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[submodule "comic"]
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path = comic
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url = https://wxy@github.com/LCTT/comic.git
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简介
|
||||
-------------------------------
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
[](https://travis-ci.org/LCTT/TranslateProject)
|
||||
[](https://github.com/LCTT/TranslateProject/graphs/contributors)
|
||||
[](https://github.com/LCTT/TranslateProject/pulls?q=is%3Apr+is%3Aclosed)
|
||||
|
||||
简介
|
||||
-------------------------------
|
||||
|
||||
[LCTT](https://linux.cn/lctt/) 是“Linux中国”（[https://linux.cn/](https://linux.cn/)）的翻译组，负责从国外优秀媒体翻译 Linux 相关的技术、资讯、杂文等内容。
|
||||
|
||||
LCTT 已经拥有几百名活跃成员，并欢迎更多的 Linux 志愿者加入我们的团队。
|
||||
|
||||
1
comic
1
comic
@ -1 +0,0 @@
|
||||
Subproject commit e5db5b880dac1302ee0571ecaaa1f8ea7cf61901
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@ -1,12 +1,13 @@
|
||||
如何使用 Apache Web 服务器配置多个站点
|
||||
|
||||
=====
|
||||
|
||||
> 如何在流行而强大的 Apache Web 服务器上托管两个或多个站点。
|
||||
|
||||
|
||||
|
||||
在我的[上一篇文章][1]中，我解释了如何为单个站点配置 Apache Web 服务器，事实证明这很容易。在这篇文章中，我将向你展示如何使用单个 Apache 实例来服务多个站点。
|
||||
|
||||
注意：我写这篇文章的环境是 Fedora 27 虚拟机，配置了 Apache 2.4.29。如果你有另一个 Fedora 的发行版，那么你使用的命令以及配置文件的位置和内容可能会有所不同。
|
||||
注意：我写这篇文章的环境是 Fedora 27 虚拟机，配置了 Apache 2.4.29。如果你用另一个发行版或不同的 Fedora 版本，那么你使用的命令以及配置文件的位置和内容可能会有所不同。
|
||||
|
||||
正如我之前的文章中提到的，Apache 的所有配置文件都位于 `/etc/httpd/conf` 和 `/etc/httpd/conf.d`。默认情况下，站点的数据位于 `/var/www` 中。对于多个站点，你需要提供多个位置，每个位置对应托管的站点。
|
||||
|
||||
@ -14,113 +15,93 @@
|
||||
|
||||
使用基于名称的虚拟主机，你可以为多个站点使用一个 IP 地址。现代 Web 服务器，包括 Apache，使用指定 URL 的 `hostname` 部分来确定哪个虚拟 Web 主机响应页面请求。这仅仅需要比一个站点更多的配置。
|
||||
|
||||
即使你只从单个站点开始，我也建议你将其设置为虚拟主机，这样可以在以后更轻松地添加更多站点。在本文中，我将在上一篇文章中介绍我们停止的位置，因此你需要设置原始站点，即基于名称的虚拟站点。
|
||||
即使你只从单个站点开始，我也建议你将其设置为虚拟主机，这样可以在以后更轻松地添加更多站点。在本文中，我将从上一篇文章中我们停止的地方开始，因此你需要设置原来的站点，即基于名称的虚拟站点。
|
||||
|
||||
### 准备原始站点
|
||||
### 准备原来的站点
|
||||
|
||||
在设置第二个站点之前，你需要为现有网站提供基于名称的虚拟主机。如果你现在没有网站，[请返回并立即创建一个][1]。
|
||||
在设置第二个站点之前，你需要为现有网站提供基于名称的虚拟主机。如果你现在没有站点，[请返回并立即创建一个][1]。
|
||||
|
||||
一旦你有了站点，将以下内容添加到 `/etc/httpd/conf/httpd.conf` 配置文件的底部（添加此内容是你需要对 `httpd.conf` 文件进行的唯一更改）：
|
||||
|
||||
```
|
||||
<VirtualHost 127.0.0.1:80>
|
||||
|
||||
DocumentRoot /var/www/html
|
||||
|
||||
ServerName www.site1.org
|
||||
|
||||
</VirtualHost>
|
||||
|
||||
```
|
||||
|
||||
这将是第一个虚拟主机节（to 校正：这里虚拟主机节不太清除），它应该保持为第一个，以使其成为默认定义。这意味着通过 IP 地址或解析为此 IP 地址但没有特定命名主机配置节的其它名称对服务器的 HTTP 访问将定向到此虚拟主机。所有其它虚拟主机配置节都应遵循此节。
|
||||
这将是第一个虚拟主机配置节，它应该保持为第一个，以使其成为默认定义。这意味着通过 IP 地址或解析为此 IP 地址但没有特定命名主机配置节的其它名称对服务器的 HTTP 访问将定向到此虚拟主机。所有其它虚拟主机配置节都应跟在此节之后。
|
||||
|
||||
你还需要使用 `/etc/hosts` 中的条目设置你的网站以提供名称解析。上次，我们只使用了 `localhost` 的 IP 地址。通常，这可以使用你使用的任何名称服务来完成，例如 Google 或 Godaddy。对于你的测试网站，通过在 `/etc/hosts` 中的 `localhost` 行添加一个新名称来完成此操作。添加两个网站的条目，方便你以后不需再次编辑此文件。结果如下：
|
||||
|
||||
```
|
||||
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4 www.site1.org www.site2.org
|
||||
```
|
||||
|
||||
让我们将 `/var/www/html/index.html` 文件改变得更加明显一点。它应该看起来像这样（带有一些额外的文本来识别这是站点 1）：
|
||||
|
||||
```
|
||||
<h1>Hello World</h1>
|
||||
|
||||
Web site 1.
|
||||
|
||||
```
|
||||
|
||||
重新启动 HTTPD 服务器，已启用对 `httpd` 配置的更改。然后，你可以从命令行使用 Lynx 文本模式查看网站。
|
||||
|
||||
```
|
||||
[root@testvm1 ~]# systemctl restart httpd
|
||||
|
||||
[root@testvm1 ~]# lynx www.site1.org
|
||||
|
||||
Hello World
|
||||
|
||||
Web site 1.
|
||||
|
||||
Hello World
|
||||
Web site 1.
|
||||
<snip>
|
||||
|
||||
Commands: Use arrow keys to move, '?' for help, 'q' to quit, '<-' to go back.
|
||||
|
||||
Arrow keys: Up and Down to move. Right to follow a link; Left to go back.
|
||||
|
||||
Arrow keys: Up and Down to move. Right to follow a link; Left to go back.
|
||||
H)elp O)ptions P)rint G)o M)ain screen Q)uit /=search [delete]=history list
|
||||
|
||||
```
|
||||
|
||||
你可以看到原始网站的修改内容，没有明显的错误，先按下 "Q" 键，然后按 "Y" 退出 Lynx Web 浏览器。
|
||||
你可以看到原始网站的修改内容，没有明显的错误，先按下 `Q` 键，然后按 `Y` 退出 Lynx Web 浏览器。
|
||||
|
||||
### 配置第二个站点
|
||||
|
||||
现在你已经准备好建立第二个网站。使用以下命令创建新的网站目录结构：
|
||||
|
||||
```
|
||||
[root@testvm1 html]# mkdir -p /var/www/html2
|
||||
|
||||
```
|
||||
|
||||
注意，第二个站点只是第二个 `html` 目录，与第一个站点位于同一 `/var/www` 目录下。
|
||||
|
||||
现在创建一个新的索引文件 `/var/www/html2/index.html`，其中包含以下内容（此索引文件稍有不同，以区别于原始网站）：
|
||||
现在创建一个新的索引文件 `/var/www/html2/index.html`，其中包含以下内容（此索引文件稍有不同，以区别于原来的网站）：
|
||||
|
||||
```
|
||||
<h1>Hello World -- Again</h1>
|
||||
|
||||
Web site 2.
|
||||
|
||||
```
|
||||
|
||||
在 `httpd.conf` 中为第二个站点创建一个新的配置节，并将其放在上一个虚拟主机节下面（这两个应该看起来非常相似）。此节告诉 Web 服务器在哪里可以找到第二个站点的 HTML 文件。
|
||||
在 `httpd.conf` 中为第二个站点创建一个新的配置节，并将其放在上一个虚拟主机配置节下面（这两个应该看起来非常相似）。此节告诉 Web 服务器在哪里可以找到第二个站点的 HTML 文件。
|
||||
|
||||
```
|
||||
<VirtualHost 127.0.0.1:80>
|
||||
|
||||
DocumentRoot /var/www/html2
|
||||
|
||||
ServerName www.site2.org
|
||||
|
||||
</VirtualHost>
|
||||
|
||||
```
|
||||
|
||||
重启 HTTPD，并使用 Lynx 来查看结果。
|
||||
|
||||
```
|
||||
[root@testvm1 httpd]# systemctl restart httpd
|
||||
|
||||
[root@testvm1 httpd]# lynx www.site2.org
|
||||
|
||||
Hello World -- Again
|
||||
|
||||
|
||||
Hello World -- Again
|
||||
|
||||
|
||||
|
||||
Web site 2.
|
||||
|
||||
|
||||
Web site 2.
|
||||
|
||||
<snip>
|
||||
|
||||
Commands: Use arrow keys to move, '?' for help, 'q' to quit, '<-' to go back.
|
||||
|
||||
Arrow keys: Up and Down to move. Right to follow a link; Left to go back.
|
||||
|
||||
Arrow keys: Up and Down to move. Right to follow a link; Left to go back.
|
||||
H)elp O)ptions P)rint G)o M)ain screen Q)uit /=search [delete]=history list
|
||||
|
||||
```
|
||||
@ -144,10 +125,10 @@ via: https://opensource.com/article/18/3/configuring-multiple-web-sites-apache
|
||||
|
||||
作者：[David Both][a]
|
||||
译者：[MjSeven](https://github.com/MjSeven)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
校对：[wxy](https://github.com/wxy)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:https://opensource.com/users/dboth
|
||||
[1]:https://opensource.com/article/18/2/how-configure-apache-web-server
|
||||
[1]:https://linux.cn/article-9506-1.html
|
||||
[2]:https://httpd.apache.org/docs/2.4/
|
||||
@ -1,13 +1,13 @@
|
||||
用 GNOME Boxes 下载一个镜像
|
||||
用 GNOME Boxes 下载一个操作系统镜像
|
||||
======
|
||||
|
||||
|
||||
|
||||
Boxes 是 GNOME 上的虚拟机应用。最近 Boxes 添加了一个新的特性，使得它在运行不同的 Linux 发行版时更加容易。你现在可以在 Boxes 中自动安装列表中这些发行版。该列表甚至包括红帽企业 Linux。红帽开发人员计划包括[免费订阅红帽企业版 Linux][1]。 使用[红帽开发者][2]帐户，Boxes 可以自动设置一个名为 Developer Suite 订阅的 RHEL 虚拟机。 下面是它的工作原理。
|
||||
Boxes 是 GNOME 上的虚拟机应用。最近 Boxes 添加了一个新的特性，使得它在运行不同的 Linux 发行版时更加容易。你现在可以在 Boxes 中自动安装那些发行版以及像 FreeBSD 和 FreeDOS 这样的操作系统，甚至还包括红帽企业 Linux。红帽开发者计划包括了一个[红帽企业版 Linux 的免费订阅][1]。 使用[红帽开发者][2]帐户，Boxes 可以自动设置一个名为 Developer Suite 订阅的 RHEL 虚拟机。 下面是它的工作原理。
|
||||
|
||||
### 红帽企业版 Linux
|
||||
### 红帽企业版 Linux
|
||||
|
||||
要创建一个红帽企业版 Linux 的虚拟机，启动 Boxes，点击新建。从源选择列表中选择下载一个镜像。在顶部，点击红帽企业版 Linux。这将会打开网址为 [developers.redhat.com][2] 的一个网络表单。使用已有的红帽开发者账号登录，或是新建一个。
|
||||
要创建一个红帽企业版 Linux 的虚拟机，启动 Boxes，点击“新建”。从源选择列表中选择“下载一个镜像”。在顶部，点击“红帽企业版 Linux”。这将会打开网址为 [developers.redhat.com][2] 的一个 Web 表单。使用已有的红帽开发者账号登录，或是新建一个。
|
||||
|
||||
![][3]
|
||||
|
||||
@ -15,11 +15,11 @@ Boxes 是 GNOME 上的虚拟机应用。最近 Boxes 添加了一个新的特性
|
||||
|
||||
![][5]
|
||||
|
||||
点击提交，然后就会开始下载安装磁盘镜像。下载需要的时间取决于你的网络状况。在这期间你可以去喝杯茶或者咖啡歇息一下。
|
||||
点击“提交”，然后就会开始下载安装磁盘镜像。下载需要的时间取决于你的网络状况。在这期间你可以去喝杯茶或者咖啡歇息一下。
|
||||
|
||||
![][6]
|
||||
|
||||
等媒体下载完成（一般位于 ~/Downloads ），Boxes 会有一个快速安装的显示。填入账号和密码然后点击继续，当你确认了虚拟机的信息之后点击创建。快速安装会自动完成接下来的整个安装！（现在你可以去享受你的第二杯茶或者咖啡了）
|
||||
等介质下载完成（一般位于 `~/Downloads` ），Boxes 会有一个“快速安装”的显示。填入账号和密码然后点击“继续”，当你确认了虚拟机的信息之后点击“创建”。“快速安装”会自动完成接下来的整个安装！（现在你可以去享受你的第二杯茶或者咖啡了）
|
||||
|
||||
![][7]
|
||||
|
||||
@ -27,7 +27,7 @@ Boxes 是 GNOME 上的虚拟机应用。最近 Boxes 添加了一个新的特性
|
||||
|
||||
![][9]
|
||||
|
||||
等到安装结束，虚拟机会直接重启并登录到桌面。在虚拟机里，在应用菜单的系统工具一栏启动红帽订阅管理。这一步需要输入管理员密码。
|
||||
等到安装结束，虚拟机会直接重启并登录到桌面。在虚拟机里，在应用菜单的“系统工具”一栏启动“红帽订阅管理”。这一步需要输入 root 密码。
|
||||
|
||||
![][10]
|
||||
|
||||
@ -37,13 +37,13 @@ Boxes 是 GNOME 上的虚拟机应用。最近 Boxes 添加了一个新的特性
|
||||
|
||||
![][12]
|
||||
|
||||
现在你可以通过任何一种更新方法，像是 yum 或是 GNOME Software 进行下载和更新了。
|
||||
现在你可以通过任何一种更新方法，像是 `yum` 或是 GNOME Software 进行下载和更新了。
|
||||
|
||||
![][13]
|
||||
|
||||
### FreeDOS 或是其他
|
||||
|
||||
Boxes 可以安装很多的 Linux 发行版，而不仅仅只是红帽企业版。 作为 KVM 和 qemu 的前端，Boxes 支持各种操作系统。 使用 [libosinfo][14]，Boxes 可以自动下载（在某些情况下安装）相当多不同操作系统。
|
||||
Boxes 可以安装很多操作系统，而不仅仅只是红帽企业版。 作为 KVM 和 qemu 的前端，Boxes 支持各种操作系统。使用 [libosinfo][14]，Boxes 可以自动下载（在某些情况下安装）相当多不同操作系统。
|
||||
|
||||
![][15]
|
||||
|
||||
@ -53,13 +53,23 @@ Boxes 可以安装很多的 Linux 发行版，而不仅仅只是红帽企业版
|
||||
|
||||
![][17]
|
||||
|
||||
### 在 Boxes 上受欢迎的操作系统
|
||||
### Boxes 上流行的操作系统
|
||||
|
||||
这里仅仅是一些目前在它上面比较受欢迎的选择。
|
||||
|
||||
![][18]![][19]![][20]![][21]![][22]![][23]
|
||||
![][18]
|
||||
|
||||
Fedora 会定期更新它的操作系统信息数据库。确保你会经常检查是否有新的操作系统选项。
|
||||
![][19]
|
||||
|
||||
![][20]
|
||||
|
||||
![][21]
|
||||
|
||||
![][22]
|
||||
|
||||
![][23]
|
||||
|
||||
Fedora 会定期更新它的操作系统信息数据库（osinfo-db）。确保你会经常检查是否有新的操作系统选项。
|
||||
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
@ -69,7 +79,7 @@ via: https://fedoramagazine.org/download-os-gnome-boxes/
|
||||
作者：[Link Dupont][a]
|
||||
选题：[lujun9972](https://github.com/lujun9972)
|
||||
译者：[dianbanjiu](https://github.com/dianbanjiu)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
校对：[wxy](https://github.com/wxy)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
59
published/20180830 6 places to host your git repository.md
Normal file
59
published/20180830 6 places to host your git repository.md
Normal file
@ -0,0 +1,59 @@
|
||||
6 个托管 git 仓库的地方
|
||||
======
|
||||
> GitHub 被收购导致一些用户去寻找这个流行的代码仓库的替代品。这里有一些你可以考虑一下。
|
||||
|
||||
|
||||
|
||||
也许你是少数一些没有注意到的人之一，就在之前，[微软收购了 GitHub][1]。两家公司达成了共识。微软在近些年已经变成了开源的有力支持者，而 GitHub 从成立起，就已经成为了大量的开源项目的实际代码库。
|
||||
|
||||
然而，最近发生的这次收购可能会带给你一些苦恼。毕竟公司的收购让你意识到了你的开源代码放在了一个商业平台上。可能你现在还没准备好迁移到其他的平台上去，但是至少这可以给你提供一些可选项。让我们找找网上现在都有哪些可用的平台。
|
||||
|
||||
### 选择之一： GitHub
|
||||
|
||||
严格来说，这是一个合格的选项。[GitHub][2] 历史上没有什么失信的地方，而且微软后来也一直笑对开源。把你的项目继续放在 GitHub 上，保持观望没有什么不可以。它现在依然是最大的软件开发的网络社区，同时还有许多对于问题追踪、代码审查、持续集成、通用的代码管理等很有用的工具。而且它还是基于 Git 的，这是每个人都喜欢的开源版本控制系统。你的代码还是你的代码。如果没有出现什么问题，那保持原状是没错的。
|
||||
|
||||
### 选择之二： GitLab
|
||||
|
||||
[GitLab][3] 是考虑替代代码库平台时的主要竞争者。它是完全开源的。你可以像在 GitHub 一样把你的代码托管在 GitLab，但你也可以选择在你自己的服务器上自行托管自己的 GitLab 实例，并完全控制谁可以访问那里的所有内容以及如何访问和管理。GitLab 与 GitHub 功能几乎相同，有些人甚至可能会说它的持续集成和测试工具更优越。尽管 GitLab 上的开发者社区肯定比 GitHub 上的开发者社区要小，但这并没有什么。你可能会在那里的人群中找到更多志同道合的开发者。
|
||||
|
||||
### 选择之三： Bitbucket
|
||||
|
||||
[Bitbucket][4] 已经存在很多年了。在某些方面，它可以作为 GitHub 未来的一面镜子。Bitbucket 八年前被一家大公司（Atlassian）收购，并且已经经历了一些变化。它仍然是一个像 GitHub 这样的商业平台，但它远不是一个创业公司，而且从组织上说它的基础相当稳定。Bitbucket 具有 GitHub 和 GitLab 上的大部分功能，以及它自己的一些新功能，如对 [Mercurial][5] 仓库的原生支持。
|
||||
|
||||
### 选择之四： SourceForge
|
||||
|
||||
[SourceForge][6] 是开源代码库的鼻祖。如果你曾经有一个开源项目，Sourceforge 就是那个托管你的代码并向其他人分享你的发布版本的地方。它迁移到 Git 版本控制用了一段时间，它有一些商业收购和再次收购的历史，以及一些对某些开源项目糟糕的捆绑决策。也就是说，SourceForge 从那时起似乎已经恢复，该网站仍然是一个有着不少开源项目的地方。然而，很多人仍然感到有点受伤，而且有些人并不是很支持它的平台货币化的各种尝试，所以一定要睁大眼睛。
|
||||
|
||||
### 选择之五： 自己管理
|
||||
|
||||
如果你想自己掌握自己项目的命运（除了你自己没人可以指责你），那么一切都由自己来做可能对你来说是最佳的选择。无论对于大项目还是小项目，都是好的选择。Git 是开源的，所以自己托管也很容易。如果你想要问题追踪和代码审查功能，你可以运行一个 GitLab 或者 [Phabricator][7] 的实例。对于持续集成，你可以设置自己的 [Jenkins][8] 自动化服务实例。是的，你需要对自己的基础架构开销和相关的安全要求负责。但是，这个设置过程并不是很困难。所以如果你不想自己的代码被其他人的平台所吞没，这就是一种很好的方法。
|
||||
|
||||
### 选择之六：以上全部
|
||||
|
||||
以下是所有这些的美妙之处：尽管这些平台上有一些专有的选项，但它们仍然建立在坚实的开源技术之上。而且不仅仅是开源，而是明确设计为分布在大型网络（如互联网）上的多个节点上。你不需要只使用一个。你可以使用一对……或者全部。使用 GitLab 将你自己的设施作为保证的基础，并在 GitHub 和 Bitbucket 上安装克隆存储库，以进行问题跟踪和持续集成。将你的主代码库保留在 GitHub 上，但是出于你自己的考虑，可以在 GitLab 上安装“备份”克隆。
|
||||
|
||||
关键在于你可以选择。我们能有这么多选择，都是得益于那些非常有用而强大的项目之上的开源许可证。未来一片光明。
|
||||
|
||||
当然，在这个列表中我肯定忽略了一些开源平台。方便的话请补充给我们。你是否使用了多个平台？哪个是你最喜欢的？你都可以在这里说出来！
|
||||
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/18/8/github-alternatives
|
||||
|
||||
作者：[Jason van Gumster][a]
|
||||
选题：[lujun9972](https://github.com/lujun9972)
|
||||
译者：[dianbanjiu](https://github.com/dianbanjiu)
|
||||
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/mairin
|
||||
[1]: https://www.theverge.com/2018/6/4/17422788/microsoft-github-acquisition-official-deal
|
||||
[2]: https://github.com/
|
||||
[3]: https://gitlab.com
|
||||
[4]: https://bitbucket.org
|
||||
[5]: https://www.mercurial-scm.org/wiki/Repository
|
||||
[6]: https://sourceforge.net
|
||||
[7]: https://phacility.com/phabricator/
|
||||
[8]: https://jenkins.io
|
||||
166
published/20180924 Why Linux users should try Rust.md
Normal file
166
published/20180924 Why Linux users should try Rust.md
Normal file
@ -0,0 +1,166 @@
|
||||
为什么 Linux 用户应该试一试 Rust
|
||||
======
|
||||
> 在 Linux 系统上安装 Rust 编程语言可能是你近年来所做的最有价值的事情之一。
|
||||
|
||||
|
||||
|
||||
Rust 是一种相当年轻和现代的编程语言，具有许多使其非常灵活而及其安全的功能。数据显示它正在变得非常受欢迎，连续三年（[2016][1]、[2017][2] 和 [2018][3]）在 Stack Overflow 开发者调查中获得“最受喜爱的编程语言”的第一名。
|
||||
|
||||
Rust 也是开源语言的一种，它具有一系列特殊的功能，使得它可以适应许多不同的编程项目。 它最初源于 2006 年 Mozilla 员工的个人项目，几年后（2009 年）被 Mozilla 选为特别项目，然后在 2010 年宣布供公众使用。
|
||||
|
||||
Rust 程序运行速度极快，可防止段错误，并能保证线程安全。这些属性使该语言极大地吸引了专注于应用程序安全性的开发人员。Rust 也是一种非常易读的语言，可用于从简单程序到非常大而复杂的项目。
|
||||
|
||||
Rust 优点：
|
||||
|
||||
* 内存安全 —— Rust 不会受到悬空指针、缓冲区溢出或其他与内存相关的错误的影响。它提供内存安全，无回收垃圾。
|
||||
* 通用 —— Rust 是适用于任何类型编程的语言
|
||||
* 快速 —— Rust 在性能上与 C / C++ 相当，但具有更好的安全功能。
|
||||
* 高效 —— Rust 是为了便于并发编程而构建的。
|
||||
* 面向项目 —— Rust 具有内置的依赖关系和构建管理系统 Cargo。
|
||||
* 得到很好的支持 —— Rust 有一个令人印象深刻的[支持社区][4]。
|
||||
|
||||
Rust 还强制执行 RAII（<ruby>资源获取初始化<rt>Resource Acquisition Is Initialization</rt></ruby>）。这意味着当一个对象超出范围时，将调用其析构函数并释放其资源，从而提供防止资源泄漏的屏蔽。它提供了功能抽象和一个很棒的[类型系统][5]，并具有速度和数学健全性。
|
||||
|
||||
简而言之，Rust 是一种令人印象深刻的系统编程语言，具有其它大多数语言所缺乏的功能，使其成为 C、C++ 和 Objective-C 等多年来一直被使用的语言的有力竞争者。
|
||||
|
||||
### 安装 Rust
|
||||
|
||||
安装 Rust 是一个相当简单的过程。
|
||||
|
||||
```
|
||||
$ curl https://sh.rustup.rs -sSf | sh
|
||||
```
|
||||
|
||||
安装 Rust 后，使用 `rustc --version` 或 `which` 命令显示版本信息。
|
||||
|
||||
```
|
||||
$ which rustc
|
||||
rustc 1.27.2 (58cc626de 2018-07-18)
|
||||
$ rustc --version
|
||||
rustc 1.27.2 (58cc626de 2018-07-18)
|
||||
```
|
||||
|
||||
### Rust 入门
|
||||
|
||||
Rust 即使是最简单的代码也与你之前使用过的语言输入的完全不同。
|
||||
|
||||
```
|
||||
$ cat hello.rs
|
||||
fn main() {
|
||||
// Print a greeting
|
||||
println!("Hello, world!");
|
||||
}
|
||||
```
|
||||
|
||||
在这些行中，我们正在设置一个函数（`main`），添加一个描述该函数的注释，并使用 `println` 语句来创建输出。您可以使用下面显示的命令编译然后运行程序。
|
||||
|
||||
```
|
||||
$ rustc hello.rs
|
||||
$ ./hello
|
||||
Hello, world!
|
||||
```
|
||||
|
||||
另外，你也可以创建一个“项目”（通常仅用于比这个更复杂的程序！）来保持代码的有序性。
|
||||
|
||||
```
|
||||
$ mkdir ~/projects
|
||||
$ cd ~/projects
|
||||
$ mkdir hello_world
|
||||
$ cd hello_world
|
||||
```
|
||||
|
||||
请注意，即使是简单的程序，一旦编译，就会变成相当大的可执行文件。
|
||||
|
||||
```
|
||||
$ ./hello
|
||||
Hello, world!
|
||||
$ ls -l hello*
|
||||
-rwxrwxr-x 1 shs shs 5486784 Sep 23 19:02 hello <== executable
|
||||
-rw-rw-r-- 1 shs shs 68 Sep 23 15:25 hello.rs
|
||||
```
|
||||
|
||||
当然，这只是一个开始且传统的“Hello, world!” 程序。 Rust 语言具有一系列可帮助你快速进入高级编程技能的功能。
|
||||
|
||||
### 学习 Rust
|
||||
|
||||
![rust programming language book cover][6]
|
||||
|
||||
*No Starch Press*
|
||||
|
||||
Steve Klabnik 和 Carol Nichols 的《[Rust 编程语言][7]》 （2018）一书提供了学习 Rust 的最佳方法之一。 这本书由核心开发团队的两名成员撰写，可从 [No Starch Press][7] 出版社获得纸制书或者从 [rust-lang.org][8] 获得电子书。它已经成为 Rust 开发者社区中的参考书。
|
||||
|
||||
在所涉及的众多主题中，你将了解这些高级主题：
|
||||
|
||||
* 所有权和 borrowing
|
||||
* 安全保障
|
||||
* 测试和错误处理
|
||||
* 智能指针和多线程
|
||||
* 高级模式匹配
|
||||
* 使用 Cargo（内置包管理器）
|
||||
* 使用 Rust 的高级编译器
|
||||
|
||||
#### 目录
|
||||
|
||||
- 前言（Nicholas Matsakis 和 Aaron Turon 编写）
|
||||
- 致谢
|
||||
- 介绍
|
||||
- 第 1 章：新手入门
|
||||
- 第 2 章：猜谜游戏
|
||||
- 第 3 章：通用编程概念
|
||||
- 第 4 章：了解所有权
|
||||
- 第 5 章：结构
|
||||
- 第 6 章：枚举和模式匹配
|
||||
- 第 7 章：模块
|
||||
- 第 8 章：常见集合
|
||||
- 第 9 章：错误处理
|
||||
- 第 10 章：通用类型、特征和生命周期
|
||||
- 第 11 章：测试
|
||||
- 第 12 章：输入/输出项目
|
||||
- 第 13 章：迭代器和闭包
|
||||
- 第 14 章：关于货物和 Crates.io 的更多信息
|
||||
- 第 15 章：智能指针
|
||||
- 第 16 章：并发
|
||||
- 第 17 章：Rust 是面向对象的吗？
|
||||
- 第 18 章：模式
|
||||
- 第 19 章：关于生命周期的更多信息
|
||||
- 第 20 章：高级类型系统功能
|
||||
- 附录 A：关键字
|
||||
- 附录 B：运算符和符号
|
||||
- 附录 C：可衍生的特征
|
||||
- 附录 D：宏
|
||||
- 索引
|
||||
|
||||
《[Rust 编程语言][7]》 将你从基本安装和语言语法带到复杂的主题，例如模块、错误处理、crates（与其他语言中的 “library”
|
||||
或“package”同义），模块（允许你将你的代码分配到 crate 本身），生命周期等。
|
||||
|
||||
可能最重要的是，本书可以让您从基本的编程技巧转向构建和编译复杂、安全且非常有用的程序。
|
||||
|
||||
### 结束
|
||||
|
||||
如果你已经准备好用一种非常值得花时间和精力学习并且越来越受欢迎的语言进行一些严肃的编程，那么 Rust 是一个不错的选择！
|
||||
|
||||
加入 [Facebook][9] 和 [LinkedIn][10] 上的 Network World 社区，评论最重要的话题。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
|
||||
via: https://www.networkworld.com/article/3308162/linux/why-you-should-try-rust.html
|
||||
|
||||
作者：[Sandra Henry-Stocker][a]
|
||||
选题：[lujun9972](https://github.com/lujun9972)
|
||||
译者：[way-ww](https://github.com/way-ww)
|
||||
校对：[wxy](https://github.com/wxy)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]: https://www.networkworld.com/author/Sandra-Henry_Stocker/
|
||||
[1]: https://insights.stackoverflow.com/survey/2016#technology-most-loved-dreaded-and-wanted
|
||||
[2]: https://insights.stackoverflow.com/survey/2017#technology-most-loved-dreaded-and-wanted-languages
|
||||
[3]: https://insights.stackoverflow.com/survey/2018#technology-most-loved-dreaded-and-wanted-languages
|
||||
[4]: https://www.rust-lang.org/en-US/community.html
|
||||
[5]: https://doc.rust-lang.org/reference/type-system.html
|
||||
[6]: https://images.idgesg.net/images/article/2018/09/rust-programming-language_book-cover-100773679-small.jpg
|
||||
[7]: https://nostarch.com/Rust
|
||||
[8]: https://doc.rust-lang.org/book/2018-edition/index.html
|
||||
[9]: https://www.facebook.com/NetworkWorld/
|
||||
[10]: https://www.linkedin.com/company/network-world
|
||||
@ -3,64 +3,64 @@
|
||||
|
||||
|
||||
|
||||
Linux容器是有由 Linux 内核提供的具有特定隔离功能的进程 - 包括文件系统、进程和网络隔离。容器有助于实现可移植性 - 应用可以在容器镜像中与其依赖项一起分发，并可在几乎任何有容器运行时的 Linux 系统上运行。
|
||||
Linux 容器是由 Linux 内核所提供的具有特定隔离功能的进程 —— 包括文件系统、进程和网络的隔离。容器有助于实现可移植性 —— 应用可以在容器镜像中与其依赖项一起分发，并可在几乎任何有容器运行时环境的 Linux 系统上运行。
|
||||
|
||||
虽然容器技术存在了很长时间，但 Linux 容器是由 Docker 广泛推广。 “Docker” 这个词可以指几个不同的东西，包括容器技术和工具，周围的社区，或者 Docker Inc. 公司。但是，在本文中，我将用来指管理 Linux 容器的技术和工具。
|
||||
虽然容器技术存在了很长时间，但 Linux 容器是由 Docker 而得到了广泛推广。 “Docker” 这个词可以指几个不同的东西，包括容器技术和工具，周围的社区，或者 Docker Inc. 公司。但是，在本文中，我将用来指管理 Linux 容器的技术和工具。
|
||||
|
||||
### 什么是 Docker
|
||||
|
||||
[Docker][1] 是一个以 root 身份在你的系统上运行的守护程序，它利用 Linux 内核的功能来管理正在运行的容器。除了运行容器之外，它还可以轻松管理容器镜像 - 与容器托管交互、存储映像、管理容器版本等。它基本上支持运行单个容器所需的所有操作。
|
||||
[Docker][1] 是一个以 root 身份在你的系统上运行的守护程序，它利用 Linux 内核的功能来管理正在运行的容器。除了运行容器之外，它还可以轻松管理容器镜像 —— 与容器注册库交互、存储映像、管理容器版本等。它基本上支持运行单个容器所需的所有操作。
|
||||
|
||||
但即使 Docker 是管理 Linux 容器的一个非常方便的工具，它也有两个缺点：它是一个需要在你的系统上运行的守护进程，并且需要以 root 权限运行，这可能有一定的安全隐患。然而，Podman 在解决这两个问题。
|
||||
|
||||
### Podman 介绍
|
||||
|
||||
[Podman][2] 是一个容器运行时，提供与 Docker 非常相似的功能。正如已经提示的那样，它不需要在你的系统上运行任何守护进程，并且它也可以在没有 root 权限的情况下运行。让我们看看使用 Podman 运行 Linux 容器的一些示例。
|
||||
[Podman][2] 是一个容器运行时环境，提供与 Docker 非常相似的功能。正如已经提示的那样，它不需要在你的系统上运行任何守护进程，并且它也可以在没有 root 权限的情况下运行。让我们看看使用 Podman 运行 Linux 容器的一些示例。
|
||||
|
||||
#### 使用 Podman 运行容器
|
||||
|
||||
其中一个最简单的例子可能是运行 Fedora 容器，在命令行中打印 “Hello world!”：
|
||||
|
||||
```
|
||||
$ podman run --rm -it fedora:28 echo "Hello world!"
