mirror of
https://github.com/LCTT/TranslateProject.git
synced 2024-12-26 21:30:55 +08:00
Merge remote-tracking branch 'LCTT/master'
This commit is contained in:
Xingyu Wang
commit
3e9ce8b579
@ -0,0 +1,201 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: (wxy)
|
||||
[#]: reviewer: (wxy)
|
||||
[#]: publisher: (wxy)
|
||||
[#]: url: (https://linux.cn/article-12674-1.html)
|
||||
[#]: subject: (Recovering deleted files on Linux with testdisk)
|
||||
[#]: via: (https://www.networkworld.com/article/3575524/recovering-deleted-files-on-linux-with-testdisk.html)
|
||||
[#]: author: (Sandra Henry-Stocker https://www.networkworld.com/author/Sandra-Henry_Stocker/)
|
||||
|
||||
用 testdisk 恢复 Linux 上已删除的文件
|
||||
======
|
||||
|
||||
> 这篇文章介绍了 testdisk，这是恢复最近删除的文件（以及用其他方式修复分区）的工具之一，非常方便。
|
||||
|
||||
|
||||
|
||||
当你在 Linux 系统上删除一个文件时，它不一定会永远消失，特别是当你最近才刚刚删除了它的时候。
|
||||
|
||||
除非你用 `shred` 等工具把它擦掉，否则数据仍然会放在你的磁盘上 —— 而恢复已删除文件的最佳工具之一 `testdisk` 可以帮助你拯救它。虽然 `testdisk` 具有广泛的功能，包括恢复丢失或损坏的分区和使不能启动磁盘可以重新启动，但它也经常被用来恢复被误删的文件。
|
||||
|
||||
在本篇文章中，我们就来看看如何使用 `testdisk` 恢复已删除的文件，以及该过程中的每一步是怎样的。由于这个过程需要不少的步骤，所以当你做了几次之后，你可能会觉得操作起来会更加得心应手。
|
||||
|
||||
### 安装 testdisk
|
||||
|
||||
可以使用 `apt install testdisk` 或 `yum install testdisk` 等命令安装 `testdisk`。有趣的是，它不仅是一个 Linux 工具，而且还适用于 MacOS、Solaris 和 Windows。
|
||||
|
||||
文档可在 [cgsecurity.org][1] 中找到。
|
||||
|
||||
### 恢复文件
|
||||
|
||||
首先，你必须以 `root` 身份登录，或者有 `sudo` 权限才能使用 `testdisk`。如果你没有 `sudo` 访问权限，你会在这个过程一开始就被踢出，而如果你选择创建了一个日志文件的话，最终会有这样的消息：
|
||||
|
||||
```
|
||||
TestDisk exited normally.
|
||||
jdoe is not in the sudoers file. This incident will be reported.
|
||||
```
|
||||
|
||||
当你用 `testdisk` 恢复被删除的文件时，你最终会将恢复的文件放在你启动该工具的目录下，而这些文件会属于 `root`。出于这个原因，我喜欢在 `/home/recovery` 这样的目录下启动。一旦文件被成功地还原和验证，就可以将它们移回它们的所属位置，并将它们的所有权也恢复。
|
||||
|
||||
在你可以写入的选定目录下开始：
|
||||
|
||||
```
|
||||
$ cd /home/recovery
|
||||
$ testdisk
|
||||
```
|
||||
|
||||
`testdisk` 提供的第一页信息描述了该工具并显示了一些选项。至少在刚开始，创建个日志文件是个好主意，因为它提供的信息可能会被证明是有用的。下面是如何做的：
|
||||
|
||||
```
|
||||
Use arrow keys to select, then press Enter key:
|
||||
>[ Create ] Create a new log file
|
||||
[ Append ] Append information to log file
|
||||
[ No Log ] Don’t record anything
|
||||
```
|
||||
|
||||
左边的 `>` 以及你看到的反转的字体和背景颜色指出了你按下回车键后将使用的选项。在这个例子中，我们选择了创建日志文件。
|
||||
|
||||
然后会提示你输入密码（除非你最近使用过 `sudo`）。
|
||||
|
||||
下一步是选择被删除文件所存储的磁盘分区（如果没有高亮显示的话）。根据需要使用上下箭头移动到它。然后点两次右箭头，当 “Proceed” 高亮显示时按回车键。
|
||||
|
||||
```
|
||||
Select a media (use Arrow keys, then press Enter):
|
||||
Disk /dev/sda - 120 GB / 111 GiB - SSD2SC120G1CS1754D117-551
|
||||
>Disk /dev/sdb - 500 GB / 465 GiB - SAMSUNG HE502HJ
|
||||
Disk /dev/loop0 - 13 MB / 13 MiB (RO)
|
||||
Disk /dev/loop1 - 101 MB / 96 MiB (RO)
|
||||
Disk /dev/loop10 - 148 MB / 141 MiB (RO)
|
||||
Disk /dev/loop11 - 36 MB / 35 MiB (RO)
|
||||
Disk /dev/loop12 - 52 MB / 49 MiB (RO)
|
||||
Disk /dev/loop13 - 78 MB / 75 MiB (RO)
|
||||
Disk /dev/loop14 - 173 MB / 165 MiB (RO)
|
||||
Disk /dev/loop15 - 169 MB / 161 MiB (RO)
|
||||
>[Previous] [ Next ] [Proceed ] [ Quit ]
|
||||
```
|
||||
|
||||
在这个例子中，被删除的文件在 `/dev/sdb` 的主目录下。
|
||||
|
||||
此时，`testdisk` 应该已经选择了合适的分区类型。
|
||||
|
||||
```
|
||||
Disk /dev/sdb - 500 GB / 465 GiB - SAMSUNG HE502HJ
|
||||
|
||||
Please select the partition table type, press Enter when done.
