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56
translated/tech/20191116 6 Methods to Quickly Check if a Website is up or down from the Linux Terminal.md → published/20191116 6 Methods to Quickly Check if a Website is up or down from the Linux Terminal.md
View File

@ -1,24 +1,26 @@
[#]: collector: (lujun9972)
[#]: translator: (lxbwolf)
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: reviewer: (wxy)
[#]: publisher: (wxy)
[#]: url: (https://linux.cn/article-11661-1.html)
[#]: subject: (6 Methods to Quickly Check if a Website is up or down from the Linux Terminal)
[#]: via: (https://www.2daygeek.com/linux-command-check-website-is-up-down-alive/)
[#]: author: (Magesh Maruthamuthu https://www.2daygeek.com/author/magesh/)
在 Linux Terminal 快速检测网站是否宕机的 6 个方法
在 Linux 终端快速检测网站是否宕机的 6 个方法
======
本教程教你怎样在 Linux terminal 快速检测一个网站是否宕机。
> 本教程教你怎样在 Linux 终端快速检测一个网站是否宕机。
你可能已经了解了一些类似的命令，像 ping，curl 和 wget。我们在本教程中又加入了一些其他命令。同时，对于要检测单个和多个主机的信息我们也加入了不同的选项。
![](https://img.linux.net.cn/data/attachment/album/201912/10/093801u332115oocxz4531.jpg)
本文将帮助你检测网站是否宕机。但是如果你在维护一个网站，希望网站宕掉时得到实时的报警，我推荐你去使用实时网站监控工具。这种工具有很多，有些是免费的，大部分收费。根据你的需求，选择合适的工具。在后续的文章中我们会涉及这个主题。
你可能已经了解了一些类似的命令，像 `ping`、`curl` 和 `wget`。我们在本教程中又加入了一些其他命令。同时，我们也加入了不同的选项来检测单个和多个主机的信息。
本文将帮助你检测网站是否宕机。但是如果你在维护一些网站，希望网站宕掉时得到实时的报警，我推荐你去使用实时网站监控工具。这种工具有很多，有些是免费的，大部分收费。根据你的需求，选择合适的工具。在后续的文章中我们会涉及这个主题。
### 方法 1：使用 fping 命令检测一个网站是否宕机
**[fping 命令][1]** 是一个类似 ping 的程序，使用互联网控制消息协议回应请求报文（ICMP echo request）来判断目标主机是否能回应。fping 与 ping 的不同之处在于它可以并行地 ping 任意数量的主机，也可以从一个文本文件读入主机。fping 发送一个 ICMP echo request 后不等待目标主机响应，就以 round-robin 模式向下一个目标主机发请求。如果一个目标主机有响应，那么它就被标记为存活的（active）然后从检查目标列表里去掉。如果一个目标主机在限定的时间和（或）重试次数内没有响应，则被指定为网站无法到达（unreachable）。
[fping 命令][1] 是一个类似 `ping` 的程序，使用互联网控制消息协议（ICMP）的<ruby>回应请求报文<rt>echo request</rt></ruby>来判断目标主机是否能回应。`fping` 与 `ping` 的不同之处在于它可以并行地 `ping` 任意数量的主机，也可以从一个文本文件读入主机名称。`fping` 发送一个 ICMP 回应请求后不等待目标主机响应，就以轮询模式向下一个目标主机发请求。如果一个目标主机有响应，那么它就被标记为存活的，然后从检查目标列表里去掉。如果一个目标主机在限定的时间和（或）重试次数内没有响应，则被指定为网站无法到达的。
```
# fping 2daygeek.com linuxtechnews.com magesh.co.in
@ -30,7 +32,7 @@ magesh.co.in is alive
### 方法 2：使用 http 命令检测一个网站是否宕机
HTTPie（读作 aitch-tee-tee-pie）是一个命令行 HTTP 客户端。**[httpie tool][2]** 是一个可以与 web 服务通过 CLI（command-line interface）进行交互的现代工具。httpie tool 提供了简单的 http 命令，可以通过发送简单的、自然语言语法的任意 HTTP 请求得到多彩的结果输出。HTTPie 可以用来对 HTTP 服务器进行测试、调试和基本的交互。
HTTPie（读作 aitch-tee-tee-pie）是一个命令行 HTTP 客户端。[httpie][2] 是一个可以与 web 服务通过 CLI 进行交互的现代工具。httpie 工具提供了简单的 `http` 命令，可以通过发送简单的、自然语言语法的任意 HTTP 请求得到多彩的结果输出。HTTPie 可以用来对 HTTP 服务器进行测试、调试和基本的交互。
```
# http 2daygeek.com
@ -49,7 +51,7 @@ Vary: Accept-Encoding
### 方法 3：使用 curl 命令检测一个网站是否宕机
**[curl 命令](https://www.2daygeek.com/curl-linux-command-line-download-manager/)** 是一个用于在服务器间通过支持的协议（DICT, FILE, FTP, FTPS, GOPHER, HTTP, HTTPS, IMAP, IMAPS, LDAP, LDAPS, POP3, POP3S, RTMP, RTSP, SCP, SFTP, SMTP, SMTPS, TELNET 和 TFTP）传输数据的工具。这个工具不支持用户交互。curl 也支持使用代理、用户认证、FTP 上传、HTTP post、SSL 连接、cookies、断点续传、Metalink等等。curl 由 libcurl 库提供所有与传输有关的能力。
[curl 命令][3] 是一个用于在服务器间通过支持的协议（DICT、FILE、FTP、FTPS、GOPHER、HTTP、HTTPS、IMAP、IMAPS、LDAP、LDAPS、POP3、POP3S、RTMP、RTSP、SCP、SFTP、SMTP、SMTPS、TELNET 和 TFTP）传输数据的工具。这个工具不支持用户交互。`curl` 也支持使用代理、用户认证、FTP 上传、HTTP POST 请求、SSL 连接、cookie、断点续传、Metalink 等等。`curl `由 libcurl 库提供所有与传输有关的能力。
```
# curl -I https://www.magesh.co.in
@ -67,7 +69,7 @@ server: cloudflare
cf-ray: 535b74123ca4dbf3-LHR
```
如果你只想看 HTTP 状态码而不是返回的全部信息，用下面的 curl 命令：
如果你只想看 HTTP 状态码而不是返回的全部信息，用下面的 `curl` 命令：
```
# curl -I "www.magesh.co.in" 2>&1 | awk '/HTTP\// {print $2}'
@ -87,7 +89,7 @@ else
fi
```
当你把脚本内容添加到一个文件后，执行文件，查看结果
当你把脚本内容添加到一个文件后，执行文件，查看结果：
```
# sh curl-url-check.sh
@ -113,7 +115,7 @@ echo "----------------------------------"
done
```
当你把上面脚本内容添加到一个文件后，执行文件，查看结果
当你把上面脚本内容添加到一个文件后，执行文件，查看结果：
```
# sh curl-url-check-1.sh
@ -130,7 +132,7 @@ www.xyzzz.com is down
### 方法 4：使用 wget 命令检测一个网站是否宕机
**[wget 命令][4]** （前身是 Geturl）是一个免费的开源命令行下载工具，通过 HTTP、HTTPS、FTP和其他广泛使用的互联网协议检索文件。wget 是非交互式的命令行工具，由 World Wide Web 和 get 得名。wget 相对于其他工具来说更优秀，功能包括后台运行、递归下载、多文件下载、断点续传、非交互式下载和大文件下载。
[wget 命令][4]（前身是 Geturl）是一个自由开源的命令行下载工具，通过 HTTP、HTTPS、FTP 和其他广泛使用的互联网协议获取文件。`wget` 是非交互式的命令行工具，由 World Wide Web 和 get 得名。`wget` 相对于其他工具来说更优秀，功能包括后台运行、递归下载、多文件下载、断点续传、非交互式下载和大文件下载。
```
# wget -S --spider https://www.magesh.co.in
@ -158,7 +160,7 @@ Remote file exists and could contain further links,
but recursion is disabled -- not retrieving.