|
||||
$ podman run --rm -it fedora:28 echo "Hello world!"
|
||||
```
|
||||
|
||||
使用通用 Dockerfile 构建镜像的方式与 Docker 相同：
|
||||
|
||||
```
|
||||
$ cat Dockerfile
|
||||
FROM fedora:28
|
||||
RUN dnf -y install cowsay
|
||||
$ cat Dockerfile
|
||||
FROM fedora:28
|
||||
RUN dnf -y install cowsay
|
||||
|
||||
$ podman build . -t hello-world
|
||||
... output omitted ...
|
||||
$ podman build . -t hello-world
|
||||
... output omitted ...
|
||||
|
||||
$ podman run --rm -it hello-world cowsay "Hello!"
|
||||
$ podman run --rm -it hello-world cowsay "Hello!"
|
||||
```
|
||||
|
||||
为了构建容器，Podman 在后台调用另一个名为 Buildah 的工具。你可以阅读最近一篇[关于使用 Buildah 构建容器镜像的文章][3] - 它不仅仅是使用典型的 Dockerfile。
|
||||
为了构建容器，Podman 在后台调用另一个名为 Buildah 的工具。你可以阅读最近一篇[关于使用 Buildah 构建容器镜像的文章][3] —— 它不仅仅是使用典型的 Dockerfile。
|
||||
|
||||
除了构建和运行容器外，Podman 还可以与容器托管进行交互。要登录容器托管，例如广泛使用的 Docker Hub，请运行：
|
||||
除了构建和运行容器外，Podman 还可以与容器托管进行交互。要登录容器注册库，例如广泛使用的 Docker Hub，请运行：
|
||||
|
||||
```
|
||||
$ podman login docker.io
|
||||
$ podman login docker.io
|
||||
```
|
||||
|
||||
为了推送我刚刚构建的镜像，我只需打上标记来代表特定的容器托管，然后直接推送它。
|
||||
为了推送我刚刚构建的镜像，我只需打上标记来代表特定的容器注册库，然后直接推送它。
|
||||
|
||||
```
|
||||
$ podman -t hello-world docker.io/asamalik/hello-world
|
||||
$ podman push docker.io/asamalik/hello-world
|
||||
$ podman -t hello-world docker.io/asamalik/hello-world
|
||||
$ podman push docker.io/asamalik/hello-world
|
||||
```
|
||||
|
||||
顺便说一下，你是否注意到我如何以非 root 用户身份运行所有内容？此外，我的系统上没有运行大的守护进程！
|
||||
顺便说一下，你是否注意到我如何以非 root 用户身份运行所有内容？此外，我的系统上没有运行又大又重的守护进程！
|
||||
|
||||
#### 安装 Podman
|
||||
|
||||
Podman 默认在 [Silverblue][4] 上提供 - 一个基于容器的工作流的新一代 Linux 工作站。要在任何 Fedora 版本上安装它，只需运行：
|
||||
Podman 默认在 [Silverblue][4] 上提供 —— 一个基于容器的工作流的新一代 Linux 工作站。要在任何 Fedora 版本上安装它，只需运行：
|
||||
|
||||
```
|
||||
$ sudo dnf install podman
|
||||
$ sudo dnf install podman
|
||||
```
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
@ -70,7 +70,7 @@ via: https://fedoramagazine.org/running-containers-with-podman/
|
||||
作者：[Adam Šamalík][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
|
||||
|
||||
@ -1,6 +1,6 @@
|
||||
使用 Lakka Linux 将你的旧 PC 变成复古游戏主机
|
||||
======
|
||||
**如果你有一台吃灰的旧计算机，你可以用 Lakka Linux 将它变成像 PlayStation 那样的复古游戏主机。**
|
||||
> 如果你有一台吃灰的旧计算机，你可以用 Lakka Linux 将它变成像 PlayStation 那样的复古游戏主机。
|
||||
|
||||
你可能已经了解[专门用于复活旧计算机的 Linux 发行版][1]。但是你知道有个 Linux 发行版专门是为了将旧电脑变成复古游戏主机创建的么？
|
||||
|
||||
@ -12,8 +12,7 @@
|
||||
|
||||
Lakka 提供类似的界面和类似的体验。我稍后会谈到“体验”。先看一下界面。
|
||||
|
||||
<https://itsfoss.com/wp-content/uploads/2018/10/lakka-linux-gaming-console.webm>
|
||||
Lakka 复古游戏界面
|
||||
[Lakka 复古游戏界面](https://itsfoss.com/wp-content/uploads/2018/10/lakka-linux-gaming-console.webm)
|
||||
|
||||
### Lakka：为复古游戏而生的 Linux 发行版
|
||||
|
||||
@ -27,20 +26,18 @@ Lakka 是轻量级的，你可以将它安装在大多数老系统或单板计
|
||||
|
||||
它支持大量的模拟器。你只需要在系统上下载 ROM，Lakka 将从这些 ROM 运行游戏。你可以在[这里][6]找到支持的模拟器和硬件列表。
|
||||
|
||||
它通过器顺滑的图形界面让你能够在许多计算机和主机上运行经典游戏。设置也是统一的，因此可以一劳永逸地完成配置。
|
||||
它通过其顺滑的图形界面让你能够在许多计算机和主机上运行经典游戏。设置也是统一的，因此可以一劳永逸地完成配置。
|
||||
|
||||
让我总结一下 Lakka 的主要特点：
|
||||
|
||||
* RetroArch 中与 PlayStation 类似的界面
|
||||
* 支持许多复古游戏模拟器
|
||||
* 支持最多 5 名玩家在同一系统上玩游戏
|
||||
* 存档允许你随时保存游戏中的进度
|
||||
* 你可以使用各种图形过滤器改善旧游戏的外表
|
||||
* 你可以通过网络加入多人游戏
|
||||
* 开箱即用支持 XBOX360、Dualshock 3 和 8bitdo 等多种游戏手柄
|
||||
* 连接到 [RetroAchievements] [7] 获取奖杯和徽章
|
||||
|
||||
|
||||
* RetroArch 中与 PlayStation 类似的界面
|
||||
* 支持许多复古游戏模拟器
|
||||
* 支持最多 5 名玩家在同一系统上玩游戏
|
||||
* 存档允许你随时保存游戏中的进度
|
||||
* 你可以使用各种图形过滤器改善旧游戏的外表
|
||||
* 你可以通过网络加入多人游戏
|
||||
* 开箱即用支持 XBOX360、Dualshock 3 和 8bitdo 等多种游戏手柄
|
||||
* 连接到 [RetroAchievements] [7] 获取奖杯和徽章
|
||||
|
||||
### 获取 Lakka
|
||||
|
||||
@ -50,7 +47,7 @@ Lakka 是轻量级的，你可以将它安装在大多数老系统或单板计
|
||||
|
||||
[项目的 FAQ 部分][8]回答了常见的疑问，所以如有任何其他的问题，请参考它。
|
||||
|
||||
[获取 Lakka][9]
|
||||
- [获取 Lakka][9]
|
||||
|
||||
你喜欢复古游戏吗？你使用什么模拟器？你以前用过 Lakka 吗？在评论区与我们分享你的观点。
|
||||
|
||||
@ -61,7 +58,7 @@ via: https://itsfoss.com/lakka-retrogaming-linux/
|
||||
作者：[Abhishek Prakash][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
|
||||
|
||||
@ -75,4 +72,4 @@ via: https://itsfoss.com/lakka-retrogaming-linux/
|
||||
[6]: http://www.lakka.tv/powerful/
|
||||
[7]: https://retroachievements.org/
|
||||
[8]: http://www.lakka.tv/doc/FAQ/
|
||||
[9]; http://www.lakka.tv/disclaimer/
|
||||
[9]: http://www.lakka.tv/disclaimer/
|
||||
@ -5,7 +5,7 @@ set -e
|
||||
function help()
|
||||
{
|
||||
cat <<EOF
|
||||
Usage: ${0##*/} [+-s} [published] [translated] [translating] [sources]
|
||||
Usage: ${0##*/} [+-s] [published] [translated] [translating] [sources]
|
||||
|
||||
显示已发布、已翻译、正在翻译和待翻译的数量
|
||||
|
||||
@ -27,7 +27,9 @@ shift $(( OPTIND - 1 ))
|
||||
OPTIND=1
|
||||
|
||||
declare -A catalog_comment_dict
|
||||
catalog_comment_dict=([translated]="待校对" [published]="已发布" [translating]="翻译中" [sources]="待翻译")
|
||||
declare -A catalog_color_dict
|
||||
catalog_comment_dict=([sources]="待翻译" [translating]="翻译中" [translated]="待校对" [published]="已发布")
|
||||
catalog_color_dict=([sources]="#97CA00" [translating]="#00BCD5" [translated]="#FF9800" [published]="#FF5722")
|
||||
|
||||
function count_files_under_dir()
|
||||
{
|
||||
@ -60,26 +62,27 @@ for catalog in "$@";do
|
||||
esac
|
||||
|
||||
comment=${catalog_comment_dict[${catalog}]}
|
||||
color=${catalog_color_dict[${catalog}]}
|
||||
if [[ "${show_format}" == "svg" ]];then
|
||||
cat <<EOF
|
||||
<svg xmlns="http://www.w3.org/2000/svg" width="120" height="20">
|
||||
<svg xmlns="http://www.w3.org/2000/svg" width="100" height="20">
|
||||
<linearGradient id="b" x2="0" y2="100%">
|
||||
<stop offset="0" stop-color="#bbb" stop-opacity=".1" />
|
||||
<stop offset="1" stop-opacity=".1" />
|
||||
</linearGradient>
|
||||
<mask id="a">
|
||||
<rect width="132.53125" height="20" rx="3" fill="#fff" />
|
||||
<rect width="100" height="20" rx="3" fill="#fff" />
|
||||
</mask>
|
||||
<g mask="url(#a)">
|
||||
<path fill="#555" d="M0 0 h70.53125 v20 H0 z" />
|
||||
<path fill="#97CA00" d="M70.53125 0 h62.0 v20 H70.53125 z" />
|
||||
<path fill="url(#b)" d="M0 0 h132.53125 v20 H0 z" />
|
||||
<path fill="#555" d="M0 0 h60 v20 H0 z" />
|
||||
<path fill="${color}" d="M60 0 h40 v20 H60 z" />
|
||||
<path fill="url(#b)" d="M0 0 h100 v20 H0 z" />
|
||||
</g>
|
||||
<g fill="#fff" font-family="DejaVu Sans" font-size="11">
|
||||
<text x="6" y="15" fill="#010101" fill-opacity=".3">${comment}</text>
|
||||
<text x="6" y="14">${comment}</text>
|
||||
<text x="74.53125" y="15" fill="#010101" fill-opacity=".3">${num}</text>
|
||||
<text x="74.53125" y="14">${num}</text>
|
||||
<text x="12" y="15" fill="#010101" fill-opacity=".3">${comment}</text>
|
||||
<text x="12" y="14">${comment}</text>
|
||||
<text x="70" y="15" fill="#010101" fill-opacity=".3">${num}</text>
|
||||
<text x="70" y="14">${num}</text>
|
||||
</g>
|
||||
</svg>
|
||||
EOF
|
||||
|
||||
22
sign.md
22
sign.md
@ -1,22 +0,0 @@
|
||||
|
||||
---
|
||||
|
||||
via：来源链接
|
||||
|
||||
作者：[作者名][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，
|
||||
[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:作者链接
|
||||
[1]:文内链接
|
||||
[2]:
|
||||
[3]:
|
||||
[4]:
|
||||
[5]:
|
||||
[6]:
|
||||
[7]:
|
||||
[8]:
|
||||
[9]:
|
||||
@ -1,110 +0,0 @@
|
||||
HankChow translating
|
||||
|
||||
3 areas to drive DevOps change
|
||||
======
|
||||
Driving large-scale organizational change is painful, but when it comes to DevOps, the payoff is worth the pain.
|
||||
|
||||
|
||||
Pain avoidance is a powerful motivator. Some studies hint that even [plants experience a type of pain][1] and take steps to defend themselves. Yet we have plenty of examples of humans enduring pain on purpose—exercise often hurts, but we still do it. When we believe the payoff is worth the pain, we'll endure almost anything.
|
||||
|
||||
The truth is that driving large-scale organizational change is painful. It hurts for those having to change their values and behaviors, it hurts for leadership, and it hurts for the people just trying to do their jobs. In the case of DevOps, though, I can tell you the pain is worth it.
|
||||
|
||||
I've seen firsthand how teams learn they must spend time improving their technical processes, take ownership of their automation pipelines, and become masters of their fate. They gain the tools they need to be successful.
|
||||
|
||||
![Improvements after DevOps transformation][3]
|
||||
|
||||
Image by Lee Eason. CC BY-SA 4.0
|
||||
|
||||
This chart shows the value of that change. In a company where I directed a DevOps transformation, its 60+ teams submitted more than 900 requests per month to release management. If you add up the time those tickets stayed open, it came to more than 350 days per month. What could your company do with an extra 350 person-days per month? In addition to the improvements seen above, they went from 100 to 9,000 deployments per month, a 24% decrease in high-severity bugs, happier engineers, and improved net promoter scores (NPS). The biggest NPS improvements link to the teams furthest along on their DevOps journey, as the [Puppet State of DevOps][4] report predicted. The bottom line is that investments into technical process improvement translate into better business outcomes.
|
||||
|
||||
DevOps leaders must focus on three main areas to drive this change: executives, culture, and team health.
|
||||
|
||||
### Executives
|
||||
|
||||
The bottom line is that investments into technical process improvement translate into better business outcomes.
|
||||
|
||||
The larger your organization, the greater the distance (and opportunities for misunderstanding) between business leadership and the individuals delivering services to your customers. To make things worse, the landscape of tools and practices in technology is changing at an accelerating rate. This makes it practically impossible for business leaders to understand on their own how transformations like DevOps or agile work.
|
||||
|
||||
The larger your organization, the greater the distance (and opportunities for misunderstanding) between business leadership and the individuals delivering services to your customers. To make things worse, the landscape of tools and practices in technology is changing at an accelerating rate. This makes it practically impossible for business leaders to understand on their own how transformations like DevOps or agile work.
|
||||
|
||||
DevOps leaders must help executives come along for the ride. Educating leaders gives them options when they're making decisions and makes it more likely they'll choose paths that help your company.
|
||||
|
||||
For example, let's say your executives believe DevOps is going to improve how you deploy your products into production, but they don't understand how. You've been working with a software team to help automate their deployment. When an executive hears about a deploy failure (and there will be failures), they will want to understand how it occurred. When they learn the software team did the deployment rather than the release management team, they may try to protect the business by decreeing all production releases must go through traditional change controls. You will lose credibility, and teams will be far less likely to trust you and accept further changes.
|
||||
|
||||
It takes longer to rebuild trust with executives and get their support after an incident than it would have taken to educate them in the first place. Put the time in upfront to build alignment, and it will pay off as you implement tactical changes.
|
||||
|
||||
Two pieces of advice when building that alignment:
|
||||
|
||||
* First, **don't ignore any constraints** they raise. If they have worries about contracts or security, make the heads of legal and security your new best friends. By partnering with them, you'll build their trust and avoid making costly mistakes.
|
||||
* Second, **use metrics to build a bridge** between what your delivery teams are doing and your executives' concerns. If the business has a goal to reduce customer churn, and you know from research that many customers leave because of unplanned downtime, reinforce that your teams are committed to tracking and improving Mean Time To Detection and Resolution (MTTD and MTTR). You can use those key metrics to show meaningful progress that teams and executives understand and get behind.
|
||||
|
||||
|
||||
|
||||
### Culture
|
||||
|
||||
DevOps is a culture of continuous improvement focused on code, build, deploy, and operational processes. Culture describes the organization's values and behaviors. Essentially, we're talking about changing how people behave, which is never easy.
|
||||
|
||||
I recommend reading [The Wolf in CIO's Clothing][5]. Spend time thinking about psychology and motivation. Read [Drive][6] or at least watch Daniel Pink's excellent [TED Talk][7]. Read [The Hero with a Thousand Faces][8] and learn to identify the different journeys everyone is on. If none of these things sound interesting, you are not the right person to drive change in your company. Otherwise, read on!
|
||||
|
||||
Essentially, we're talking about changing how people behave, which is never easy.
|
||||
|
||||
Most rational people behave according to their values. Most organizations don't have explicit values everyone understands and lives by. Therefore, you'll need to identify the organization's values that have led to the behaviors that have led to the current state. You also need to make sure you can tell the story about how those values came to be and how they led to where you are. When you tell that story, be careful not to demonize those values—they aren't immoral or evil. People did the best they could at the time, given what they knew and what resources they had.
|
||||
|
||||
Most rational people behave according to their values. Most organizations don't have explicit values everyone understands and lives by. Therefore, you'll need to identify the organization's values that have led to the behaviors that have led to the current state. You also need to make sure you can tell the story about how those values came to be and how they led to where you are. When you tell that story, be careful not to demonize those values—they aren't immoral or evil. People did the best they could at the time, given what they knew and what resources they had.
|
||||
|
||||
Explain that the company and its organizational goals are changing, and the team must alter its values. It's helpful to express this in terms of contrast. For example, your company may have historically valued cost savings above all else. That value is there for a reason—the company was cash-strapped. To get new products out, the infrastructure group had to tightly couple services by sharing database clusters or servers. Over time, those practices created a real mess that became hard to maintain. Simple changes started breaking things in unexpected ways. This led to tight change-control processes that were painful for delivery teams, so they stopped changing things.
|
||||
|
||||
Play that movie for five years, and you end up with little to no innovation, legacy technology, attraction and retention problems, and poor-quality products. You've grown the company, but you've hit a ceiling, and you can't continue to grow with those same values and behaviors. Now you must put engineering efficiency above cost saving. If one option will help teams maintain their service easier, but the other option is cheaper in the short term, you go with the first option.
|
||||
|
||||
You must tell this story again and again. Then you must celebrate any time a team expresses the new value through their behavior—even if they make a mistake. When a team has a deploy failure, congratulate them for taking the risk and encourage them to keep learning. Explain how their behavior is leading to the right outcome and support them. Over time, teams will see the message is real, and they'll feel safe altering their behavior.
|
||||
|
||||
### Team health
|
||||
|
||||
Have you ever been in a planning meeting and heard something like this: "We can't really estimate that story until John gets back from vacation. He's the only one who knows that area of the code well enough." Or: "We can't get this task done because it's got a cross-team dependency on network engineering, and the guy that set up the firewall is out sick." Or: "John knows that system best; if he estimated the story at a 3, then let's just go with that." When the team works on that story, who will most likely do the work? That's right, John will, and the cycle will continue.
|
||||
|
||||
For a long time, we've accepted that this is just the nature of software development. If we don't solve for it, we perpetuate the cycle.
|
||||
|
||||
Entropy will always drive teams naturally towards disorder and bad health. Our job as team members and leaders is to intentionally manage against that entropy and keep our teams healthy. Transformations like DevOps, agile, moving to the cloud, or refactoring a legacy application all amplify and accelerate that entropy. That's because transformations add new skills and expertise needed for the team to take on that new type of work.
|
||||
|
||||
Let's look at an example of a product team refactoring its legacy monolith. As usual, they build those new services in AWS. The legacy monolith was deployed to the data center, monitored, and backed up by IT. IT made sure the application's infosec requirements were met at the infrastructure layer. They conducted disaster recovery tests, patched the servers, and installed and configured required intrusion detection and antivirus agents. And they kept change control records, required for the annual audit process, of everything was done to the application's infrastructure.
|
||||
|
||||
I often see product teams make the fatal mistake of thinking IT is all cost and bottleneck. They're hungry to shed the skin of IT and use the public cloud, but they never stop to appreciate the critical services IT provides. Moving to the cloud means you implement these things differently; they don't go away. AWS is still a data center, and any team utilizing it accepts the related responsibilities.
|
||||
|
||||
In practice, this means product teams must learn how to do those IT services when they move to the cloud. So, when our fictional product team starts refactoring its legacy application and putting new services in in the cloud, it will need a vastly expanded skillset to be successful. Those skills don't magically appear—they're learned or hired—and team leaders and managers must actively manage the process.
|
||||
|
||||
I built [Tekata.io][9] because I couldn't find any tools to support me as I helped my teams evolve. Tekata is free and easy to use, but the tool is not as important as the people and process. Make sure you build continuous learning into your cadence and keep track of your team's weak spots. Those weak spots affect your ability to deliver, and filling them usually involves learning new things, so there's a wonderful synergy here. In fact, 76% of millennials think professional development opportunities are [one of the most important elements][10] of company culture.
|
||||
|
||||
### Proof is in the payoff
|
||||
|
||||
DevOps transformations involve altering the behavior, and therefore the culture, of your teams. That must be done with executive support and understanding. At the same time, those behavior changes mean learning new skills, and that process must also be managed carefully. But the payoff for pulling this off is more productive teams, happier and more engaged team members, higher quality products, and happier customers.
|
||||
|
||||
Lee Eason will present [Tales From A DevOps Transformation][11] at [All Things Open][12], October 21-23 in Raleigh, N.C.
|
||||
|
||||
Disclaimer: All opinions are statements in this article are exclusively those of Lee Eason and are not representative of Ipreo or IHS Markit.
|
||||
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/18/10/tales-devops-transformation
|
||||
|
||||
作者：[Lee Eason][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/leeeason
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://link.springer.com/article/10.1007%2Fs00442-014-2995-6
|
||||
[2]: /file/411061
|
||||
[3]: https://opensource.com/sites/default/files/uploads/devops-delays.png (Improvements after DevOps transformation)
|
||||
[4]: https://puppet.com/resources/whitepaper/state-of-devops-report
|
||||
[5]: https://www.gartner.com/en/publications/wolf-cio
|
||||
[6]: https://en.wikipedia.org/wiki/Drive:_The_Surprising_Truth_About_What_Motivates_Us
|
||||
[7]: https://www.ted.com/talks/dan_pink_on_motivation?language=en#t-2094
|
||||
[8]: https://en.wikipedia.org/wiki/The_Hero_with_a_Thousand_Faces
|
||||
[9]: https://tekata.io/
|
||||
[10]: https://www.execu-search.com/~/media/Resources/pdf/2017_Hiring_Outlook_eBook
|
||||
[11]: https://allthingsopen.org/talk/tales-from-a-devops-transformation/
|
||||
[12]: https://allthingsopen.org/
|
||||
@ -1,3 +1,5 @@
|
||||
Northurland Translating
|
||||
|
||||
How Lisp Became God's Own Programming Language
|
||||
======
|
||||
When programmers discuss the relative merits of different programming languages, they often talk about them in prosaic terms as if they were so many tools in a tool belt—one might be more appropriate for systems programming, another might be more appropriate for gluing together other programs to accomplish some ad hoc task. This is as it should be. Languages have different strengths and claiming that a language is better than other languages without reference to a specific use case only invites an unproductive and vitriolic debate.
|
||||
|
||||
@ -0,0 +1,60 @@
|
||||
5 tips for facilitators of agile meetings
|
||||
======
|
||||
Boost your team's productivity and motivation with these agile principles.
|
||||
|
||||
|
||||
|
||||
As Agile practitioner, I often hear that the best way to have business meetings is to avoid more meetings, or to cancel them altogether.
|
||||
|
||||
Do your meetings fail to keep attendees engaged or run longer than they should? Perhaps you have mixed feelings about participating in meetings—but don't want to be excluded?
|
||||
|
||||
If all this sounds familiar, read on.
|
||||
|
||||
### How do we fix meetings?
|
||||
|
||||
To succeed in this role, you must understand that agile is not something that you do, but something that you can become.
|
||||
|
||||
Meetings are an integral part of work culture, so improving them can bring important benefits. But improving how meetings are structured requires a change in how the entire organization is led and managed. This is where the agile mindset comes into play.
|
||||
|
||||
An agile mindset is an _attitude that equates failure and problems with opportunities for learning, and a belief that we can all improve over time._ Meetings can bring great value to an organization, as long as they are not pointless. The best way to eliminate pointless meetings is to have a meeting facilitator with an agile mindset. The key attribute of agile-driven facilitation is to focus on problem-solving.
|
||||
|
||||
Agile meeting facilitators confronting a complex problem start by breaking the meeting agenda down into modules. They also place more value on adapting to change than sticking to a plan. They work with meeting attendees to develop a solution based on feedback loops. This assures audience engagement and makes the meetings productive. The result is an integrated, agreed-upon solution that comprises a set of coherent action items aligned on a goal
|
||||
|
||||
### What are the skills of an agile meeting facilitator?
|
||||
|
||||
An agile meeting facilitator is able to quickly adapt to changing circumstances. He or she integrates all stakeholders and encourages them to share knowledge and skills.
|
||||
|
||||
To succeed in this role, you must understand that agile is not something that you do, but something that you can become. As the [Manifesto for Agile Software Development][1] notes, tools and processes are important, but it is more important to have competent people working together effectively.
|
||||
|
||||
### 5 tips for agile meeting facilitation
|
||||
|
||||
1. **Start with the problem in mind.** Identify the purpose of the meeting and narrow the agenda items to those that are most important. Stay tuned in and focused.
|
||||
|
||||
2. **Make sure that a senior leader doesn’t run the meeting.** Many senior leaders tend to create an environment in which the team expects to be told what to do. Instead, create an environment in which diverse ideas are the norm. Encourage open discussion in which leaders share where—but not how—innovation is needed. This reduces the layer of control and approval, increases the time focused on decision-making, and boosts the team’s motivation.
|
||||
|
||||
3. **Identify bottlenecks early.** Bureaucratic procedures or lack of collaboration between team members leads to meeting meltdowns and poor results. Anticipate how things might go wrong and be prepared to offer suggestions, not dictate solutions.
|
||||
|
||||
4. **Show, don’t tell.** Share the meeting goals and create the meeting agenda in advance. Allow time to adjust the agenda items and their order to achieve the best flow. Make sure that the meeting’s agenda is clear and visible to all attendees.
|
||||
|
||||
5. **Know when to wait.** Map out a clear timeline for the meeting and help keep the meeting on track. Understand when you should allow an item to go long versus when you should table a discussion. This will go a long way toward helping you stay on track.
|
||||
|
||||
|
||||
|
||||
|
||||
The ultimate goal is to create a work environment that encourages contribution and empowers the team. Improving how meetings are run will help your organization transition from a traditional hierarchy to a more agile enterprise.
|
||||
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/18/10/agile-culture-5-tips-meeting-facilitators
|
||||
|
||||
作者：[Dominika Bula][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/dominika
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: http://agilemanifesto.org/
|
||||
@ -0,0 +1,74 @@
|
||||
Why it matters that Microsoft released old versions of MS-DOS as open source
|
||||
======
|
||||
|
||||
Microsoft's release of MS-DOS 1.25 and 2.0 on GitHub adopts an open source license that's compatible with GNU GPL.
|
||||
|
||||
|
||||
One open source software project I work on is the FreeDOS Project. It's a complete, free, DOS-compatible operating system that you can use to play classic DOS games, run legacy business software, or develop embedded systems. Any program that works on MS-DOS should also run on FreeDOS.
|
||||
|
||||
So I took notice when Microsoft recently released the source code to MS-DOS 1.25 and 2.0 via a [GitHub repository][1]. This is a huge step for Microsoft, and I’d like to briefly explain why it is significant.
|
||||
|
||||
### MS-DOS as open source software
|
||||
|
||||
Some open source fans may recall that this is not the first time Microsoft has officially released the MS-DOS source code. On March 25, 2014, Microsoft posted the source code to MS-DOS 1.1 and 2.0 via the [Computer History Museum][2]. Unfortunately, this source code was released under a “look but do not touch” license that limited what you could do with it. According to the license from the 2014 source code release, users were barred from re-using it in other projects and could use it “[solely for non-commercial research, experimentation, and educational purposes.][3]”
|
||||
|
||||
The museum license wasn’t friendly to open source software, and as a result, the MS-DOS source code was ignored. On the FreeDOS Project, we interpreted the “look but do not touch” license as a potential risk to FreeDOS, so we decided developers who had viewed the MS-DOS source code could not contribute to FreeDOS.
|
||||
|
||||
But Microsoft’s recent MS-DOS source code release represents a significant change. This MS-DOS source code uses the MIT License (also called the Expat License). Quoting Microsoft’s [LICENSE.md][4] file on GitHub:
|
||||
|
||||
> ## MS-DOS v1.25 and v2.0 Source Code
|
||||
>
|
||||
> Copyright © Microsoft Corporation.
|
||||
>
|
||||
> All rights reserved.
|
||||
>
|
||||
> MIT License.
|
||||
>
|
||||
> Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the Software), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
|
||||
>
|
||||
> The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
|
||||
>
|
||||
> THE SOFTWARE IS PROVIDED AS IS, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,TORT OR OTHERWISE, ARISING FROM OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
|
||||
|
||||
If that text looks familiar to you, it is because that’s the same text as the MIT License recognized by the [Open Source Initiative][5]. It’s also the same as the Expat License recognized by the [Free Software Foundation][6].
|
||||
|
||||
The Free Software Foundation (via GNU) says the Expat License is compatible with the [GNU General Public License][7]. Specifically, GNU describes the Expat License as “a lax, permissive non-copyleft free software license, compatible with the GNU GPL. It is sometimes ambiguously referred to as the MIT License.” Also according to GNU, when they say a license is [compatible with the GNU GPL][8], “you can combine code released under the other license [MIT/Expat License] with code released under the GNU GPL in one larger program.”
|
||||
|
||||
Microsoft’s use of the MIT/Expat License for the original MS-DOS source code is significant because the license is not only open source software but free software.
|
||||
|
||||
### What does it mean?
|
||||
|
||||
This is great, but there’s a practical side to the source code release. You might think, “If Microsoft has released the MS-DOS source code under a license compatible with the GNU GPL, will that help FreeDOS?”
|
||||
|
||||
Not really. Here's why: FreeDOS started from an original source code base, independent from MS-DOS. Certain functions and behaviors of MS-DOS were identified and documented in the comprehensive [Interrupt List by Ralf Brown][9], and we provided MS-DOS compatibility in FreeDOS by referencing the Interrupt List. But many significant fundamental technical differences remain between FreeDOS and MS-DOS. For example, FreeDOS uses a completely different memory structure and memory layout. You can’t simply forklift MS-DOS source code into FreeDOS and expect it to work. The code assumptions are quite different.
|
||||
|
||||
There’s also the simple matter that these are very old versions of MS-DOS. For example, MS-DOS 2.0 was the first version to support directories and redirection. But these versions of MS-DOS did not yet include more advanced features, including networking, CDROM support, and ’386 support such as EMM386. These features have been standard in FreeDOS for a long time.
|
||||
|
||||
So the MS-DOS source code release is interesting, but FreeDOS would not be able to reuse this code for any modern features anyway. FreeDOS has already surpassed these versions of MS-DOS in functionality and features.
|
||||
|
||||
### Congratulations
|
||||
|
||||
Still, it’s important to recognize the big step that Microsoft has taken in releasing these versions of MS-DOS as open source software. The new MS-DOS source code release on GitHub does away with the restrictive license from 2014 and adopts a recognized open source software license that is compatible with the GNU GPL. Congratulations to Microsoft for releasing MS-DOS 1.25 and 2.0 under an open source license!