|
||||
[Intel ] Intel/PC partition
|
||||
>[EFI GPT] EFI GPT partition map (Mac i386, some x86_64...)
|
||||
[Humax ] Humax partition table
|
||||
[Mac ] Apple partition map (legacy)
|
||||
[None ] Non partitioned media
|
||||
[Sun ] Sun Solaris partition
|
||||
[XBox ] XBox partition
|
||||
[Return ] Return to disk selection
|
||||
```
|
||||
|
||||
在下一步中，按向下箭头指向 “[ Advanced ] Filesystem Utils”。
|
||||
|
||||
```
|
||||
[ Analyse ] Analyse current partition structure and search for lost partitions
|
||||
>[ Advanced ] Filesystem Utils
|
||||
[ Geometry ] Change disk geometry
|
||||
[ Options ] Modify options
|
||||
[ Quit ] Return to disk selection
|
||||
```
|
||||
|
||||
接下来，查看选定的分区。
|
||||
|
||||
```
|
||||
Partition Start End Size in sectors
|
||||
> 1 P Linux filesys. data 2048 910155775 910153728 [drive2]
|
||||
```
|
||||
|
||||
然后按右箭头选择底部的 “[ List ]”，按回车键。
|
||||
|
||||
```
|
||||
[ Type ] [Superblock] >[ List ] [Image Creation] [ Quit ]
|
||||
```
|
||||
|
||||
请注意，它看起来就像我们从根目录 `/` 开始，但实际上这是我们正在工作的文件系统的基点。在这个例子中，就是 `/home`。
|
||||
|
||||
```
|
||||
Directory / <== 开始点
|
||||
|
||||
>drwxr-xr-x 0 0 4096 23-Sep-2020 17:46 .
|
||||
drwxr-xr-x 0 0 4096 23-Sep-2020 17:46 ..
|
||||
drwx——— 0 0 16384 22-Sep-2020 11:30 lost+found
|
||||
drwxr-xr-x 1008 1008 4096 9-Jul-2019 14:10 dorothy
|
||||
drwxr-xr-x 1001 1001 4096 22-Sep-2020 12:12 nemo
|
||||
drwxr-xr-x 1005 1005 4096 19-Jan-2020 11:49 eel
|
||||
drwxrwxrwx 0 0 4096 25-Sep-2020 08:08 recovery
|
||||
...
|
||||
```
|
||||
|
||||
接下来，我们按箭头指向具体的主目录。
|
||||
|
||||
```
|
||||
drwxr-xr-x 1016 1016 4096 17-Feb-2020 16:40 gino
|
||||
>drwxr-xr-x 1000 1000 20480 25-Sep-2020 08:00 shs
|
||||
```
|
||||
|
||||
按回车键移动到该目录，然后根据需要向下箭头移动到子目录。注意，如果选错了，可以选择列表顶部附近的 `..` 返回。
|
||||
|
||||
如果找不到文件，可以按 `/`（就像在 `vi` 中开始搜索时一样），提示你输入文件名或其中的一部分。
|
||||
|
||||
```
|
||||
Directory /shs <== current location
|
||||
Previous
|
||||
...
|
||||
-rw-rw-r— 1000 1000 426 8-Apr-2019 19:09 2-min-topics
|
||||
>-rw-rw-r— 1000 1000 24667 8-Feb-2019 08:57 Up_on_the_Roof.pdf
|
||||
```
|
||||
|
||||
一旦你找到需要恢复的文件，按 `c` 选择它。
|
||||
|
||||
注意：你会在屏幕底部看到有用的说明：
|
||||
|
||||
```
|
||||
Use Left arrow to go back, Right to change directory, h to hide deleted files
|
||||
q to quit, : to select the current file, a to select all files
|
||||
C to copy the selected files, c to copy the current file <==
|
||||
```
|
||||
|
||||
这时，你就可以在起始目录内选择恢复该文件的位置了（参见前面的说明，在将文件移回原点之前，先在一个合适的地方进行检查）。在这种情况下，`/home/recovery` 目录没有子目录，所以这就是我们的恢复点。
|
||||
|
||||
注意：你会在屏幕底部看到有用的说明：
|
||||
|
||||
```
|
||||
Please select a destination where /shs/Up_on_the_Roof.pdf will be copied.