```
如果你只想看 HTTP 状态码而不是返回的全部结果，用下面的 wget 命令：
如果你只想看 HTTP 状态码而不是返回的全部结果，用下面的 `wget` 命令：
```
# wget --spider -S "www.magesh.co.in" 2>&1 | awk '/HTTP\// {print $2}'
@ -178,7 +180,7 @@ else
fi
```
当你把脚本内容添加到一个文件后，执行文件，查看结果
当你把脚本内容添加到一个文件后，执行文件，查看结果：
```
# wget-url-check.sh
@ -221,7 +223,7 @@ www.xyzzz.com is down
### 方法 5：使用 lynx 命令检测一个网站是否宕机
**[lynx][5]** 是一个在可寻址光标字符单元终端上使用的基于文本的高度可配的 web 浏览器，它是最古老的 web 浏览器并且现在仍在开发。
[lynx][5] 是一个在<ruby>可寻址光标字符单元终端<rt>cursor-addressable character cell terminals</rt></ruby>上使用的基于文本的高度可配的 web 浏览器，它是最古老的 web 浏览器并且现在仍在活跃开发。
```
# lynx -head -dump http://www.magesh.co.in
@ -240,7 +242,7 @@ Server: cloudflare
CF-RAY: 535fc5704a43e694-LHR
```
如果你只想看 HTTP 状态码而不是返回的全部结果，用下面的 lynx 命令：
如果你只想看 HTTP 状态码而不是返回的全部结果，用下面的 `lynx` 命令：
```
# lynx -head -dump https://www.magesh.co.in 2>&1 | awk '/HTTP\// {print $2}'
@ -260,7 +262,7 @@ else
fi
```
当你把脚本内容添加到一个文件后，执行文件，查看结果
当你把脚本内容添加到一个文件后，执行文件，查看结果：
```
# sh lynx-url-check.sh
@ -303,7 +305,7 @@ www.xyzzz.com is down
### 方法 6：使用 ping 命令检测一个网站是否宕机
**[ping 命令][1]** （Packet Internet Groper）是网络工具的代表，用于在互联网协议（IP）的网络中测试一个目标主机是否可用/可连接。通过向目标主机发送 ICMP 回应请求报文包并等待 ICMP 回应响应报文来检测主机的可用性。它基于已发送的包、接收到的包和丢失了的包来统计结果数据，通常包含最小/平均/最大响应时间。
[ping 命令][1]（Packet Internet Groper）是网络工具的代表，用于在互联网协议（IP）的网络中测试一个目标主机是否可用/可连接。通过向目标主机发送 ICMP 回应请求报文包并等待 ICMP 回应响应报文来检测主机的可用性。它基于已发送的包、接收到的包和丢失了的包来统计结果数据，通常包含最小/平均/最大响应时间。
```
# ping -c 5 2daygeek.com
@ -320,9 +322,9 @@ PING 2daygeek.com (104.27.157.177) 56(84) bytes of data.
rtt min/avg/max/mdev = 170.668/213.824/250.295/28.320 ms
```
### 方法 7：使用 telnet 命令检测一个网站是否宕机
### 附加 1：使用 telnet 命令检测一个网站是否宕机
telnet 命令是一个使用 TELNET 协议用于 TCP/IP 网络中多个主机相互通信的古老的网络协议。它通过 23 端口连接其他设备如计算机和网络设备。telnet 是不安全的协议，现在由于用这个协议发送的数据没有经过加密可能被黑客拦截，所以不推荐使用。大家都使用经过加密且非常安全的 SSH 协议来代替 telnet。
`telnet` 命令是一个使用 TELNET 协议用于 TCP/IP 网络中多个主机相互通信的古老的网络协议。它通过 23 端口连接其他设备如计算机和网络设备。`telnet` 是不安全的协议，现在由于用这个协议发送的数据没有经过加密可能被黑客拦截，所以不推荐使用。大家都使用经过加密且非常安全的 SSH 协议来代替 `telnet`。
```
# telnet google.com 80
@ -335,11 +337,11 @@ telnet> quit
Connection closed.