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/18/10/microsoft-open-source-old-versions-ms-dos
|
||||
|
||||
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://github.com/Microsoft/MS-DOS
|
||||
[2]: http://www.computerhistory.org/press/ms-source-code.html
|
||||
[3]: http://www.computerhistory.org/atchm/microsoft-research-license-agreement-msdos-v1-1-v2-0/
|
||||
[4]: https://github.com/Microsoft/MS-DOS/blob/master/LICENSE.md
|
||||
[5]: https://opensource.org/licenses/MIT
|
||||
[6]: https://directory.fsf.org/wiki/License:Expat
|
||||
[7]: https://www.gnu.org/licenses/license-list.en.html#Expat
|
||||
[8]: https://www.gnu.org/licenses/gpl-faq.html#WhatDoesCompatMean
|
||||
[9]: http://www.cs.cmu.edu/~ralf/files.html
|
||||
@ -0,0 +1,158 @@
|
||||
The 5 Best Linux Distributions for Development
|
||||
============================================================
|
||||
|
||||
|
||||
Jack Wallen looks at some of the best LInux distributions for development efforts.[Creative Commons Zero][6]
|
||||
|
||||
When considering Linux, there are so many variables to take into account. What package manager do you wish to use? Do you prefer a modern or old-standard desktop interface? Is ease of use your priority? How flexible do you want your distribution? What task will the distribution serve?
|
||||
|
||||
It is that last question which should often be considered first. Is the distribution going to work as a desktop or a server? Will you be doing network or system audits? Or will you be developing? If you’ve spent much time considering Linux, you know that for every task there are several well-suited distributions. This certainly holds true for developers. Even though Linux, by design, is an ideal platform for developers, there are certain distributions that rise above the rest, to serve as great operating systems to serve developers.
|
||||
|
||||
I want to share what I consider to be some of the best distributions for your development efforts. Although each of these five distributions can be used for general purpose development (with maybe one exception), they each serve a specific purpose. You may or may not be surprised by the selections.
|
||||
|
||||
With that said, let’s get to the choices.
|
||||
|
||||
### Debian
|
||||
|
||||
The [Debian][14] distribution winds up on the top of many a Linux list. With good reason. Debian is that distribution from which so many are based. It is this reason why many developers choose Debian. When you develop a piece of software on Debian, chances are very good that package will also work on [Ubuntu][15], [Linux Mint][16], [Elementary OS][17], and a vast collection of other distributions.
|
||||
|
||||
Beyond that obvious answer, Debian also has a very large amount of applications available, by way of the default repositories (Figure 1).
|
||||
|
||||
|
||||
Figure 1: Available applications from the standard Debian repositories.[Used with permission][1]
|
||||
|
||||
To make matters even programmer-friendly, those applications (and their dependencies) are simple to install. Take, for instance, the build-essential package (which can be installed on any distribution derived from Debian). This package includes the likes of dkpg-dev, g++, gcc, hurd-dev, libc-dev, and make—all tools necessary for the development process. The build-essential package can be installed with the command sudo apt install build-essential.
|
||||
|
||||
There are hundreds of other developer-specific applications available from the standard repositories, tools such as:
|
||||
|
||||
* Autoconf—configure script builder
|
||||
|
||||
* Autoproject—creates a source package for a new program
|
||||
|
||||
* Bison—general purpose parser generator
|
||||
|
||||
* Bluefish—powerful GUI editor, targeted towards programmers
|
||||
|
||||
* Geany—lightweight IDE
|
||||
|
||||
* Kate—powerful text editor
|
||||
|
||||
* Eclipse—helps builders independently develop tools that integrate with other people’s tools
|
||||
|
||||
The list goes on and on.
|
||||
|
||||
Debian is also as rock-solid a distribution as you’ll find, so there’s very little concern you’ll lose precious work, by way of the desktop crashing. As a bonus, all programs included with Debian have met the [Debian Free Software Guidelines][18], which adheres to the following “social contract”:
|
||||
|
||||
* Debian will remain 100% free.
|
||||
|
||||
* We will give back to the free software community.
|
||||
|
||||
* We will not hide problems.
|
||||
|
||||
* Our priorities are our users and free software
|
||||
|
||||
* Works that do not meet our free software standards are included in a non-free archive.
|
||||
|
||||
Also, if you’re new to developing on Linux, Debian has a handy [Programming section in their user manual][19].
|
||||
|
||||
### openSUSE Tumbleweed
|
||||
|
||||
If you’re looking to develop with a cutting-edge, rolling release distribution, [openSUSE][20] offers one of the best in [Tumbleweed][21]. Not only will you be developing with the most up to date software available, you’ll be doing so with the help of openSUSE’s amazing administrator tools … of which includes YaST. If you’re not familiar with YaST (Yet another Setup Tool), it’s an incredibly powerful piece of software that allows you to manage the whole of the platform, from one convenient location. From within YaST, you can also install using RPM Groups. Open YaST, click on RPM Groups (software grouped together by purpose), and scroll down to the Development section to see the large amount of groups available for installation (Figure 2).
|
||||
|
||||
|
||||
|
||||
Figure 2: Installing package groups in openSUSE Tumbleweed.[Creative Commons Zero][2]
|
||||
|
||||
openSUSE also allows you to quickly install all the necessary devtools with the simple click of a weblink. Head over to the [rpmdevtools install site][22] and click the link for Tumbleweed. This will automatically add the necessary repository and install rpmdevtools.
|
||||
|
||||
By developing with a rolling release distribution, you know you’re working with the most recent releases of installed software.
|
||||
|
||||
### CentOS
|
||||
|
||||
Let’s face it, [Red Hat Enterprise Linux][23] (RHEL) is the de facto standard for enterprise businesses. If you’re looking to develop for that particular platform, and you can’t afford a RHEL license, you cannot go wrong with [CentOS][24]—which is, effectively, a community version of RHEL. You will find many of the packages found on CentOS to be the same as in RHEL—so once you’re familiar with developing on one, you’ll be fine on the other.
|
||||
|
||||
If you’re serious about developing on an enterprise-grade platform, you cannot go wrong starting with CentOS. And because CentOS is a server-specific distribution, you can more easily develop for a web-centric platform. Instead of developing your work and then migrating it to a server (hosted on a different machine), you can easily have CentOS setup to serve as an ideal host for both developing and testing.
|
||||
|
||||
Looking for software to meet your development needs? You only need open up the CentOS Application Installer, where you’ll find a Developer section that includes a dedicated sub-section for Integrated Development Environments (IDEs - Figure 3).
|
||||
|
||||
|
||||
Figure 3: Installing a powerful IDE is simple in CentOS.[Used with permission][3]
|
||||
|
||||
CentOS also includes Security Enhanced Linux (SELinux), which makes it easier for you to test your software’s ability to integrate with the same security platform found in RHEL. SELinux can often cause headaches for poorly designed software, so having it at the ready can be a real boon for ensuring your applications work on the likes of RHEL. If you’re not sure where to start with developing on CentOS 7, you can read through the [RHEL 7 Developer Guide][25].
|
||||
|
||||
### Raspbian
|
||||
|
||||
Let’s face it, embedded systems are all the rage. One easy means of working with such systems is via the Raspberry Pi—a tiny footprint computer that has become incredibly powerful and flexible. In fact, the Raspberry Pi has become the hardware used by DIYers all over the planet. Powering those devices is the [Raspbian][26] operating system. Raspbian includes tools like [BlueJ][27], [Geany][28], [Greenfoot][29], [Sense HAT Emulator][30], [Sonic Pi][31], and [Thonny Python IDE][32], [Python][33], and [Scratch][34], so you won’t want for the necessary development software. Raspbian also includes a user-friendly desktop UI (Figure 4), to make things even easier.
|
||||
|
||||
|
||||
Figure 4: The Raspbian main menu, showing pre-installed developer software.[Used with permission][4]
|
||||
|
||||
For anyone looking to develop for the Raspberry Pi platform, Raspbian is a must have. If you’d like to give Raspbian a go, without the Raspberry Pi hardware, you can always install it as a VirtualBox virtual machine, by way of the ISO image found [here][35].
|
||||
|
||||
### Pop!_OS
|
||||
|
||||
Don’t let the name full you, [System76][36]’s [Pop!_OS][37] entry into the world of operating systems is serious. And although what System76 has done to this Ubuntu derivative may not be readily obvious, it is something special.
|
||||
|
||||
The goal of System76 is to create an operating system specific to the developer, maker, and computer science professional. With a newly-designed GNOME theme, Pop!_OS is beautiful (Figure 5) and as highly functional as you would expect from both the hardware maker and desktop designers.
|
||||
|
||||
### [devel_5.jpg][11]
|
||||
|
||||
|
||||
Figure 5: The Pop!_OS Desktop.[Used with permission][5]
|
||||
|
||||
But what makes Pop!_OS special is the fact that it is being developed by a company dedicated to Linux hardware. This means, when you purchase a System76 laptop, desktop, or server, you know the operating system will work seamlessly with the hardware—on a level no other company can offer. I would predict that, with Pop!_OS, System76 will become the Apple of Linux.
|
||||
|
||||
### Time for work
|
||||
|
||||
In their own way, each of these distributions. You have a stable desktop (Debian), a cutting-edge desktop (openSUSE Tumbleweed), a server (CentOS), an embedded platform (Raspbian), and a distribution to seamless meld with hardware (Pop!_OS). With the exception of Raspbian, any one of these distributions would serve as an outstanding development platform. Get one installed and start working on your next project with confidence.
|
||||
|
||||
_Learn more about Linux through the free ["Introduction to Linux" ][13]course from The Linux Foundation and edX._
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://www.linux.com/blog/learn/intro-to-linux/2018/1/5-best-linux-distributions-development
|
||||
|
||||
作者：[JACK WALLEN ][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:https://www.linux.com/users/jlwallen
|
||||
[1]:https://www.linux.com/licenses/category/used-permission
|
||||
[2]:https://www.linux.com/licenses/category/creative-commons-zero
|
||||
[3]:https://www.linux.com/licenses/category/used-permission
|
||||
[4]:https://www.linux.com/licenses/category/used-permission
|
||||
[5]:https://www.linux.com/licenses/category/used-permission
|
||||
[6]:https://www.linux.com/licenses/category/creative-commons-zero
|
||||
[7]:https://www.linux.com/files/images/devel1jpg
|
||||
[8]:https://www.linux.com/files/images/devel2jpg
|
||||
[9]:https://www.linux.com/files/images/devel3jpg
|
||||
[10]:https://www.linux.com/files/images/devel4jpg
|
||||
[11]:https://www.linux.com/files/images/devel5jpg
|
||||
[12]:https://www.linux.com/files/images/king-penguins1920jpg
|
||||
[13]:https://training.linuxfoundation.org/linux-courses/system-administration-training/introduction-to-linux
|
||||
[14]:https://www.debian.org/
|
||||
[15]:https://www.ubuntu.com/
|
||||
[16]:https://linuxmint.com/
|
||||
[17]:https://elementary.io/
|
||||
[18]:https://www.debian.org/social_contract
|
||||
[19]:https://www.debian.org/doc/manuals/debian-reference/ch12.en.html
|
||||
[20]:https://www.opensuse.org/
|
||||
[21]:https://en.opensuse.org/Portal:Tumbleweed
|
||||
[22]:https://software.opensuse.org/download.html?project=devel%3Atools&package=rpmdevtools
|
||||
[23]:https://www.redhat.com/en/technologies/linux-platforms/enterprise-linux
|
||||
[24]:https://www.centos.org/
|
||||
[25]:https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/pdf/developer_guide/Red_Hat_Enterprise_Linux-7-Developer_Guide-en-US.pdf
|
||||
[26]:https://www.raspberrypi.org/downloads/raspbian/
|
||||
[27]:https://www.bluej.org/
|
||||
[28]:https://www.geany.org/
|
||||
[29]:https://www.greenfoot.org/
|
||||
[30]:https://www.raspberrypi.org/blog/sense-hat-emulator/
|
||||
[31]:http://sonic-pi.net/
|
||||
[32]:http://thonny.org/
|
||||
[33]:https://www.python.org/
|
||||
[34]:https://scratch.mit.edu/
|
||||
[35]:http://rpf.io/x86iso
|
||||
[36]:https://system76.com/
|
||||
[37]:https://system76.com/pop
|
||||
@ -1,135 +0,0 @@
|
||||
Getting started with Python for data science
|
||||
======
|
||||
|
||||
|
||||
|
||||
Whether you're a budding data science enthusiast with a math or computer science background or an expert in an unrelated field, the possibilities data science offers are within your reach. And you don't need expensive, highly specialized enterprise software—the open source tools discussed in this article are all you need to get started.
|
||||
|
||||
[Python][1], its machine-learning and data science libraries ([pandas][2], [Keras][3], [TensorFlow][4], [scikit-learn][5], [SciPy][6], [NumPy][7], etc.), and its extensive list of visualization libraries ([Matplotlib][8], [pyplot][9], [Plotly][10], etc.) are excellent FOSS tools for beginners and experts alike. Easy to learn, popular enough to offer community support, and armed with the latest emerging techniques and algorithms developed for data science, these comprise one of the best toolsets you can acquire when starting out.
|
||||
|
||||
Many of these Python libraries are built on top of each other (known as dependencies), and the basis is the [NumPy][7] library. Designed specifically for data science, NumPy is often used to store relevant portions of datasets in its ndarray datatype, which is a convenient datatype for storing records from relational tables as `cvs` files or in any other format, and vice-versa. It is particularly convenient when scikit functions are applied to multidimensional arrays. SQL is great for querying databases, but to perform complex and resource-intensive data science operations, storing data in ndarray boosts efficiency and speed (but make sure you have ample RAM when dealing with large datasets). When you get to using pandas for knowledge extraction and analysis, the almost seamless conversion between DataFrame datatype in pandas and ndarray in NumPy creates a powerful combination for extraction and compute-intensive operations, respectively.
|
||||
|
||||
For a quick demonstration, let’s fire up the Python shell and load an open dataset on crime statistics from the city of Baltimore in a pandas DataFrame variable, and view a portion of the loaded frame:
|
||||
```
|
||||
>>> import pandas as pd
|
||||
|
||||
>>> crime_stats = pd.read_csv('BPD_Arrests.csv')
|
||||
|
||||
>>> crime_stats.head()
|
||||
|
||||
```
|
||||
|
||||
|
||||
|
||||
We can now perform most of the queries on this pandas DataFrame that we can with SQL in databases. For instance, to get all the unique values of the "Description" attribute, the SQL query is:
|
||||
```
|
||||
$ SELECT unique(“Description”) from crime_stats;
|
||||
|
||||
```
|
||||
|
||||
This same query written for a pandas DataFrame looks like this:
|
||||
```
|
||||
>>> crime_stats['Description'].unique()
|
||||
|
||||
['COMMON ASSAULT' 'LARCENY' 'ROBBERY - STREET' 'AGG. ASSAULT'
|
||||
|
||||
'LARCENY FROM AUTO' 'HOMICIDE' 'BURGLARY' 'AUTO THEFT'
|
||||
|
||||
'ROBBERY - RESIDENCE' 'ROBBERY - COMMERCIAL' 'ROBBERY - CARJACKING'
|
||||
|
||||
'ASSAULT BY THREAT' 'SHOOTING' 'RAPE' 'ARSON']
|
||||
|
||||
```
|
||||
|
||||
which returns a NumPy array (ndarray):
|
||||
```
|
||||
>>> type(crime_stats['Description'].unique())
|
||||
|
||||
<class 'numpy.ndarray'>
|
||||
|
||||
```
|
||||
|
||||
Next let’s feed this data into a neural network to see how accurately it can predict the type of weapon used, given data such as the time the crime was committed, the type of crime, and the neighborhood in which it happened:
|
||||
```
|
||||
>>> from sklearn.neural_network import MLPClassifier
|
||||
|
||||
>>> import numpy as np
|
||||
|
||||
>>>
|
||||
|
||||
>>> prediction = crime_stats[[‘Weapon’]]
|
||||
|
||||
>>> predictors = crime_stats['CrimeTime', ‘CrimeCode’, ‘Neighborhood’]
|
||||
|
||||
>>>
|
||||
|
||||
>>> nn_model = MLPClassifier(solver='lbfgs', alpha=1e-5, hidden_layer_sizes=(5,
|
||||
|
||||
2), random_state=1)
|
||||
|
||||
>>>
|
||||
|
||||
>>>predict_weapon = nn_model.fit(prediction, predictors)
|
||||
|
||||
```
|
||||
|
||||
Now that the learning model is ready, we can perform several tests to determine its quality and reliability. For starters, let’s feed a training set data (the portion of the original dataset used to train the model and not included in creating the model):
|
||||
```
|
||||
>>> predict_weapon.predict(training_set_weapons)
|
||||
|
||||
array([4, 4, 4, ..., 0, 4, 4])
|
||||
|
||||
```
|
||||
|
||||
As you can see, it returns a list, with each number predicting the weapon for each of the records in the training set. We see numbers rather than weapon names, as most classification algorithms are optimized with numerical data. For categorical data, there are techniques that can reliably convert attributes into numerical representations. In this case, the technique used is Label Encoding, using the LabelEncoder function in the sklearn preprocessing library: `preprocessing.LabelEncoder()`. It has a function to transform and inverse transform data and their numerical representations. In this example, we can use the `inverse_transform` function of LabelEncoder() to see what Weapons 0 and 4 are:
|
||||
```
|
||||
>>> preprocessing.LabelEncoder().inverse_transform(encoded_weapons)
|
||||
|
||||
array(['HANDS', 'FIREARM', 'HANDS', ..., 'FIREARM', 'FIREARM', 'FIREARM']
|
||||
|
||||
```
|
||||
|
||||
This is fun to see, but to get an idea of how accurate this model is, let's calculate several scores as percentages:
|
||||
```
|
||||
>>> nn_model.score(X, y)
|
||||
|
||||
0.81999999999999995
|
||||
|
||||
```
|
||||
|
||||
This shows that our neural network model is ~82% accurate. That result seems impressive, but it is important to check its effectiveness when used on a different crime dataset. There are other tests, like correlations, confusion, matrices, etc., to do this. Although our model has high accuracy, it is not very useful for general crime datasets as this particular dataset has a disproportionate number of rows that list ‘FIREARM’ as the weapon used. Unless it is re-trained, our classifier is most likely to predict ‘FIREARM’, even if the input dataset has a different distribution.
|
||||
|
||||
It is important to clean the data and remove outliers and aberrations before we classify it. The better the preprocessing, the better the accuracy of our insights. Also, feeding the model/classifier with too much data to get higher accuracy (generally over ~90%) is a bad idea because it looks accurate but is not useful due to [overfitting][11].
|
||||
|
||||
[Jupyter notebooks][12] are a great interactive alternative to the command line. While the CLI is fine for most things, Jupyter shines when you want to run snippets on the go to generate visualizations. It also formats data better than the terminal.
|
||||
|
||||
[This article][13] has a list of some of the best free resources for machine learning, but plenty of additional guidance and tutorials are available. You will also find many open datasets available to use, based on your interests and inclinations. As a starting point, the datasets maintained by [Kaggle][14], and those available at state government websites are excellent resources.
|
||||
|
||||
Payal Singh will be presenting at SCaLE16x this year, March 8-11 in Pasadena, California. To attend and get 50% of your ticket, [register][15] using promo code **OSDC**
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/18/3/getting-started-data-science
|
||||
|
||||
作者：[Payal Singh][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:https://opensource.com/users/payalsingh
|
||||
[1]:https://www.python.org/
|
||||
[2]:https://pandas.pydata.org/
|
||||
[3]:https://keras.io/
|
||||
[4]:https://www.tensorflow.org/
|
||||
[5]:http://scikit-learn.org/stable/
|
||||
[6]:https://www.scipy.org/
|
||||
[7]:http://www.numpy.org/
|
||||
[8]:https://matplotlib.org/
|
||||
[9]:https://matplotlib.org/api/pyplot_api.html
|
||||
[10]:https://plot.ly/
|
||||
[11]:https://www.kdnuggets.com/2014/06/cardinal-sin-data-mining-data-science.html
|
||||
[12]:http://jupyter.org/
|
||||
[13]:https://machinelearningmastery.com/best-machine-learning-resources-for-getting-started/
|
||||
[14]:https://www.kaggle.com/
|
||||
[15]:https://register.socallinuxexpo.org/reg6/
|
||||
@ -1,166 +0,0 @@
|
||||
LuuMing translating
|
||||
Setting Up a Timer with systemd in Linux
|
||||
======
|
||||
|
||||
|
||||
|
||||
Previously, we saw how to enable and disable systemd services [by hand][1], [at boot time and on power down][2], [when a certain device is activated][3], and [when something changes in the filesystem][4].
|
||||
|
||||
Timers add yet another way of starting services, based on... well, time. Although similar to cron jobs, systemd timers are slightly more flexible. Let's see how they work.
|
||||
|
||||
### "Run when"
|
||||
|
||||
Let's expand the [Minetest][5] [service you set up][1] in [the first two articles of this series][2] as our first example on how to use timer units. If you haven't read those articles yet, you may want to go and give them a look now.
|
||||
|
||||
So you will "improve" your Minetest set up by creating a timer that will run the game's server 1 minute after boot up has finished instead of right away. The reason for this could be that, as you want your service to do other stuff, like send emails to the players telling them the game is available, you will want to make sure other services (like the network) are fully up and running before doing anything fancy.
|
||||
|
||||
Jumping in at the deep end, your _minetest.timer_ unit will look like this:
|
||||
```
|
||||
# minetest.timer
|
||||
[Unit]
|
||||
Description=Runs the minetest.service 1 minute after boot up
|
||||
|
||||
[Timer]
|
||||
OnBootSec=1 m
|
||||
Unit=minetest.service
|
||||
|
||||
[Install]
|
||||
WantedBy=basic.target
|
||||
|
||||
```
|
||||
|
||||
Not hard at all.
|
||||
|
||||
As usual, you have a `[Unit]` section with a description of what the unit does. Nothing new there. The `[Timer]` section is new, but it is pretty self-explanatory: it contains information on when the service will be triggered and the service to trigger. In this case, the `OnBootSec` is the directive you need to tell systemd to run the service after boot has finished.
|
||||
|
||||
Other directives you could use are:
|
||||
|
||||
* `OnActiveSec=`, which tells systemd how long to wait after the timer itself is activated before starting the service.
|
||||
* `OnStartupSec=`, on the other hand, tells systemd how long to wait after systemd was started before starting the service.
|
||||
* `OnUnitActiveSec=` tells systemd how long to wait after the service the timer is activating was last activated.
|
||||
* `OnUnitInactiveSec=` tells systemd how long to wait after the service the timer is activating was last deactivated.
|
||||
|
||||
|
||||
|
||||
Continuing down the _minetest.timer_ unit, the `basic.target` is usually used as a synchronization point for late boot services. This means it makes _minetest.timer_ wait until local mount points and swap devices are mounted, sockets, timers, path units and other basic initialization processes are running before letting _minetest.timer_ start. As we explained in [the second article on systemd units][2], _targets_ are like the old run levels and can be used to put your machine into one state or another, or, like here, to tell your service to wait until a certain state has been reached.
|
||||
|
||||
The _minetest.service_ you developed in the first two articles [ended up][2] looking like this:
|
||||
```
|
||||
# minetest.service
|
||||
[Unit]
|
||||
Description= Minetest server
|
||||
Documentation= https://wiki.minetest.net/Main_Page
|
||||
|
||||
[Service]
|
||||
Type= simple
|
||||
User=
|
||||
|
||||
ExecStart= /usr/games/minetest --server
|
||||
ExecStartPost= /home//bin/mtsendmail.sh "Ready to rumble?" "Minetest Starting up"
|
||||
|
||||
TimeoutStopSec= 180
|
||||
ExecStop= /home//bin/mtsendmail.sh "Off to bed. Nightie night!" "Minetest Stopping in 2 minutes"
|
||||
ExecStop= /bin/sleep 120
|
||||
ExecStop= /bin/kill -2 $MAINPID
|
||||
|
||||
[Install]
|
||||
WantedBy= multi-user.target
|
||||
|
||||
```
|
||||
|
||||
There’s nothing you need to change here. But you do have to change _mtsendmail.sh_ (your email sending script) from this:
|
||||
```
|
||||
#!/bin/bash
|
||||
# mtsendmail
|
||||
sleep 20
|
||||
echo $1 | mutt -F /home/<username>/.muttrc -s "$2" my_minetest@mailing_list.com
|
||||
sleep 10
|
||||
|
||||
```
|
||||
|
||||
to this:
|
||||
```
|
||||
#!/bin/bash
|
||||
# mtsendmail.sh
|
||||
echo $1 | mutt -F /home/paul/.muttrc -s "$2" pbrown@mykolab.com
|
||||
|
||||
```
|
||||
|
||||
What you are doing is stripping out those hacky pauses in the Bash script. Systemd does the waiting now.
|
||||
|
||||
### Making it work
|
||||
|
||||
To make sure things work, disable _minetest.service_ :
|
||||
```
|
||||
sudo systemctl disable minetest
|
||||
|
||||
```
|
||||
|
||||
so it doesn't get started when the system starts; and, instead, enable _minetest.timer_ :
|
||||
```
|
||||
sudo systemctl enable minetest.timer
|
||||
|
||||
```
|
||||
|
||||
Now you can reboot you server machine and, when you run `sudo journalctl -u minetest.*` you will see how, first the _minetest.timer_ unit gets executed and then the _minetest.service_ starts up after a minute... more or less.
|
||||
|
||||
![minetest timer][7]
|
||||
|
||||
Figure 1: The minetest.service gets started one minute after the minetest.timer... more or less.
|
||||
|
||||
[Used with permission][8]
|
||||
|
||||
### A Matter of Time
|
||||
|
||||
A couple of clarifications about why the _minetest.timer_ entry in the systemd's Journal shows its start time as 09:08:33, while the _minetest.service_ starts at 09:09:18, that is less than a minute later: First, remember we said that the `OnBootSec=` directive calculates when to start a service from when boot is complete. By the time _minetest.timer_ comes along, boot has finished a few seconds ago.
|
||||
|
||||
The other thing is that systemd gives itself a margin of error (by default, 1 minute) to run stuff. This helps distribute the load when several resource-intensive processes are running at the same time: by giving itself a minute, systemd can wait for some processes to power down. This also means that _minetest.service_ will start somewhere between the 1 minute and 2 minute mark after boot is completed, but when exactly within that range is anybody's guess.
|
||||
|
||||
For the record, [you can change the margin of error with `AccuracySec=` directive][9].
|
||||
|
||||
Another thing you can do is check when all the timers on your system are scheduled to run or the last time the ran:
|
||||
```
|
||||
systemctl list-timers --all
|
||||
|
||||
```
|
||||
|
||||
![check timer][11]
|
||||
|
||||
Figure 2: Check when your timers are scheduled to fire or when they fired last.
|
||||
|
||||
[Used with permission][8]
|
||||
|
||||
The final thing to take into consideration is the format you should use to express the periods of time. Systemd is very flexible in that respect: `2 h`, `2 hours` or `2hr` will all work to express a 2 hour delay. For seconds, you can use `seconds`, `second`, `sec`, and `s`, the same way as for minutes you can use `minutes`, `minute`, `min`, and `m`. You can see a full list of time units systemd understands by checking `man systemd.time`.
|
||||
|
||||
### Next Time
|
||||
|
||||
You'll see how to use calendar dates and times to run services at regular intervals and how to combine timers and device units to run services at defined point in time after you plug in some hardware.
|
||||
|
||||
See you then!
|
||||
|
||||
Learn more about Linux through the free ["Introduction to Linux" ][12]course from The Linux Foundation and edX.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://www.linux.com/blog/learn/intro-to-linux/2018/7/setting-timer-systemd-linux
|
||||
|
||||
作者：[Paul Brown][a]
|
||||
选题：[lujun9972](https://github.com/lujun9972)
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:https://www.linux.com/users/bro66
|
||||
[1]:https://www.linux.com/blog/learn/intro-to-linux/2018/5/writing-systemd-services-fun-and-profit
|
||||
[2]:https://www.linux.com/blog/learn/2018/5/systemd-services-beyond-starting-and-stopping
|
||||
[3]:https://www.linux.com/blog/intro-to-linux/2018/6/systemd-services-reacting-change
|
||||
[4]:https://www.linux.com/blog/learn/intro-to-linux/2018/6/systemd-services-monitoring-files-and-directories
|
||||
[5]:https://www.minetest.net/
|
||||
[6]:/files/images/minetest-timer-1png
|
||||
[7]:https://www.linux.com/sites/lcom/files/styles/rendered_file/public/minetest-timer-1.png?itok=TG0xJvYM (minetest timer)
|
||||
[8]:/licenses/category/used-permission
|
||||
[9]:https://www.freedesktop.org/software/systemd/man/systemd.timer.html#AccuracySec=
|
||||
[10]:/files/images/minetest-timer-2png
|
||||
[11]:https://www.linux.com/sites/lcom/files/styles/rendered_file/public/minetest-timer-2.png?itok=pYxyVx8- (check timer)
|
||||
[12]:https://training.linuxfoundation.org/linux-courses/system-administration-training/introduction-to-linux
|
||||
@ -1,96 +0,0 @@
|
||||
Translateing By DavidChenLiang
|
||||
Top Linux developers' recommended programming books
|
||||
======
|
||||
Without question, Linux was created by brilliant programmers who employed good computer science knowledge. Let the Linux programmers whose names you know share the books that got them started and the technology references they recommend for today's developers. How many of them have you read?
|
||||
|
||||
Linux is, arguably, the operating system of the 21st century. While Linus Torvalds made a lot of good business and community decisions in building the open source community, the primary reason networking professionals and developers adopted Linux is the quality of its code and its usefulness. While Torvalds is a programming genius, he has been assisted by many other brilliant developers.
|
||||
|
||||
I asked Torvalds and other top Linux developers which books helped them on their road to programming excellence. This is what they told me.
|
||||
|
||||
### By shining C
|
||||
|
||||
Linux was developed in the 1990s, as were other fundamental open source applications. As a result, the tools and languages the developers used reflected the times, which meant a lot of C programming language. While [C is no longer as popular][1], for many established developers it was their first serious language, which is reflected in their choice of influential books.
|
||||
|
||||
“You shouldn't start programming with the languages I started with or the way I did,” says Torvalds. He started with BASIC, moved on to machine code (“not even assembly language, actual ‘just numbers’ machine code,” he explains), then assembly language and C.
|
||||
|
||||
“None of those languages are what anybody should begin with anymore,” Torvalds says. “Some of them make no sense at all today (BASIC and machine code). And while C is still a major language, I don't think you should begin with it.”
|
||||
|
||||
It's not that he dislikes C. After all, Linux is written in [GNU C][2]. "I still think C is a great language with a pretty simple syntax and is very good for many things,” he says. But the effort to get started with it is much too high for it to be a good beginner language by today's standards. “I suspect you'd just get frustrated. Going from your first ‘Hello World’ program to something you might actually use is just too big of a step."
|
||||
|
||||
From that era, the only programming book that stood out for Torvalds is Brian W. Kernighan and Dennis M. Ritchie's [C Programming Language][3], known in serious programming circles as K&R. “It was small, clear, concise,” he explains. “But you need to already have a programming background to appreciate it."
|
||||
|
||||
Torvalds is not the only open source developer to recommend K&R. Several others cite their well-thumbed copies as influential references, among them Wim Coekaerts, senior vice president for Linux and virtualization development at Oracle; Linux developer Alan Cox; Google Cloud CTO Brian Stevens; and Pete Graner, Canonical's vice president of technical operations.
|
||||
|
||||
If you want to tackle C today, Jeremy Allison, co-founder of Samba, recommends [21st Century C][4]. Then, Allison suggests, follow it up with the older but still thorough [Expert C Programming][5] as well as the 20-year-old [Programming with POSIX Threads][6].
|
||||
|
||||
### If not C, what?
|
||||
|
||||
Linux developers’ recommendations for current programming books naturally are an offshoot of the tools and languages they think are most suitable for today’s development projects. They also reflect the developers’ personal preferences. For example, Allison thinks young developers would be well served by learning Go with the help of [The Go Programming Language][7] and Rust with [Programming Rust][8].
|
||||
|
||||
But it may make sense to think beyond programming languages (and thus books to teach you their techniques). To do something meaningful today, “start from some environment with a toolkit that does 99 percent of the obscure details for you, so that you can script things around it," Torvalds recommends.
|
||||
|
||||
"Honestly, the language itself isn't nearly as important as the infrastructure around it,” he continues. “Maybe you'd start with Java or Kotlin—not because of those languages per se, but because you want to write an app for your phone and the Android SDK ends up making those better choices. Or, maybe you're interested in games, so you start with one of the game engines, which often have some scripting language of their own."
|
||||
|
||||
That infrastructure includes programming books specific to the operating system itself. Graner followed K&R by reading W. Richard Stevens' [Unix Network Programming][10] books. In particular, Stevens' [TCP/IP Illustrated, Volume 1: The Protocols][11] is considered still relevant even though it's almost 30 years old. Because Linux development is largely [relevant to networking infrastructure][12], Graner also recommends the many O’Reilly books on [Sendmail][13], [Bash][14], [DNS][15], and [IMAP/POP][16].
|
||||
|
||||
Coekaerts is also fond of Maurice Bach's [The Design of the Unix Operating System][17]. So is James Bottomley, a Linux kernel developer who used Bach's tome to pull apart Linux when the OS was new.
|
||||
|
||||
### Design knowledge never goes stale
|
||||
|
||||
But even that may be too tech-specific. "All developers should start with design before syntax,” says Stevens. “[The Design of Everyday Things][18] is one of my favorites.”
|
||||
|
||||
Coekaerts likes Kernighan and Rob Pike's [The Practice of Programming][19]. The design-practice book wasn't around when Coekaerts was in school, “but I recommend it to everyone to read," he says.
|
||||
|
||||
Whenever you ask serious long-term developers about their favorite books, sooner or later someone's going to mention Donald Knuth’s [The Art of Computer Programming][20]. Dirk Hohndel, VMware's chief open source officer, considers it timeless though, admittedly, “not necessarily super-useful today."
|
||||
|
||||
### Read code. Lots of code
|
||||
|
||||
While programming books can teach you a lot, don’t miss another opportunity that is unique to the open source community: [reading the code][21]. There are untold megabytes of examples of how to solve a given programming problem—and how you can get in trouble, too. Stevens says his No. 1 “book” for honing programming skills is having access to the Unix source code.
|
||||
|
||||
Don’t overlook the opportunity to learn in person, too. “I learned BASIC by being in a computer club with other people all learning together,” says Cox. “In my opinion, that is still by far the best way to learn." He learned machine code from [Mastering Machine Code on Your ZX81][22] and the Honeywell L66 B compiler manuals, but working with other developers made a big difference.
|
||||
|
||||
“I still think the way to learn best remains to be with a group of people having fun and trying to solve a problem you care about together,” says Cox. “It doesn't matter if you are 5 or 55."
|
||||
|
||||
What struck me the most about these recommendations is how often the top Linux developers started at a low level—not just C or assembly language but machine language. Obviously, it’s been very useful in helping developers understand how computing works at a very basic level.
|
||||
|
||||
So, ready to give hard-core Linux development a try? Greg Kroah-Hartman, the Linux stable branch kernel maintainer, recommends Steve Oualline's [Practical C Programming][23] and Samuel Harbison and Guy Steele's [C: A Reference Manual][24]. Next, read "[HOWTO do Linux kernel development][25]." Then, says Kroah-Hartman, you'll be ready to start.
|
||||
|
||||
In the meantime, study hard, program lots, and best of luck to you in following the footsteps of Linux's top programmers.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://www.hpe.com/us/en/insights/articles/top-linux-developers-recommended-programming-books-1808.html
|
||||
|
||||
作者：[Steven Vaughan-Nichols][a]
|
||||
选题：[lujun9972](https://github.com/lujun9972)
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:https://www.hpe.com/us/en/insights/contributors/steven-j-vaughan-nichols.html
|
||||
[1]:https://www.codingdojo.com/blog/7-most-in-demand-programming-languages-of-2018/
|
||||
[2]:https://www.gnu.org/software/gnu-c-manual/
|
||||
[3]:https://amzn.to/2nhyjEO
|
||||
[4]:https://amzn.to/2vsL8k9
|
||||
[5]:https://amzn.to/2KBbWn9
|
||||
[6]:https://amzn.to/2M0rfeR
|
||||
[7]:https://amzn.to/2nhyrnMe
|
||||
[8]:http://shop.oreilly.com/product/0636920040385.do
|
||||
[9]:https://www.hpe.com/us/en/resources/storage/containers-for-dummies.html?jumpid=in_510384402_linuxbooks_containerebook0818
|
||||
[10]:https://amzn.to/2MfpbyC
|
||||
[11]:https://amzn.to/2MpgrTn
|
||||
[12]:https://www.hpe.com/us/en/insights/articles/how-to-see-whats-going-on-with-your-linux-system-right-now-1807.html
|
||||
[13]:http://shop.oreilly.com/product/9780596510299.do
|
||||
[14]:http://shop.oreilly.com/product/9780596009656.do
|
||||
[15]:http://shop.oreilly.com/product/9780596100575.do
|
||||
[16]:http://shop.oreilly.com/product/9780596000127.do
|
||||
[17]:https://amzn.to/2vsCJgF
|
||||
[18]:https://amzn.to/2APzt3Z
|
||||
[19]:https://www.amazon.com/Practice-Programming-Addison-Wesley-Professional-Computing/dp/020161586X/ref=as_li_ss_tl?ie=UTF8&linkCode=sl1&tag=thegroovycorpora&linkId=e6bbdb1ca2182487069bf9089fc8107e&language=en_US
|
||||
[20]:https://amzn.to/2OknFsJ
|
||||
[21]:https://amzn.to/2M4VVL3
|
||||
[22]:https://amzn.to/2OjccJA
|
||||
[23]:http://shop.oreilly.com/product/9781565923065.do
|
||||
[24]:https://amzn.to/2OjzgrT
|
||||
[25]:https://www.kernel.org/doc/html/v4.16/process/howto.html
|
||||
@ -1,3 +1,5 @@
|
||||
translating by Flowsnow
|
||||
|
||||
Quiet log noise with Python and machine learning
|
||||
======
|
||||
|
||||
|
||||
@ -1,3 +1,5 @@
|
||||
fuowang 翻译中
|
||||
|
||||
4 open source invoicing tools for small businesses
|
||||
======
|
||||
Manage your billing and get paid with easy-to-use, web-based invoicing software.