|
||||
Keys: Arrow keys to select another directory
|
||||
C when the destination is correct
|
||||
Q to quit
|
||||
Directory /home/recovery <== 恢复位置
|
||||
```
|
||||
|
||||
一旦你看到 “Copy done! 1 ok, 0 failed” 的绿色字样，你就会知道文件已经恢复了。
|
||||
|
||||
在这种情况下，文件被留在 `/home/recovery/shs` 下（起始目录，附加所选目录）。
|
||||
|
||||
在将文件移回原来的位置之前，你可能应该先验证恢复的文件看起来是否正确。确保你也恢复了原来的所有者和组，因为此时文件由 root 拥有。
|
||||
|
||||
**注意：** 对于文件恢复过程中的很多步骤，你可以使用退出（按 `q` 或“[ Quit ]”）来返回上一步。如果你愿意，可以选择退出选项一直回到该过程中的第一步，也可以选择按下 `^c` 立即退出。
|
||||
|
||||
#### 恢复训练
|
||||
|
||||
使用 `testdisk` 恢复文件相对来说没有痛苦，但有些复杂。在恐慌时间到来之前，最好先练习一下恢复文件，让自己有机会熟悉这个过程。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://www.networkworld.com/article/3575524/recovering-deleted-files-on-linux-with-testdisk.html
|
||||
|
||||
作者：[Sandra Henry-Stocker][a]
|
||||
选题：[lujun9972][b]
|
||||
译者：[wxy](https://github.com/wxy)
|
||||
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/
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://www.cgsecurity.org/testdisk.pdf
|
||||
[2]: https://www.facebook.com/NetworkWorld/
|
||||
[3]: https://www.linkedin.com/company/network-world
|
||||
@ -1,5 +1,5 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: translator: (rakino)
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
|
||||
@ -0,0 +1,85 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (VMware highlights security in COVID-era networking)
|
||||
[#]: via: (https://www.networkworld.com/article/3584412/vmware-highlights-security-in-covid-era-networking.html)
|
||||
[#]: author: (Michael Cooney https://www.networkworld.com/author/Michael-Cooney/)
|
||||
|
||||
VMware highlights security in COVID-era networking
|
||||
======
|
||||
VMware is tackling the challenges of securing distributed enterprise resources with product enhancements including the new Carbon Black Cloud Workload software and upgrades to its SD-WAN and SASE products.
|
||||
ArtyStarty / Getty Images
|
||||
|
||||
As enterprise workloads continue to move off-premises and employees continue to work remotely during the COVID-19 pandemic, securing that environment remains a critical challenge for IT.
|
||||
|
||||
At its virtual VWworld 2020 gathering, VMware detailed products and plans to help customers deal with the challenges of securing distributed enterprise resources.
|
||||
|
||||
**More about SD-WAN**: [How to buy SD-WAN technology: Key questions to consider when selecting a supplier][1] • [What SD-Branch is and why you'll need it][2] • [What are the options for securing SD-WAN?][3]
|
||||
|
||||
"Amid global disruption, the key to survival for many companies has meant an accelerated shift to the cloud and, ultimately, bolting on security products in their data centers," said Sanjay Poonen, VMware's Chief Operating Officer, Customer Operations. "But legacy security systems are no longer sufficient for organizations that are using the cloud as part of their computing infrastructure. It's time to rethink security for the cloud. Organizations need protection at the workload level, not just at the endpoint."
|
||||
|
||||
With that in mind, VMware introduced Carbon Black Cloud Workload software that combines vulnerability reporting with security detection and response capabilities to protect workloads running in virtualized, private and hybrid cloud environments, VMware stated.
|
||||
|
||||
The new packages – along with [other upgrades to its security software][4] – represent VMware's continued development and integration of the Carbon Black security technology it [acquired a year ago][5] for $2.1 billion.
|
||||
|
||||
"Tightly integrated with vSphere, VMware Carbon Black Cloud Workload provides agentless security that alleviates installation and management overhead and consolidates the collection of [telemetry][6] for multiple workload security use cases," VMware stated.
|
||||
|
||||
The idea is to allow security and infrastructure teams to automatically secure new and existing workloads at every point in the security lifecycle, while simplifying operations and consolidating the IT and security stack. With the software, customers can analyze attacker behavior patterns over time to detect and stop never-seen-before attacks, including those manipulating known-good software. If an attacker bypasses perimeter defenses, security teams can shut down the attack before it escalates to a data breach, VMware stated.
|
||||
|
||||
All current vSphere 6.5 and VMware Cloud Foundation 4.0 customers can give the package a try for free for the next six months, VMware stated. VMware plans to introduce a Carbon Black Cloud module for hardening and better securing Kubernetes workloads as well.
|
||||
|
||||
The company also enhanced its Workspace ONE platform that securely manages end users' mobile devices and cloud-hosted virtual desktops and applications from the cloud or on-premise.