```
### 方法 8：使用 bash 脚本检测一个网站是否宕机
### 附加 2：使用 bash 脚本检测一个网站是否宕机
简而言之，一个 **[shell 脚本][6]** 就是一个包含一系列命令的文件。shell 从文件读取内容按输入顺序逐行在命令行执行。为了让它更有效，我们添加一些条件。这也减轻了 Linux 管理员的负担。
简而言之，一个 [shell 脚本][6] 就是一个包含一系列命令的文件。shell 从文件读取内容按输入顺序逐行在命令行执行。为了让它更有效，我们添加一些条件。这也减轻了 Linux 管理员的负担。
如果你想想用 wget 命令看多个网站的状态，使用下面的 shell 脚本：
如果你想想用 `wget` 命令看多个网站的状态，使用下面的 shell 脚本：
```
# vi wget-url-check-2.sh
@ -365,7 +367,7 @@ google.co.in is up
www.xyzzz.com is down
```
如果你想想用 wget 命令看多个网站的状态，使用下面的 **[shell 脚本][7]**：
如果你想用 `wget` 命令看多个网站的状态，使用下面的 [shell 脚本][7]：
```
# vi curl-url-check-2.sh
@ -398,7 +400,7 @@ via: https://www.2daygeek.com/linux-command-check-website-is-up-down-alive/
作者：[Magesh Maruthamuthu][a]
选题：[lujun9972][b]
译者：[lxbwolf](https://github.com/lxbwolf)
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

34
translated/tech/20191203 Why use the Pantheon desktop for Linux Elementary OS.md → published/20191203 Why use the Pantheon desktop for Linux Elementary OS.md
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@ -1,30 +1,32 @@
[#]: collector: (lujun9972)
[#]: translator: (geekpi)
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: reviewer: (wxy)
[#]: publisher: (wxy)
[#]: url: (https://linux.cn/article-11660-1.html)
[#]: subject: (Why use the Pantheon desktop for Linux Elementary OS)
[#]: via: (https://opensource.com/article/19/12/pantheon-linux-desktop)
[#]: author: (Seth Kenlon https://opensource.com/users/seth)
为何在 Elementary OS 中使用 Pantheon 桌面
为何 Elementary OS 中使用 Pantheon 桌面
======
本文是 Linux 桌面特别系列的一部分。通过 Pantheon 在 Elementary OS 上获得受喜爱的 Mac OS 特性。
![A person programming][1]
你愿意为 Linux 桌面支付 20 美元吗？事实上，我会在下载免费软件时选择支付更多！我这样做的原因是开源是值得的。对于 [Elementary OS][2]的拷贝，默认价格是 20 美元（你可以用 1 美元，如果你无法负担，你甚至可以用 0 美元下载）。作为回报，你将获得一个出色且精心制作的发行版，同时拥有 Pantheon 桌面设计。
> 本文是 Linux 桌面特别系列的一部分。通过在 Elementary OS 上运行 Pantheon 桌面获得广受喜爱的 Mac OS 特性。
你可能会发现 Pantheon 已包含在软件仓库中，因为它是开源的，但你更可能需要下载并安装 [Elementary][3] Linux 才能体验它。如果你还不准备在计算机上将 Elementary 作为主操作系统安装，那么可以将其安装到虚拟机中，例如 [GNOME Boxes][4] 中。
![](https://img.linux.net.cn/data/attachment/album/201912/10/085342dfgngrpt6sgzl3af.jpg)
Pantheon 桌面整洁、吸引人，并有许多用户希望在桌面中获得的东西，但在普通的 Linux 桌面上却无法获得。
你愿意为 Linux 桌面支付 20 美元吗？事实上，我会在下载自由软件时选择支付更多的钱！我这样做的原因是开源是值得的。对于 [Elementary OS][2] 的拷贝，默认价格是 20 美元（你可以选择 1 美元，如果你无法负担，你甚至可以用 0 美元下载）。作为回报，你将获得一个出色且精心制作的发行版，同时拥有它自己的 Pantheon 桌面设计。
你可能会发现 Pantheon 已包含在软件仓库中，因为它是开源的，但你更可能需要下载并安装 [Elementary][3] Linux 才能体验它。如果你还不准备在计算机上将 Elementary 作为主操作系统，那么可以将其安装到虚拟机中，例如 [GNOME Boxes][4] 中。
Pantheon 桌面整洁、吸引人，并且有许多用户希望在桌面中获得的东西，但在普通的 Linux 桌面上却无法获得。
### Pantheon 桌面之旅
乍一看，Pantheon 桌面看起来有点像 Cinnamon 或 Budgie 或 GNOME 3 的经典模式。但是，Pantheon 最令人兴奋的功能是最小的触摸。它在你最少注意到的地方都表现出色，直到有一天这里成为了你一天都会看的地方，并且意识到它的工作方式确实改善了你的生活质量，更不用说让你过得愉快了好多了。
乍一看，Pantheon 桌面看起来有点像 Cinnamon、Budgie 或 GNOME 3 的经典模式。但是，Pantheon 最令人兴奋的功能是极小的接触。它在你很少注意到的地方都表现出色，直到有一天这里成为了你一天都会看的地方，并且会意识到它的工作方式确实改善了你的生活质量，更不用说让你过得愉快多了。
最明显的例子是“文件名高亮”。几十年来，Mac OS 一直有一个广受欢迎的功能，你从而可以高亮显示重要文件的名称。人们使用此功能作为快速的视觉指示器，来告诉自己哪个文件是这几个的“最佳”版本，或者哪个文件应该发送给朋友，或者哪个文件仍然需要处理。它们可以是任意颜色，可以表示用户想要的任何含义。最重要的是，它是引人注目的视觉元数据。
最明显的例子是“文件名高亮”。几十年来，Mac OS 一直有一个广受欢迎的功能，你可以高亮显示重要文件的名称。人们使用此功能作为快速视觉指示器，来告诉自己哪个文件是这几个的“最佳”版本，或者哪个文件应该发送给朋友，或者哪个文件仍然需要处理。它们可以是任意颜色，可以表示用户想要的任何含义。最重要的是，它是引人注目的视觉元数据。
从 Mac OS 切换过来用户往往会错过 GNOME 和 KDE 以及其他 Linux 桌面提供的这个功能。Pantheon 悄悄和随意地就解决了这个问题。
从 Mac OS 切换过来用户往往会错过 GNOME 和 KDE 以及其他 Linux 桌面提供的这个功能。Pantheon 悄悄地随手解决了这个问题。
![A highlighted file in the Pantheon desktop][5]
@ -38,15 +40,15 @@ Pantheon 桌面整洁、吸引人，并有许多用户希望在桌面中获得
Pantheon 桌面表达了如何操作计算机的清晰愿景。这种设计的“问题”（至少在开源之外）是，一个人的偏好可能无法满足另一个人的效率。
但它是开源的。它可以更改，任何不能改变的东西都可以被丢弃。Pantheon 绝对是针对特定用户的桌面，但是即使对于那些对桌面应该如何工作抱有自己期望的人，Pantheon 也会比初次出现时更加灵活。许多内置设计都具有替代选项，当你无法根据自己的喜好进行调整时，你可以轻松选择其他应用。主题引擎可确保你的替换应用看起来与桌面的其他部分集成在一起，而平常的 Linux 系统总线可确保你选择的所有应用都能按预期相互通信。
但它是开源的。它可以更改，任何不能改变的东西都可以被丢弃。Pantheon 绝对是针对特定用户群的桌面，但是即使对于那些对桌面应该如何工作抱有自己期望的人，Pantheon 也会比初看上去更加灵活。许多内置设计都具有替代选项，当你无法根据自己的喜好进行调整时，你可以轻松选择其他应用。主题引擎可确保你的替换应用看起来与桌面的其它部分和谐一致，而通常的 Linux 系统兼容性可确保你选择的所有应用都能按预期相互配合。
![Which one is the guest?][7]
随着折衷的进行，这一过程在中途会做很多事情。
这些替代品，可使你事半功倍。
### 受欢迎的补充
除开词源，此桌面确实是许多 Linux 用户祈祷的答案。无论它是否是你的风格，Pantheon 桌面都是 Linux 用户体验中重要且受欢迎的补充。自己尝试一下，看看它是否是你一直期待的。
撇开这个桌面的词源不说，此桌面确实是许多 Linux 用户祈祷的答案（LCTT 译注：Pantheon 的意思是“万神庙”）。无论它是否是你的风格，Pantheon 桌面都是 Linux 用户体验中重要且受欢迎的补充。自己尝试一下，看看它是否是你一直期待的。
--------------------------------------------------------------------------------
@ -55,7 +57,7 @@ via: https://opensource.com/article/19/12/pantheon-linux-desktop
作者：[Seth Kenlon][a]
选题：[lujun9972][b]
译者：[geekpi](https://github.com/geekpi)
校对：[校对者ID](https://github.com/校对者ID)
校对：[wxy](https://github.com/wxy)
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[#]: collector: (lujun9972)
[#]: translator: (geekpi)