|
||||
|
||||
@ -1,3 +1,5 @@
|
||||
HackChow translating
|
||||
|
||||
5 alerting and visualization tools for sysadmins
|
||||
======
|
||||
These open source tools help users understand system behavior and output, and provide alerts for potential problems.
|
||||
|
||||
@ -1,3 +1,6 @@
|
||||
Translating by MjSeven
|
||||
|
||||
|
||||
Kali Linux: What You Must Know Before Using it – FOSS Post
|
||||
======
|
||||
|
||||
|
||||
@ -1,80 +0,0 @@
|
||||
Browsing the web with Min, a minimalist open source web browser
|
||||
======
|
||||
Not every web browser needs to carry every single feature. Min puts a minimalist spin on the everyday web browser.
|
||||
|
||||
|
||||
Does the world need another web browser? Even though the days of having a multiplicity of browsers to choose from are long gone, there still are folks out there developing new applications that help us use the web.
|
||||
|
||||
One of those new-fangled browsers is [Min][1]. As its name suggests (well, suggests to me, anyway), Min is a minimalist browser. That doesn't mean it's deficient in any significant way, and its open source, Apache 2.0 license piques my interest.
|
||||
|
||||
But is Min worth a look? Let's find out.
|
||||
|
||||
### Getting going
|
||||
|
||||
Min is one of many applications written using a development framework called [Electron][2]. (It's the same framework that brought us the [Atom text editor][3].) You can [get installers][4] for Linux, MacOS, and Windows. You can also grab the [source code from GitHub][5] and compile it if you're inclined.
|
||||
|
||||
I run Manjaro Linux, and there isn't an installer for that distro. Luckily, I was able to install Min from Manjaro's package manager.
|
||||
|
||||
Once that was done, I fired up Min by pressing Alt+F2, typing **min** in the run-application box, and pressing Enter, and I was ready to go.
|
||||
|
||||
|
||||
|
||||
Min is billed as a smarter, faster web browser. It definitely is fast—at the risk of drawing the ire of denizens of certain places on the web, I'll say that it starts faster than Firefox and Chrome on the laptops with which I tried it.
|
||||
|
||||
Browsing with Min is like browsing with Firefox or Chrome. Type a URL in the address bar, press Enter, and away you go.
|
||||
|
||||
### Min's features
|
||||
|
||||
While Min doesn't pack everything you'd find in browsers like Firefox or Chrome, it doesn't do too badly.
|
||||
|
||||
Like any other browser these days, Min supports multiple tabs. It also has a feature called Tasks, which lets you group your open tabs.
|
||||
|
||||
Min's default search engine is [DuckDuckGo][6]. I really like that touch because DuckDuckGo is one of my search engines of choice. If DuckDuckGo isn't your thing, you can set another search engine as the default in Min's preferences.
|
||||
|
||||
Instead of using tools like AdBlock to filter out content you don't want, Min has a built-in ad blocker. It uses the [EasyList filters][7], which were created for AdBlock. You can block scripts and images, and Min also has a built-in tracking blocker.
|
||||
|
||||
Like Firefox, Min has a reading mode called Reading List. Flipping the Reading List switch (well, clicking the icon in the address bar) removes most of the cruft from a page so you can focus on the words you're reading. Pages stay in the Reading List for 30 days.
|
||||
|
||||
|
||||
|
||||
Speaking of focus, Min also has a Focus Mode that hides and prevents you from opening other tabs. So, if you're working in a web application, you'll need to click a few times if you feel like procrastinating.
|
||||
|
||||
Of course, Min has a number of keyboard shortcuts that can make using it a lot faster. You can find a reference for those shortcuts [on GitHub][8]. You can also change a number of them in Min's preferences.
|
||||
|
||||
I was pleasantly surprised to find Min can play videos on YouTube, Vimeo, Dailymotion, and similar sites. I also played sample tracks at music retailer 7Digital. I didn't try playing music on popular sites like Spotify or Last.fm (because I don't have accounts with them).
|
||||
|
||||
|
||||
|
||||
### What's not there
|
||||
|
||||
The features that Min doesn't pack are as noticeable as the ones it does. There doesn't seem to be a way to bookmark sites. You either have to rely on Min's search history to find your favorite links, or you'll have to rely on a bookmarking service.
|
||||
|
||||
On top of that, Min doesn't support plugins. That's not a deal breaker for me—not having plugins is undoubtedly one of the reasons the browser starts and runs so quickly. I know a number of people who are … well, I wouldn't go so far to say junkies, but they really like their plugins. Min wouldn't cut it for them.
|
||||
|
||||
### Final thoughts
|
||||
|
||||
Min isn't a bad browser. It's light and fast enough to appeal to the minimalists out there. That said, it lacks features that hardcore web browser users clamor for.
|
||||
|
||||
If you want a zippy browser that isn't weighed down by all the features of so-called modern web browsers, I suggest giving Min a serious look.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/18/10/min-web-browser
|
||||
|
||||
作者：[Scott Nesbitt][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/scottnesbitt
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://minbrowser.github.io/min/
|
||||
[2]: http://electron.atom.io/apps/
|
||||
[3]: https://opensource.com/article/17/5/atom-text-editor-packages-writers
|
||||
[4]: https://github.com/minbrowser/min/releases/
|
||||
[5]: https://github.com/minbrowser/min
|
||||
[6]: http://duckduckgo.com
|
||||
[7]: https://easylist.to/
|
||||
[8]: https://github.com/minbrowser/min/wiki
|
||||
@ -1,3 +1,4 @@
|
||||
(translating by runningwater)
|
||||
How To Determine Which System Manager Is Running On Linux System
|
||||
======
|
||||
We all are heard about this word many times but only few of us know what is this exactly. We will show you how to identify the system manager.
|
||||
@ -164,7 +165,7 @@ via: https://www.2daygeek.com/how-to-determine-which-init-system-manager-is-runn
|
||||
|
||||
作者：[Prakash Subramanian][a]
|
||||
选题：[lujun9972][b]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
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
|
||||
|
||||
@ -1,133 +0,0 @@
|
||||
Understanding Linux Links: Part 1
|
||||
======
|
||||
|
||||
|
||||
|
||||
Along with `cp` and `mv`, both of which we talked about at length in [the previous installment of this series][1], links are another way of putting files and directories where you want them to be. The advantage is that links let you have one file or directory show up in several places at the same time.
|
||||
|
||||
As noted previously, at the physical disk level, things like files and directories don't really exist. A filesystem conjures them up for our human convenience. But at the disk level, there is something called a _partition table_ , which lives at the beginning of every partition, and then the data scattered over the rest of the disk.
|
||||
|
||||
Although there are different types of partition tables, the ones at the beginning of a partition containing your data will map where each directory and file starts and ends. The partition table acts like an index: When you load a file from your disk, your operating system looks up the entry on the table and the table says where the file starts on the disk and where it finishes. The disk header moves to the start point, reads the data until it reaches the end point and, hey presto: here's your file.
|
||||
|
||||
### Hard Links
|
||||
|
||||
A hard link is simply an entry in the partition table that points to an area on a disk that **has already been assigned to a file**. In other words, a hard link points to data that has already been indexed by another entry. Let's see how this works.
|
||||
|
||||
Open a terminal, create a directory for tests and move into it:
|
||||
|
||||
```
|
||||
mkdir test_dir
|
||||
cd test_dir
|
||||
```
|
||||
|
||||
Create a file by [touching][1] it:
|
||||
|
||||
```
|
||||
touch test.txt
|
||||
```
|
||||
|
||||
For extra excitement (?), open _test.txt_ in a text editor and add some a few words into it.
|
||||
|
||||
Now make a hard link by executing:
|
||||
|
||||
```
|
||||
ln test.txt hardlink_test.txt
|
||||
```
|
||||
|
||||
Run `ls`, and you'll see your directory now contains two files... Or so it would seem. As you read before, really what you are seeing is two names for the exact same file: _hardlink_test.txt_ contains the same content, has not filled any more space in the disk (try with a large file to test this), and shares the same inode as _test.txt_ :
|
||||
|
||||
```
|
||||
$ ls -li *test*
|
||||
16515846 -rw-r--r-- 2 paul paul 14 oct 12 09:50 hardlink_test.txt
|
||||
16515846 -rw-r--r-- 2 paul paul 14 oct 12 09:50 test.txt
|
||||
```
|
||||
|
||||
_ls_ 's `-i` option shows the _inode number_ of a file. The _inode_ is the chunk of information in the partition table that contains the location of the file or directory on the disk, the last time it was modified, and other data. If two files share the same inode, they are, to all practical effects, the same file, regardless of where they are located in the directory tree.
|
||||
|
||||
### Fluffy Links
|
||||
|
||||
Soft links, also known as _symlinks_ , are different: a soft link is really an independent file, it has its own inode and its own little slot on the disk. But it only contains a snippet of data that points the operating system to another file or directory.
|
||||
|
||||
You can create a soft link using `ln` with the `-s` option:
|
||||
|
||||
```
|
||||
ln -s test.txt softlink_test.txt
|
||||
```
|
||||
|
||||
This will create the soft link _softlink_test.txt_ to _test.txt_ in the current directory.
|
||||
|
||||
By running `ls -li` again, you can see the difference between the two different kinds of links:
|
||||
|
||||
```
|
||||
$ ls -li
|
||||
total 8
|
||||
16515846 -rw-r--r-- 2 paul paul 14 oct 12 09:50 hardlink_test.txt
|
||||
16515855 lrwxrwxrwx 1 paul paul 8 oct 12 09:50 softlink_test.txt -> test.txt
|
||||
16515846 -rw-r--r-- 2 paul paul 14 oct 12 09:50 test.txt
|
||||
```
|
||||
|
||||
_hardlink_test.txt_ and _test.txt_ contain some text and take up the same space *literally*. They also share the same inode number. Meanwhile, _softlink_test.txt_ occupies much less and has a different inode number, marking it as a different file altogether. Using the _ls_ 's `-l` option also shows the file or directory your soft link points to.
|
||||
|
||||
### Why Use Links?
|
||||
|
||||
They are good for **applications that come with their own environment**. It often happens that your Linux distro does not come with the latest version of an application you need. Take the case of the fabulous [Blender 3D][2] design software. Blender allows you to create 3D still images as well as animated films and who wouldn't to have that on their machine? The problem is that the current version of Blender is always at least one version ahead of that found in any distribution.
|
||||
|
||||
Fortunately, [Blender provides downloads][3] that run out of the box. These packages come, apart from with the program itself, a complex framework of libraries and dependencies that Blender needs to work. All these bits and piece come within their own hierarchy of directories.
|
||||
|
||||
Every time you want to run Blender, you could `cd` into the folder you downloaded it to and run:
|
||||
|
||||
```
|
||||
./blender
|
||||
```
|
||||
|
||||
But that is inconvenient. It would be better if you could run the `blender` command from anywhere in your file system, as well as from your desktop command launchers.
|
||||
|
||||
The way to do that is to link the _blender_ executable into a _bin/_ directory. On many systems, you can make the `blender` command available from anywhere in the file system by linking to it like this:
|
||||
|
||||
```
|
||||
ln -s /path/to/blender_directory/blender /home/<username>/bin
|
||||
```
|
||||
|
||||
Another case in which you will need links is for **software that needs outdated libraries**. If you list your _/usr/lib_ directory with `ls -l,` you will see a lot of soft-linked files fly by. Take a closer look, and you will see that the links usually have similar names to the original files they are linking to. You may see _libblah_ linking to _libblah.so.2_ , and then, you may even notice that _libblah.so.2_ links in turn to _libblah.so.2.1.0_ , the original file.
|
||||
|
||||
This is because applications often require older versions of alibrary than what is installed. The problem is that, even if the more modern versions are still compatible with the older versions (and usually they are), the program will bork if it doesn't find the version it is looking for. To solve this problem distributions often create links so that the picky application believes it has found the older version, when, in reality, it has only found a link and ends up using the more up to date version of the library.
|
||||
|
||||
Somewhat related is what happens with **programs you compile yourself from the source code**. Programs you compile yourself often end up installed under _/usr/local_ : the program itself ends up in _/usr/local/bin_ and it looks for the libraries it needs _/_ in the _/usr/local/lib_ directory. But say that your new program needs _libblah_ , but _libblah_ lives in _/usr/lib_ and that's where all your other programs look for it. You can link it to _/usr/local/lib_ by doing:
|
||||
|
||||
```
|
||||
ln -s /usr/lib/libblah /usr/local/lib
|
||||
```
|
||||
|
||||
Or, if you prefer, by `cd`ing into _/usr/local/lib_...
|
||||
|
||||
```
|
||||
cd /usr/local/lib
|
||||
```
|
||||
|
||||
... and then linking with:
|
||||
|
||||
```
|
||||
ln -s ../lib/libblah
|
||||
```
|
||||
|
||||
There are dozens more cases in which linking proves useful, and you will undoubtedly discover them as you become more proficient in using Linux, but these are the most common. Next time, we’ll look at some linking quirks you need to be aware of.
|
||||
|
||||
Learn more about Linux through the free ["Introduction to Linux" ][4]course from The Linux Foundation and edX.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://www.linux.com/blog/intro-to-linux/2018/10/linux-links-part-1
|
||||
|
||||
作者：[Paul Brown][a]
|
||||
选题：[lujun9972][b]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]: https://www.linux.com/users/bro66
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://www.linux.com/blog/2018/8/linux-beginners-moving-things-around
|
||||
[2]: https://www.blender.org/
|
||||
[3]: https://www.blender.org/download/
|
||||
[4]: https://training.linuxfoundation.org/linux-courses/system-administration-training/introduction-to-linux
|
||||
@ -1,55 +0,0 @@
|
||||
translating----geekpi
|
||||
|
||||
Edit your videos with Pitivi on Fedora
|
||||
======
|
||||
|
||||
|
||||
Looking to produce a video of your adventures this weekend? There are many different options for editing videos out there. However, if you are looking for a video editor that is simple to pick up, and also available in the official Fedora Repositories, give [Pitivi][1] a go.
|
||||
|
||||
Pitivi is an open source, non-linear video editor that uses the GStreamer framework. Out of the box on Fedora, Pitivi supports OGG Video, WebM, and a range of other formats. Additionally, more support for for video formats is available via gstreamer plugins. Pitivi is also tightly integrated with the GNOME Desktop, so the UI will feel at home among the other newer applications on Fedora Workstation.
|
||||
|
||||
### Installing Pitivi on Fedora
|
||||
|
||||
Pitivi is available in the Fedora Repositories. On Fedora Workstation, simply search and install Pitivi from the Software application.
|
||||
|
||||
![][2]
|
||||
|
||||
Alternatively, install Pitivi using the following command in the Terminal:
|
||||
|
||||
```
|
||||
sudo dnf install pitivi
|
||||
```
|
||||
|
||||
### Basic Editing
|
||||
|
||||
Pitivi has a wide range of tools built-in to allow quick and effective editing of your clips. Simply import videos, audio, and images into the Pitivi media library, then drag them onto the timeline. Additionally, pitivi allows you to easily split, trim, and group parts of clips together, in addition to simple fade transitions on the timeline.
|
||||
|
||||
![][3]
|
||||
|
||||
### Transitions and Effects
|
||||
|
||||
In addition to a basic fade between two clips, Pitivi also features a range of different transitions and wipes. Additionally, there are over a hundred effects that can be applied to either videos or audio to change how the media elements are played or displayed in your final presentation
|
||||
|
||||
![][4]
|
||||
|
||||
Pitivi also features a range of other great features, so be sure to check out the [tour][5] on their website for a full description of the features of the awesome Pitivi.
|
||||
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://fedoramagazine.org/edit-your-videos-with-pitivi-on-fedora/
|
||||
|
||||
作者：[Ryan Lerch][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://fedoramagazine.org/introducing-flatpak/
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: http://www.pitivi.org/
|
||||
[2]: https://fedoramagazine.org/wp-content/uploads/2018/10/Screenshot-from-2018-10-19-14-46-12.png
|
||||
[3]: https://fedoramagazine.org/wp-content/uploads/2018/10/Screenshot-from-2018-10-19-15-37-29.png
|
||||
[4]: http://www.pitivi.org/i/screenshots/archive/0.94.jpg
|
||||
[5]: http://www.pitivi.org/?go=tour
|
||||
@ -1,341 +0,0 @@
|
||||
How to use Pandoc to produce a research paper
|
||||
======
|
||||
Learn how to manage section references, figures, tables, and more in Markdown.
|
||||
|
||||
|
||||
This article takes a deep dive into how to produce a research paper using (mostly) [Markdown][1] syntax. We'll cover how to create and reference sections, figures (in Markdown and [LaTeX][2]) and bibliographies. We'll also discuss troublesome cases and why writing them in LaTeX is the right approach.
|
||||
|
||||
### Research
|
||||
|
||||
Research papers usually contain references to sections, figures, tables, and a bibliography. [Pandoc][3] by itself cannot easily cross-reference these, but it can leverage the [pandoc-crossref][4] filter to do the automatic numbering and cross-referencing of sections, figures, and tables.
|
||||
|
||||
Let’s start by rewriting [an example of an educational research paper][5] originally written in LaTeX and rewrites it in Markdown (and some LaTeX) with Pandoc and pandoc-crossref.
|
||||
|
||||
#### Adding and referencing sections
|
||||
|
||||
Sections are automatically numbered and must be written using the Markdown heading H1. Subsections are written with subheadings H2-H4 (it is uncommon to need more than that). For example, to write a section titled “Implementation”, write `# Implementation {#sec:implementation}`, and Pandoc produces `3. Implementation` (or the corresponding numbered section). The title “Implementation” uses heading H1 and declares a label `{#sec:implementation}` that authors can use to refer to that section. To reference a section, type the `@` symbol followed by the label of the section and enclose it in square brackets: `[@sec:implementation]`.
|
||||
|
||||
[In this paper][5], we find the following example:
|
||||
|
||||
```
|
||||
we lack experience (consistency between TAs, [@sec:implementation]).
|
||||
```
|
||||
|
||||
Pandoc produces:
|
||||
|
||||
```
|
||||
we lack experience (consistency between TAs, Section 4).
|
||||
```
|
||||
|
||||
Sections are numbered automatically (this is covered in the `Makefile` at the end of the article). To create unnumbered sections, type the title of the section, followed by `{-}`. For example, `### Designing a game for maintainability {-}` creates an unnumbered subsection with the title “Designing a game for maintainability”.
|
||||
|
||||
#### Adding and referencing figures
|
||||
|
||||
Adding and referencing a figure is similar to referencing a section and adding a Markdown image:
|
||||
|
||||
```
|
||||
{#fig:scatter-matrix}
|
||||
```
|
||||
|
||||
The line above tells Pandoc that there is a figure with the caption Scatterplot matrix and the path to the image is `data/scatterplots/RScatterplotMatrix2.png`. `{#fig:scatter-matrix}` declares the name that should be used to reference the figure.
|
||||
|
||||
Here is an example of a figure reference from the example paper:
|
||||
|
||||
```
|
||||
The boxes "Enjoy", "Grade" and "Motivation" ([@fig:scatter-matrix]) ...
|
||||
```
|
||||
|
||||
Pandoc produces the following output:
|
||||
|
||||
```
|
||||
The boxes "Enjoy", "Grade" and "Motivation" (Fig. 1) ...
|
||||
```
|
||||
|
||||
#### Adding and referencing a bibliography
|
||||
|
||||
Most research papers keep references in a BibTeX database file. In this example, this file is named [biblio.bib][6] and it contains all the references of the paper. Here is what this file looks like:
|
||||
|
||||
```
|
||||
@inproceedings{wrigstad2017mastery,
|
||||
Author = {Wrigstad, Tobias and Castegren, Elias},
|
||||
Booktitle = {SPLASH-E},
|
||||
Title = {Mastery Learning-Like Teaching with Achievements},
|
||||
Year = 2017
|
||||
}
|
||||
|
||||
@inproceedings{review-gamification-framework,
|
||||
Author = {A. Mora and D. Riera and C. Gonzalez and J. Arnedo-Moreno},
|
||||
Publisher = {IEEE},
|
||||
Booktitle = {2015 7th International Conference on Games and Virtual Worlds
|
||||
for Serious Applications (VS-Games)},
|
||||
Doi = {10.1109/VS-GAMES.2015.7295760},
|
||||
Keywords = {formal specification;serious games (computing);design
|
||||
framework;formal design process;game components;game design
|
||||
elements;gamification design frameworks;gamification-based
|
||||
solutions;Bibliographies;Context;Design
|
||||
methodology;Ethics;Games;Proposals},
|
||||
Month = {Sept},
|
||||
Pages = {1-8},
|
||||
Title = {A Literature Review of Gamification Design Frameworks},
|
||||
Year = 2015,
|
||||
Bdsk-Url-1 = {http://dx.doi.org/10.1109/VS-GAMES.2015.7295760}
|
||||
}
|
||||
|
||||
...
|
||||
```
|
||||
|
||||
The first line, `@inproceedings{wrigstad2017mastery,`, declares the type of publication (`inproceedings`) and the label used to refer to that paper (`wrigstad2017mastery`).
|
||||
|
||||
To cite the paper with its title, Mastery Learning-Like Teaching with Achievements, type:
|
||||
|
||||
```
|
||||
the achievement-driven learning methodology [@wrigstad2017mastery]
|
||||
```
|
||||
|
||||
Pandoc will output:
|
||||
|
||||
```
|
||||
the achievement- driven learning methodology [30]
|
||||
```
|
||||
|
||||
The paper we will produce includes a bibliography section with numbered references like these:
|
||||
|
||||
|
||||
|
||||
Citing a collection of articles is easy: Simply cite each article, separating the labeled references using a semi-colon: `;`. If there are two labeled references—i.e., `SEABORN201514` and `gamification-leaderboard-benefits`—cite them together, like this:
|
||||
|
||||
```
|
||||
Thus, the most important benefit is its potential to increase students' motivation
|
||||
|
||||
and engagement [@SEABORN201514;@gamification-leaderboard-benefits].
|
||||
```
|
||||
|
||||
Pandoc will produce:
|
||||
|
||||
```
|
||||
Thus, the most important benefit is its potential to increase students’ motivation
|
||||
|
||||
and engagement [26, 28]
|
||||
```
|
||||
|
||||
### Problematic cases
|
||||
|
||||
A common problem involves objects that do not fit in the page. They then float to wherever they fit best, even if that position is not where the reader expects to see it. Since papers are easier to read when figures or tables appear close to where they are mentioned, we need to have some control over where these elements are placed. For this reason, I recommend the use of the `figure` LaTeX environment, which enables users to control the positioning of figures.
|
||||
|
||||
Let’s take the figure example shown above:
|
||||
|
||||
```
|
||||
{#fig:scatter-matrix}
|
||||
```
|
||||
|
||||
And rewrite it in LaTeX:
|
||||
|
||||
```
|
||||
\begin{figure}[t]
|
||||
\includegraphics{data/scatterplots/RScatterplotMatrix2.png}
|
||||
\caption{\label{fig:matrix}Scatterplot matrix}
|
||||
\end{figure}
|
||||
```
|
||||
|
||||
In LaTeX, the `[t]` option in the `figure` environment declares that the image should be placed at the top of the page. For more options, refer to the Wikibooks article [LaTex/Floats, Figures, and Captions][7].
|
||||
|
||||
### Producing the paper
|
||||
|
||||
So far, we've covered how to add and reference (sub-)sections and figures and cite the bibliography—now let's review how to produce the research paper in PDF format. To generate the PDF, we will use Pandoc to generate a LaTeX file that can be compiled to the final PDF. We will also discuss how to generate the research paper in LaTeX using a customized template and a meta-information file, and how to compile the LaTeX document into its final PDF form.
|
||||
|
||||
Most conferences provide a **.cls** file or a template that specifies how papers should look; for example, whether they should use a two-column format and other design treatments. In our example, the conference provided a file named **acmart.cls**.
|
||||
|
||||
Authors are generally expected to include the institution to which they belong in their papers. However, this option was not included in the default Pandoc’s LaTeX template (note that the Pandoc template can be inspected by typing `pandoc -D latex`). To include the affiliation, take the default Pandoc’s LaTeX template and add a new field. The Pandoc template was copied into a file named `mytemplate.tex` as follows:
|
||||
|
||||
```
|
||||
pandoc -D latex > mytemplate.tex
|
||||
```
|
||||
|
||||
The default template contains the following code:
|
||||
|
||||
```
|
||||
$if(author)$
|
||||
\author{$for(author)$$author$$sep$ \and $endfor$}
|
||||
$endif$
|
||||
$if(institute)$
|
||||
\providecommand{\institute}[1]{}
|
||||
\institute{$for(institute)$$institute$$sep$ \and $endfor$}
|
||||
$endif$
|
||||
```
|
||||
|
||||
Because the template should include the author’s affiliation and email address, among other things, we updated it to include these fields (we made other changes as well but did not include them here due to the file length):
|
||||
|
||||
```
|
||||
latex
|
||||
$for(author)$
|
||||
$if(author.name)$
|
||||
\author{$author.name$}
|
||||
$if(author.affiliation)$
|
||||
\affiliation{\institution{$author.affiliation$}}
|
||||
$endif$
|
||||
$if(author.email)$
|
||||
\email{$author.email$}
|
||||
$endif$
|
||||
$else$
|
||||
$author$
|
||||
$endif$
|
||||
$endfor$
|
||||
```
|
||||
|
||||
With these changes in place, we should have the following files:
|
||||
|
||||
* `main.md` contains the research paper
|
||||
* `biblio.bib` contains the bibliographic database
|
||||
* `acmart.cls` is the class of the document that we should use
|
||||
* `mytemplate.tex` is the template file to use (instead of the default)
|
||||
|
||||
|
||||
|
||||
Let’s add the meta-information of the paper in a `meta.yaml`file:
|
||||
|
||||
```
|
||||
---
|
||||
template: 'mytemplate.tex'
|
||||
documentclass: acmart
|
||||
classoption: sigconf
|
||||
title: The impact of opt-in gamification on `\\`{=latex} students' grades in a software design course
|
||||
author:
|
||||
- name: Kiko Fernandez-Reyes
|
||||
affiliation: Uppsala University
|
||||
email: kiko.fernandez@it.uu.se
|
||||
- name: Dave Clarke
|
||||
affiliation: Uppsala University
|
||||
email: dave.clarke@it.uu.se
|
||||
- name: Janina Hornbach
|
||||
affiliation: Uppsala University
|
||||
email: janina.hornbach@fek.uu.se
|
||||
bibliography: biblio.bib
|
||||
abstract: |
|
||||
An achievement-driven methodology strives to give students more control over their learning with enough flexibility to engage them in deeper learning. (more stuff continues)
|
||||
|
||||
include-before: |
|
||||
\```{=latex}
|
||||
\copyrightyear{2018}
|
||||
\acmYear{2018}
|
||||
\setcopyright{acmlicensed}
|
||||
\acmConference[MODELS '18 Companion]{ACM/IEEE 21th International Conference on Model Driven Engineering Languages and Systems}{October 14--19, 2018}{Copenhagen, Denmark}
|
||||
\acmBooktitle{ACM/IEEE 21th International Conference on Model Driven Engineering Languages and Systems (MODELS '18 Companion), October 14--19, 2018, Copenhagen, Denmark}
|
||||
\acmPrice{XX.XX}
|
||||
\acmDOI{10.1145/3270112.3270118}
|
||||
\acmISBN{978-1-4503-5965-8/18/10}
|
||||
|
||||
\begin{CCSXML}
|
||||
<ccs2012>
|
||||
<concept>
|
||||
<concept_id>10010405.10010489</concept_id>
|
||||
<concept_desc>Applied computing~Education</concept_desc>
|
||||
<concept_significance>500</concept_significance>
|
||||
</concept>
|
||||
</ccs2012>
|
||||
\end{CCSXML}
|
||||
|
||||
\ccsdesc[500]{Applied computing~Education}
|
||||
|
||||
\keywords{gamification, education, software design, UML}
|
||||
\```
|
||||
figPrefix:
|
||||
- "Fig."
|
||||
- "Figs."
|
||||
secPrefix:
|
||||
- "Section"
|
||||
- "Sections"
|
||||
...
|
||||
```
|
||||
|
||||
This meta-information file sets the following variables in LaTeX:
|
||||
|
||||
* `template` refers to the template to use (‘mytemplate.tex’)
|
||||
* `documentclass` refers to the LaTeX document class to use (`acmart`)
|
||||
* `classoption` refers to the options of the class, in this case `sigconf`
|
||||
* `title` specifies the title of the paper
|
||||
* `author` is an object that contains other fields, such as `name`, `affiliation`, and `email`.
|
||||
* `bibliography`refers to the file that contains the bibliography (biblio.bib)
|
||||
* `abstract` contains the abstract of the paper
|
||||
* `include-before`is information that should be included before the actual content of the paper; this is known as the [preamble][8] in LaTeX. I have included it here to show how to generate a computer science paper, but you may choose to skip it
|
||||
* `figPrefix` specifies how to refer to figures in the document, i.e., what should be displayed when one refers to the figure `[@fig:scatter-matrix]`. For example, the current `figPrefix` produces in the example `The boxes "Enjoy", "Grade" and "Motivation" ([@fig:scatter-matrix])` this output: `The boxes "Enjoy", "Grade" and "Motivation" (Fig. 3)`. If there are multiple figures, the current setup declares that it should instead display `Figs.` next to the figure numbers.
|
||||
* `secPrefix` specifies how to refer to sections mentioned elsewhere in the document (similar to figures, described above)
|
||||
|
||||
|
||||
|
||||
Now that the meta-information is set, let’s create a `Makefile` that produces the desired output. This `Makefile` uses Pandoc to produce the LaTeX file, `pandoc-crossref` to produce the cross-references, `pdflatex` to compile the LaTeX to PDF, and `bibtex `to process the references.
|
||||
|
||||
The `Makefile` is shown below:
|
||||
|
||||
```
|
||||
all: paper
|
||||
|
||||
paper:
|
||||
@pandoc -s -F pandoc-crossref --natbib meta.yaml --template=mytemplate.tex -N \
|
||||
-f markdown -t latex+raw_tex+tex_math_dollars+citations -o main.tex main.md
|
||||
@pdflatex main.tex &> /dev/null
|
||||
@bibtex main &> /dev/null
|
||||
@pdflatex main.tex &> /dev/null
|
||||
@pdflatex main.tex &> /dev/null
|
||||
|
||||
clean:
|
||||
rm main.aux main.tex main.log main.bbl main.blg main.out
|
||||
|
||||
.PHONY: all clean paper
|
||||
```
|
||||
|
||||
Pandoc uses the following flags:
|
||||
|
||||
* `-s` to create a standalone LaTeX document
|
||||
* `-F pandoc-crossref` to make use of the filter `pandoc-crossref`
|
||||
* `--natbib` to render the bibliography with `natbib` (you can also choose `--biblatex`)
|
||||
* `--template` sets the template file to use
|
||||
* `-N` to number the section headings
|
||||
* `-f` and `-t` specify the conversion from and to which format. `-t` usually contains the format and is followed by the Pandoc extensions used. In the example, we declared `raw_tex+tex_math_dollars+citations` to allow use of `raw_tex` LaTeX in the middle of the Markdown file. `tex_math_dollars` enables us to type math formulas as in LaTeX, and `citations` enables us to use [this extension][9].
|
||||
|
||||
|
||||
|
||||
To generate a PDF from LaTeX, follow the guidelines [from bibtex][10] to process the bibliography:
|
||||
|
||||
```
|
||||
@pdflatex main.tex &> /dev/null
|
||||
@bibtex main &> /dev/null
|
||||
@pdflatex main.tex &> /dev/null
|
||||
@pdflatex main.tex &> /dev/null
|
||||
```
|
||||
|
||||
The script contains `@` to ignore the output, and we redirect the file handle of the standard output and error to `/dev/null`so that we don’t see the output generated from the execution of these commands.
|
||||
|
||||
The final result is shown below. The repository for the article can be found [on GitHub][11]:
|
||||
|
||||
|
||||
|
||||
### Conclusion
|
||||
|
||||
In my opinion, research is all about collaboration, dissemination of ideas, and improving the state of the art in whatever field one happens to be in. Most computer scientists and engineers write papers using the LaTeX document system, which provides excellent support for math. Researchers from the social sciences seem to stick to DOCX documents.
|
||||
|
||||
When researchers from different communities write papers together, they should first discuss which format they will use. While DOCX may not be convenient for engineers if there is math involved, LaTeX may be troublesome for researchers who lack a programming background. As this article shows, Markdown is an easy-to-use language that can be used by both engineers and social scientists.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/18/9/pandoc-research-paper
|
||||
|
||||
作者：[Kiko Fernandez-Reyes][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/kikofernandez
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://en.wikipedia.org/wiki/Markdown
|
||||
[2]: https://www.latex-project.org/
|
||||
[3]: https://pandoc.org/
|
||||
[4]: http://lierdakil.github.io/pandoc-crossref/
|
||||
[5]: https://dl.acm.org/citation.cfm?id=3270118
|
||||
[6]: https://github.com/kikofernandez/pandoc-examples/blob/master/research-paper/biblio.bib
|
||||
[7]: https://en.wikibooks.org/wiki/LaTeX/Floats,_Figures_and_Captions#Figures
|
||||
[8]: https://www.sharelatex.com/learn/latex/Creating_a_document_in_LaTeX#The_preamble_of_a_document
|
||||
[9]: http://pandoc.org/MANUAL.html#citations
|
||||
[10]: http://www.bibtex.org/Using/
|
||||
[11]: https://github.com/kikofernandez/pandoc-examples/tree/master/research-paper
|
||||
@ -1,79 +0,0 @@
|
||||
5 tips for choosing the right open source database
|
||||
======
|
||||
When selecting a mission-critical application, you can't afford to make mistakes.
|
||||
|
||||
|
||||
|
||||
So, your company has a directive to adopt more open source database technologies, and they've recruited you to select the right direction. Whether you are an open source technology veteran or a newcomer, this is a daunting and overwhelming task.