|
||||
|
||||
The company says it blended VMware Workspace ONE Horizon and VMware Carbon Black Cloud to offer behavioral detection to protect against ransomware and file-less malware. On VMware vSphere, the solution is integrated into VMware Tools, removing the need to install and manage additional security agents, according to the company.
|
||||
|
||||
Bolstering support for Apple Mac and Microsoft Windows 10 remote users, VMware added Workspace Security Remote, which includes the antivirus, audit and remediation, and detection and response capabilities of Carbon Black Cloud. It also includes the analytics, automation, device health, orchestration, and zero-trust access capabilities of the Workspace ONE platform.
|
||||
|
||||
Securing the remote work environment is a common theme among other VMWare announcements, including news around its [SD-WAN and secure access service edge (SASE)][7] products and its overarching Virtual Cloud Network architecture.
|
||||
|
||||
Taken together, the enhancements further VMware's goal of integrating security features within its infrastructure – a concept it calls intrinsic security – in an effort to better protect networked workloads than traditional piecemeal protection systems could.
|
||||
|
||||
The democratization of compute was already underway before the COVID situation pushed it further, faster, said Sanjay Uppal, senior vice president and general manager of the VeloCloud Business Unit at VMware. "So with the remote workforce growing we need to make privacy and security drop-dead simple, and that is the goal."
|
||||
|
||||
A more futuristic goal for the company is to provide a unified approach to security incident detection and response that can leverage multiple domains – from endpoint to workload to user to network. An emerging architecture that promises those capabilities is Extended Detection and Response (XDR), and VMware says it intends to support it.
|
||||
|
||||
In a recent _[CSO][8]_ [column][8], Enterprise Strategy Group senior principal analyst Jon Oltsik defined XDR as "an integrated suite of security products spanning hybrid IT architectures, designed to interoperate and coordinate on threat prevention, detection and response. In other words, XDR unifies control points, security telemetry, analytics, and operations into one enterprise system."
|
||||
|
||||
ESG research indicates that 84% of organizations are actively integrating security technologies so XDR can act as a turnkey security technology integration solution.
|
||||
|
||||
"While vendors will offer different XDR bundles, ESG research indicates that large organizations really want XDR to include endpoint/server/cloud workload security, network security, coverage of the most common threat vectors (i.e., email/web), file detonation (i.e., sandboxing), threat intelligence, and analytics," Oltsik stated.
|
||||
|
||||
Gartner said of XDR: "Although XDR tools are similar in function to security incident and event monitoring (SIEM) and security orchestration, automation and response tools, they are primarily differentiated by the level of integration at deployment and the focus on incident response."
|
||||
|
||||
The primary goals of an XDR solution are to increase detection accuracy by correlating threat intelligence and signals across multiple security solutions, and to improve security operations efficiency and productivity.
|
||||
|
||||
For its part, VMware said XDR is the opportunity to do just that: provide a unified approach to security incident detection and response that can leverage multiple domains from endpoint to workload to user to network.
|
||||
|
||||
VMware called XDR "a multi-year effort to build the most advanced and comprehensive security incident detection and response solutions available" and will include cross-platform integration across its portfolio including Workspace ONE, vSphere, Carbon Black Cloud, and NSX Service-defined Firewall.
|
||||
|
||||
Join the Network World communities on [Facebook][9] and [LinkedIn][10] to comment on topics that are top of mind.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://www.networkworld.com/article/3584412/vmware-highlights-security-in-covid-era-networking.html
|
||||
|
||||
作者：[Michael Cooney][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/Michael-Cooney/
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://www.networkworld.com/article/3323407/sd-wan/how-to-buy-sd-wan-technology-key-questions-to-consider-when-selecting-a-supplier.html
|
||||
[2]: https://www.networkworld.com/article/3250664/lan-wan/sd-branch-what-it-is-and-why-youll-need-it.html
|
||||
[3]: https://www.networkworld.com/article/3285728/sd-wan/what-are-the-options-for-securing-sd-wan.html
|
||||
[4]: https://www.networkworld.com/article/3529369/vmware-amps-up-its-cloud-and-data-center-security.html
|
||||
[5]: https://www.networkworld.com/article/3445383/vmware-builds-security-unit-around-carbon-black-tech.html
|
||||
[6]: https://www.networkworld.com/article/3575837/streaming-telemetry-gains-interest-as-snmp-reliance-fades.html
|
||||
[7]: https://www.networkworld.com/article/3583939/vmware-amps-up-security-for-network-sase-sd-wan-products.html
|
||||
[8]: https://www.csoonline.com/article/3561291/what-is-xdr-10-things-you-should-know-about-this-security-buzz-term.html
|
||||
[9]: https://www.facebook.com/NetworkWorld/
|
||||
[10]: https://www.linkedin.com/company/network-world
|
||||
@ -1,5 +1,5 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: translator: (gxlct008)
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
|
||||
@ -1,5 +1,5 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: translator: (HankChow)
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
|
||||
@ -1,288 +0,0 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (Create a mobile app with Flutter)
|
||||
[#]: via: (https://opensource.com/article/20/9/mobile-app-flutter)
|
||||
[#]: author: (Vitaly Kuprenko https://opensource.com/users/kooper)
|
||||
|
||||
Create a mobile app with Flutter
|
||||
======
|
||||
Start your journey toward cross-platform development with the popular
|
||||
Flutter framework.