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: subject: (Java vs. Python: Which should you choose?)
[#]: via: (https://opensource.com/article/19/12/java-vs-python)
[#]: author: (Archit Modi https://opensource.com/users/architmodi)
Java vs. Python: Which should you choose?
======
Compare the two most popular programming languages in the world, and let
us know which one you prefer in our poll.
![Developing code.][1]
Let's compare the two most popular and powerful programming languages in the world: Java and Python! Both languages have huge community support and libraries to perform almost any programming task, although selecting a programming language usually depends on the developer's use case. After you compare and contrast, please make sure to answer our poll to [share your opinion][2] on which is best.
### What is it?
* **Java** is a general-purpose object-oriented programming language used mostly for developing a wide range of applications from mobile to web to enterprise apps.
* **Python** is a high-level object-oriented programming language used mostly for web development, artificial intelligence, machine learning, automation, and other data science applications.
### Creator
* **Java** was created by James Gosling (Sun Microsystems).
* **Python** was created by Guido van Rossum.
### Open source status
* **Java** is free and (mostly) open source except for corporate use.
* **Python** is free and open source for all use cases.
### Platform dependencies
* **Java** is platform-independent (although JVM isn't) per its WORA ("write once, run anywhere") philosophy.
* **Python** is platform-dependent.
### Compiled or interpreted
* **Java** is a compiled language. Java programs are translated to byte code at compile time and not runtime.
* **Python** is an interpreted language. Python programs are translated at runtime.
### File creation
* **Java**: After compilation, **&lt;filename&gt;.class** is generated.
* **Python**: During runtime, **&lt;filename&gt;.pyc** is created.
### Errors types
* **Java** has ****2 ****types of errors: compile and runtime errors.
* **Python** has 1 error type: traceback (or runtime) error.
### Statically or dynamically typed
* **Java** is statically typed. When initiating variables, their types need to be specified in the program because type checking is done at compile time.
* **Python** is dynamically typed. Variables don't need to have a type specified when initiated because type checking is done at runtime.
### Syntax
* **Java**: Every statement needs to end with a semicolon ( **;** ), and blocks of code are separated by curly braces ( **{}** ).
* **Python**: Blocks of code are separated by indentation (the user can choose how many white spaces to use, but it should be consistent throughout the block).
### Number of classes
* **Java**: Only one public top-level class can exist in a single file in Java.
* **Python**: Any number of classes can exist in a single file in Python.
### More or less code?
* **Java** generally involves writing more lines of code compared to Python.
* **Python** involves writing fewer lines of code compared to Java.
### Multiple inheritance
* **Java** does not support multiple inheritance (inheriting from two or more base classes)
* **Python** supports multiple inheritance although it is rarely implemented due to various issues like inheritance complexity, hierarchy, dependency issues, etc.
### Multi-threading
* **Java** multi-threading can support two or more concurrent threads running at the same time.
* **Python** uses a global interpreter lock (GIL), allowing only a single thread (CPU core) to run at a time.
### Execution speed
* **Java** is usually faster in execution time than Python.
* **Python** is usually slower in execution time than Java.
### Hello world in Java
```
public class Hello {
   public static void main([String][3][] args) {
      [System][4].out.println("Hello Opensource.com from Java!");
   }
}
```
### Hello world in Python
```
`print("Hello Opensource.com from Java!")`
```
### Run the programs
![Java vs. Python][5]
To run the java program "Hello.java" you need to compile it first which creates a "Hello.class" file. To run just the class name, use "java Hello." For Python, you would just run the file "python3 helloworld.py."
--------------------------------------------------------------------------------
via: https://opensource.com/article/19/12/java-vs-python
作者：[Archit Modi][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/architmodi
[b]: https://github.com/lujun9972
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/code_development_programming.png?itok=M_QDcgz5 (Developing code.)