|
||||
|
||||
Over the past several years, open source technology adoption has steadily increased in the enterprise space. With its popularity comes a crowded marketplace with open source software companies promising that their solution will solve every problem and fit every workload. Be wary of these promises. Choosing the right open source technology—especially a database—is an important and difficult decision you can't make lightly.
|
||||
|
||||
In my experience as an IT professional at [Percona][1] and other companies, I've been fortunate to work hands-on in adopting open source technologies and guiding others in making the right decisions. There are many important factors to consider; hopefully, this article will shine a light on a few.
|
||||
|
||||
### 1. Have a goal.
|
||||
|
||||
This may seem simple, but based on my many conversations with people exploring MySQL, MongoDB, or PostgreSQL, it is top of the list in importance.
|
||||
|
||||
To avoid getting overwhelmed by the unlimited combinations of open source database software in the market, have a specific goal in mind. Maybe your goal is to provide your internal developers with a standardized, open source database backend that is managed by your internal database team. Perhaps your goal is to rip and replace the entire functionality of a legacy application and database backend with new open source technology.
|
||||
|
||||
Once you have defined a goal, you can focus your efforts. This will lead to better conversations internally as well as externally with open source database software vendors and advocates.
|
||||
|
||||
### 2. Understand your workload.
|
||||
|
||||
Despite the increasing ability of database technologies to wear many hats, each specializes in certain areas, e.g., MongoDB is now transactional, MySQL now has JSON storage. A growing trend in open source databases involves providing check boxes claiming certain features are available. One of the biggest mistakes is not using the right tool for the right job. Something leads a company down the wrong path—perhaps an overzealous developer or a manager with tunnel vision. The unfortunate thing is that the wrong tool can work fine for smaller volumes of transactions and data, but later there will be bottlenecks that can be solved only by using a different tool.
|
||||
|
||||
If you want a data analytics warehouse, an open source relational database is probably not the right choice. If you want a transaction-processing app with rigid data integrity and consistency, NoSQL options may not be the right option.
|
||||
|
||||
### 3. Don't reinvent the wheel.
|
||||
|
||||
Open source database technologies have rapidly grown, expanded, and hardened over the past several decades. We've seen a transformation from new, questionably production-ready databases to proven, enterprise-grade database backends. It's no longer necessary to be a bleeding edge, early adopter to choose open source database technologies. Organizations have grown around these communities to provide production support and tooling in the open source database space for a growing number of startups, midsized businesses, and Fortune 500 companies.
|
||||
|
||||
Battery Ventures, a tech-focused investment firm, recently introduced its [BOSS Index][2] for tracking the most popular open source projects. It's not perfect, but it provides great insight into some of the most widely adopted and active open source projects. Not surprisingly, database technologies dominate the list, comprising five of the top 10 technologies. This is a great starting point for someone new to the open source database space. A lot of times, vendors have already produced suitable architectures for solving specific problems.
|
||||
|
||||
My point is that someone has probably already done what you are trying to do. Learn from their successes and failures. Even if it is not a perfect fit, a solution can likely be modified to suit your needs. For example, Amazon provides a [CloudFormation script][3] for deploying MongoDB in its EC2 environment.
|
||||
|
||||
If you are a bleeding-edge early adopter, that doesn't mean you can't explore. If you have a unique challenge or workload that seems to fit a new open source database technology, go for it. Keep in mind that there are inherent risks (and rewards!) to being an early adopter.
|
||||
|
||||
### 4\. Start simple
|
||||
|
||||
|
||||
How many [nines][4] does your database truly need? "Achieving high availability" is often a nebulous goal for many companies. Of course, the most common answer is "it's mission-critical, and we cannot afford any downtime."
|
||||
|
||||
The more complicated your database environment, the more difficult and costly it is to manage. You can theoretically achieve higher uptime, but the tradeoffs will be the feasibility of management and performance. When in doubt, start simple. There are always options to scale out when the need arises.
|
||||
|
||||
For example, Booking.com is a widely known travel reservation site. It might be less widely known that it uses MySQL as a database backend. Nicolai Plum, a Booking.com senior systems architect, gave [a talk][5] outlining the evolution of the company's MySQL database. One of the takeaways was that the database started simple. It had to evolve over time, but in the beginning, simple master–replica architecture sufficed. As the workload and dataset increased, it introduced load balancers, multiple read replicas, archiving to Hadoop for analytics, etc. However, the early architecture was extremely simple.
|
||||
|
||||
|
||||
|
||||
### 5. When in doubt, ask an expert.
|
||||
|
||||
If you're unsure whether a database would be a good fit, reach out on forums, websites, or to vendors and strike up a conversation. This can be exciting as you research which database technologies meet your requirements and which do not. Often there are suitable alternatives that you haven't considered. The open source community is all about sharing knowledge.
|
||||
|
||||
There is one important thing to be aware of when reaching out to open source software and services vendors. Many have open-core business models that incentivize adopting their database software. Take their advice or guidance with a grain of salt and use your own ability to research, create proofs of concept, and explore alternatives.
|
||||
|
||||
### Conclusion
|
||||
|
||||
Choosing the right open source database is an important decision. Start by asking the right questions. All too often, people put the cart before the horse, making decisions before really understanding their needs.
|
||||
|
||||
Barrett Chambers will present [Choosing the Right Open Source Database][6] at [All Things Open][7], October 21-23 in Raleigh, N.C.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/18/10/tips-choosing-right-open-source-database
|
||||
|
||||
作者：[Barrett Chambers][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/barrettc
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://www.percona.com/
|
||||
[2]: https://techcrunch.com/2017/04/07/tracking-the-explosive-growth-of-open-source-software/
|
||||
[3]: https://docs.aws.amazon.com/quickstart/latest/mongodb/welcome.html
|
||||
[4]: https://en.wikipedia.org/wiki/Five_nines
|
||||
[5]: https://www.percona.com/live/mysql-conference-2015/sessions/bookingcom-evolution-mysql-system-design
|
||||
[6]: https://allthingsopen.org/talk/choosing-the-right-open-source-database/
|
||||
[7]: https://allthingsopen.org/
|
||||
@ -0,0 +1,85 @@
|
||||
4 cool new projects to try in COPR for October 2018
|
||||
======
|
||||
|
||||
|
||||
|
||||
COPR is a [collection][1] of personal repositories for software that isn’t carried in the standard Fedora repositories. Some software doesn’t conform to standards that allow easy packaging. Or it may not meet other Fedora standards, despite being free and open source. COPR can offer these projects outside the standard set of Fedora Fedora packages. Software in COPR isn’t supported by Fedora infrastructure or signed by the project. However, it can be a neat way to try new or experimental software.
|
||||
|
||||
Here’s a set of new and interesting projects in COPR.
|
||||
|
||||
### GitKraken
|
||||
|
||||
[GitKraken][2] is a useful git client for people who prefer a graphical interface over command-line, providing all the features you expect. Additionally, GitKraken can create repositories and files, and has a built-in editor. A useful feature of GitKraken is the ability to stage lines or hunks of files, and to switch between branches fast. However, in some cases, you may experience performance issues with larger projects.
|
||||
![][3]
|
||||
|
||||
#### Installation instructions
|
||||
|
||||
The repo currently provides GitKraken for Fedora 27, 28, 29 and Rawhide, and for OpenSUSE Tumbleweed. To install GitKraken, use these commands:
|
||||
|
||||
```
|
||||
sudo dnf copr enable elken/gitkraken
|
||||
sudo dnf install gitkraken
|
||||
```
|
||||
|
||||
### Music On Console
|
||||
|
||||
[Music On Console][4] player, or mocp, is a simple console audio player. It has an interface similar to the Midnight Commander and is easy use. You simply navigate to a directory with music files and select a file or directory to play. In addition, mocp provides a set of commands, allowing it to be controlled directly from command line.
|
||||
|
||||
![][5]
|
||||
|
||||
#### Installation instructions
|
||||
|
||||
The repo currently provides Music On Console player for Fedora 28 and 29. To install mocp, use these commands:
|
||||
|
||||
```
|
||||
sudo dnf copr enable Krzystof/Moc
|
||||
sudo dnf install moc
|
||||
```
|
||||
|
||||
### cnping
|
||||
|
||||
[Cnping][6] is a small graphical ping tool for IPv4, useful for visualization of changes in round-trip time. It offers an option to control the time period between each packet as well as the size of data sent. In addition to the graph shown, cnping provides basic statistics on round-trip times and packet loss.![][7]
|
||||
|
||||
#### Installation instructions
|
||||
|
||||
The repo currently provides cnping for Fedora 27, 28, 29 and Rawhide. To install cnping, use these commands:
|
||||
|
||||
```
|
||||
sudo dnf copr enable dreua/cnping
|
||||
sudo dnf install cnping
|
||||
```
|
||||
|
||||
### Pdfsandwich
|
||||
|
||||
[Pdfsandwich][8] is a tool for adding text to PDF files which contain text in an image form — such as scanned books. It uses optical character recognition (OCR) to create an additional layer with the recognized text behind the original page. This can be useful for copying and working with the text.
|
||||
|
||||
#### Installation instructions
|
||||
|
||||
The repo currently provides pdfsandwich for Fedora 27, 28, 29 and Rawhide, and for EPEL 7. To install pdfsandwich, use these commands:
|
||||
|
||||
```
|
||||
sudo dnf copr enable merlinm/pdfsandwich
|
||||
sudo dnf install pdfsandwich
|
||||
```
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://fedoramagazine.org/4-cool-new-projects-try-copr-october-2018/
|
||||
|
||||
作者：[Dominik Turecek][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://fedoramagazine.org
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://copr.fedorainfracloud.org/
|
||||
[2]: https://www.gitkraken.com/git-client
|
||||
[3]: https://fedoramagazine.org/wp-content/uploads/2018/10/copr-gitkraken.png
|
||||
[4]: http://moc.daper.net/
|
||||
[5]: https://fedoramagazine.org/wp-content/uploads/2018/10/copr-mocp.png
|
||||
[6]: https://github.com/cnlohr/cnping
|
||||
[7]: https://fedoramagazine.org/wp-content/uploads/2018/10/copr-cnping.png
|
||||
[8]: http://www.tobias-elze.de/pdfsandwich/
|
||||
@ -0,0 +1,87 @@
|
||||
translating---geekpi
|
||||
|
||||
Get organized at the Linux command line with Calcurse
|
||||
======
|
||||
|
||||
Keep up with your calendar and to-do list with Calcurse.
|
||||
|
||||
|
||||
|
||||
Do you need complex, feature-packed graphical or web applications to get and stay organized? I don't think so. The right command line tool can do the job and do it well.
|
||||
|
||||
Of course, uttering the words command and line together can strike fear into the hearts of some Linux users. The command line, to them, is terra incognita.
|
||||
|
||||
Organizing yourself at the command line is easy with [Calcurse][1]. Calcurse brings a graphical look and feel to a text-based interface. You get the simplicity and focus of the command line married to ease of use and navigation.
|
||||
|
||||
Let's take a closer look at Calcurse, which is open sourced under the BSD License.
|
||||
|
||||
### Getting the software
|
||||
|
||||
If compiling code is your thing (it's not mine, generally), you can grab the source code from the [Calcurse website][1]. Otherwise, get the [binary installer][2] for your Linux distribution. You might even be able to get Calcurse from your Linux distro's package manager. It never hurts to check.
|
||||
|
||||
Compile or install Calcurse (neither takes all that long), and you're ready to go.
|
||||
|
||||
### Using Calcurse
|
||||
|
||||
Crack open a terminal window and type **calcurse**.
|
||||
|
||||
|
||||
|
||||
Calcurse's interface consists of three panels:
|
||||
|
||||
* Appointments (the left side of the screen)
|
||||
* Calendar (the top right)
|
||||
* To-do list (the bottom right)
|
||||
|
||||
|
||||
|
||||
Move between the panels by pressing the Tab key on your keyboard. To add a new item to a panel, press **a**. Calcurse walks you through what you need to do to add the item.
|
||||
|
||||
One interesting quirk is that the Appointment and Calendar panels work together. You add an appointment by tabbing to the Calendar panel. There, you choose the date for your appointment. Once you do that, you tab back to the Appointments panel. I know …
|
||||
|
||||
Press **a** to set a start time, a duration (in minutes), and a description of the appointment. The start time and duration are optional. Calcurse displays appointments on the day they're due.
|
||||
|
||||
|
||||
|
||||
Here's what a day's appointments look like:
|
||||
|
||||
|
||||
|
||||
The to-do list works on its own. Tab to the ToDo panel and (again) press **a**. Type a description of the task, then set a priority (1 is the highest and 9 is the lowest). Calcurse lists your uncompleted tasks in the ToDo panel.
|
||||
|
||||
|
||||
|
||||
If your task has a long description, Calcurse truncates it. You can view long descriptions by navigating to the task using the up or down arrow keys on your keyboard, then pressing **v**.
|
||||
|
||||
|
||||
|
||||
Calcurse saves its information in text files in a hidden folder called **.calcurse** in your home directory—for example, **/home/scott/.calcurse**. If Calcurse stops working, it's easy to find your information.
|
||||
|
||||
### Other useful features
|
||||
|
||||
Other Calcurse features include the ability to set recurring appointments. To do that, find the appointment you want to repeat and press **r** in the Appointments panel. You'll be asked to set the frequency (for example, daily or weekly) and how long you want the appointment to repeat.
|
||||
|
||||
You can also import calendars in [ICAL][3] format or export your data in either ICAL or [PCAL][4] format. With ICAL, you can share your data with other calendar applications. With PCAL, you can generate a Postscript version of your calendar.
|
||||
|
||||
There are also a number of command line arguments you can pass to Calcurse. You can read about them [in the documentation][5].
|
||||
|
||||
While simple, Calcurse does a solid job of helping you keep organized. You'll need to be a bit more mindful of your tasks and appointments, but you'll be able to focus better on what you need to do and where you need to be.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/18/10/calcurse
|
||||
|
||||
作者：[Scott Nesbitt][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/scottnesbitt
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: http://www.calcurse.org/
|
||||
[2]: http://www.calcurse.org/downloads/#packages
|
||||
[3]: https://tools.ietf.org/html/rfc2445
|
||||
[4]: http://pcal.sourceforge.net/
|
||||
[5]: http://www.calcurse.org/files/manual.chunked/ar01s04.html#_invocation
|
||||
@ -0,0 +1,82 @@
|
||||
Monitoring database health and behavior: Which metrics matter?
|
||||
======
|
||||
Monitoring your database can be overwhelming or seem not important. Here's how to do it right.
|
||||
|
||||
|
||||
We don’t talk about our databases enough. In this age of instrumentation, we monitor our applications, our infrastructure, and even our users, but we sometimes forget that our database deserves monitoring, too. That’s largely because most databases do their job so well that we simply trust them to do it. Trust is great, but confirmation of our assumptions is even better.
|
||||
|
||||
|
||||
|
||||
### Why monitor your databases?
|
||||
|
||||
There are plenty of reasons to monitor your databases, most of which are the same reasons you'd monitor any other part of your systems: Knowing what’s going on in the various components of your applications makes you a better-informed developer who makes smarter decisions.
|
||||
|
||||
|
||||
|
||||
More specifically, databases are great indicators of system health and behavior. Odd behavior in the database can point to problem areas in your applications. Alternately, when there’s odd behavior in your application, you can use database metrics to help expedite the debugging process.
|
||||
|
||||
### The problem
|
||||
|
||||
The slightest investigation reveals one problem with monitoring databases: Databases have a lot of metrics. "A lot" is an understatement—if you were Scrooge McDuck, you could swim through all of the metrics available. If this were Wrestlemania, the metrics would be folding chairs. Monitoring them all doesn’t seem practical, so how do you decide which metrics to monitor?
|
||||
|
||||
|
||||
|
||||
### The solution
|
||||
|
||||
The best way to start monitoring databases is to identify some foundational, database-agnostic metrics. These metrics create a great start to understanding the lives of your databases.
|
||||
|
||||
### Throughput: How much is the database doing?
|
||||
|
||||
The easiest way to start monitoring a database is to track the number of requests the database receives. We have high expectations for our databases; we expect them to store data reliably and handle all of the queries we throw at them, which could be one massive query a day or millions of queries from users all day long. Throughput can tell you which of those is true.
|
||||
|
||||
You can also group requests by type (reads, writes, server-side, client-side, etc.) to begin analyzing the traffic.
|
||||
|
||||
### Execution time: How long does it take the database to do its job?
|
||||
|
||||
This metric seems obvious, but it often gets overlooked. You don’t just want to know how many requests the database received, but also how long the database spent on each request. It’s important to approach execution time with context, though: What's slow for a time-series database like InfluxDB isn’t the same as what's slow for a relational database like MySQL. Slow in InfluxDB might mean milliseconds, whereas MySQL’s default value for its `SLOW_QUERY` variable is ten seconds.
|
||||
|
||||
|
||||
|
||||
Monitoring execution time is not the same thing as improving execution time, so beware of the temptation to spend time on optimizations if you have other problems in your app to fix.
|
||||
|
||||
### Concurrency: How many jobs is the database doing at the same time?
|
||||
|
||||
Once you know how many requests the database is handling and how long each one takes, you need to add a layer of complexity to start getting real value from these metrics.
|
||||
|
||||
If the database receives ten requests and each one takes ten seconds to complete, is the database busy for 100 seconds, ten seconds—or somewhere in between? The number of concurrent tasks changes the way the database’s resources are used. When you consider things like the number of connections and threads, you’ll start to get a fuller picture of your database metrics.
|
||||
|
||||
Concurrency can also affect latency, which includes not only the time it takes for the task to be completed (execution time) but also the time the task needs to wait before it’s handled.
|
||||
|
||||
### Utilization: What percentage of the time was the database busy?
|
||||
|
||||
Utilization is a culmination of throughput, execution time, and concurrency to determine how often the database was available—or alternatively, how often the database was too busy to respond to a request.
|
||||
|
||||
|
||||
|
||||
This metric is particularly useful for determining the overall health and performance of your database. If it’s available to respond to requests only 80% of the time, you can reallocate resources, work on optimization, or otherwise make changes to get closer to high availability.
|
||||
|
||||
### The good news
|
||||
|
||||
It can seem overwhelming to monitor and analyze, especially because most of us aren’t database experts and we may not have time to devote to understanding these metrics. But the good news is that most of this work is already done for us. Many databases have an internal performance database (Postgres: pg_stats, CouchDB: Runtime_Statistics, InfluxDB: _internal, etc.), which is designed by database engineers to monitor the metrics that matter for that particular database. You can see things as broad as the number of slow queries or as detailed as the average microseconds each event in the database takes.
|
||||
|
||||
### Conclusion
|
||||
|
||||
Databases create enough metrics to keep us all busy for a long time, and while the internal performance databases are full of useful information, it’s not always clear which metrics you should care about. Start with throughput, execution time, concurrency, and utilization, which provide enough information for you to start understanding the patterns in your database.
|
||||
|
||||
|
||||
|
||||
Are you monitoring your databases? Which metrics have you found to be useful? Tell me about it!
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/18/10/database-metrics-matter
|
||||
|
||||
作者：[Katy Farmer][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/thekatertot
|
||||
[b]: https://github.com/lujun9972
|
||||
99
translated/talk/20181008 3 areas to drive DevOps change.md
Normal file
99
translated/talk/20181008 3 areas to drive DevOps change.md
Normal file
@ -0,0 +1,99 @@
|
||||
推动 DevOps 变革的三个方面
|
||||
======
|
||||
推动大规模的组织变革是一个痛苦的过程。对于 DevOps 来说，尽管也有阵痛，但变革带来的价值则相当可观。
|
||||
|
||||
|
||||
|
||||
避免痛苦是一种强大的动力。一些研究表明，[植物也会通过遭受疼痛的过程][1]以采取措施来保护自己。我们人类有时也会刻意让自己受苦——在剧烈运动之后，身体可能会发生酸痛，但我们仍然坚持运动。那是因为当人认为整个过程利大于弊时，几乎可以忍受任何事情。
|
||||
|
||||
推动大规模的组织变革得过程确实是痛苦的。有人可能会因难以改变价值观和行为而感到痛苦，有人可能会因难以带领团队而感到痛苦，也有人可能会因难以开展工作而感到痛苦。但就 DevOps 而言，我可以说这些痛苦都是值得的。
|
||||
|
||||
我也曾经关注过一个团队耗费大量时间优化技术流程的过程，在这个过程中，团队逐渐将流程进行自动化改造，并最终获得了成功。
|
||||
|
||||
![Improvements after DevOps transformation][3]
|
||||
|
||||
图片来源：Lee Eason. CC BY-SA 4.0
|
||||
|
||||
这张图表充分表明了变革的价值。一家公司在我主导实行了 DevOps 转型之后，60 多个团队每月提交了超过 900 个发布请求。这些工作量的原耗时高达每个月 350 天，而这么多的工作量对于任何公司来说都是不可忽视的。除此以外，他们每月的部署次数从 100 次增加到了 9000 次，高危 bug 减少了 24%，工程师们更轻松了，<ruby>净推荐值<rt>Net Promoter Score</rt></ruby>（NPS）也提高了，而 NPS 提高反过来也让团队的 DevOps 转型更加顺利。正如 [Puppet 发布的 DevOps 报告][4]所预测的，用在技术流程改进上的投资可以在业务成果上明显地体现出来。
|
||||
|
||||
而 DevOps 主导者在推动变革是必须关注这三个方面：团队管理，团队文化和团队活力。
|
||||
|
||||
### 团队管理
|
||||
|
||||
组织架构越大，业务领导与一线员工之间的距离就会越大，当然发生误解的可能性也会越大。而且各种技术工具和实际应用都在以日新月异的速度变化，这就导致业务领导几乎不可能对 DevOps 或敏捷开发的转型方向有一个亲身的了解。
|
||||
|
||||
DevOps 主导者必须和管理层密切合作，在进行决策的时候给出相关的意见，以帮助他们做出正确的决策。
|
||||
|
||||
公司的管理层只是知道 DevOps 会对产品部署的方式进行改进，而并不了解其中的具体过程。当管理层发现你在和软件团队执行自动化部署失败时，就会想要了解这件事情的细节。如果管理层了解到进行部署的是软件团队而不是专门的发布管理团队，就可能会坚持使用传统的变更流程来保证业务的正常运作。你可能会失去团队的信任，团队也可能不愿意作出进一步的改变。
|
||||
|
||||
如果没有和管理层做好心理上的预期，一旦发生意外的生产事件，都会对你和管理层之间的信任造成难以消除的影响。所以，最好事先和管理层之间在各方面协调好，这会让你在后续的工作中避免很多麻烦。
|
||||
|
||||
对于和管理层之间的协调，这里有两条建议：
|
||||
|
||||
* 一是**重视所有规章制度**。如果管理层对合同、安全等各方面有任何疑问，你都可以向法务或安全负责人咨询，这样做可以避免犯下后果严重的错误。
|
||||
* 二是**将管理层的重点关注的方面输出为量化指标**。举个例子，如果公司的目标是减少客户流失，而你调查得出计划外的停机是造成客户流失的主要原因，那么就可以让团队对故障的<ruby>平均检测时间<rt>Mean Time To Detection</rt></ruby>（MTTD）和<ruby>平均解决时间<rt>Mean Time To Resolution</rt></ruby>（MTTR）实行重点优化。你可以使用这些关键指标来量化团队的工作成果，而管理层对此也可以有一个直观的了解。
|
||||
|
||||
|
||||
|
||||
### 团队文化
|
||||
|
||||
DevOps 是一种专注于持续改进代码、构建、部署和操作流程的文化，而团队文化代表了团队的价值观和行为。从本质上说，团队文化是要塑造团队成员的行为方式，而这并不是一件容易的事。
|
||||
|
||||
我推荐一本叫做《[披着狼皮的 CIO][5]》的书。另外，研究心理学、阅读《[Drive][6]》、观看 Daniel Pink 的 [TED 演讲][7]、阅读《[千面英雄][7]》、了解每个人的心路历程，以上这些都是你推动公司技术变革所应该尝试去做的事情。
|
||||
|
||||
理性的人大多都按照自己的价值观工作，然而团队通常没有让每个人都能达成共识的明确价值观。因此，你需要明确团队目前的价值观，包括价值观的形成过程和价值观的目标导向。也不能将这些价值观强加到团队成员身上，只需要让团队成员在目前的硬件条件下力所能及地做到最好就可以了
|
||||
|
||||
同时需要向团队成员阐明，公司正在发生组织上的变化，团队的价值观也随之改变，最好也厘清整个过程中将会作出什么变化。例如，公司以往或许是由于资金有限，一直将节约成本的原则放在首位，在研发新产品的时候，基础架构团队不得不通过共享数据库集群或服务器，从而导致了服务之间的紧密耦合。然而随着时间的推移，这种做法会产生难以维护的混乱，即使是一个小小的变化也可能造成无法预料的后果。这就导致交付团队难以执行变更控制流程，进而令变更停滞不前。
|
||||
|
||||
如果这种状况持续多年，最终的结果将会是毫无创新、技术老旧、问题繁多以及产品品质低下，公司的发展到达了瓶颈，原本的价值观已经不再适用。所以，工作效率的优先级必须高于节约成本。
|
||||
|
||||
你必须强调团队的价值观。每当团队按照价值观取得了一定的工作进展，都应该对团队作出激励。在团队部署出现失败时，鼓励他们承担风险、继续学习，同时指导团队如何改进他们的工作并表示支持。长此下来，团队成员就会对你产生信任，并逐渐切合团队的价值观。
|
||||
|
||||
### 团队活力
|
||||
|
||||
你有没有在会议上听过类似这样的话？“在张三度假回来之前，我们无法对这件事情做出评估。他是唯一一个了解代码的人”，或者是“我们完成不了这项任务，它在网络上需要跨团队合作，而防火墙管理员刚好请病假了”，又或者是“张三最清楚这个系统最好，他说是怎么样，通常就是怎么样”。那么如果团队在处理工作时，谁才是主力？就是张三。而且也一直会是他。
|
||||
|
||||
我们一直都认为这就是软件开发的本质。但是如果我们不作出改变，这种循环就会一直保持下去。
|
||||
|
||||
熵的存在会让团队自发地变得混乱和缺乏活力，团队的成员和主导者的都有责任控制这个熵并保持团队的活力。DevOps、敏捷开发、上云、代码重构这些行为都会令熵增加速，这是因为转型让团队需要学习更多新技能和专业知识以开展新工作。
|
||||
|
||||
我们来看一个产品团队重构遗留代码的例子。像往常一样，他们在 AWS 上构建新的服务。而传统的系统则在数据中心部署，并由 IT 部门进行监控和备份。IT 部门会确保在基础架构的层面上满足应用的安全需求、进行灾难恢复测试、系统补丁、安装配置了入侵检测和防病毒代理，而且 IT 部门还保留了年度审计流程所需的变更控制记录。
|
||||
|
||||
产品团队经常会犯一个致命的错误，就是认为 IT 部门是需要突破的瓶颈。他们希望脱离已有的 IT 部门并使用公有云，但实际上是他们忽视了 IT 部门提供的关键服务。迁移到云上只是以不同的方式实现这些关键服务，因为 AWS 也是一个数据中心，团队即使使用 AWS 也需要完成 IT 运维任务。
|
||||
|
||||
实际上，产品团队在迁移到云时候也必须学习如何使用这些 IT 服务。因此，当产品团队开始重构遗留的代码并部署到云上时，也需要学习大量的技能才能正常运作。这些技能不会无师自通，必须自行学习或者聘用相关的人员，团队的主导者也必须积极进行管理。
|
||||
|
||||
在带领团队时，我找不到任何适合我的工具，因此我建立了 [Tekita.io][9] 这个项目。Tekata 免费而且容易使用。但相比起来，把注意力集中在人员和流程上更为重要，你需要不断学习，持续关注团队的弱项，因为它们会影响团队的交付能力，而修补这些弱项往往需要学习大量的新知识，这就需要团队成员之间有一个很好的协作。因此 76％ 的年轻人都认为个人发展机会是公司文化[最重要的的一环][10]。
|
||||
|
||||
### 效果就是最好的证明
|
||||
|
||||
DevOps 转型会改变团队的工作方式和文化，这需要得到管理层的支持和理解。同时，工作方式的改变意味着新技术的引入，所以在管理上也必须谨慎。但转型的最终结果是团队变得更高效、成员变得更积极、产品变得更优质，客户也变得更快乐。
|
||||
|
||||
免责声明：本文中的内容仅为 Lee Eason 的个人立场，不代表 Ipreo 或 IHS Markit。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/18/10/tales-devops-transformation
|
||||
|
||||
作者：[Lee Eason][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/leeeason
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://link.springer.com/article/10.1007%2Fs00442-014-2995-6
|
||||
[2]: /file/411061
|
||||
[3]: https://opensource.com/sites/default/files/uploads/devops-delays.png "Improvements after DevOps transformation"
|
||||
[4]: https://puppet.com/resources/whitepaper/state-of-devops-report
|
||||
[5]: https://www.gartner.com/en/publications/wolf-cio
|
||||
[6]: https://en.wikipedia.org/wiki/Drive:_The_Surprising_Truth_About_What_Motivates_Us
|
||||
[7]: https://www.ted.com/talks/dan_pink_on_motivation?language=en#t-2094
|
||||
[8]: https://en.wikipedia.org/wiki/The_Hero_with_a_Thousand_Faces
|
||||
[9]: https://tekata.io/
|
||||
[10]: https://www.execu-search.com/~/media/Resources/pdf/2017_Hiring_Outlook_eBook
|
||||
[11]: https://allthingsopen.org/talk/tales-from-a-devops-transformation/
|
||||
[12]: https://allthingsopen.org/
|
||||
|
||||
@ -12,7 +12,7 @@
|
||||
|
||||
在本实验及后面的实验中，你将逐步构建你的内核。我们将会为你提供一些附加的资源。使用 Git 去获取这些资源、提交自实验 1 以来的改变（如有需要的话）、获取课程仓库的最新版本、以及在我们的实验 2 （origin/lab2）的基础上创建一个称为 lab2 的本地分支：
|
||||
|
||||
```
|
||||
```c
|
||||
athena% cd ~/6.828/lab
|
||||
athena% add git
|
||||
athena% git pull
|
||||
@ -23,9 +23,11 @@ Switched to a new branch "lab2"
|
||||
athena%
|
||||
```
|
||||
|
||||
上面的 `git checkout -b` 命令其实做了两件事情：首先它创建了一个本地分支 `lab2`，它跟踪给我们提供课程内容的远程分支 `origin/lab2` ，第二件事情是，它更改的你的 `lab` 目录的内容反映到 `lab2` 分支上存储的文件中。Git 允许你在已存在的两个分支之间使用 `git checkout *branch-name*` 命令去切换，但是在你切换到另一个分支之前，你应该去提交那个分支上你做的任何出色的变更。
|
||||
|
||||
现在，你需要将你在 lab1 分支中的改变合并到 lab2 分支中，命令如下：
|
||||
|
||||
```
|
||||
```c
|
||||
athena% git merge lab1
|
||||
Merge made by recursive.
|
||||
kern/kdebug.c | 11 +++++++++--
|
||||
@ -35,6 +37,8 @@ Merge made by recursive.