|
||||
![A person looking at a phone][1]
|
||||
|
||||
[Flutter][2] is a popular project among mobile developers around the world. The framework has a massive, friendly community of enthusiasts, which continues to grow as Flutter helps programmers take their projects into the mobile space.
|
||||
|
||||
This tutorial is meant to help you start doing mobile development with Flutter. After reading it, you'll know how to quickly install and set up the framework to start coding for smartphones, tablets, and other platforms.
|
||||
|
||||
This how-to assumes you have [Android Studio][3] installed on your computer and some experience working with it.
|
||||
|
||||
### What is Flutter?
|
||||
|
||||
Flutter enables developers to build apps for several platforms, including:
|
||||
|
||||
* Android
|
||||
* iOS
|
||||
* Web (in beta)
|
||||
* macOS (in development)
|
||||
* Linux (in development)
|
||||
|
||||
|
||||
|
||||
Support for macOS and Linux is in early development, while web support is expected to be released soon. This means that you can try out its capabilities now (as I'll describe below).
|
||||
|
||||
### Install Flutter
|
||||
|
||||
I'm using Ubuntu 18.04, but the installation process is similar with other Linux distributions, such as Arch or Mint.
|
||||
|
||||
#### Install with snapd
|
||||
|
||||
To install Flutter on Ubuntu or similar distributions using [snapd][4], enter this in a terminal:
|
||||
|
||||
|
||||
```
|
||||
$ sudo snap install flutter --classic
|
||||
|
||||
$ sudo snap install flutter –classic
|
||||
flutter 0+git.142868f from flutter Team/ installed
|
||||
```
|
||||
|
||||
Then launch it using the `flutter` command. Upon the first launch, the framework downloads to your computer:
|
||||
|
||||
|
||||
```
|
||||
$ flutter
|
||||
Initializing Flutter
|
||||
Downloading <https://storage.googleapis.com/flutter\_infra\[...\]>
|
||||
```
|
||||
|
||||
Once the download is finished, you'll see a message telling you that Flutter is initialized:
|
||||
|
||||
![Flutter initialized][5]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
#### Install manually
|
||||
|
||||
If you don't have snapd or your distribution isn't Ubuntu, the installation process will be a little bit different. In that case, [download][7] the version of Flutter recommended for your operating system.
|
||||
|
||||
![Install Flutter manually][8]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
Then extract it to your home directory.
|
||||
|
||||
Open the `.bashrc` file in your home directory (or `.zshrc` if you use the [Z shell][9]) in your favorite text editor. Because it's a hidden file, you must first enable showing hidden files in your file manager or open it from a terminal with:
|
||||
|
||||
|
||||
```
|
||||
`$ gedit ~/.bashrc &`
|
||||
```
|
||||
|
||||
Add the following line to the end of the file:
|
||||
|
||||
|
||||
```
|
||||
`export PATH="$PATH:~/flutter/bin"`
|
||||
```
|
||||
|
||||
Save and close the file. Keep in mind that if you extracted Flutter somewhere other than your home directory, the [path to Flutter SDK][10] will be different.
|
||||
|
||||
Close your terminal and then open it again so that your new configuration loads. Alternatively, you can source the configuration with:
|
||||
|
||||
|
||||
```
|
||||
`$ . ~/.bashrc`
|
||||
```
|
||||
|
||||
If you don't see an error, then everything is fine.
|
||||
|
||||
This installation method is a little bit harder than using the `snap` command, but it's pretty versatile and lets you install the framework on almost any distribution.
|
||||
|
||||
#### Check the installation
|
||||
|
||||
To check the result, enter the following in the terminal:
|
||||
|
||||
|
||||
```
|
||||
`flutter doctor -v`
|
||||
```
|
||||
|
||||
You'll see information about installed components. Don't worry if you see errors. You haven't installed any IDE plugins for working with Flutter SDK yet.
|
||||
|
||||
![Checking Flutter installation with the doctor command][11]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
### Install IDE plugins
|
||||
|
||||
You should install plugins in your [integrated development environment (IDE)][12] to help it interface with the Flutter SDK, interact with devices, and build code.
|
||||
|
||||
The three main IDE tools that are commonly used for Flutter development are IntelliJ IDEA (Community Edition), Android Studio, and VS Code (or [VSCodium][13]). I'm using Android Studio in this tutorial, but the steps are similar to how they work on IntelliJ IDEA (Community Edition) since they're built on the same platform.
|
||||
|
||||
First, launch **Android Studio**. Open **Settings** and go to the **Plugins** pane, and select the **Marketplace** tab. Enter **Flutter** in the search line and click **Install**.