[2]: tmp.Bpi8QYfp8j#poll
[3]: http://www.google.com/search?hl=en&q=allinurl%3Adocs.oracle.com+javase+docs+api+string
[4]: http://www.google.com/search?hl=en&q=allinurl%3Adocs.oracle.com+javase+docs+api+system
[5]: https://opensource.com/sites/default/files/uploads/python-java-hello-world_0.png (Java vs. Python)

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[#]: collector: (lujun9972)
[#]: translator: ( )
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: subject: (Data centers in 2020: Automation, cheaper memory)
[#]: via: (https://www.networkworld.com/article/3487684/data-centers-in-2020-automation-cheaper-memory.html)
[#]: author: (Andy Patrizio https://www.networkworld.com/author/Andy-Patrizio/)
Data centers in 2020: Automation, cheaper memory
======
As data centers grow in 2020, enterprises will refine the balance between on-premises and cloud resources, adopt AI on servers and try to manage data sprawl effectively.
[Arthur Ogleznev / Unsplash][1] [(CC0)][2]
It’s that time of year again when those of us in the press make our annual prognostications for the coming year. Some things we saw coming; the rise of the cloud and the advance of SSD. Others, like the return of many cloud migrations to on-premises or the roaring comeback of AMD, went right by us. We do our best but occasionally there are surprises.
So with that, let’s take a peek into the always cloudy (no pun intended) crystal ball and make 10 data-center-oriented predictions.
### IoT spawns data-center growth in urban areas
This isn’t a hard prediction to make since it’s already happening. For the longest time, [data centers][3] were placed in the middle of nowhere near renewable energy (usually hydro), but need is going to force more expansion in major metro areas. [IoT][3] will be one driver but so will the increasing use of data center providers like Equinix and DRT as interconnection providers.
[][4]
BrandPost Sponsored by HPE
[Take the Intelligent Route with Consumption-Based Storage][4]
Combine the agility and economics of HPE storage with HPE GreenLake and run your IT department with efficiency.
### Rise of network accelerators
Big Data and artificial intelligence of all flavors mean enormous amounts of data, and not all of it can be found in one place. Add to it that for now, CPUs are required to power network traffic controllers, thus taking them away from their main job of crunching data.
So you will see more and more network accelerators coming to market like Mellanox’s [ConnectX line][5] to let CPUs do the job of processing data and accelerators do the job of moving around massive amounts of data faster than is done now.
### NVMe over fabrics grows
Non-volatile memory express ([NVMe][6]) is a storage interface, like serial advanced technology attachment (SATA). The downside of SATA is that its legacy is in hard disks so it fails to take full advantage of the speed and parallelism of [SSD][7]s. But early enterprise SSDs had a problem: They could only talk to the physical server in which they were installed. Either that or a server needed storage arrays, which meant network hops, which meant latency.
NVMe over fabrics ([NVMeoF][8]) is an important advance. It lets an SSD in one server communicate over the network to another drive somewhere else on the network. This direct communication will be vital for improved data movement in enterprise computing and digital transformation.
* [Backup vs. archive: Why it’s important to know the difference][9]
* [How to pick an off-site data-backup method][10]
* [Tape vs. disk storage: Why isn’t tape dead yet?][11]
* [The correct levels of backup save time, bandwidth, space][12]
### Cheaper storage-class memory
Storage-class memory is memory that goes in a DRAM slot and can function like DRAM but can also function like an SSD. It has near-DRAM-like speed but has storage capabilities, too, effectively turning it into a cache for SSD.
Intel and Micron were working on SCM together but parted company. Intel released its SCM product, [Optane][13], in May, and Micron came to market in October with QuantX. South Korean memory giant SK Hynix is also working on a SCM product that’s different from the 3D XPoint technology Micron and Intel use as well.
All of this should do wonders to advance the technology and hopefully bring the price down. Right now a 512GB stick of Optane runs an insane $8,000. Granted, Xeons sell for even more than that, but after a while it becomes prohibitively expensive to assemble a fully decked-out server. Advancement of the technology and competition should lower prices, which will make this class of memory more attractive to enterprises.
### AI automation on brand-name servers
All of the server vendors are adding AI to their systems but Oracle is really taking the lead with its autonomous everything, from the hardware through OS and application and middleware stack. HPE, Dell, and Lenovo will continue to make their own advances as well but the hyperscale-server vendors like Inspur and Supermicro will lag because they have only the hardware stack and have done next to nothing in the OS space. They also are lagging in storage, something the big-three server vendors excel at.
Oracle may not be a top-five server vendor, but no one can ignore what they are doing in the automation space. Expect the other brand name-vendors to provide their own increasing levels of automation.
### Cloud migrations slow
Remember when everyone was looking forward to shutting down their data centers entirely and moving to the cloud? So much for that idea. IDC’s latest CloudPulse survey suggests that 85% of enterprises plan to move workload from public to private environments over the next year. And a recent survey by Nutanix found 73% of respondents reported that they are moving some applications off the public cloud and back on-prem. Security was cited as the primary reason.
And since it’s doubtful security will ever be good enough for some companies and some data, it seems the mad rush to the cloud will likely slow a little as people become more picky about what they put in the cloud and what they keep behind their firewall.
### Data sprawl, Part 1
Most data is not where it should be, according to IDC. Only 10% of corporate data is “hot” –  data that is repeatedly accessed and used – while 30% is “warm ” – used semi-regularly – and the other 60% belongs in cold storage where it is rarely if ever accessed.
But the problem is that data is scattered all over the place and often in the wrong tier. Many storage firms have focused on deduplication but not on storage tiers. A startup called Spectra Logic is targeting that very problem, and I suspect it won’t be the last firm to make such an effort. If it really takes off, I expect HPE and Dell to lock horns over the company, too.
### Data sprawl, Part 2
IDC [predicts][14] the total global data haul to weigh in at 175 zettabytes by 2025, and we are already at 32ZB of data, much of it useless. There was a time when data warehousing ruled that data was sorted and processed and stored as something useful. Now people fill data lakes with an endless supply of data from a growing number of sources, like social media and IoT.
