
||||
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.networkworld.com/author/Sandra-Henry_Stocker/
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://images.idgesg.net/images/article/2017/10/birthday-cake-candles-100739452-large.jpg
|
||||
[2]: https://creativecommons.org/publicdomain/zero/1.0/
|
||||
[3]: https://www.networkworld.com/article/3440100/take-the-intelligent-route-with-consumption-based-storage.html?utm_source=IDG&utm_medium=promotions&utm_campaign=HPE20773&utm_content=sidebar ( Take the Intelligent Route with Consumption-Based Storage)
|
||||
[4]: https://www.facebook.com/NetworkWorld/
|
||||
[5]: https://www.linkedin.com/company/network-world
|
||||
Loading…
Reference in New Issue
Block a user