|
||||
|
||||
![Flutter plugins][14]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
You'll probably see an option to install the **Dart** plugin; agree to it. If you don't see the Dart option, then install it manually by repeating the steps above. I also recommend using the **Rainbow Brackets** plugin, which makes code navigation easier.
|
||||
|
||||
That's it! You've installed all the plugins you need. You can check by entering a familiar command in the terminal:
|
||||
|
||||
|
||||
```
|
||||
`flutter doctor -v`
|
||||
```
|
||||
|
||||
![Checking Flutter plugins with the doctor command][15]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
### Build your "Hello World" application
|
||||
|
||||
To start a new project, create a Flutter project:
|
||||
|
||||
1. Select **New -> New Flutter project**.
|
||||
|
||||
![Creating a new Flutter plugin][16]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
2. In the window, choose the type of project you want. In this case, you need **Flutter Application**.
|
||||
|
||||
3. Name your project **hello_world**. Note that you should use a merged name, so use an underscore instead of a space. You may also need to specify the path to the SDK.
|
||||
|
||||
![Naming a new Flutter plugin][17]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
4. Enter the package name.
|
||||
|
||||
|
||||
|
||||
|
||||
You've created a project! Now you can launch it on a device or by using an emulator.
|
||||
|
||||
![Device options in Flutter][18]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
Select the device you want and press **Run**. In a moment, you will see the result.
|
||||
|
||||
![Flutter demo on mobile device][19]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
Now you can start working on an [intermediate project][20].
|
||||
|
||||
### Try Flutter for web
|
||||
|
||||
Before you install Flutter components for the web, you should know that Flutter's support for web apps is pretty raw at the moment. So it's not a good idea to use it for complicated projects yet.
|
||||
|
||||
Flutter for web is not active in the basic SDK by default. To switch it on, go to the beta channel. To do this, enter the following command in the terminal:
|
||||
|
||||
|
||||
```
|
||||
`flutter channel beta`
|
||||
```
|
||||
|
||||
![flutter channel beta output][21]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
Next, upgrade Flutter according to the beta branch by using the command:
|
||||
|
||||
|
||||
```
|
||||
`flutter upgrade`
|
||||
```
|
||||
|
||||
![flutter upgrade output][22]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
To make Flutter for web work, enter:
|
||||
|
||||
|
||||
```
|
||||
`flutter config --enable-web`
|
||||
```
|
||||
|
||||
Restart your IDE; this helps Android Studio index the new IDE and reload the list of devices. You should see several new devices:
|
||||
|
||||
![Flutter for web device options][23]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
Selecting **Chrome** launches an app in the browser, while **Web Server** gives you the link to your web app, which you can open in any browser.
|
||||
|
||||
Still, it's not time to rush into development because your current project doesn't support the web. To improve it, open the terminal in the project's root and enter:
|
||||
|
||||
|
||||
```
|
||||
`flutter create`
|
||||
```
|
||||
|
||||
This command recreates the project, adding web support. The existing code won't be deleted.
|
||||
|
||||
Note that the tree has changed and now has a "web" directory:
|
||||
|
||||
![File tree with web directory][24]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
Now you can get to work. Select **Chrome** and press **Run**. In a moment, you'll see the browser window with your app.
|
||||
|
||||
![Flutter web app demo][25]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
Congratulations! You've just launched a project for the browser and can continue working with it as with any other website.
|
||||
|
||||
All of this comes from the same codebase because Flutter makes it possible to write code for both mobile platforms and the web with little to no changes.
|
||||
|
||||
### Do more with Flutter
|
||||
|
||||
Flutter is a powerful tool for mobile development, and moreover, it's an important evolutionary step toward cross-platform development. Learn it, use it, and deliver your apps to all the platforms!