Sooner or later, something will have to give. People will take a look at petabytes of data-lake junk and say enough is enough and start to become considerably more picky about what they store. They will question the rationale behind spending a fortune on hard disks and storage arrays to store vast quantities of unused and valueless data. The pendulum will swing back to the data-warehouse model of keeping usable data. It has to or people will be overwhelmed.
### More servers with a mix of processors
Ten years ago, it didn’t matter if your definition of a server was a single-socket Xeon tower sitting under a desk or four-socket rack-mount in a seven-foot cabinet, they were defined by an x86 processor. But now we are seeing more server designs with on-board GPUs, Arm processors, AI accelerators, and network accelerators.
This will require some changes in server designs. First, liquid cooling will become more necessary with this multitude of chips running faster and hotter and in an enclosed space. Second, the software stack will need to be more robust to handle all these chips, requiring some work on the part of Microsoft and the Linux distros.
### IT workload will change
Don’t think that automation means you can sit around playing games on your iPhone. Thanks to their ever-evolving systems, IT pros will have a bunch of new headaches including:
* Combating shadow IT
* Addressing digital transformation
* Developing AI strategies to keep up with competitors
* Reacting appropriately to the fallout from new AI strategies
* Maintaining security governance across the company
* Handling an increasing inflow of data and figuring out what to do with it
* Responding faster than ever to customers and to company reputation on social media
Join the Network World communities on [Facebook][15] and [LinkedIn][16] to comment on topics that are top of mind.
--------------------------------------------------------------------------------
via: https://www.networkworld.com/article/3487684/data-centers-in-2020-automation-cheaper-memory.html
作者：[Andy Patrizio][a]
选题：[lujun9972][b]
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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/Andy-Patrizio/
[b]: https://github.com/lujun9972
[1]: https://unsplash.com/photos/rWDumHFt8E8
[2]: https://creativecommons.org/publicdomain/zero/1.0/
[3]: https://www.networkworld.com/article/3223692/what-is-a-data-centerhow-its-changed-and-what-you-need-to-know.html
[4]: https://www.networkworld.com/article/3440100/take-the-intelligent-route-with-consumption-based-storage.html?utm_source=IDG&utm_medium=promotions&utm_campaign=HPE20773&utm_content=sidebar ( Take the Intelligent Route with Consumption-Based Storage)
[5]: https://www.networkworld.com/article/3433924/mellanox-introduces-smartnics-to-eliminate-network-load-on-cpus.html
[6]: https://www.networkworld.com/article/3280991/what-is-nvme-and-how-is-it-changing-enterprise-storage.html
[7]: https://www.networkworld.com/article/3326058/what-is-an-ssd.html
[8]: https://www.networkworld.com/article/3394296/nvme-over-fabrics-creates-data-center-storage-disruption.html
[9]: https://www.networkworld.com/article/3285652/storage/backup-vs-archive-why-its-important-to-know-the-difference.html
[10]: https://www.networkworld.com/article/3328488/backup-systems-and-services/how-to-pick-an-off-site-data-backup-method.html
[11]: https://www.networkworld.com/article/3315156/storage/tape-vs-disk-storage-why-isnt-tape-dead-yet.html
[12]: https://www.networkworld.com/article/3302804/storage/the-correct-levels-of-backup-save-time-bandwidth-space.html
[13]: https://www.networkworld.com/article/3279271/intel-launches-optane-the-go-between-for-memory-and-storage.html
[14]: https://www.networkworld.com/article/3325397/idc-expect-175-zettabytes-of-data-worldwide-by-2025.html
[15]: https://www.facebook.com/NetworkWorld/
[16]: https://www.linkedin.com/company/network-world

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[#]: collector: (lujun9972)
[#]: translator: ( )
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: subject: (Google Cloud bare-metal initiative targets migrating legacy apps from on-prem)
[#]: via: (https://www.networkworld.com/article/3487626/google-cloud-bare-metal-initiative-targets-migrating-legacy-apps-from-on-prem.html)
[#]: author: (Andy Patrizio https://www.networkworld.com/author/Andy-Patrizio/)
Google Cloud bare-metal initiative targets migrating legacy apps from on-prem
======
Google Cloud now offers Google Bare Metal Solution, a service that supplies hardware in the cloud for enterprises that want full control of the entire stack from operating system on up to their most important legacy apps.
Google
In the cloud-services market, [bare metal offerings][1] have lagged behind virtualized ones, mostly because the use of the cloud for things like elastic apps and developer environments are better suited to instances with a native operating system.
The term “bare metal” simply means no software of any kind, not even a [hypervisor][2]. Customers provide their own operating environments, and the provider offers nothing more than CPUs, memory, and storage. Up to now, IBM has led the charge with bare-metal services because SoftLayer, the major data-center provider it acquired in 2014, was heavily involved in that business.
Now Google Cloud is going after that market, especially targeting “lift and shift” of an entire operating environment – OS, hypervisor, apps, and data -- from on-premises data centers to the cloud.
[][3]
BrandPost Sponsored by HPE
[HPE Synergy For Dummies][3]
Here’s how IT can provide an anytime, anywhere, any workload infrastructure.
Google [recently announced][4] the Google Bare Metal Solution for legacy applications that must run on dedicated hardware and have strict hardware certification requirements, as well as dedicated, low-latency and highly resilient interconnects, and connections to all native Google Cloud services.
Bare Metal Solution uses OEM hardware that is certified for many ISV software applications as well as custom-built applications, with Oracle Database the one commercial software product specifically named. The hardware is a bit of a mystery, since Google, like most hyperscale data-center operators, uses off-brand hardware from Gigabyte, Inspur, and Supermicro, but it’s usually hardware from HPE, Dell, and Lenovo that gets those kinds of certifications. Not that the white-box brands don’t have it, but it’s usually not as much of a priority for them.
These hardware configurations are offered as a subscription, billed monthly with a preferred term length of 36 months, which means they want you to stick around a while. There are no data ingress and egress charges between Bare Metal Solution and Google Cloud in the same region, however for now, Bare Metal Solutions are only available in East Coast data centers.
Moving an Oracle database to the cloud isn’t trivial. If the database stretches into the petabytes, that could get very expensive. Not to mention Oracle is doing its darnedest to keep that business by making it easier for customers to migrate their databases into Oracle’s cloud infrastructure.