|
||||
athena%
|
||||
```
|
||||
|
||||
在一些案例中，Git 或许并不能找到如何将你的更改与新的实验任务合并（例如，你在第二个实验任务中变更了一些代码的修改）。在那种情况下，你使用 git 命令去合并，它会告诉你哪个文件发生了冲突，你必须首先去解决冲突（通过编辑冲突的文件），然后使用 `git commit -a` 去重新提交文件。
|
||||
|
||||
实验 2 包含如下的新源代码，后面你将遍历它们：
|
||||
|
||||
- inc/memlayout.h
|
||||
@ -53,13 +57,15 @@ athena%
|
||||
|
||||
在你准备进行实验和写代码之前，先添加你的 `answers-lab2.txt` 文件到 Git 仓库，提交你的改变然后去运行 `make handin`。
|
||||
|
||||
```
|
||||
```c
|
||||
athena% git add answers-lab2.txt
|
||||
athena% git commit -am "my answer to lab2"
|
||||
[lab2 a823de9] my answer to lab2 4 files changed, 87 insertions(+), 10 deletions(-)
|
||||
athena% make handin
|
||||
```
|
||||
|
||||
正如前面所说的，我们将使用一个评级程序来分级你的解决方案，你可以在 `lab` 目录下运行 `make grade`，使用评级程序来测试你的内核。为了完成你的实验，你可以改变任何你需要的内核源代码和头文件。但毫无疑问的是，你不能以任何形式去改变或破坏评级代码。
|
||||
|
||||
### 第 1 部分：物理页面管理
|
||||
|
||||
操作系统必须跟踪物理内存页是否使用的状态。JOS 以页为最小粒度来管理 PC 的物理内存，以便于它使用 MMU 去映射和保护每个已分配的内存片段。
|
||||
@ -98,6 +104,8 @@ athena% make handin
|
||||
|
||||
|
||||
|
||||
一个 C 指针是虚拟地址的“偏移量”部分。在 `boot/boot.S` 中我们安装了一个全局描述符表（GDT），它通过设置所有的段基址为 0，并且限制为 `0xffffffff` 来有效地禁用段转换。因此“段选择器”并不会生效，而线性地址总是等于虚拟地址的偏移量。在实验 3 中，为了设置权限级别，我们将与段有更多的交互。但是对于内存转换，我们将在整个 JOS 实验中忽略段，只专注于页转换。
|
||||
|
||||
回顾实验 1 中的第 3 部分，我们安装了一个简单的页表，这样内核就可以在 0xf0100000 链接的地址上运行，尽管它实际上是加载在 0x00100000 处的 ROM BIOS 的物理内存上。这个页表仅映射了 4MB 的内存。在实验中，你将要为 JOS 去设置虚拟内存布局，我们将从虚拟地址 0xf0000000 处开始扩展它，首先将物理内存扩展到 256MB，并映射许多其它区域的虚拟内存。
|
||||
|
||||
> 练习 3
|
||||
@ -165,9 +173,9 @@ JOS 分割处理器的 32 位线性地址空间为两部分：用户环境（进
|
||||
|
||||
你可以在 `inc/memlayout.h` 中找到一个图表，它有助于你去理解 JOS 内存布局，这在本实验和后面的实验中都会用到。
|
||||
|
||||
### 权限和缺页隔离
|
||||
### 权限和故障隔离
|
||||
|
||||
由于内核和用户的内存都存在于它们各自环境的地址空间中，因此我们需要在 x86 的页表中使用权限位去允许用户代码只能访问用户所属地址空间的部分。否则的话，用户代码中的 bug 可能会覆写内核数据，导致系统崩溃或者发生各种莫名其妙的的故障；用户代码也可能会偷窥其它环境的私有数据。
|
||||
由于内核和用户的内存都存在于它们各自环境的地址空间中，因此我们需要在 x86 的页表中使用权限位去允许用户代码只能访问用户所属地址空间的部分。否则，用户代码中的 bug 可能会覆写内核数据，导致系统崩溃或者发生各种莫名其妙的的故障；用户代码也可能会偷窥其它环境的私有数据。
|
||||
|
||||
对于 ULIM 以上部分的内存，用户环境没有任何权限，只有内核才可以读取和写入这部分内存。对于 [UTOP,ULIM] 地址范围，内核和用户都有相同的权限：它们可以读取但不能写入这个地址范围。这个地址范围是用于向用户环境暴露某些只读的内核数据结构。最后，低于 UTOP 的地址空间是为用户环境所使用的；用户环境将为访问这些内核设置权限。
|
||||
|
||||
|
||||
@ -1,102 +0,0 @@
|
||||
对于开发者来说5个最好的Linux发行版
|
||||
============================================================
|
||||
|
||||
Jack Wallen介绍了一些非常适合用来做开发工作的Linux发行版本.[Creative Commons Zero][6]
|
||||
在考虑使用Linux时，需要做很多的考量。你希望使用什么包管理器？你更喜欢现代还是比较旧的桌面界面？易用性是你使用Linux的首选吗？你希望分发的灵活性？发行版的服务性任务是什么？
|
||||
这是你在开始使用Linux之前必须考虑的问题。发行版是作为桌面还是服务器运行？你会做网络或者系统审计吗？或者你会开发？如果你花了很多时间考虑Linux，你知道每个任务都有非常合适的Linux发行版。这当然非常适用于开发人员。尽管Linux在设计上对于开发人员来说是一个理想的平台，但某些发行版高于其他的发行版，可以作为最好的开发人员的操作系统去服务开发人员。
|
||||
我想来分享我自己认为是你在做开发工作当中的最佳Linux发行版。虽然这五个发行版的每一个都可以用来通用开发（可能有一个是例外），但是它们都有各自的特定目的，你看会或不会对这些选择感觉到惊讶
|
||||
话虽如此，让我们做出选择
|
||||
### Debian
|
||||
在[Debian][14]的发行版中许多Linux列表中排名靠前。 有充分的理由。 Debian是许多人所依赖的发行版. 这就是为什么更多的开发人员去选择debian的理由。 当你在Debian上开发一个软件的时候，很有可能该软件包可以适用于[Ubuntu][15], [Linux Mint][16], [Elementary OS][17],以及大量的其他Debian发行版。
|
||||
除了这个非常明显的答案之外，Debian还通过默认存储库提供了大量可用的应用程序（图1）。
|
||||
|
||||
图 1: 标准的Debian存储库里面可用的应用程序。[Used with permission][1]
|
||||
为了让程序员友好,这些应用程序 (以及它们的依赖项) 易于安装.例如，构建必需的包（可以安装在Debian的任何衍生发行版上）。该软件包包括dkpg-dev，g ++，gcc，hurd-dev，libc-dev以及开发过程所需的make-all工具。可以使用命令sudo apt install build-essential安装build-essential软件包。
|
||||
标准存储库当中提供了数百种的特定于开发人员的应用程序，例如:
|
||||
* Autoconf—配置构建脚本的软件
|
||||
* Autoproject—为新程序创建源码包
|
||||
* Bison—通用的解析生成器
|
||||
* Bluefish—面向程序员的强大GUI编辑器
|
||||
* Geany—轻量化的IDE
|
||||
* Kate—强大的文本编辑器
|
||||
* Eclipse—帮助构建者独立开发与其他工具的集成性软件
|
||||
这个清单一直在继续更新.
|
||||
Debian也是你能找到的坚于磐石的发行版，因此很少有人担心因为桌面崩溃而让你失去宝贵的工作。作为奖励，Debian的所有应用程序都必须符合[Debian自由软件指南][18], 该指南遵守以下 “社会契约”:
|
||||
* Debian 保持完全免费.
|
||||
* 我们将无偿回馈自由软件社区.
|
||||
* 我们不会隐藏问题.
|
||||
* 我们的首要任务是我们的用户和自由软件
|
||||
* 不符合我们的免费软件标准的作品在非免费档案中..
|
||||
此外，你不熟悉在Linux上进行开发，Debian在其[用户手册][19]中有一个方便编程的部分。
|
||||
### openSUSE Tumbleweed （滚动更新版)
|
||||
如果你希望开发出最前沿的滚动发行版本， [openSUSE][20] 将提供最好的[Tumbleweed][21]之一。 还可以借助openSUSE当中令人惊叹的管理员工具（其中包括YaST）来实现这一目标。如果你不熟悉YaST（又一个设置工具）的话，它是一个非常强大的软件，允许您从一个方便的位置来管理整个平台。在YaST中，您还可以使用RPM组进行安装。打开YaST，单击RPM Groups（按目的分组的软件），然后向下滚动到Development部分以查看可安装的大量组（图2）
|
||||
|
||||
图 2: 在openSUSE Tumbleweed中安装软件包组.[Creative Commons Zero][2]
|
||||
openSUSE还允许您通过简单的单击链接快速安装所有必需的devtools [rpmdevtools安装页面][22]， 然后单击Tumbleweed的链接。这将自动添加必要的存储库并安装rpmdevtools
|
||||
对于开发者来说，通过滚动版本进行开发，你可以知道你已安装的软件是最新版本。
|
||||
### CentOS
|
||||
让我们来看一下, [红帽企业版Linux][23] (RHEL) 是企业事务的事实标准. 如果你正在寻找针对特定平台进行开发，并且你有点担心无法承担RHEL的许可证，那么[CentOS][24]就是你不错的选择— 实际上，它是RHEL的社区版本。你会发现CentOS上的许多软件包与RHEL中的软件包相同 - 所以一旦熟悉了一个软件包，你就可以使用其他的软件包。
|
||||
如果你认真考虑在企业级平台上进行开发，那么CentOS就是不错的选择。而且由于CentOS是特定于服务器的发行版，因此您可以更轻松地以Web为中心的平台进行开发。您可以轻松地将CentOS作为开发和测试的理想主机，而不是开发您的工作然后将其迁移到服务器（托管在不同的计算机上）.
|
||||
寻找满足你开发需求的软件? 你只需要打开CentOS软件中心, 其中包含了集成开发环境（IDE - 图3）的专用子部分
|
||||
|
||||
图 3: 在CentOS中安装功能强大的IDE很简单。.[Used with permission][3]
|
||||
Centos还包括安全增强性的Linux（SElinux），它使你可以更加轻松的去测试你的软件与RHEL中的同一安全平台的集成功能，SElinux经常会让设计不佳的软件感到头疼，因此准备了它可以真正有利于确保你的应用程序在RHEL之类的应用程序上面运行。如果你不确定如何在Centos上进行开发工作。你可以阅读[RHEL 7 开发人员指南][25].
|
||||
### Raspbian
|
||||
让我们来看一下, 嵌入式操作系统风靡一时. 使用这种 操作系统最简单的一种方法就是通过Raspberry Pi——一种极小的单片机（也可以称为小型计算机）. 事实上,Raspberry Pi 已经成为了全球喜爱DIY用户使用的硬件. 为这些 设备供电的是 [Raspbian][26]操作系统. Raspbian包含[BlueJ][27], [Geany][28], [Greenfoot][29], [Sense HAT Emulator][30], [Sonic Pi][31], 和 [Thonny Python IDE][32], [Python][33], 和 [Scratch][34]等一些工具, 因此你不需要开发软件。Raspbian还包括一个用户友好的桌面UI（图4），使事情变得更加容易。
|
||||
|
||||
图 4: Raspbian主菜单，显示预安装的开发人员软件.[Used with permission][4]
|
||||
对于任何想要对Raspberry Pi平台开发的人来说，Raspbian是必要的。如果你想在不使用Raspberry Pi硬件的情况下使用Raspbian系统，您可以通过下载[此处][35]的ISO映像将其安装在VirtualBox虚拟机中
|
||||
### Pop!_OS
|
||||
不要让这个名字迷惑你,,不要让这个名字迷惑你, 进入[System76][36]的 [Pop!_OS][37]操作系统世界是非常严格的. 虽然System76对这个Ubuntu衍生产品做了很多修改但不是很明显，但这是特别的。
|
||||
System76的目标是创建一个特定于开发人员，制造商和计算机科学专业人员的操作系统。通过新设计的GNOME主题，Pop！_OS非常漂亮（图5），并且功能与硬件制造商使桌面设计人员一样强大。
|
||||
### [devel_5.jpg][11]
|
||||
|
||||
图 5: Pop!_OS 桌面.[Used with permission][5]
|
||||
但是，Pop！_OS的特殊之处在于它是由一家致力于Linux硬件的公司开发的。这意味着，当您购买System76笔记本电脑，台式机或服务器时，您就会知道操作系统将与硬件无缝协作 - 这是其他公司无法提供的。我预测，Pop！_OS将使System76将成为Linux界Apple。
|
||||
### 工作时间
|
||||
以他们自己的方式，每个发行版。你有一个稳定的桌面（Debian），一个尖端的桌面（openSUSE Tumbleweed），一个服务器（CentOS），一个嵌入式平台（Raspbian），以及一个与硬件无缝融合的发行版（Pop！_OS）。除了Raspbian之外，这些发行版中的任何一个都将成为一个出色的开发平台。安装一个并开始自信地开展下一个项目。
|
||||
可以通过Linux Foundation和edX 免费提供的["Linux简介" ][13]来了解更多的有关Linux信息
|
||||
--------------------------------------------------------------------------------
|
||||
via: https://www.linux.com/blog/learn/intro-to-linux/2018/1/5-best-linux-distributions-development
|
||||
作者：[JACK WALLEN ][a]
|
||||
译者：[geekmar](https://github.com/geekmar)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
[a]:https://www.linux.com/users/jlwallen
|
||||
[1]:https://www.linux.com/licenses/category/used-permission
|
||||
[2]:https://www.linux.com/licenses/category/creative-commons-zero
|
||||
[3]:https://www.linux.com/licenses/category/used-permission
|
||||
[4]:https://www.linux.com/licenses/category/used-permission
|
||||
[5]:https://www.linux.com/licenses/category/used-permission
|
||||
[6]:https://www.linux.com/licenses/category/creative-commons-zero
|
||||
[7]:https://www.linux.com/files/images/devel1jpg
|
||||
[8]:https://www.linux.com/files/images/devel2jpg
|
||||
[9]:https://www.linux.com/files/images/devel3jpg
|
||||
[10]:https://www.linux.com/files/images/devel4jpg
|
||||
[11]:https://www.linux.com/files/images/devel5jpg
|
||||
[12]:https://www.linux.com/files/images/king-penguins1920jpg
|
||||
[13]:https://training.linuxfoundation.org/linux-courses/system-administration-training/introduction-to-linux
|
||||
[14]:https://www.debian.org/
|
||||
[15]:https://www.ubuntu.com/
|
||||
[16]:https://linuxmint.com/
|
||||
[17]:https://elementary.io/
|
||||
[18]:https://www.debian.org/social_contract
|
||||
[19]:https://www.debian.org/doc/manuals/debian-reference/ch12.en.html
|
||||
[20]:https://www.opensuse.org/
|
||||
[21]:https://en.opensuse.org/Portal:Tumbleweed
|
||||
[22]:https://software.opensuse.org/download.html?project=devel%3Atools&package=rpmdevtools
|
||||
[23]:https://www.redhat.com/en/technologies/linux-platforms/enterprise-linux
|
||||
[24]:https://www.centos.org/
|
||||
[25]:https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/pdf/developer_guide/Red_Hat_Enterprise_Linux-7-Developer_Guide-en-US.pdf
|
||||
[26]:https://www.raspberrypi.org/downloads/raspbian/
|
||||
[27]:https://www.bluej.org/
|
||||
[28]:https://www.geany.org/
|
||||
[29]:https://www.greenfoot.org/
|
||||
[30]:https://www.raspberrypi.org/blog/sense-hat-emulator/
|
||||
[31]:http://sonic-pi.net/
|
||||
[32]:http://thonny.org/
|
||||
[33]:https://www.python.org/
|
||||
[34]:https://scratch.mit.edu/
|
||||
[35]:http://rpf.io/x86iso
|
||||
[36]:https://system76.com/
|
||||
[37]:https://system76.com/pop
|
||||
@ -0,0 +1,134 @@
|
||||
Python 数据科学入门
|
||||
======
|
||||
|
||||
|
||||
|
||||
无论你是一个具有数学或计算机科学背景的数据科学爱好者，还是一个其它领域的专家，数据科学提供的可能性都在你力所能及的范围内，而且你不需要昂贵的，高度专业化的企业软件。本文中讨论的开源工具就是你入门时所需的全部内容。
|
||||
|
||||
[Python][1]，其机器学习和数据科学库（[pandas][2], [Keras][3], [TensorFlow][4], [scikit-learn][5], [SciPy][6], [NumPy][7] 等），以及大量可视化库（[Matplotlib][8], [pyplot][9], [Plotly][10] 等）对于初学者和专家来说都是优秀的 FOSS（译注：全称为 Free and Open Source Software）工具。它们易于学习，很受欢迎且受到社区支持，并拥有为数据科学开发的最新技术和算法。它们是你在开始学习时可以获得的最佳工具集之一。
|
||||
|
||||
许多 Python 库都是建立在彼此之上的（称为依赖项），其基础是 [NumPy][7] 库。NumPy 专门为数据科学设计，经常用于在其 ndarray 数据类型中存储数据集的相关部分。ndarray 是一种方便的数据类型，用于将关系表中的记录存储为 `cvs` 文件或其它任何格式，反之亦然。将 scikit 功能应用于多维数组时，它特别方便。SQL 非常适合查询数据库，但是对于执行复杂和资源密集型的数据科学操作，在 ndarray 中存储数据可以提高效率和速度（确保在处理大量数据集时有足够的 RAM）。当你使用 pandas 进行知识提取和分析时，pandas 中的 DataFrame 数据类型和 NumPy 中的 ndarray 之间的无缝转换分别为提取和计算密集型操作创建了一个强大的组合。
|
||||
|
||||
为了快速演示，让我们启动 Python shel 并在 pandas DataFrame 变量中加载来自巴尔的摩（Baltimore）的犯罪统计数据的开放数据集，并查看加载 frame 的一部分：
|
||||
```
|
||||
>>> import pandas as pd
|
||||
|
||||
>>> crime_stats = pd.read_csv('BPD_Arrests.csv')
|
||||
|
||||
>>> crime_stats.head()
|
||||
```
|
||||
|
||||
|
||||
|
||||
我们现在可以在这个 pandas DataFrame 上执行大多数查询就像我们可以在数据库中使用 SQL。例如，要获取 "Description"属性的所有唯一值，SQL 查询是：
|
||||
```
|
||||
$ SELECT unique(“Description”) from crime_stats;
|
||||
|
||||
```
|
||||
|
||||
利用 pandas DataFrame 编写相同的查询如下所示：
|
||||
```
|
||||
>>> crime_stats['Description'].unique()
|
||||
|
||||
['COMMON ASSAULT' 'LARCENY' 'ROBBERY - STREET' 'AGG. ASSAULT'
|
||||
|
||||
'LARCENY FROM AUTO' 'HOMICIDE' 'BURGLARY' 'AUTO THEFT'
|
||||
|
||||
'ROBBERY - RESIDENCE' 'ROBBERY - COMMERCIAL' 'ROBBERY - CARJACKING'
|
||||
|
||||
'ASSAULT BY THREAT' 'SHOOTING' 'RAPE' 'ARSON']
|
||||
|
||||
```
|
||||
|
||||
它返回的是一个 NumPy 数组（ndarray 类型）：
|
||||
```
|
||||
>>> type(crime_stats['Description'].unique())
|
||||
|
||||
<class 'numpy.ndarray'>
|
||||
|
||||
```
|
||||
|
||||
接下来让我们将这些数据输入神经网络，看看它能多准确地预测使用的武器类型，给出的数据包括犯罪事件，犯罪类型以及发生的地点：
|
||||
```
|
||||
>>> from sklearn.neural_network import MLPClassifier
|
||||
|
||||
>>> import numpy as np
|
||||
|
||||
>>>
|
||||
|
||||
>>> prediction = crime_stats[[‘Weapon’]]
|
||||
|
||||
>>> predictors = crime_stats['CrimeTime', ‘CrimeCode’, ‘Neighborhood’]
|
||||
|
||||
>>>
|
||||
|
||||
>>> nn_model = MLPClassifier(solver='lbfgs', alpha=1e-5, hidden_layer_sizes=(5,2), random_state=1)
|
||||
|
||||
>>>
|
||||
|
||||
>>>predict_weapon = nn_model.fit(prediction, predictors)
|
||||
|
||||
```
|
||||
|
||||
现在学习模型准备就绪，我们可以执行一些测试来确定其质量和可靠性。对于初学者，让我们输入一个训练集数据（用于训练模型的原始数据集的一部分，不包括在创建模型中）：
|
||||
```
|
||||
>>> predict_weapon.predict(training_set_weapons)
|
||||
|
||||
array([4, 4, 4, ..., 0, 4, 4])
|
||||
|
||||
```
|
||||
|
||||
如你所见，它返回一个列表，每个数字预测训练集中每个记录的武器。我们之所以看到的是数字而不是武器名称，是因为大多数分类算法都是用数字优化的。对于分类数据，有一些技术可以将属性转换为数字表示。在这种情况下，使用的技术是 Label Encoder，使用 sklearn 预处理库中的 LabelEncoder 函数：`preprocessing.LabelEncoder()`。它能够对一个数据和其对应的数值表示来进行变换和逆变换。在这个例子中，我们可以使用 LabelEncoder() 的 `inverse_transform` 函数来查看武器 0 和 4 是什么:
|
||||
```
|
||||
>>> preprocessing.LabelEncoder().inverse_transform(encoded_weapons)
|
||||
|
||||
array(['HANDS', 'FIREARM', 'HANDS', ..., 'FIREARM', 'FIREARM', 'FIREARM']
|
||||
|
||||
```
|
||||
|
||||
这很有趣，但为了了解这个模型的准确程度，我们将几个分数计算为百分比：
|
||||
```
|
||||
>>> nn_model.score(X, y)
|
||||
|
||||
0.81999999999999995
|
||||
|
||||
```
|
||||
|
||||
这表明我们的神经网络模型准确度约为 82%。这个结果似乎令人印象深刻，但用于不同的犯罪数据集时，检查其有效性非常重要。还有其它测试来做这个，如相关性，混淆，矩阵等。尽管我们的模型有很高的准确率，但它对于一般犯罪数据集并不是非常有用，因为这个特定数据集具有不成比例的行数，其列出 ‘FIREARM’ 作为使用的武器。除非重新训练，否则我们的分类器最有可能预测 ‘FIREARM’，即使输入数据集有不同的分布。
|
||||
|
||||
在对数据进行分类之前清洗数据并删除异常值和畸形数据非常重要。预处理越好，我们的见解准确性就越高。此外，为模型或分类器提供过多数据（通常超过 90%）以获得更高的准确度是一个坏主意，因为它看起来准确但由于[过度拟合][11]而无效。
|
||||
|
||||
[Jupyter notebooks][12] 相对于命令行来说是一个很好的交互式替代品。虽然 CLI 对大多数事情都很好，但是当你想要运行代码片段以生成可视化时，Jupyter 会很出色。它比终端更好地格式化数据。
|
||||
|
||||
[这篇文章][13] 列出了一些最好的机器学习免费资源，但是还有很多其它的指导和教程。根据你的兴趣和爱好，你还会发现许多开放数据集可供使用。作为起点，由 [Kaggle][14] 维护的数据集，以及在州政府网站上提供的数据集是极好的资源。
|
||||
|
||||
(to 校正：最后这句话不知该如何理解)
|
||||
Payal Singh 将出席今年 3 月 8 日至 11 日在 California（加利福尼亚）的 Pasadena（帕萨迪纳）举行的 SCaLE16x。要参加并获得 50% 的门票优惠，[注册][15]使用优惠码**OSDC**。
|
||||
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/18/3/getting-started-data-science
|
||||
|
||||
作者：[Payal Singh][a]
|
||||
译者：[MjSeven](https://github.com/MjSeven)
|
||||
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/payalsingh
|
||||
[1]:https://www.python.org/
|
||||
[2]:https://pandas.pydata.org/
|
||||
[3]:https://keras.io/
|
||||
[4]:https://www.tensorflow.org/
|
||||
[5]:http://scikit-learn.org/stable/
|
||||
[6]:https://www.scipy.org/
|
||||
[7]:http://www.numpy.org/
|
||||
[8]:https://matplotlib.org/
|
||||
[9]:https://matplotlib.org/api/pyplot_api.html
|
||||
[10]:https://plot.ly/
|
||||
[11]:https://www.kdnuggets.com/2014/06/cardinal-sin-data-mining-data-science.html
|
||||
[12]:http://jupyter.org/
|
||||
[13]:https://machinelearningmastery.com/best-machine-learning-resources-for-getting-started/
|
||||
[14]:https://www.kaggle.com/
|
||||
[15]:https://register.socallinuxexpo.org/reg6/
|
||||
@ -0,0 +1,167 @@
|
||||
在 Linux 上使用 systemd 设置定时器
|
||||
======
|
||||
|
||||
|
||||
|
||||
之前，我们看到了如何[手动的][1]、[在开机与关机时][2]、[在启用某个设备时][3]、[在文件系统发生改变时][4]启用与禁用 systemd 服务。
|
||||
|
||||
定时器增加了另一种启动服务的方式，基于...时间。尽管与定时任务很相似，但 systemd 定时器稍微地灵活一些。让我们看看它是怎么工作的。
|
||||
|
||||
### “定时运行”
|
||||
|
||||
让我们展开[本系列前两篇文章][2]中[你所设置的 ][1] [Minetest][5] 服务器作为如何使用定时器单元的第一个例子。如果你还没有读过那几篇文章，可以现在去看看。
|
||||
|
||||
你将通过创建一个定时器来改进 Minetest 服务器，使得在定时器启动 1 分钟后运行游戏服务器而不是立即运行。这样做的原因可能是，在启动之前可能会用到其他的服务，例如发邮件给其他玩家告诉他们游戏已经准备就绪，你要确保其他的服务（例如网络）在开始前完全启动并运行。
|
||||
|
||||
跳到最底下，你的 `_minetest.timer_` 单元看起来就像这样：
|
||||
|
||||
```
|
||||
# minetest.timer
|
||||
[Unit]
|
||||
Description=Runs the minetest.service 1 minute after boot up
|
||||
|
||||
[Timer]
|
||||
OnBootSec=1 m
|
||||
Unit=minetest.service
|
||||
|
||||
[Install]
|
||||
WantedBy=basic.target
|
||||
|
||||
```
|
||||
|
||||
一点也不难吧。
|
||||
|
||||
通常，开头是 `[Unit]` 和一段描述单元作用的信息，这儿没什么新东西。`[Timer]` 这一节是新出现的，但它的作用不言自明：它包含了何时启动服务，启动哪个服务的信息。在这个例子当中，`OnBootSec` 是告诉 systemd 在系统启动后运行服务的指令。
|
||||
|
||||
其他的指令有：
|
||||
|
||||
* `OnActiveSec=`，告诉 systemd 在定时器启动后多长时间运行服务。
|
||||
* `OnStartupSec=`，同样的，它告诉 systemd 在 systemd 进程启动后多长时间运行服务。
|
||||
* `OnUnitActiveSec=`，告诉 systemd 在上次由定时器激活的服务启动后多长时间运行服务。
|
||||
* `OnUnitInactiveSec=`，告诉 systemd 在上次由定时器激活的服务停用后多长时间运行服务。
|
||||
|
||||
继续 `_minetest.timer_` 单元，`basic.target` 通常用作<ruby>后期引导服务<rt>late boot services</rt></ruby>的<ruby>同步点<rt>synchronization point</rt></ruby>。这就意味着它可以让 `_minetest.timer_` 单元运行在安装完<ruby>本地挂载点<rt>local mount points</rt></ruby>或交换设备，套接字、定时器、路径单元和其他基本的初始化进程之后。就像在[第二篇文章中 systemd 单元][2]里解释的那样，`_targets_` 就像<ruby>旧的运行等级<rt>old run levels</rt></ruby>，可以将你的计算机置于某个状态，或像这样告诉你的服务在达到某个状态后开始运行。
|
||||
|
||||
在前两篇文章中你配置的`_minetest.service_`文件[最终][2]看起来就像这样：
|
||||
|
||||
```
|
||||
# minetest.service
|
||||
[Unit]
|
||||
Description= Minetest server
|
||||
Documentation= https://wiki.minetest.net/Main_Page
|
||||
|
||||
[Service]
|
||||
Type= simple
|
||||
User=
|
||||
|
||||
ExecStart= /usr/games/minetest --server
|
||||
ExecStartPost= /home//bin/mtsendmail.sh "Ready to rumble?" "Minetest Starting up"
|
||||
|
||||
TimeoutStopSec= 180
|
||||
ExecStop= /home//bin/mtsendmail.sh "Off to bed. Nightie night!" "Minetest Stopping in 2 minutes"
|
||||
ExecStop= /bin/sleep 120
|
||||
ExecStop= /bin/kill -2 $MAINPID
|
||||
|
||||
[Install]
|
||||
WantedBy= multi-user.target
|
||||
|
||||
```
|
||||
|
||||
这儿没什么需要修改的。但是你需要将 `_mtsendmail.sh_`（发送你的 email 的脚本）从：
|
||||
|
||||
```
|
||||
#!/bin/bash
|
||||
# mtsendmail
|
||||
sleep 20
|
||||
echo $1 | mutt -F /home/<username>/.muttrc -s "$2" my_minetest@mailing_list.com
|
||||
sleep 10
|
||||
|
||||
```
|
||||
|
||||
改成：
|
||||
|
||||
```
|
||||
#!/bin/bash
|
||||
# mtsendmail.sh
|
||||
echo $1 | mutt -F /home/paul/.muttrc -s "$2" pbrown@mykolab.com
|
||||
|
||||
```
|
||||
|
||||
你做的事是去除掉 Bash 脚本中那些蹩脚的停顿。Systemd 现在正在等待。
|
||||
|
||||
### 让它运行起来
|
||||
|
||||
确保一切运作正常，禁用 `_minetest.service_`：
|
||||
```
|
||||
sudo systemctl disable minetest
|
||||
|
||||
```
|
||||
|
||||
这使得系统启动时它不会一同启动；然后，相反地，启用 `_minetest.timer_`：
|
||||
```
|
||||
sudo systemctl enable minetest.timer
|
||||
|
||||
```
|
||||
|
||||
现在你就可以重启服务器了，当运行`sudo journalctl -u minetest.*`后，你就会看到 `_minetest.timer_` 单元执行后大约一分钟，`_minetest.service_` 单元开始运行。
|
||||
|
||||
![minetest timer][7]
|
||||
|
||||
图 1：minetest.timer 运行大约 1 分钟后 minetest.service 开始运行
|
||||
|
||||
[经许可使用][8]
|
||||
|
||||
### 时间的问题
|
||||
|
||||
`_minetest.timer_` 在 systemd 的日志里显示的启动时间为 09:08:33 而 `_minetest.service` 启动时间是 09:09:18，它们之间少于 1 分钟，关于这件事有几点需要说明一下：首先，请记住我们说过 `OnBootSec=` 指令是从引导完成后开始计算服务启动的时间。当 `_minetest.timer_` 的时间到来时，引导已经在几秒之前完成了。
|
||||
|
||||
另一件事情是 systemd 给自己设置了一个<ruby>误差幅度<rt>margin of error</rt></ruby>（默认是 1 分钟）来运行东西。这有助于在多个<ruby>资源密集型进程<rt>resource-intensive processes</rt></ruby>同时运行时分配负载：通过分配 1 分钟的时间，systemd 可以等待某些进程关闭。这也意味着 `_minetest.service_`会在引导完成后的 1~2 分钟之间启动。但精确的时间谁也不知道。
|
||||
|
||||
作为记录，你可以用 `AccuracySec=` 指令[修改误差幅度][9]。
|
||||
|
||||
你也可以检查系统上所有的定时器何时运行或是上次运行的时间：
|
||||
|
||||
```
|
||||
systemctl list-timers --all
|
||||
```
|
||||
|
||||
![check timer][11]
|
||||
|
||||
图 2：检查定时器何时运行或上次运行的时间
|
||||
|
||||
[经许可使用][8]
|
||||
|
||||
最后一件值得思考的事就是你应该用怎样的格式去表示一段时间。Systemd 在这方面非常灵活：`2 h`，`2 hours` 或 `2hr` 都可以用来表示 2 个小时。对于“秒”，你可以用 `seconds`，`second`，`sec` 和 `s`。“分”也是同样的方式：`minutes`，`minute`，`min` 和 `m`。你可以检查 `man systemd.time` 来查看 systemd 能够理解的所有时间单元。
|
||||
|
||||
### 下一次
|
||||
|
||||
下次你会看到如何使用日历中的日期和时间来定期运行服务，以及如何通过组合定时器与设备单元在插入某些硬件时运行服务。
|
||||
|
||||
回头见！
|
||||
|
||||
在 Linux 基金会和 edx 上通过免费课程 [“Introduction to Linux”][12] 学习更多关于 Linux 的知识。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://www.linux.com/blog/learn/intro-to-linux/2018/7/setting-timer-systemd-linux
|
||||
|
||||
作者：[Paul Brown][a]
|
||||
选题：[lujun9972](https://github.com/lujun9972)
|
||||
译者：[LuuMing](https://github.com/LuuMing)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:https://www.linux.com/users/bro66
|
||||
[1]:https://www.linux.com/blog/learn/intro-to-linux/2018/5/writing-systemd-services-fun-and-profit
|
||||
[2]:https://www.linux.com/blog/learn/2018/5/systemd-services-beyond-starting-and-stopping
|
||||
[3]:https://www.linux.com/blog/intro-to-linux/2018/6/systemd-services-reacting-change
|
||||
[4]:https://www.linux.com/blog/learn/intro-to-linux/2018/6/systemd-services-monitoring-files-and-directories
|
||||
[5]:https://www.minetest.net/
|
||||
[6]:/files/images/minetest-timer-1png
|
||||
[7]:https://www.linux.com/sites/lcom/files/styles/rendered_file/public/minetest-timer-1.png?itok=TG0xJvYM (minetest timer)
|
||||
[8]:/licenses/category/used-permission
|
||||
[9]:https://www.freedesktop.org/software/systemd/man/systemd.timer.html#AccuracySec=
|
||||
[10]:/files/images/minetest-timer-2png
|
||||
[11]:https://www.linux.com/sites/lcom/files/styles/rendered_file/public/minetest-timer-2.png?itok=pYxyVx8- (check timer)
|
||||
[12]:https://training.linuxfoundation.org/linux-courses/system-administration-training/introduction-to-linux
|
||||
@ -0,0 +1,110 @@
|
||||
|
||||
顶级 Linux 开发者推荐的编程书籍
|
||||
======
|
||||
|
||||
毫无疑问，Linux 是由那些拥有深厚计算机知识背景而且才华横溢的程序员发明的。让那些大名鼎鼎的 Linux 程序员向今日的开发者分享一些曾经带领他们登堂入室的好书和技术参考吧，你会不会也读过其中几本呢？
|
||||
|
||||
Linux，毫无争议的属于21世纪的操作系统。虽然Linus Torvalds 在建立开源社区这件事上做了很多工作和社区决策，不过那些网络专家和开发者愿意接受Linux的原因还是因为它卓越的代码质量和高可用性。Torvalds 是个编程天才，同时必须承认他还是得到了很多其他同样极具才华的开发者的无私帮助。
|
||||
|
||||
就此我咨询了Torvalds 和其他一些顶级Linux开发者，有哪些书籍帮助他们走上了成为顶级开发者的道路，下面请听我一一道来。
|
||||
|
||||
### 熠熠生辉的 C语言
|
||||
|
||||
Linux 是在大约90年代开发出来的，与它一起问世的还有其他一些完成基础功能的开源软件。与此相应，那时的开发者使用的工具和语言反映了那个时代的印记。可能[C 语言不再流行了][1]，可对于很多已经建功立业的开发者来说，C 语言是他们的第一个实际开发中使用的语言，这一点也在他们推选的对他们有着深远影响的书单中反映出来。
|
||||
|
||||
Torvalds 说，“你不应该再选用我那个时代使用的语言或者开发方式”，他的开发道路始于BASIC，然后转向机器码（“甚至都不是汇编语言，而是真真正正的’二进制‘机器码”，他解释道），再然后转向汇编语言和 C 语言。
|
||||
|
||||
“任何人都不应该再从这些语言开始进入开发这条路了”，他补充道。“这些语言中的一些今天已经没有什么意义（如 BASIC 和机器语言）。尽管 C 还是一个主流语言，我也不推荐你从它开始你的开发工作”。
|
||||
|
||||
并不是他不喜欢 C。不管怎样，Linux 是用[<ruby>C语言<rt>GNU C</rt></ruby>][2]写就的。“我始终认为 C 是一个伟大的语言，它有着非常简单的语法，对于很多方向的开发都很合适，但是我怀疑你会挫折重重，从你的第一个'Hello World'程序开始到你真正能开发出能用的东西当中有很大一步要走”。他认为，如果用现在的标准，如果作为现在的入门语言的话，从 C语言开始的代价太大。
|
||||
|
||||
在他那个时代，Torvalds 的唯一选择的书就只能是Brian W. Kernighan 和Dennis M. Ritchie 合著的[<ruby>C 编程语言<rt>C Programming Language, 2nd Edition</rt></ruby>][3]，在编程圈内也被尊称为K&R。“这本书简单精炼，但是你要先有编程的背景才能欣赏它”。Torvalds 说到。
|
||||
|
||||
Torvalds 并不是唯一一个推荐K&R 的开源开发者。以下几位也同样引用了这本他们认为值得推荐的书籍，他们有：Linux 和 Oracle 虚拟化开发副总裁，Wim Coekaerts；Linux 开发者Alan Cox; Google 云 CTO Brian Stevens; Canonical 技术运营部副总裁Pete Graner。
|
||||
|
||||
|
||||
如果你今日还想同 C 语言较量一番的话，Jeremy Allison，Samba 的共同发起人，推荐[<ruby>21世纪的 C 语言<rt>21st Century C: C Tips from the New School</rt></ruby>][4]。他还建议，同时也去阅读一本比较旧但是写的更详细的[<ruby>C专家编程<rt>Expert C Programming: Deep C Secrets</rt></ruby>][5]和有着20年历史的[<ruby>UNIX POSIX多线程编程<rt>Programming with POSIX Threads</rt></ruby>][6]。
|
||||
|
||||
|
||||
### 如果不选C 语言， 那选什么？
|
||||
|
||||
Linux 开发者推荐的书籍自然都是他们认为适合今时今日的开发项目的语言工具。这也折射了开发者自身的个人偏好。例如, Allison认为年轻的开发者应该在[<ruby>Go 编程语言<rt>The Go Programming Language </rt></ruby>][7]和[<ruby>Rust 编程<rt>Rust with Programming Rust</rt></ruby>][8]的帮助下去学习 Go 语言和 Rust 语言。
|
||||
|
||||
|
||||
但是超越编程语言来考虑问题也不无道理（尽管这些书传授了你编程技巧）。今日要做些有意义的开发工作的话，"要从那些已经完成了99%显而易见工作的框架开始，然后你就能围绕着它开始写脚本了"， Torvalds 推荐了这种做法。