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/20/9/mobile-app-flutter
|
||||
|
||||
作者：[Vitaly Kuprenko][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/kooper
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/idea_innovation_mobile_phone.png?itok=RqVtvxkd (A person looking at a phone)
|
||||
[2]: https://flutter.dev/
|
||||
[3]: https://developer.android.com/studio
|
||||
[4]: https://snapcraft.io/docs/getting-started
|
||||
[5]: https://opensource.com/sites/default/files/uploads/flutter1_initialized.png (Flutter initialized)
|
||||
[6]: https://creativecommons.org/licenses/by-sa/4.0/
|
||||
[7]: https://flutter.dev/docs/get-started/install/linux
|
||||
[8]: https://opensource.com/sites/default/files/uploads/flutter2_manual-install.png (Install Flutter manually)
|
||||
[9]: https://opensource.com/article/19/9/getting-started-zsh
|
||||
[10]: https://opensource.com/article/17/6/set-path-linux
|
||||
[11]: https://opensource.com/sites/default/files/uploads/flutter3_doctor.png (Checking Flutter installation with the doctor command)
|
||||
[12]: https://www.redhat.com/en/topics/middleware/what-is-ide
|
||||
[13]: https://opensource.com/article/20/6/open-source-alternatives-vs-code
|
||||
[14]: https://opensource.com/sites/default/files/uploads/flutter4_plugins.png (Flutter plugins)
|
||||
[15]: https://opensource.com/sites/default/files/uploads/flutter5_plugincheck.png (Checking Flutter plugins with the doctor command)
|
||||
[16]: https://opensource.com/sites/default/files/uploads/flutter6_newproject.png (Creating a new Flutter plugin)
|
||||
[17]: https://opensource.com/sites/default/files/uploads/flutter7_projectname.png (Naming a new Flutter plugin)
|
||||
[18]: https://opensource.com/sites/default/files/uploads/flutter8_launchflutter.png (Device options in Flutter)
|
||||
[19]: https://opensource.com/sites/default/files/uploads/flutter9_demo.png (Flutter demo on mobile device)
|
||||
[20]: https://opensource.com/article/18/6/flutter
|
||||
[21]: https://opensource.com/sites/default/files/uploads/flutter10_beta.png (flutter channel beta output)
|
||||
[22]: https://opensource.com/sites/default/files/uploads/flutter11_upgrade.png (flutter upgrade output)
|
||||
[23]: https://opensource.com/sites/default/files/uploads/flutter12_new-devices.png (Flutter for web device options)
|
||||
[24]: https://opensource.com/sites/default/files/uploads/flutter13_tree.png (File tree with web directory)
|
||||
[25]: https://opensource.com/sites/default/files/uploads/flutter14_webapp.png (Flutter web app demo)
|
||||
@ -1,77 +0,0 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: (rakino)
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (Create template files in GNOME)
|
||||
[#]: via: (https://opensource.com/article/20/9/gnome-templates)
|
||||
[#]: author: (Alan Formy-Duval https://opensource.com/users/alanfdoss)
|
||||
|
||||
Create template files in GNOME
|
||||
======
|
||||
Make boilerplates so you can get started on a new document faster.
|
||||
![Digital images of a computer desktop][1]
|
||||
|
||||
I just stumbled onto a new (to me) feature of the [GNOME][2] desktop that enables you to create a document template. A template is generally an empty shell of a document with certain things configured and is often referred to as boilerplate. An example might be a letterhead for a law firm, with its corporate title and address at the top. Another might be a bank or insurance carrier letter that contains certain disclaimers in the footer at the bottom of the document. Since this sort of information rarely changes, you can add it to an empty document to use as a template.
|
||||
|
||||
I was browsing through files on my Linux system one day and clicked on the **Templates** directory. I just happened to notice a message at the top of the window that stated, "Put files in this folder to use them as templates for new documents." There was also a link to **Learn more…** that opens the [GNOME help][3] for templates.
|
||||
|
||||
![Message at top of Templates folder in GNOME Desktop][4]
|
||||
|
||||
(Alan Formy-Duval, [CC BY-SA 4.0][5])
|
||||
|
||||
### Create a template
|
||||
|
||||
Creating a template for the GNOME desktop is quite simple. There are several ways you can place a file into this folder: You can copy or move a file from another location through either the graphical user interface (GUI) or the command-line interface (CLI), or you can create an entirely new file. I chose the latter; actually, I created two files.
|
||||
|
||||
![My first two GNOME templates][6]
|
||||
|
||||
(Alan Formy-Duval, [CC BY-SA 4.0][5])
|
||||
|
||||
The first template I created is for an Opensource.com article. It provides a place to enter a title and several lines for my name and the license terms under which I am providing the content of the article. I use the Markdown document format for my articles, so I create the template as a new Markdown document—**Opensource.com Article.md**:
|
||||
|
||||
|
||||
```
|
||||
# Title
|
||||
```
|
||||
An article for Opensource.com
|
||||
by: Alan Formy-Duval
|
||||
Creative Commons BY-SA 4.0
|
||||
```
|
||||
|
||||
```
|
||||
|
||||
I saved this document as a file in `/home/alan/Templates`. Now GNOME recognizes this file as a template and suggests it whenever I want to create a new document.
|
||||
|
||||
### Use a template
|
||||
|
||||
Whenever I get a spark or epiphany for a new article, I can just right-click in the folder where I plan to organize my content and select the template from the **New Document** list.
|
||||
|
||||
![Select the template by name][7]
|
||||
|
||||
(Alan Formy-Duval, [CC BY-SA 4.0][5])
|
||||
|
||||
You can make a template for all sorts of documents or files. I am writing this article using a template I created for my Opensource.com articles. Programmers might use templates for software code; perhaps you want a template that just contains `main()`.
|
||||
|
||||
The GNOME desktop environment provides a very useful, feature-rich user interface for users of Linux and related operating systems. What are your favorite GNOME desktop features, and how do you use them? Please share in the comments!