[[Get regularly scheduled insights by signing up for Network World newsletters.]][5]
Storage comes in 1TB increments, either a mix of HDD and SSD or all-flash. As for the rest of the configurations:
Dual-socket x86 systems
* 16 core with 384 GB DRAM
* 24 core with 768 GB DRAM
* 56 core with 1536 GB DRAM
Quad-socket x86 systems
* 56 core with 1536 GB DRAM
* 112 core with 3072 GB DRAM
Other benefits of the service are:
* End-to-end infrastructure management such as compute, storage and networking, as well as fully managed and monitored environments such as power, cooling and facilities.
* Support for infrastructure, including defined SLAs for initial response; 24X7 coverage for all Priority 1 and 2 issues; unified billing across Google Cloud and Bare Metal Solution.
* Enterprise-grade SLAs for hardware uptime and interconnect availability.
Bare metal has its appeal but caveats, too. The allure of the cloud is its bursty elasticity. Many on-prem apps are used to running all out for much if not all of the day. In a cloud setting that can get expensive in a hurry, so it’s up to IT staff to decide if it’s a good idea to migrate an Oracle database to the cloud. If it's serving up reads and writes constantly, any savings from moving it off premises will be immediately offset by paying to run it at high utilization in the cloud.
Join the Network World communities on [Facebook][6] and [LinkedIn][7] to comment on topics that are top of mind.
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via: https://www.networkworld.com/article/3487626/google-cloud-bare-metal-initiative-targets-migrating-legacy-apps-from-on-prem.html
作者：[Andy Patrizio][a]
选题：[lujun9972][b]
译者：[译者ID](https://github.com/译者ID)
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本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://www.networkworld.com/author/Andy-Patrizio/
[b]: https://github.com/lujun9972
[1]: https://www.networkworld.com/article/3261113/why-a-bare-metal-cloud-provider-might-be-just-what-you-need.html
[2]: https://www.networkworld.com/article/3243262/what-is-a-hypervisor.html
[3]: https://www.networkworld.com/article/3399618/hpe-synergy-for-dummies.html?utm_source=IDG&utm_medium=promotions&utm_campaign=HPE19718&utm_content=sidebar (HPE Synergy For Dummies)
[4]: https://cloud.google.com/blog/products/gcp/bare-metal-solution-enabling-specialized-workloads-in-google-cloud
[5]: https://www.networkworld.com/newsletters/signup.html
[6]: https://www.facebook.com/NetworkWorld/
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[#]: translator: ( )
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[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )

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[#]: url: ( )
[#]: subject: (Counting down the days using bash)
[#]: via: (https://www.networkworld.com/article/3487712/counting-down-the-days-using-bash.html)
[#]: author: (Sandra Henry-Stocker https://www.networkworld.com/author/Sandra-Henry_Stocker/)
Counting down the days using bash
======
Need to know how many days there are before some important event? Let Linux bash and the date command help with that!
Thinkstock
With some pretty important holidays right around the corner, you might need to be reminded how much longer you have to prepare.
Fortunately, you can get a lot of help from the **date** command. In this post, we’ll look at ways that **date** and bash scripts can tell you how many days there are between today and some event that you’re anticipating.
[[Get regularly scheduled insights by signing up for Network World newsletters.]][1]
First a couple hints at how this is going to work. The **date** command’s **%j** option is going to show you today’s date as a number between 1 and 366. January 1st, as you’d expect, will be displayed as 1 and December 31st will be 365 or 366 depending on whether it’s leap year. Go ahead and try it. You should see something like this:
[][2]
BrandPost Sponsored by HPE
[Take the Intelligent Route with Consumption-Based Storage][2]
Combine the agility and economics of HPE storage with HPE GreenLake and run your IT department with efficiency.
```
$ date +%j
339
```
You can, however, get the **date** command to give you the day-of-the-year number for _any_ date by supplying it in a **date** command like this:
```
$ date -d "Mar 18" +%j
077
```
One important thing to keep in mind is that this command will show you the date in the _current year_ even if that date is in the past. However, you can add a year to the command and fix that:
```
$ date -d "Apr 29" +%j
119
$ date -d "Apr 29 2020" +%j
120
```
In a leap year, Apr 29th will be the 120th day of the year, not the 119th.
If you want to count down the days until Christmas and don’t want to end up with fingerprints on your wall calendar, you can use a script like this:
```
#!/bin/sh
XMAS=`date -d "Dec 25" +%j`
TODAY=`date +%j`
DAYS=$(($XMAS - $TODAY))
case $DAYS in
0) echo "It's today! Merry Christmas!";;
[0-9]*) echo "$DAYS days remaining";;
-[0-9]*) echo "Oops, you missed it";;
esac
```
In this script, we get the day numbers for Dec 25th and today and then subtract one from the other. If the result is positive, we display the number of days remaining. If it’s zero, we issue a “Merry Christmas” message and, if it’s negative, we just tell the person running the script that they missed the holiday. Maybe they got carried away with the egg nog.
The case statement is made up of ready-to-print statements for remaining-day counts that equal zero, those that that include any digits and those that start with a **-** sign (i.e., in the past).
The same idea can be generalized for any date that someone wants to keep in focus. In fact, we can ask the person running our script to supply the date and then let them know how many days remain between now and then. This version of the script does just that.
```
#!/bin/sh
echo -n "Enter event date (e.g., June 6): "
read dt
EVENT=`date -d "$dt" +%j`
TODAY=`date +%j`
DAYS=`expr $EVENT - $TODAY`
case $DAYS in
0) echo "It's today!";;
[0-9]*) echo "$DAYS days remaining";;
-[0-9]*) echo "Oops, you missed it";;
esac
```
One problem you’ll have with this script is that, if the person running it is hoping to find out how many days must pass before they reach a special day the following year, they’ll be disappointed. Even if they supply a year when they enter the date, the date -d command will still only supply the day number in that year, not the days between now and then.
Calculating the number of days between today and some date years from now can be a bit tricky. You’d need to include all the intervening years and pay attention to those that are leap years.