|
||||
|
||||
|
||||
“坦率来说，语言本身远远没有围绕着它的基础架构重要”，他继续道，“可能你会从 Java 或者Kotlin 开始,但那是因为你想为自己的手机开发一个应用，因此安卓 SDK 成为了最佳的选择，又或者，你对游戏开发感兴趣，你选择了一个游戏开发引擎来开始，而通常它们有着自己的脚本语言”。
|
||||
|
||||
|
||||
这里提及的基础架构包括那些和操作系统本身相关的编程书籍。
|
||||
Garner 在读完了大名鼎鼎的 K&R后又拜读了W. Richard Steven 的[<ruby>Unix 网络编程<rt>Unix: Network Programming</rt></ruby>][10]。特别的是，Steven 的[<ruby>TCP/IP详解，卷1：协议<rt>TCP/IP Illustrated, Volume 1: The Protocols</rt></ruby>][11]在出版了30年之后仍然被认为是必读的。因为 Linux 开发很大程度上和[和网络基础架构有关][12]，Garner 也推荐了很多 O’Reilly 的书，包括[Sendmail][13],[Bash][14],[DNS][15],以及[IMAP/POP][16]。
|
||||
|
||||
Coekaerts也是Maurice Bach的[<ruby>UNIX操作系统设计<rt>The Design of the Unix Operation System</rt></ruby>][17]的书迷之一。James Bottomley 也是这本书的推崇者，作为一个 Linux 内核开发者，当 Linux 刚刚问世时James就用Bach 的这本书所传授的知识将它研究了个底朝天。
|
||||
|
||||
### 软件设计知识永不过时
|
||||
|
||||
尽管这样说有点太局限在技术领域。Stevens 还是说到，“所有的开发者都应该在开始钻研语法前先研究如何设计，[<ruby>日常物品的设计<rt>The Design of Everyday Things</rt></ruby>][18]是我的最爱”。
|
||||
|
||||
Coekaerts 喜欢Kernighan 和 Rob Pike合著的[<ruby>程序设计实践<rt>The Practic of Programming</rt></ruby>][19]。这本关于设计实践的书当 Coekaerts 还在学校念书的时候还未出版，他说道,“但是我把它推荐给每一个人”。
|
||||
|
||||
|
||||
不管何时，当你问一个长期认真对待开发工作的开发者他最喜欢的计算机书籍时，你迟早会听到一个名字和一本书:
|
||||
Donald Knuth和他所著的[<ruby>计算机程序设计艺术(1-4A)<rt>The Art of Computer Programming, Volumes 1-4A</rt></ruby>][20]。Dirk Hohndel,VMware 首席开源官，认为这本书尽管有永恒的价值，但他也承认，“今时今日并非及其有用”。（译注：不代表译者观点）
|
||||
|
||||
|
||||
### 读代码。大量的读。
|
||||
|
||||
编程书籍能教会你很多，也请别错过另外一个在开源社区特有的学习机会：[<ruby>如何阅读代码<rt>Code Reading: The Open Source Perspective</rt></ruby>][21]。那里有不可计数的代码例子阐述如何解决编程问题（以及如何让你陷入麻烦...）。Stevens 说，谈到磨炼编程技巧，在他的书单里排名第一的“书”是 Unix 的源代码。
|
||||
|
||||
"也请不要忽略从他人身上学习的各种机会。", Cox道，“我是在一个计算机俱乐部里和其他人一起学的 BASIC，在我看来，这仍然是一个学习的最好办法”，他从[<ruby>精通 ZX81机器码<rt>Mastering machine code on your ZX81</rt></ruby>][22]这本书和 Honeywell L66 B 编译器手册里学习到了如何编写机器码，但是学习技术这点来说，单纯阅读和与其他开发者在工作中共同学习仍然有着很大的不同。
|
||||
|
||||
|
||||
Cox 说,“我始终认为最好的学习方法是和一群人一起试图去解决你们共同关心的一些问题并从中找到快乐，这和你是5岁还是55岁无关”。
|
||||
|
||||
|
||||
最让我吃惊的是这些顶级 Linux 开发者都是在非常底层级别开始他们的开发之旅的，甚至不是从汇编语言或 C 语言，而是从机器码开始开发。毫无疑问，这对帮助开发者理解计算机在非常微观的底层级别是怎么工作的起了非常大的作用。
|
||||
|
||||
|
||||
那么现在你准备好尝试一下硬核 Linux 开发了吗？Greg Kroah-Hartman,这位 Linux 内核过期分支的维护者，推荐了Steve Oualline 的[<ruby>实用 C 语言编程<rt>Practical C Programming</rt></ruby>][23]和Samuel harbison 以及Guy Steels 合著的[<ruby>C语言参考手册<rt>C: A Reference Manual</rt></ruby>][24]。接下来请阅读“[<ruby>如何进行 Linux 内核开发<rt>HOWTO do Linux kernel development</rt></ruby>][25]”,到这时，就像Kroah-Hartman所说，你已经准备好启程了。
|
||||
|
||||
于此同时，还请你刻苦学习并大量编码，最后祝你在跟随顶级 Linux 开发者脚步的道路上好运相随。
|
||||
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://www.hpe.com/us/en/insights/articles/top-linux-developers-recommended-programming-books-1808.html
|
||||
|
||||
作者：[Steven Vaughan-Nichols][a]
|
||||
选题：[lujun9972](https://github.com/lujun9972)
|
||||
译者：DavidChenLiang(https://github.com/DavidChenLiang)
|
||||
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.hpe.com/us/en/insights/contributors/steven-j-vaughan-nichols.html
|
||||
[1]:https://www.codingdojo.com/blog/7-most-in-demand-programming-languages-of-2018/
|
||||
[2]:https://www.gnu.org/software/gnu-c-manual/
|
||||
[3]:https://amzn.to/2nhyjEO
|
||||
[4]:https://amzn.to/2vsL8k9
|
||||
[5]:https://amzn.to/2KBbWn9
|
||||
[6]:https://amzn.to/2M0rfeR
|
||||
[7]:https://amzn.to/2nhyrnMe
|
||||
[8]:http://shop.oreilly.com/product/0636920040385.do
|
||||
[9]:https://www.hpe.com/us/en/resources/storage/containers-for-dummies.html?jumpid=in_510384402_linuxbooks_containerebook0818
|
||||
[10]:https://amzn.to/2MfpbyC
|
||||
[11]:https://amzn.to/2MpgrTn
|
||||
[12]:https://www.hpe.com/us/en/insights/articles/how-to-see-whats-going-on-with-your-linux-system-right-now-1807.html
|
||||
[13]:http://shop.oreilly.com/product/9780596510299.do
|
||||
[14]:http://shop.oreilly.com/product/9780596009656.do
|
||||
[15]:http://shop.oreilly.com/product/9780596100575.do
|
||||
[16]:http://shop.oreilly.com/product/9780596000127.do
|
||||
[17]:https://amzn.to/2vsCJgF
|
||||
[18]:https://amzn.to/2APzt3Z
|
||||
[19]:https://www.amazon.com/Practice-Programming-Addison-Wesley-Professional-Computing/dp/020161586X/ref=as_li_ss_tl?ie=UTF8&linkCode=sl1&tag=thegroovycorpora&linkId=e6bbdb1ca2182487069bf9089fc8107e&language=en_US
|
||||
[20]:https://amzn.to/2OknFsJ
|
||||
[21]:https://amzn.to/2M4VVL3
|
||||
[22]:https://amzn.to/2OjccJA
|
||||
[23]:http://shop.oreilly.com/product/9781565923065.do
|
||||
[24]:https://amzn.to/2OjzgrT
|
||||
[25]:https://www.kernel.org/doc/html/v4.16/process/howto.html
|
||||
@ -1,59 +0,0 @@
|
||||
6 个托管你 git 仓库的地方
|
||||
======
|
||||
|
||||
|
||||
|
||||
也许你是少数一些没有注意到的人之一就在几周前，[微软收购了 GitHub][1]。两家公司达成了共识。微软在近些年已经变成了开源的有力支持者，GitHub 从成立起，就已经成为了许多开源项目的实际代码库。
|
||||
|
||||
然而，最近的购买可能会带给你一些烦躁。毕竟公司的收购让你意识到了你的开源代码放在了一个商业平台上。可能你现在还没准备好迁移到其他的平台上去，但是至少这可以给你提供一些可选项。让我们找找网上现在都有哪些可用的平台。
|
||||
|
||||
### 选择之一： GitHub
|
||||
|
||||
严格来说，这是一个合格的选项。[GitHub][2] 历史上没有什么糟糕的失败，而且微软最近也确实发展了不少开源项目。把你的项目继续放在 GitHub 上，继续保持观望没有什么不可以。它现在依然是最大的软件开发的网络社区,同时还有许多对于问题追踪、代码复查、持续集成、通用的代码管理很有用的工具。而且它还是基于 Git 的，Git 是每个人都喜欢的开源版本控制系统。你的代码还是你的代码。
|
||||
|
||||
### 选择之二： GitLab
|
||||
|
||||
[GitLab][3] 是代码库平台主要的竞争者。它是完全开源的。你可以像在 GitHhub 一样把你的代码托管在 GitLab，但你也可以选择在你自己的服务器上自行托管你自己的 GitLab 实例，并完全控制谁可以访问那里的所有内容以及如何访问、管理。 GitLab 与 GitHub 功能几乎相同，有些人甚至可能会说它的持续集成和测试工具更优越。尽管 GitLab 上的开发者社区肯定比 GitHub 上的开发者社区要小，但它仍然没有什么可以被指责的。你可能会在那里的人群中找到更多志同道合的开发者。
|
||||
|
||||
### 选择之三： Bitbucket
|
||||
|
||||
[Bitbucket][4] 已经存在很多年了。在某些方面，它可以作为 GitHub 未来的一面镜子。 Bitbucket 八年前被一家大公司（Atlassian）收购，并且已经经历了一些转换过程。 它仍然是一个像 GitHub 这样的商业平台，但它远不是一个创业公司，而且从组织上说它的基础相当稳定。 Bitbucket 分享了 GitHub 和 GitLab 上的大部分功能，以及它自己的一些新功能，如对 [Mercurial][5] 存储库的本机支持。
|
||||
|
||||
### 选择之四： SourceForge
|
||||
|
||||
[SourceForge][6] 是开源代码库的鼻祖。如果你曾经有一个开源项目，Sourceforge 是一个托管你的代码和向他人分享你的发行版的地方。迁移到 Git 进行版本控制需要一段时间，它有自己的商业收购和重新组构的事件，以及一些开源项目的一些不幸的捆绑决策。也就是说，SourceForge 从那时起似乎已经恢复，该网站仍然是一个有着不少开源项目的地方。 然而，很多人仍然感到有点受伤，而且有些人并不是各种尝试通过平台货币化的忠实粉丝，所以一定要睁大眼睛。
|
||||
|
||||
### 选择之五： 自己管理
|
||||
|
||||
如果你想自己掌握自己项目的命运（除了你自己没人可以责备你），然后一切都由自己来做对你来说可能是最佳的选择。无论对于大项目还是小项目。Git 是开源的，所以自己托管也很容易。如果你问题追踪和代码审查，你可以运行一个 GitLab 或者 [Phabricator][7] 的实例。对于持续集成，你可以设置自己的 [Jenkins][8] 自动化服务的实例。是的，你需要对自己的基础架构开销和相关的安全要求负责。但是，这个设置过程并不是很困难。所以如果你不想自己的代码被其他人的平台所吞没，这就是一种很好的方法。
|
||||
|
||||
### 选择之六：以上全部
|
||||
|
||||
以下是所有这些的美妙之处：尽管这些平台上有一些专有的选项，但它们仍然建立在坚实的开源技术之上。 而且不仅仅是开源，而是明确设计为分布在大型网络（如互联网）上的多个节点上。 你不需要只使用一个。 你可以使用一对......或者全部。 使用 GitLab 将你自己的设置作为保证的基础，并在 GitHub 和 Bitbucket 上安装克隆存储库，以进行问题跟踪和持续集成。 将你的主代码库保留在 GitHub 上，但是为了你自己的想法，可以在 GitLab 上安装“备份”克隆。
|
||||
|
||||
关键在于你的选择是什么。我们能有这么多选择，都是得益于那些非常有用的项目上的开源协议。未来一片光明。
|
||||
|
||||
当然，在这个列表中我肯定忽略了一些开源平台。你是否使用了很多的平台？哪个是你最喜欢的？你都可以在这里说出来！
|
||||
|
||||
：）
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/18/8/github-alternatives
|
||||
|
||||
作者：[Jason van Gumster][a]
|
||||
选题：[lujun9972](https://github.com/lujun9972)
|
||||
译者：[dianbanjiu](https://github.com/dianbanjiu)
|
||||
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/mairin
|
||||
[1]: https://www.theverge.com/2018/6/4/17422788/microsoft-github-acquisition-official-deal
|
||||
[2]: https://github.com/
|
||||
[3]: https://gitlab.com
|
||||
[4]: https://bitbucket.org
|
||||
[5]: https://www.mercurial-scm.org/wiki/Repository
|
||||
[6]: https://sourceforge.net
|
||||
[7]: https://phacility.com/phabricator/
|
||||
[8]: https://jenkins.io
|
||||
@ -1,177 +0,0 @@
|
||||
为什么linux用户应该尝试Rust
|
||||
======
|
||||
|
||||
|
||||
|
||||
Rust是一种相当年轻和现代的编程语言，因为具有许多功能，所以它非常灵活而且非常安全。 数据显示它正在变得非常受欢迎，连续三年在Stack Overflow开发者调查中获得“最受喜爱的编程语言”的第一名 - [2016] [1]，[2017] [2]和[2018] [3]。
|
||||
|
||||
Rust也是开源语言的一种，它具有一系列特功能，使得它可以适应许多不同的编程项目。 它最初源于2006年Mozilla员工的个人项目，几年后（2009年）被Mozilla收集为特别项目，然后在2010年宣布供公众使用。
|
||||
|
||||
Rust程序运行速度极快，可防止段错误，并保证线程安全。 这些属性使该语言极大地吸引了专注于应用程序安全性的开发人员。 Rust也是一种非常易读的语言，可用于从简单程序到非常大而复杂的项目。
|
||||
|
||||
Rust 优点:
|
||||
|
||||
* 内存安全—— Rust不会受到悬空指针，缓冲区溢出或其他与内存相关的错误的影响。 它提供内存安全，无回收垃圾。
|
||||
* 通用 - Rust是适用于任何类型编程的适当语言
|
||||
* 快速 - Rust在性能上与C / C ++相当，但具有更好的安全功能。
|
||||
* 高效 - Rust是为了便于并发编程而构建的。
|
||||
* 面向项目 - Rust具有内置的依赖关系和构建管理系统Cargo。
|
||||
* 得到很好的支持 - Rust有一个令人印象深刻的[支持社区] [4]。
|
||||
|
||||
|
||||
|
||||
Rust还强制执行RAII（资源获取初始化）。 这意味着当一个对象超出范围时，将调用其析构函数并释放其资源，从而提供防止资源泄漏的屏蔽。 它提供了功能抽象和一个伟大的[类型系统] [5]以及速度和数学健全性。
|
||||
|
||||
简而言之，Rust是一种令人印象深刻的系统编程语言，具有其他大多数语言所缺乏的功能，使其成为C，C++和Objective-C等多年来一直被使用的语言的有力竞争者。
|
||||
|
||||
### 安装 Rust
|
||||
|
||||
安装Rust是一个相当简单的过程。
|
||||
|
||||
```
|
||||
$ curl https://sh.rustup.rs -sSf | sh
|
||||
```
|
||||
|
||||
安装Rust后，使用rustc** --version **或** which **命令显示版本信息。
|
||||
|
||||
```
|
||||
$ which rustc
|
||||
rustc 1.27.2 (58cc626de 2018-07-18)
|
||||
$ rustc --version
|
||||
rustc 1.27.2 (58cc626de 2018-07-18)
|
||||
```
|
||||
|
||||
### Rust入门
|
||||
|
||||
Rust即使是最简单的代码也与你之前使用过的语言的输入完全不同。
|
||||
|
||||
```
|
||||
$ cat hello.rs
|
||||
fn main() {
|
||||
// Print a greeting
|
||||
println!("Hello, world!");
|
||||
}
|
||||
```
|
||||
|
||||
在这些行中，我们正在设置一个函数（main），添加一个描述该函数的注释，并使用println语句来创建输出。 您可以使用下面显示的命令编译然后运行这样的程序。
|
||||
|
||||
```
|
||||
$ rustc hello.rs
|
||||
$ ./hello
|
||||
Hello, world!
|
||||
```
|
||||
|
||||
你可以创建一个“项目”（通常仅用于比这个更复杂的程序！）来保持代码的有序性。
|
||||
|
||||
```
|
||||
$ mkdir ~/projects
|
||||
$ cd ~/projects
|
||||
$ mkdir hello_world
|
||||
$ cd hello_world
|
||||
```
|
||||
|
||||
请注意，即使是简单的程序，一旦编译，就会变成相当大的可执行文件。
|
||||
|
||||
```
|
||||
$ ./hello
|
||||
Hello, world!
|
||||
$ ls -l hello*
|
||||
-rwxrwxr-x 1 shs shs 5486784 Sep 23 19:02 hello <== executable
|
||||
-rw-rw-r-- 1 shs shs 68 Sep 23 15:25 hello.rs
|
||||
```
|
||||
|
||||
当然，这只是一个开始且传统的“Hello, world!” 程序。 Rust语言具有一系列功能，可帮助你快速进入高级编程技能。
|
||||
|
||||
### 学习 Rust
|
||||
|
||||
![rust programming language book cover][6]
|
||||
No Starch Press
|
||||
|
||||
Steve Klabnik和Carol Nichols（2018）的Rust Programming Language一书提供了学习Rust的最佳方法之一。 这本书由核心开发团队的两名成员撰写，可从[No Starch Press] [7]出版社获得纸制书或者从[rust-lang.org] [8]获得电子书。 它已经成为Rust开发者社区中的参考书。
|
||||
|
||||
在所涉及的众多主题中，你将了解这些高级主题：
|
||||
|
||||
* 所有权和borrowing
|
||||
|
||||
* 安全保障
|
||||
|
||||
* 测试和错误处理
|
||||
|
||||
* 智能指针和多线程
|
||||
|
||||
* 高级模式匹配
|
||||
|
||||
* 使用Cargo（内置包管理器）
|
||||
|
||||
* 使用Rust的高级编译器
|
||||
|
||||
|
||||
|
||||
#### 目录
|
||||
|
||||
|
||||
```
|
||||
前言（Nicholas Matsakis和Aaron Turon编写）
|
||||
致谢
|
||||
介绍
|
||||
第1章：新手入门
|
||||
第2章：猜谜游戏
|
||||
第3章：通用编程概念
|
||||
第4章：了解所有权
|
||||
第五章：结构
|
||||
第6章：枚举和模式匹配
|
||||
第7章：模块
|
||||
第8章：常见集合
|
||||
第9章：错误处理
|
||||
第10章：通用类型，特征和生命周期
|
||||
第11章：测试
|
||||
第12章：输入/输出项目
|
||||
第13章：迭代器和闭包
|
||||
第14章：关于货物和Crates.io的更多信息
|
||||
第15章：智能指针
|
||||
第16章：并发
|
||||
第17章：Rust面向对象？
|
||||
第18章：模式
|
||||
第19章：关于生命周期的更多信息
|
||||
第20章：高级类型系统功能
|
||||
附录A：关键字
|
||||
附录B：运算符和符号
|
||||
附录C：可衍生的特征
|
||||
附录D：宏
|
||||
索引
|
||||
|
||||
```
|
||||
|
||||
[Rust编程语言] [7]将你从基本安装和语言语法带到复杂的主题，例如模块，错误处理，crates（与其他语言中的'library'或'package'同义），模块（允许你 将你的代码分配到包箱本身，生命周期等。
|
||||
|
||||
可能最重要的是，本书可以让您从基本的编程技巧转向构建和编译复杂，安全且非常有用的程序。
|
||||
|
||||
### 结束
|
||||
|
||||
如果你已经准备好用一种非常值得花时间和精力学习并且越来越受欢迎的语言进行一些严肃的编程，那么Rust是一个不错的选择！
|
||||
|
||||
加入[Facebook] [9]和[LinkedIn] [10]上的Network World社区，评论最重要的话题。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
|
||||
via: https://www.networkworld.com/article/3308162/linux/why-you-should-try-rust.html
|
||||
|
||||
作者：[Sandra Henry-Stocker][a]
|
||||
选题：[lujun9972](https://github.com/lujun9972)
|
||||
译者：[way-ww](https://github.com/way-ww)
|
||||
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/
|
||||
[1]: https://insights.stackoverflow.com/survey/2016#technology-most-loved-dreaded-and-wanted
|
||||
[2]: https://insights.stackoverflow.com/survey/2017#technology-most-loved-dreaded-and-wanted-languages
|
||||
[3]: https://insights.stackoverflow.com/survey/2018#technology-most-loved-dreaded-and-wanted-languages
|
||||
[4]: https://www.rust-lang.org/en-US/community.html
|
||||
[5]: https://doc.rust-lang.org/reference/type-system.html
|
||||
[6]: https://images.idgesg.net/images/article/2018/09/rust-programming-language_book-cover-100773679-small.jpg
|
||||
[7]: https://nostarch.com/Rust
|
||||
[8]: https://doc.rust-lang.org/book/2018-edition/index.html
|
||||
[9]: https://www.facebook.com/NetworkWorld/
|
||||
[10]: https://www.linkedin.com/company/network-world
|
||||
@ -0,0 +1,82 @@
|
||||
使用极简浏览器 Min 浏览网页
|
||||
======
|
||||
> 并非所有 web 浏览器都要做到无所不能，Min 就是一个极简主义风格的浏览器。
|
||||
|
||||
|
||||
现在还有开发新的网络浏览器的需要吗？即使现在浏览器领域已经成为了寡头市场，但仍然不断涌现出各种前所未有的浏览器产品。
|
||||
|
||||
[Min][1] 就是其中一个。顾名思义，Min 是一个小的浏览器，也是一个极简主义的浏览器。但它麻雀虽小五脏俱全，而且还是一个开源的浏览器，它的 Apache 2.0 许可证引起了我的注意。
|
||||
|
||||
让我们来看看 Min 有什么值得关注的方面。
|
||||
|
||||
### 开始
|
||||
|
||||
Min 基于 [Electron][2] 框架开发，值得一提的是，[Atom 文本编辑器][3]也是基于这个框架开发的。它提供 Linux、MacOS 和 Windows 的[安装程序][4]，当然也可以[从 GitHub 获取它的源代码][5]自行编译安装。
|
||||
|
||||
我使用的 Linux 发行版是 Manjaro，但没有完全匹配这个发行版的安装程序。还好，我通过 Manjaro 的包管理器也能安装 Min。
|
||||
|
||||
安装完成后，在终端就可以直接启动 Min。
|
||||
|
||||
|
||||
|
||||
Min 号称是更智能、更快速的浏览器。经过尝试以后，我觉得它比我在其它电脑上使用过的 Firefox 和 Chrome 浏览器启动得更快。
|
||||
|
||||
而使用 Min 浏览网页的过程则和 Firefox 或 Chrome 一样，只要再地址栏输入 URL，回车，就好了。
|
||||
|
||||
### Min 的功能
|
||||
|
||||
尽管 Min 不可能带有 Firefox 或 Chrome 等浏览器得所有功能，但它也有可取之处。
|
||||
|
||||
Min 和其它浏览器一样，支持页面选项卡。它还有一个称为 Tasks 的功能，可以对打开的选项卡进行分组。
|
||||
|
||||
[DuckDuckGo][6]是我最喜欢的搜索引擎，而 Min 的默认搜索引擎恰好就是它，这正合我意。当然，如果你喜欢另一个搜索引擎，也可以在 Min 的偏好设置中配置你喜欢的搜索引擎作为默认搜索引擎。
|
||||
|
||||
Min 没有使用类似 AdBlock 这样的插件来过滤你不想看到的内容，而是使用了一个名为 [EasyList][7] 的内置的广告拦截器，你可以使用它来屏蔽脚本和图片。另外 Min 还带有一个内置的防跟踪软件。
|
||||
|
||||
类似 Firefox，Min 有一个名为叫做 Reading List 的阅读模式。只需点击地址栏中的对应图标，就可以去除页面中的大部分无关内容，让你专注于正在阅读的内容。网页在阅读列表中可以保留 30 天。
|
||||
|
||||
|
||||
|
||||
Min 还有一个专注模式，可以隐藏其它选项卡并阻止你打开新的选项卡。在专注模式下，如果一个 web 页面中进行工作，需要多点击好几次才能打开一个新页面。
|
||||
|
||||
Min 也有很多快捷键让你快速使用某个功能。你可以[在 GitHub 上][8]找到这些这些快捷键的参考文档，也可以在 Min 的偏好设置中进行更改。
|
||||
|
||||
我发现 Min 可以在 YouTube、Vimeo、Dailymotion 等视频网站上播放视频，还可以在音乐网站 7Digital 上播放音乐。但由于我没有账号，所以没法测试是否能在 Spotify 或 Last.fm 等这些网站上播放音乐。
|
||||
|
||||
|
||||
|
||||
### Min 的弱点
|
||||
|
||||
Min 确实也有自己的缺点，例如它无法将网站添加为书签。替代方案要么是查看 Min 的搜索历史来找回你需要的链接，要么是使用一个第三方的书签服务。
|
||||
|
||||
最大的缺点是 Min 不支持插件。这对我来说不是一件坏事，因为浏览器启动速度和运行速度快的主要原因就在于此。当然也有一些人非常喜欢使用浏览器插件，Min 就不是他们的选择。
|
||||
|
||||
### 总结
|
||||
|
||||
Min 算是一个中规中矩的浏览器，它可以凭借轻量、快速的优点吸引很多极简主义的用户。但是对于追求多功能的用户来说，Min 就显得相当捉襟见肘了。
|
||||
.
|
||||
所以，如果你想摆脱当今多功能浏览器的束缚，我觉得可以试用一下 Min。
|
||||
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/18/10/min-web-browser
|
||||
|
||||
作者：[Scott Nesbitt][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/scottnesbitt
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://minbrowser.github.io/min/
|
||||
[2]: http://electron.atom.io/apps/
|
||||
[3]: https://opensource.com/article/17/5/atom-text-editor-packages-writers
|
||||
[4]: https://github.com/minbrowser/min/releases/
|
||||
[5]: https://github.com/minbrowser/min
|
||||
[6]: http://duckduckgo.com
|
||||
[7]: https://easylist.to/
|
||||
[8]: https://github.com/minbrowser/min/wiki
|
||||
|
||||
123
translated/tech/20181018 Understanding Linux Links- Part 1.md
Normal file
123
translated/tech/20181018 Understanding Linux Links- Part 1.md
Normal file
@ -0,0 +1,123 @@
|
||||
理解 Linux 链接：第一部分
|
||||
======
|
||||
|
||||
|
||||
|
||||
除了 `cp` 和 `mv` 这两个我们在[本系列的前一部分][1]中详细讨论过的，链接是另一种方式可以将文件和目录放在你希它们放在的位置。它的优点是可以让你同时在多个位置显示一个文件或目录。
|
||||
|
||||
如前所述，在物理磁盘这个级别上，文件和目录之类的东西并不真正存在。文件系统为了方便人类使用，将它们虚构出来。但在磁盘级别上，有一个名为 _partition table_（分区表）的东西，它位于每个分区的开头，然后数据分散在磁盘的其余部分。
|
||||
|
||||
虽然有不同类型的分区表，但是在分区开头的表包含的数据将映射每个目录和文件的开始和结束位置。分区表的就像一个索引：当从磁盘加载文件时，操作系统会查找表中的条目，分区表会告诉文件在磁盘上的起始位置和结束位置。然后磁盘头移动到起点，读取数据，直到它到达终点，最后告诉 presto：这就是你的文件。
|
||||
|
||||
### 硬链接
|
||||
|
||||
硬链接只是分区表中的一个条目，它指向磁盘上的某个区域，表示该区域**已经被分配给文件**。换句话说，硬链接指向已经被另一个条目索引的数据。让我们看看它是如何工作的。
|
||||
|
||||
打开终端，创建一个实验目录并进入：
|
||||
```
|
||||
mkdir test_dir
|
||||
cd test_dir
|
||||
```
|
||||
|
||||
使用 [touch][1] 创建一个文件：
|
||||
```
|
||||
touch test.txt
|
||||
```
|
||||
|
||||
为了获得更多的体验（？），在文本编辑器中打开 _test.txt_ 并添加一些单词。
|
||||
|
||||
现在通过执行以下命令来建立硬链接：
|
||||
```
|
||||
ln test.txt hardlink_test.txt
|
||||
```
|
||||
|
||||
运行 `ls`，你会看到你的目录现在包含两个文件，或者看起来如此。正如你之前读到的那样，你真正看到的是完全相同的文件的两个名称： _hardlink\_test.txt_ 包含相同的内容，没有填充磁盘中的任何更多空间（尝试使用大文件来测试），并与 _test.txt_ 使用相同的 inode：
|
||||
```
|
||||
$ ls -li *test*
|
||||
16515846 -rw-r--r-- 2 paul paul 14 oct 12 09:50 hardlink_test.txt
|
||||
16515846 -rw-r--r-- 2 paul paul 14 oct 12 09:50 test.txt
|
||||
```
|
||||
|
||||
_ls_ 的 `-i` 选项显示一个文件的 _inode 数值_。_inode_ 是分区表中的信息块，它包含磁盘上文件或目录的位置，上次修改的时间以及其它数据。如果两个文件使用相同的 inode，那么无论它们在目录树中的位置如何，它们在实际效果上都是相同的文件。
|
||||
|
||||
### 软链接
|
||||
|
||||
软链接，也称为 _symlinks_（系统链接），它是不同的：软链接实际上是一个独立的文件，它有自己的 inode 和它自己在磁盘上的小插槽。但它只包含一小段数据，将操作系统指向另一个文件或目录。
|
||||
|
||||
你可以使用 `ln` 的 `-s` 选项来创建一个软链接：
|
||||
```
|
||||
ln -s test.txt softlink_test.txt
|
||||
```
|
||||
|
||||
这将在当前目录中创建软链接 _softlink\_test.txt_，它指向 _test.txt_。
|
||||
|
||||
再次执行 `ls -li`，你可以看到两种链接的不同之处：
|
||||
```
|
||||
$ ls -li
|
||||
total 8
|
||||
16515846 -rw-r--r-- 2 paul paul 14 oct 12 09:50 hardlink_test.txt
|
||||
16515855 lrwxrwxrwx 1 paul paul 8 oct 12 09:50 softlink_test.txt -> test.txt
|
||||
16515846 -rw-r--r-- 2 paul paul 14 oct 12 09:50 test.txt
|
||||
```
|
||||
|
||||
_hardlink\_test.txt_ 和 _test.txt_ 包含一些文本并占据相同的空格*字面*。它们使用相同的 inode 数值。与此同时，_softlink\_test.txt_ 占用少得多，并且具有不同的 inode 数值，将其标记为完全不同的文件。使用 _ls_ 的 `-l` 选项还会显示软链接指向的文件或目录。
|
||||
|
||||
### 为什么要用链接？
|
||||
|
||||
它们适用于**带有自己环境的应用程序**。你的 Linux 发行版通常不会附带你需要应用程序的最新版本。以优秀的 [Blender 3D][2] 设计软件为例，Blender 允许你创建 3D 静态图像以及动画电影，人人都想在自己的机器上拥有它。问题是，当前版本的 Blender 至少比任何发行版中的自带的高一个版本。
|
||||
|
||||
幸运的是，[Blender 提供下载][3]开箱即用。除了程序本身之外，这些软件包还包含了 Blender 需要运行的复杂的库和依赖框架。所有这些数据和块都在它们自己的目录层次中。
|
||||
|
||||
每次你想运行 Blender，你都可以 `cd` 到你下载它的文件夹并运行：
|
||||
```
|
||||
./blender
|
||||
```
|
||||
|
||||
但这很不方便。如果你可以从文件系统的任何地方，比如桌面命令启动器中运行 `blender` 命令会更好。
|
||||
|
||||
这样做的方法是将 _blender_ 可执行文件链接到 _bin/_ 目录。在许多系统上，你可以通过将其链接到文件系统中的任何位置来使 `blender` 命令可用，就像这样。
|
||||
```
|
||||
ln -s /path/to/blender_directory/blender /home/<username>/bin
|
||||
```
|
||||
|
||||
你需要链接的另一个情况是**软件需要过时的库**。如果你用 `ls -l` 列出你的 _/usr/lib_ 目录，你会看到许多软链接文件飞过。仔细看看，你会看到软链接通常与它们链接到的原始文件具有相似的名称。你可能会看到 _libblah_ 链接到 _libblah.so.2_，你甚至可能会注意到 _libblah.so.2_ 依次链接到原始文件 _libblah.so.2.1.0_。
|
||||
|
||||
这是因为应用程序通常需要安装比已安装版本更老的库。问题是，即使新版本仍然与旧版本（通常是）兼容，如果程序找不到它正在寻找的版本，程序将会出现问题。为了解决这个问题，发行版通常会创建链接，以便挑剔的应用程序相信它找到了旧版本，实际上它只找到了一个链接并最终使用了更新的库版本。
|
||||
|
||||
有些是和**你自己从源代码编译的程序**相关。你自己编译的程序通常最终安装在 _/usr/local_ 下，程序本身最终在 _/usr/local/bin_ 中，它在 _/usr/local/bin_ 目录中查找它需要的库。但假设你的新程序需要 _libblah_，但 _libblah_ 在 _/usr/lib_ 中，这就是所有其它程序都会寻找到它的地方。你可以通过执行以下操作将其链接到 _/usr/local/lib_：
|
||||
```
|
||||
ln -s /usr/lib/libblah /usr/local/lib
|
||||
```
|
||||
|
||||
或者如果你愿意，可以 `cd` 到 _/usr/local/lib_：
|
||||
```
|
||||
cd /usr/local/lib
|
||||
```
|
||||
|
||||
然后使用链接：
|
||||
```
|
||||
ln -s ../lib/libblah
|
||||
```
|
||||
|
||||
还有几十个案例证明软链接是有用的，当你使用 Linux 更熟练时，你肯定会发现它们，但这些是最常见的。下一次，我们将看一些你需要注意的链接怪异。
|
||||
|
||||
通过 Linux 基金会和 edX 的免费 ["Linux 简介"][4]课程了解有关 Linux 的更多信息。
|
||||
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://www.linux.com/blog/intro-to-linux/2018/10/linux-links-part-1
|
||||
|
||||
作者：[Paul Brown][a]
|
||||
选题：[lujun9972][b]
|
||||
译者：[MjSeven](https://github.com/MjSeven)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]: https://www.linux.com/users/bro66
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://www.linux.com/blog/2018/8/linux-beginners-moving-things-around
|
||||
[2]: https://www.blender.org/
|
||||
[3]: https://www.blender.org/download/
|
||||
[4]: https://training.linuxfoundation.org/linux-courses/system-administration-training/introduction-to-linux
|
||||
@ -0,0 +1,53 @@
|
||||
在 Fedora 上使用 Pitivi 编辑你的视频
|
||||
======
|
||||
|
||||
|
||||
想制作一部你本周末冒险的视频吗？视频编辑有很多选择。但是，如果你在寻找一个容易上手的视频编辑器，并且也可以在官方 Fedora 仓库中找到，请尝试一下[Pitivi][1]。
|
||||
|
||||
Pitivi 是一个使用 GStreamer 框架的开源非线性视频编辑器。在 Fedora 下开箱即用，Pitivi 支持 OGG、WebM 和一系列其他格式。此外，通过 gstreamer 插件可以获得更多视频格式支持。Pitivi 也与 GNOME 桌面紧密集成，因此相比其他新的程序，它的 UI 在 Fedora Workstation 上会感觉很熟悉。
|
||||
|
||||
### 在 Fedora 上安装 Pitivi
|
||||
|
||||
Pitivi 可以在 Fedora 仓库中找到。在 Fedora Workstation 上，只需在应用中心搜索并安装 Pitivi。
|
||||
|
||||
![][2]
|
||||
|
||||
或者，使用以下命令在终端中安装 Pitivi：
|
||||
|
||||
```
|
||||
sudo dnf install pitivi
|
||||
```
|
||||
|
||||
### 基本编辑
|
||||
|
||||
Pitivi 内置了多种工具，可以快速有效地编辑剪辑。只需将视频、音频和图像导入 Pitivi 媒体库，然后将它们拖到时间线上即可。此外，除了时间线上的简单淡入淡出过渡之外，pitivi 还允许你轻松地将剪辑的各个部分分割、修剪和分组。
|
||||
|
||||
![][3]
|
||||
|
||||
### 过渡和效果
|
||||
|
||||
除了两个剪辑之间的基本淡入淡出外，Pitivi 还具有一系列不同的过渡和擦除功能。此外，有超过一百种效果可应用于视频或音频，以更改媒体元素在最终演示中的播放或显示方式。
|
||||
|
||||
![][4]
|
||||
|
||||
Pitivi 还具有一系列其他强大功能，因此请务必查看其网站上的[教程][5]来获得 Pitivi 功能的完整描述。
|
||||
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://fedoramagazine.org/edit-your-videos-with-pitivi-on-fedora/
|
||||
|
||||
作者：[Ryan Lerch][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://fedoramagazine.org/introducing-flatpak/
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: http://www.pitivi.org/
|
||||
[2]: https://fedoramagazine.org/wp-content/uploads/2018/10/Screenshot-from-2018-10-19-14-46-12.png
|
||||
[3]: https://fedoramagazine.org/wp-content/uploads/2018/10/Screenshot-from-2018-10-19-15-37-29.png
|
||||
[4]: http://www.pitivi.org/i/screenshots/archive/0.94.jpg
|
||||
[5]: http://www.pitivi.org/?go=tour
|
||||
@ -0,0 +1,339 @@
|
||||
用 Pandoc 做一篇调研论文
|
||||
======
|
||||
学习如何用 Markdown 管理引用、图像、表格、以及更多。
|
||||
|
||||
|
||||
这篇文章对于使用 [Markdown][1] 语法做一篇调研论文进行了一个深度体验。覆盖了如何创建和引用、图像（用 Markdown 和 [LaTeX][2]）和参考书目。我们也讨论了一些棘手的案例和为什么使用 LaTex 是一个正确的做法。
|
||||
|
||||
### 调查
|
||||
|
||||
调研论文一般包括引用、图像、表格和参考书目。[Pandoc][3] 本身并不能交叉引用这些，但是但是它能够利用 [pandoc-crossref][4] 过滤来完成自动编号和章节、图像、表格的交叉引用。
|
||||
|
||||
让我们开始正常的使用 LaTax 重写 [一个教育调研报告的例子][5]，然后用 Markdown（和一些 LaTax）、Pandoc 和 Pandoc-crossref 再重写。
|
||||
|
||||
#### 添加并引用章节
|
||||
|
||||
要想章节被自动编号，必须使用 Markdown 标题 H1 编写。子章节使用子标题 H2-H4 编写（通常不需要更多的东西）。例如一个章节的标题是 “履行”，写作 `# 履行 {#sec: 履行}`，然后 Pandoc 会把它转化为 `3. 履行`（或者转换为相应的章节标号）。`履行` 这个标题使用了 H1 并且声明了一个 `{#sec: 履行}` 的标签，这是作者引用了该章节的标签。要想引用一个章节，在对应章节后面输入 `@` 符号并使用方括号括起来即可： `[@sec:履行]`
|
||||
|
||||
[在这篇论文中][5], 我们发现了下面这个例子：
|
||||
|
||||
```
|
||||
we lack experience (consistency between TAs, [@sec:implementation]).
