mirror of
https://github.com/LCTT/TranslateProject.git
synced 2024-12-29 21:41:00 +08:00
Merge remote-tracking branch 'upstream/master'
This commit is contained in:
David Chen
commit
da83bc6e86
@ -1,11 +1,16 @@
|
||||
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。
|
||||
|
||||
@ -1,12 +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
|
||||
|
||||
@ -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
|
||||
@ -1,138 +0,0 @@
|
||||
Translating by MjSeven
|
||||
|
||||
|
||||
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
|
||||
@ -1,5 +1,3 @@
|
||||
Translating by jlztan
|
||||
|
||||
Top 10 Raspberry Pi blogs to follow
|
||||
======
|
||||
|
||||
|
||||
@ -1,3 +1,5 @@
|
||||
translating by Flowsnow
|
||||
|
||||
Quiet log noise with Python and machine learning
|
||||
======
|
||||
|
||||
|
||||
@ -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
|
||||
|
||||
@ -1,3 +1,5 @@
|
||||
Translating by MjSeven
|
||||
|
||||
Understanding Linux Links: Part 1
|
||||
======
|
||||
|
||||
|
||||
@ -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
|
||||
@ -1,3 +1,4 @@
|
||||
translating by dianbanjiu
|
||||
How to use Pandoc to produce a research paper
|
||||
======
|
||||
Learn how to manage section references, figures, tables, and more in Markdown.
|
||||
|
||||
@ -1,81 +0,0 @@
|
||||
HankChow translating
|
||||
|
||||
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
|
||||
@ -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
|
||||
@ -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
|
||||
|
||||
@ -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 +1,78 @@
|
||||
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