### Using Unix (Epoch) time
Another way to calculate the number of days between now and some special date is to take advantage of the way that Unix systems store dates. If you convert the number of seconds since the start of the day on Jan 1, 1970 to days, you can do this quite easily as in this script:
```
#!/bin/bash
echo -n "Enter target date (e.g., Mar 18 2021)> "
read target_date
today=`echo $(($(date --utc --date "$1" +%s)/86400))`
target=`echo $(($(date --utc --date "$target_date" +%s)/86400))`
days=`expr $target - $today`
echo "$days days until $target_date"
```
To explain, 86400 is the number of seconds in a day. Dividing the number of seconds since the epoch began by this number gives us the number of days.
```
$ ./countdown
Enter target date (e.g., Mar 18 2021)> Mar 18 2020
104 days until Mar 18 2020
```
Join the Network World communities on [Facebook][3] and [LinkedIn][4] to comment on topics that are top of mind.
--------------------------------------------------------------------------------
via: https://www.networkworld.com/article/3487712/counting-down-the-days-using-bash.html
作者：[Sandra Henry-Stocker][a]
选题：[lujun9972][b]
译者：[译者ID](https://github.com/译者ID)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://www.networkworld.com/author/Sandra-Henry_Stocker/
[b]: https://github.com/lujun9972
[1]: https://www.networkworld.com/newsletters/signup.html
[2]: https://www.networkworld.com/article/3440100/take-the-intelligent-route-with-consumption-based-storage.html?utm_source=IDG&utm_medium=promotions&utm_campaign=HPE20773&utm_content=sidebar ( Take the Intelligent Route with Consumption-Based Storage)
[3]: https://www.facebook.com/NetworkWorld/
[4]: https://www.linkedin.com/company/network-world

156
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@ -0,0 +1,156 @@
[#]: collector: (lujun9972)
[#]: translator: (geekpi)
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: subject: (Java vs. Python: Which should you choose?)
[#]: via: (https://opensource.com/article/19/12/java-vs-python)
[#]: author: (Archit Modi https://opensource.com/users/architmodi)
Java vs. Python：你应该选择哪个？
======
比较世界上最流行的两种编程语言，并在投票中让我们知道你喜欢哪一个。
![Developing code.][1]
让我们比较一下世界上两种最受欢迎、最强大的编程语言：Java 和 Python！这两种语言有巨大的社区支持和库来执行几乎任何编程任务，尽管选择编程语言通常取决于开发人员的场景。在比较和对比之后，请投票[分享你的观点][2]。
### 是什么？
* **Java** 是一门通用面向对象的编程语言，主要用于开发从移动端到 Web 到企业级应用的各种应用。
* **Python** 是一门高级面向对象的编程语言，主要用于 Web 开发、人工智能、机器学习、自动化和其他数据科学应用。
### 创建者
* **Java** 是由 James Gosling（Sun Microsystems）创造的。
* **Python** 是由 Guido van Rossum 创造的。
### 开源状态
* **Java** 是免费的，（大部分）开源，但商业用途除外。
* **Python** 所有场景均免费。
### 平台依赖
* **Java** 根据它的 WORA (”一次编写，到处运行“)哲学，它是平台无关的。
* **Python** 依赖于平台。
### 编译或解释
* **Java** 是一门编译语言。Java 程序在编译时转换为字节码，而不是运行时。
* **Python** 是一门解释性语言。Python 程序在运行时进行解释。
### 文件创建
* **Java**：编译后生成 **&lt;filename&gt;.class** 文件。
* **Python**：在运行期，创建 **&lt;filename&gt;.pyc** 文件
### 错误类型
* **Java** 有 2 种错误类型：编译和运行时错误。
* **Python** 有 1 种错误类型：回溯（或运行时）错误。
### 静态或动态类型
* **Java** 是静态类型。当初始化变量时，需要在程序中指定变量的类型，因为类型检查是在编译时完成的。
* **Python** 是动态类型。变量不需要在初始化时指定类型，因为类型检查是在运行时完成的。
### 语法
* **Java**：每个语句都需要以分号 （\*; ） 结尾，并且代码块由大括号 （ {} ） 分隔。
* **Python**：代码块通过缩进分隔（用户可以选择要使用的空格数，但在整个块中应保持一致）。
### 类的数量
* **Java**：在 Java 中的单个文件中只能存在一个公有顶级类。
* **Python**：Python 中的单个文件中可以存在任意数量的类。
### 代码更多或更少？
* **Java** 通常比 Python 要写更多代码行。
* **Python**通常比 Java 要写更少代码行。
### 多重继承
* **Java** 不支持多重继承（从两个或多个基类继承）。
* **Python** 支持多重继承，但由于继承复杂性、层次结构、依赖等各种问题，它很少实现。
### 多线程
* **Java** 多线程可以支持同时运行的两个或多个并发线程。
* **Python** 使用全局解释器锁 （GIL），一次只允许运行单个线程 （ CPU 核）。
### 执行速度
* **Java** 的执行时间通常比 Python 快。
* **Python** 的执行时间通常比 Java 慢。
### Java 的 Hello world
```
public class Hello {
   public static void main([String][3][] args) {
      [System][4].out.println("Hello Opensource.com from Java!");
   }
}
```
### Python 的 Hello world
```
`print("Hello Opensource.com from Java!")`
```
### 运行程序
![Java vs. Python][5]
要运行 java 程序 ”Hello.java“，你需要先编译它，这将创建一个 ”Hello.class“ 文件。只需运行类名 ”java Hello“。对于 Python，只需运行文件 ”python3 helloworld.py“。
--------------------------------------------------------------------------------
via: https://opensource.com/article/19/12/java-vs-python
作者：[Archit Modi][a]
选题：[lujun9972][b]
译者：[geekpi](https://github.com/geekpi)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://opensource.com/users/architmodi
[b]: https://github.com/lujun9972
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/code_development_programming.png?itok=M_QDcgz5 (Developing code.)
[2]: tmp.Bpi8QYfp8j#poll
[3]: http://www.google.com/search?hl=en&q=allinurl%3Adocs.oracle.com+javase+docs+api+string
[4]: http://www.google.com/search?hl=en&q=allinurl%3Adocs.oracle.com+javase+docs+api+system
[5]: https://opensource.com/sites/default/files/uploads/python-java-hello-world_0.png (Java vs. Python)