|
||||
```
|
||||
|
||||
Pandoc 转换：
|
||||
|
||||
```
|
||||
we lack experience (consistency between TAs, Section 4).
|
||||
```
|
||||
|
||||
章节被自动（这包含在文章最后的 `Makefile` 当中）标号。要创建无标号的章节，输入章节的标题并在最后添加 `{-}`。例如：`### 设计一个可维护的游戏 {-}` 就以标题 “设计一个可维护的游戏”，创建了一个无标号的章节。
|
||||
|
||||
#### 添加并引用图像
|
||||
|
||||
添加并引用一个图像，跟添加并引用一个章节和添加一个 Markdown 图片很相似：
|
||||
|
||||
```
|
||||
{#fig:scatter-matrix}
|
||||
```
|
||||
上面这一行是告诉 Pandoc，有一个标有 Scatterplot matrix 的图像以及这张图片路径是 `data/scatterplots/RScatterplotMatrix2.png`。`{#fig:scatter-matrix}` 表明了应该引用的图像的名字。
|
||||
|
||||
这里是从一篇论文中进行图像引用的例子：
|
||||
|
||||
```
|
||||
The boxes "Enjoy", "Grade" and "Motivation" ([@fig:scatter-matrix]) ...
|
||||
```
|
||||
|
||||
Pandoc 产生如下输出：
|
||||
|
||||
```
|
||||
The boxes "Enjoy", "Grade" and "Motivation" (Fig. 1) ...
|
||||
```
|
||||
|
||||
#### 添加及引用参考书目
|
||||
大多数调研报告都把引用放在一个 BibTeX 的数据库文件中。在这个例子中，该文件被命名为 [biblio.bib][6]，它包含了论文中所有的引用。下面是这个文件的样子：
|
||||
|
||||
```
|
||||
@inproceedings{wrigstad2017mastery,
|
||||
Author = {Wrigstad, Tobias and Castegren, Elias},
|
||||
Booktitle = {SPLASH-E},
|
||||
Title = {Mastery Learning-Like Teaching with Achievements},
|
||||
Year = 2017
|
||||
}
|
||||
|
||||
@inproceedings{review-gamification-framework,
|
||||
Author = {A. Mora and D. Riera and C. Gonzalez and J. Arnedo-Moreno},
|
||||
Publisher = {IEEE},
|
||||
Booktitle = {2015 7th International Conference on Games and Virtual Worlds
|
||||
for Serious Applications (VS-Games)},
|
||||
Doi = {10.1109/VS-GAMES.2015.7295760},
|
||||
Keywords = {formal specification;serious games (computing);design
|
||||
framework;formal design process;game components;game design
|
||||
elements;gamification design frameworks;gamification-based
|
||||
solutions;Bibliographies;Context;Design
|
||||
methodology;Ethics;Games;Proposals},
|
||||
Month = {Sept},
|
||||
Pages = {1-8},
|
||||
Title = {A Literature Review of Gamification Design Frameworks},
|
||||
Year = 2015,
|
||||
Bdsk-Url-1 = {http://dx.doi.org/10.1109/VS-GAMES.2015.7295760}
|
||||
}
|
||||
|
||||
...
|
||||
```
|
||||
|
||||
第一行的 `@inproceedings{wrigstad2017mastery,` 表明了出版物 (`inproceedings`) 的类型，以及用来指向那篇论文 (`wrigstad2017mastery`) 的标签。
|
||||
|
||||
引用这篇题为 “Mastery Learning-Like Teaching with Achievements” 的论文, 输入:
|
||||
|
||||
```
|
||||
the achievement-driven learning methodology [@wrigstad2017mastery]
|
||||
```
|
||||
|
||||
Pandoc 将会输出:
|
||||
|
||||
```
|
||||
the achievement- driven learning methodology [30]
|
||||
```
|
||||
|
||||
这篇论文将会产生像下面这样被标号的参考书目：
|
||||
|
||||
|
||||
|
||||
引用文章的集合也很容易：只要引用使用分号 `;` 分隔开被标记的参考文献就可以了。如果一个引用有两个标签 —— 例如： `SEABORN201514` 和 `gamification-leaderboard-benefits`—— 像下面这样把它们放在一起引用：
|
||||
|
||||
```
|
||||
Thus, the most important benefit is its potential to increase students' motivation
|
||||
|
||||
and engagement [@SEABORN201514;@gamification-leaderboard-benefits].
|
||||
```
|
||||
|
||||
Pandoc 将会产生:
|
||||
|
||||
```
|
||||
Thus, the most important benefit is its potential to increase students’ motivation
|
||||
|
||||
and engagement [26, 28]
|
||||
```
|
||||
|
||||
### 问题案例
|
||||
|
||||
一个常见的问题是项目与页面不匹配。不匹配的部分会自动移动到它们认为合适的地方，即便这些位置并不是读者期望看到的位置。因此在图像或者表格接近于它们被提及的地方时，我们需要调节一下它们在此处的元素组合，使得他们更加易于阅读。为了达到这个效果，我建议使用 `figure` 这个 LaTeX 环境参数，它可以让用户控制图像的位置。
|
||||
|
||||
我们看一个上面提到的图像的例子：
|
||||
|
||||
```
|
||||
{#fig:scatter-matrix}
|
||||
```
|
||||
|
||||
然后使用 LaTeX 重写：
|
||||
|
||||
```
|
||||
\begin{figure}[t]
|
||||
\includegraphics{data/scatterplots/RScatterplotMatrix2.png}
|
||||
\caption{\label{fig:matrix}Scatterplot matrix}
|
||||
\end{figure}
|
||||
```
|
||||
|
||||
在 LaTeX 中，`figure` 环境参数中的 `[t]` 选项表示这张图用该位于该页的最顶部。有关更多选项，参阅 [LaTex/Floats, Figures, and Captions][7] 这篇 Wikibooks 的文章。
|
||||
|
||||
### 产生一篇论文
|
||||
|
||||
到目前为止，我们讲了如何添加和引用（子）章节、图像和参考书目，现在让我们重温一下如何生产一篇 PDF 格式的论文，生成 PDF，我们将使用 Pandoc 生成一篇可以被构建成最终 PDF 的 LaTeX 文件。我们还会讨论如何以 LaTeX，使用一套自定义的模板和元信息文件生成一篇调研论文，以及如何构建 LaTeX 文档为最终的 PDF 格式。
|
||||
|
||||
很多会议都提供了一个 **.cls** 文件或者一套论文该有样子的模板; 例如，他们是否应该使用两列的格式以及其他的设计风格。在我们的例子中，会议提供了一个名为 **acmart.cls** 的文件。
|
||||
|
||||
作者通常想要在他们的论文中包含他们所属的机构，然而，这个选项并没有包含在默认的 Pandoc 的 LaTeX 模板（注意，可以通过输入 `pandoc -D latex` 来查看 Pandoc 模板）当中。要包含这个内容，找一个 Pandoc 默认的 LaTeX 模板，并添加一些新的内容。将这个模板像下面这样复制进一个名为 `mytemplate.tex` 的文件中：
|
||||
|
||||
```
|
||||
pandoc -D latex > mytemplate.tex
|
||||
```
|
||||
|
||||
默认的模板包含以下代码：
|
||||
|
||||
```
|
||||
$if(author)$
|
||||
\author{$for(author)$$author$$sep$ \and $endfor$}
|
||||
$endif$
|
||||
$if(institute)$
|
||||
\providecommand{\institute}[1]{}
|
||||
\institute{$for(institute)$$institute$$sep$ \and $endfor$}
|
||||
$endif$
|
||||
```
|
||||
|
||||
因为这个模板应该包含作者的联系方式和电子邮件地址，在其他一些选项之间，我们可以添加以下内容（我们还做了一些其他的更改，但是因为文件的长度，就没有包含在此处）更新这个模板
|
||||
|
||||
```
|
||||
latex
|
||||
$for(author)$
|
||||
$if(author.name)$
|
||||
\author{$author.name$}
|
||||
$if(author.affiliation)$
|
||||
\affiliation{\institution{$author.affiliation$}}
|
||||
$endif$
|
||||
$if(author.email)$
|
||||
\email{$author.email$}
|
||||
$endif$
|
||||
$else$
|
||||
$author$
|
||||
$endif$
|
||||
$endfor$
|
||||
```
|
||||
要让这些更改起作用，我们还应该有下面的文件：
|
||||
|
||||
* `main.md` 包含调研论文
|
||||
* `biblio.bib` 包含参考书目数据库
|
||||
* `acmart.cls` 我们使用的文档的集合
|
||||
* `mytemplate.tex` 是我们使用的模板文件（代替默认的）
|
||||
|
||||
|
||||
|
||||
让我们添加论文的元信息到一个 `meta.yaml` 文件：
|
||||
|
||||
```
|
||||
---
|
||||
template: 'mytemplate.tex'
|
||||
documentclass: acmart
|
||||
classoption: sigconf
|
||||
title: The impact of opt-in gamification on `\\`{=latex} students' grades in a software design course
|
||||
author:
|
||||
- name: Kiko Fernandez-Reyes
|
||||
affiliation: Uppsala University
|
||||
email: kiko.fernandez@it.uu.se
|
||||
- name: Dave Clarke
|
||||
affiliation: Uppsala University
|
||||
email: dave.clarke@it.uu.se
|
||||
- name: Janina Hornbach
|
||||
affiliation: Uppsala University
|
||||
email: janina.hornbach@fek.uu.se
|
||||
bibliography: biblio.bib
|
||||
abstract: |
|
||||
An achievement-driven methodology strives to give students more control over their learning with enough flexibility to engage them in deeper learning. (more stuff continues)
|
||||
|
||||
include-before: |
|
||||
\```{=latex}
|
||||
\copyrightyear{2018}
|
||||
\acmYear{2018}
|
||||
\setcopyright{acmlicensed}
|
||||
\acmConference[MODELS '18 Companion]{ACM/IEEE 21th International Conference on Model Driven Engineering Languages and Systems}{October 14--19, 2018}{Copenhagen, Denmark}
|
||||
\acmBooktitle{ACM/IEEE 21th International Conference on Model Driven Engineering Languages and Systems (MODELS '18 Companion), October 14--19, 2018, Copenhagen, Denmark}
|
||||
\acmPrice{XX.XX}
|
||||
\acmDOI{10.1145/3270112.3270118}
|
||||
\acmISBN{978-1-4503-5965-8/18/10}
|
||||
|
||||
\begin{CCSXML}
|
||||
<ccs2012>
|
||||
<concept>
|
||||
<concept_id>10010405.10010489</concept_id>
|
||||
<concept_desc>Applied computing~Education</concept_desc>
|
||||
<concept_significance>500</concept_significance>
|
||||
</concept>
|
||||
</ccs2012>
|
||||
\end{CCSXML}
|
||||
|
||||
\ccsdesc[500]{Applied computing~Education}
|
||||
|
||||
\keywords{gamification, education, software design, UML}
|
||||
\```
|
||||
figPrefix:
|
||||
- "Fig."
|
||||
- "Figs."
|
||||
secPrefix:
|
||||
- "Section"
|
||||
- "Sections"
|
||||
...
|
||||
```
|
||||
|
||||
这个元信息文件使用 LaTeX 设置下列参数：
|
||||
|
||||
* `template` 指向使用的模板（’mytemplate.tex‘）
|
||||
* `documentclass` 指向使用的 LaTeX 文档集合 (`acmart`)
|
||||
* `classoption` 是在 `sigconf` 的案例中，指向这个类的选项
|
||||
* `title` 指定论文的标题
|
||||
* `author` 是一个包含例如 `name`, `affiliation`, 和 `email` 的地方
|
||||
* `bibliography` 指向包含参考书目的文件 (biblio.bib)
|
||||
* `abstract` 包含论文的摘要
|
||||
* `include-before` 是这篇论文的真实内容之前应该被包含的信息；在 LaTeX 中被称为 [前言][8]。我在这里包含它去展示如何产生一篇计算机科学的论文，但是你可以选择跳过
|
||||
* `figPrefix` 指向如何引用文档中的图像，例如：当引用图像的 `[@fig:scatter-matrix]` 时应该显示什么。例如，当前的 `figPrefix` 在这个例子 `The boxes "Enjoy", "Grade" and "Motivation" ([@fig:scatter-matrix])`中，产生了这样的输出：`The boxes "Enjoy", "Grade" and "Motivation" (Fig. 3)`。如果这里有很多图像，目前的设置表明它应该在图像号码旁边显示 `Figs.`。
|
||||
* `secPrefix` 指定如何引用文档中其他地方提到的部分（类似之前的图像和概览）
|
||||
|
||||
|
||||
|
||||
现在已经设置好了元信息，让我们来创建一个 `Makefile`，它会产生你想要的输出。`Makefile` 使用 Pandoc 产生 LaTeX 文件，`pandoc-crossref` 产生交叉引用，`pdflatex` 构建 LaTeX 为 PDF，`bibtex ` 处理引用。
|
||||
|
||||
|
||||
`Makefile` 已经展示如下：
|
||||
|
||||
```
|
||||
all: paper
|
||||
|
||||
paper:
|
||||
@pandoc -s -F pandoc-crossref --natbib meta.yaml --template=mytemplate.tex -N \
|
||||
-f markdown -t latex+raw_tex+tex_math_dollars+citations -o main.tex main.md
|
||||
@pdflatex main.tex &> /dev/null
|
||||
@bibtex main &> /dev/null
|
||||
@pdflatex main.tex &> /dev/null
|
||||
@pdflatex main.tex &> /dev/null
|
||||
|
||||
clean:
|
||||
rm main.aux main.tex main.log main.bbl main.blg main.out
|
||||
|
||||
.PHONY: all clean paper
|
||||
```
|
||||
|
||||
Pandoc 使用下面的标记：
|
||||
|
||||
* `-s` 创建一个独立的 LaTeX 文档
|
||||
* `-F pandoc-crossref` 利用 `pandoc-crossref` 进行过滤
|
||||
* `--natbib` 用 `natbib` （你也可以选择 `--biblatex`）对参考书目进行渲染
|
||||
* `--template` 设置使用的模板文件
|
||||
* `-N` 为章节的标题编号
|
||||
* `-f` 和 `-t` 指定从哪个格式转换到哪个格式。`-t` 通常包含格式和 Pandoc 使用的扩展。在这个例子中，我们标明的 `raw_tex+tex_math_dollars+citations` 允许在 Markdown 中使用 `raw_tex` LaTeX。 `tex_math_dollars` 让我们能够像在 LaTeX 中一样输入数学符号，`citations` 让我们可以使用 [这个扩展][9].
|
||||
|
||||
|
||||
|
||||
由 LaTeX 产生 PDF，接着引导行 [从 bibtex][10] 处理参考书目：
|
||||
|
||||
```
|
||||
@pdflatex main.tex &> /dev/null
|
||||
@bibtex main &> /dev/null
|
||||
@pdflatex main.tex &> /dev/null
|
||||
@pdflatex main.tex &> /dev/null
|
||||
```
|
||||
|
||||
脚本用 `@` 忽略输出，并且重定向标准输出和错误到 `/dev/null` ，因此我们在使用这些命令的可执行文件时不会看到任何的输出。
|
||||
|
||||
最终的结果展示如下。这篇文章的库可以在 [GitHub][11] 找到：
|
||||
|
||||
|
||||
|
||||
### 结论
|
||||
|
||||
在我看来，研究的重点是协作，思想的传播，以及在任何一个恰好存在的领域中改进现有的技术。许多计算机科学家和工程师使用 LaTeX 文档系统来写论文，它对数学提供了完美的支持。来自社会科学的调查员似乎更喜欢 DOCX 文档。
|
||||
|
||||
当身处不同社区的调查员一同写一篇论文时，他们首先应该讨论一下他们将要使用哪种格式。然而如果包含太多的数学符号，DOCX 对于工程师来说不会是最简便的选择，LaTeX 对于缺乏编程经验的调查员来说也有一些问题。就像这篇文章中展示的，Markdown 是一门工程师和社会科学家都很轻易能够使用的语言。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/18/9/pandoc-research-paper
|
||||
|
||||
作者：[Kiko Fernandez-Reyes][a]
|
||||
选题：[lujun9972][b]
|
||||
译者：[dianbanjiu](https://github.com/dianbanjiu)
|
||||
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/kikofernandez
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://en.wikipedia.org/wiki/Markdown
|
||||
[2]: https://www.latex-project.org/
|
||||
[3]: https://pandoc.org/
|
||||
[4]: http://lierdakil.github.io/pandoc-crossref/
|
||||
[5]: https://dl.acm.org/citation.cfm?id=3270118
|
||||
[6]: https://github.com/kikofernandez/pandoc-examples/blob/master/research-paper/biblio.bib
|
||||
[7]: https://en.wikibooks.org/wiki/LaTeX/Floats,_Figures_and_Captions#Figures
|
||||
[8]: https://www.sharelatex.com/learn/latex/Creating_a_document_in_LaTeX#The_preamble_of_a_document
|
||||
[9]: http://pandoc.org/MANUAL.html#citations
|
||||
[10]: http://www.bibtex.org/Using/
|
||||
[11]: https://github.com/kikofernandez/pandoc-examples/tree/master/research-paper
|
||||
@ -0,0 +1,78 @@
|
||||
正确选择开源数据库的 5 个技巧
|
||||
======
|
||||
> 对关键应用的选择不容许丝毫错误。
|
||||
|
||||
|
||||
|
||||
你或许会遇到需要选择适合的开源数据库的情况。但这无论对于开源方面的老手或是新手，都是一项艰巨的任务。
|
||||
|
||||
在过去的几年中，采用开源技术的企业越来越多。面对这样的趋势，众多开源应用公司都纷纷承诺自己提供的解决方案能够各种问题、适应各种负载。但这些承诺不能轻信，在开源应用上的选择是重要而艰难的，尤其是数据库这种关键的应用。
|
||||
|
||||
凭借我在 [Percona][1] 和其它公司担任 IT 专家的经验，我很幸运能够指导其他人在开源技术的选择上做出正确的决策，因为需要考虑的重要因素太多了。希望通过这篇文章能够向大家分享这方面的一些技巧。
|
||||
|
||||
### 有一个明确的目标
|
||||
|
||||
这一点看似简单，但在和很多人聊过 MySQL、MongoDB、PostgreSQL 之后，我觉得这一点才是最重要的。
|
||||
|
||||
面对繁杂的开源数据库，更需要明确自己的目标。无论这个数据库是作为开发用的标准化数据库后端，抑或是用于替换遗留代码中的原有数据库，这都是一个明确的目标。
|
||||
|
||||
目标一旦确定，就可以集中精力与开源软件的提供方商讨更多细节了。
|
||||
|
||||
### 了解你的工作负载
|
||||
|
||||
尽管开源数据库技术的功能越来越丰富，但这些新加入的功能都不太具有普适性。譬如 MongoDB 新增了事务的支持、MySQL 新增了 JSON 存储的功能等等。目前开源数据库的普遍趋势是不断加入新的功能，但很多人的误区却在于没有选择最适合的工具来完成自己的工作——这样的人或许是一个自大的开发者，又或许是一个视野狭窄的主管——最终导致公司业务上的损失。最致命的是，在业务初期，使用了不适合的工具往往也可以顺利地完成任务，但随着业务的增长，很快就会到达瓶颈，尽管这个时候还可以替换更合适的工具，但成本就比较高了。
|
||||
|
||||
例如，如果你需要的是数据分析仓库，关系数据库可能不是一个适合的选择；如果你处理事务的应用要求严格的数据完整性和一致性，就不要考虑 NoSQL 了。
|
||||
|
||||
### 不要重新发明轮子
|
||||
|
||||
在过去的数十年，开源数据库技术迅速发展壮大。开源数据库从新生，到受到质疑，再到受到认可，现在已经成为很多企业生产环境的数据库。企业不再需要担心选择开源数据库技术会产生风险，因为开源数据库通常都有活跃的社区，可以为越来越多的初创公司、中型企业甚至 500 强公司提供开源数据库领域的支持和第三方工具。
|
||||
|
||||
Battery Ventures 是一家专注于技术的投资公司，最近推出了一个用于跟踪最受欢迎开源项目的 [BOSS 指数][2] 。它提供了对一些被广泛采用的开源项目和活跃的开源项目的详细情况。其中，数据库技术毫无悬念地占据了榜单的主导地位，在前十位之中占了一半。这个 BOSS 指数对于刚接触开源数据库领域的人来说，这是一个很好的切入点。当然，开源技术的提供者也会针对很多常见的典型问题给出对应的解决方案。
|
||||
|
||||
我认为，你想要做的事情很可能已经有人解决过了。即使这些先行者的解决方案不一定完全契合你的需求，但也可以从他们成功或失败案例中根据你自己的需求修改得出合适的解决方案。
|
||||
|
||||
如果你采用了一个最前沿的技术，这就是你探索的好机会了。如果你的工作负载刚好适合新的开源数据库技术，放胆去尝试吧。第一个吃螃蟹的人总是会得到意外的挑战和收获。
|
||||
|
||||
### 先从简单开始
|
||||
|
||||
你的数据库实际上需要达到多少个 [9][4] 的可用性？对许多公司来说，“实现高可用性”仅仅只是一个模糊的目标。当然，最常见的答案都会是“它是关键应用，我们无论多短的停机时间都是无法忍受的”。
|
||||
|
||||
数据库环境越复杂，管理的难度就越大，成本也会越高。理论上你总可以将数据库的可用性提得更高，但代价将会是大大增加的管理难度和性能下降。所以，先从简单开始，直到有需要时再逐步扩展。
|
||||
|
||||
例如，Booking.com 是一个有名的旅游预订网站。但少有人知的是，它使用 MySQL 作为数据库后端。 Booking.com 高级系统架构师 Nicolai Plum 曾经发表过一次[演讲][5]，讲述了他们公司使用 MySQL 数据库的历程。其中一个重点就是，在初始阶段数据库可以被配置得很简单，然后逐渐变得复杂。对于早期的数据库需求，一个简单的主从架构就足够了，但随着工作负载和数据量的增加，数据库引入了负载均衡、多个读取副本，还使用 Hadoop 进行分析。尽管如此，早期的架构仍然是非常简单的。
|
||||
|
||||
|
||||
|
||||
### 有疑问，找专家
|
||||
|
||||
如果你仍然不确定数据库选择得是否合适，可以在论坛、网站或者与软件的提供者处商讨。研究各种开源数据库是否满足自己的需求是一件很有意义的事，因为总会发现你从不知道的技术。而开源社区就是分享这些信息的地方。
|
||||
|
||||
当你接触到开源软件和软件提供者时，有一件重要的事情需要注意。很多公司都有开放的核心业务模式，鼓励采用他们的数据库软件。你可以只接受他们的部分建议和指导，然后用你自己的能力去研究和探索替代方案。
|
||||
|
||||
### 总结
|
||||
|
||||
选择正确的开源数据库是一个重要的过程。很多时候，人们都会在真正理解需求之前就做出决定，这是本末倒置的。
|
||||
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/18/10/tips-choosing-right-open-source-database
|
||||
|
||||
作者：[Barrett Chambers][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/barrettc
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://www.percona.com/
|
||||
[2]: https://techcrunch.com/2017/04/07/tracking-the-explosive-growth-of-open-source-software/
|
||||
[3]: https://docs.aws.amazon.com/quickstart/latest/mongodb/welcome.html
|
||||
[4]: https://en.wikipedia.org/wiki/Five_nines
|
||||
[5]: https://www.percona.com/live/mysql-conference-2015/sessions/bookingcom-evolution-mysql-system-design
|
||||
[6]: https://allthingsopen.org/talk/choosing-the-right-open-source-database/
|
||||
[7]: https://allthingsopen.org/
|
||||
|
||||
@ -0,0 +1,98 @@
|
||||
使用Python的toolz库开始函数式编程
|
||||
======
|
||||
|
||||
toolz库允许你操作函数，使其更容易理解，更容易测试代码。
|
||||
|
||||
|
||||
|
||||
在这个由两部分组成的系列文章的第二部分中，我们将继续探索如何将函数式编程方法中的好想法引入到 Python中，以实现两全其美。
|
||||
|
||||
在上一篇文章中，我们介绍了[不可变数据结构][1]。 这些数据结构使得我们可以编写“纯”函数，或者说是没有副作用的函数，仅仅接受一些参数并返回结果，同时保持良好的性能。
|
||||
|
||||
在这篇文章中，我们使用 toolz 库来构建。 这个库具有操作此类函数的函数，并且它们在纯函数中表现得特别好。 在函数式编程世界中，它们通常被称为“高阶函数”，因为它们将函数作为参数，将函数作为结果返回。
|
||||
|
||||
让我们从这里开始：
|
||||
|
||||
```
|
||||
def add_one_word(words, word):
|
||||
return words.set(words.get(word, 0) + 1)
|
||||
```
|
||||
|
||||
这个函数假设它的第一个参数是一个不可变的类似字典的对象，它返回一个新的类似字典的在相关位置递增的对象：这就是一个简单的频率计数器。
|
||||
|
||||
但是，只有将它应用于单词流并做归纳时才有用。 我们可以使用内置模块 `functools` 中的归纳器。 `functools.reduce(function, stream, initializer)`
|
||||
|
||||
我们想要一个函数，应用于流，并且能能返回频率计数。
|
||||
|
||||
我们首先使用 `toolz.curry` 函数：
|
||||
|
||||
```
|
||||
add_all_words = curry(functools.reduce, add_one_word)
|
||||
```
|
||||
|
||||
使用此版本，我们需要提供初始化程序。 但是，我们不能只将 `pyrsistent.m` 函数添加到 `curry` 函数中中； 因为这个顺序是错误的。
|
||||
|
||||
```
|
||||
add_all_words_flipped = flip(add_all_words)
|
||||
```
|
||||
|
||||
The `flip` higher-level function returns a function that calls the original, with arguments flipped.
|
||||
|
||||
`flip` 这个高阶函数返回一个调用原始函数的函数，并且翻转参数顺序。
|
||||
|
||||
```
|
||||
get_all_words = add_all_words_flipped(pyrsistent.m())
|
||||
```
|
||||
|
||||
我们利用 `flip` 自动调整其参数的特性给它一个初始值：一个空字典。
|
||||
|
||||
现在我们可以执行 `get_all_words(word_stream)` 这个函数来获取频率字典。 但是，我们如何获得一个单词流呢？ Python文件是行流的。
|
||||
|
||||
```
|
||||
def to_words(lines):
|
||||
for line in lines:
|
||||
yield from line.split()
|
||||
```
|
||||
|
||||
在单独测试每个函数后，我们可以将它们组合在一起：
|
||||
|
||||
```
|
||||
words_from_file = toolz.compose(get_all_words, to_words)
|
||||
```
|
||||
|
||||
在这种情况下，组合只是使两个函数很容易阅读：首先将文件的行流应用于 `to_words`，然后将 `get_all_words` 应用于 `to_words` 的结果。 散文似乎与代码相反。
|
||||
|
||||
当我们开始认真对待可组合性时，这很重要。 有时可以将代码编写为一个单元序列，单独测试每个单元，最后将它们全部组合。 如果有几个组合元素时，组合的顺序可能就很难理解。
|
||||
|
||||
`toolz` 库借用了 Unix 命令行的做法，并使用 `pipe` 作为执行相同操作的函数，但顺序相反。
|
||||
|
||||
```
|
||||
words_from_file = toolz.pipe(to_words, get_all_words)
|
||||
```
|
||||
|
||||
Now it reads more intuitively: Pipe the input into `to_words`, and pipe the results into `get_all_words`. On a command line, the equivalent would look like this:
|
||||
|
||||
现在读起来更直观了：将输入传递到 `to_words`，并将结果传递给 `get_all_words`。 在命令行上，等效写法如下所示：
|
||||
|
||||
```
|
||||
$ cat files | to_words | get_all_words
|
||||
```
|
||||
|
||||
The `toolz` library allows us to manipulate functions, slicing, dicing, and composing them to make our code easier to understand and to test.
|
||||
|
||||
`toolz` 库允许我们操作函数，切片，分割和组合，以使我们的代码更容易理解和测试。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/18/10/functional-programming-python-toolz
|
||||
|
||||
作者：[Moshe Zadka][a]
|
||||
选题：[lujun9972][b]
|
||||
译者：[Flowsnow](https://github.com/Flowsnow)
|
||||
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/article/18/10/functional-programming-python-immutable-data-structures
|
||||
Loading…
Reference in New Issue
Block a user