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/20/9/gnome-templates
|
||||
|
||||
作者：[Alan Formy-Duval][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/alanfdoss
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/computer_desk_home_laptop_browser.png?itok=Y3UVpY0l (Digital images of a computer desktop)
|
||||
[2]: https://www.gnome.org/
|
||||
[3]: https://help.gnome.org/users/gnome-help/stable/files-templates.html.en
|
||||
[4]: https://opensource.com/sites/default/files/uploads/gnome-message_at_top_border.png (Message at top of Templates folder in GNOME Desktop)
|
||||
[5]: https://creativecommons.org/licenses/by-sa/4.0/
|
||||
[6]: https://opensource.com/sites/default/files/uploads/gnome-first_two_templates_border.png (My first two GNOME templates)
|
||||
[7]: https://opensource.com/sites/default/files/uploads/gnome-new_document_menu_border.png (Select the template by name)
|
||||
@ -1,201 +0,0 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (Recovering deleted files on Linux with testdisk)
|
||||
[#]: via: (https://www.networkworld.com/article/3575524/recovering-deleted-files-on-linux-with-testdisk.html)
|
||||
[#]: author: (Sandra Henry-Stocker https://www.networkworld.com/author/Sandra-Henry_Stocker/)
|
||||
|
||||
Recovering deleted files on Linux with testdisk
|
||||
======
|
||||
This post describes testdisk, one of the tools that comes in handy for recovering recently deleted files (along with fixing partitions in other ways).
|
||||
Thinkstock
|
||||
|
||||
When you delete a file on a Linux system, it isn’t necessarily gone forever, especially if you just recently deleted it.
|
||||
|
||||
Unless you rubbed it out with a tool such as **shred**, the data will still be sitting on your disk—and one of the best tools for recovering deleted files, **testdisk,** can help you rescue it. While **testdisk** has a wide range of functionality including recovering lost or damaged partitions and making non-booting disks bootable again, it’s also frequently used to restore files that were deleted by mistake.
|
||||
|
||||
In this post, we’ll take a look at how you can recover deleted files using **testdisk** and what each step in the process looks like. Since the process requires quite a few steps, you’re likely to feel more comfortable running through them once you’ve done it a few times.
|
||||
|
||||
### Installing testdisk
|
||||
|
||||
Install **testdisk** with commands like **apt install testdisk** or **yum install testdisk**. Interestingly, it’s not just a Linux tool but is also available for MacOS, Solaris and Windows as well.
|
||||
|
||||
Documentation is available at [cgsecurity.org][1].
|
||||
|
||||
### Recovering files
|
||||
|
||||
First of all, you have to be logged in as **root** or have **sudo** access to use **testdisk**. If you don’t have **sudo** access, you’ll get kicked out early in the process, and your logfile, if you chose to create one, will end up with a message like this in it:
|
||||
|
||||
```
|
||||
TestDisk exited normally.
|
||||
jdoe is not in the sudoers file. This incident will be reported.
|
||||
```
|
||||
|
||||
When you recover deleted files with **testdisk**, you’re going to end up with the files being restored within the directory form which you started the tool and the files are going to belong to **root**. For this reason, I like to start in a directory like **/home/recovery**. Once the files are successfully restored and verified, they can be moved back to where they belong and have their ownership restored as well.
|
||||
|
||||
Make sure you can write in the directory you select to start in.
|
||||
|
||||
```
|
||||
$ cd /home/recovery
|
||||
$ testdisk
|
||||
```
|
||||
|
||||
The first page of information presented by **testdisk** describes the tool and displays some options. At least initially, it’s a good idea to create the log file as it provides information that might prove useful. Here’s how:
|
||||
|
||||
```
|
||||
Use arrow keys to select, then press Enter key:
|
||||
>[ Create ] Create a new log file
|
||||
[ Append ] Append information to log file
|
||||
[ No Log ] Don’t record anything
|
||||
```
|
||||
|
||||
The **>** on the left and the reversal of the font and background colors that you will see show the option that will be used once you press **enter**. In this example, we opted to create the log file.
|
||||
|
||||
You will then be prompted for your password (unless you very recently used **sudo**).
|
||||
|
||||
The next step is to select the disk partition in which the deleted file was stored (if not already highlighted). Use the up and down arrow keys as needed to move to it. Then tap the right arrow twice and press **enter** when **Proceed** is highlighted.
|
||||
|
||||
```
|
||||
Select a media (use Arrow keys, then press Enter):
|
||||
Disk /dev/sda - 120 GB / 111 GiB - SSD2SC120G1CS1754D117-551
|
||||
>Disk /dev/sdb - 500 GB / 465 GiB - SAMSUNG HE502HJ
|
||||
Disk /dev/loop0 - 13 MB / 13 MiB (RO)
|
||||
Disk /dev/loop1 - 101 MB / 96 MiB (RO)
|
||||
Disk /dev/loop10 - 148 MB / 141 MiB (RO)
|
||||
Disk /dev/loop11 - 36 MB / 35 MiB (RO)
|
||||
Disk /dev/loop12 - 52 MB / 49 MiB (RO)
|
||||
Disk /dev/loop13 - 78 MB / 75 MiB (RO)
|
||||
Disk /dev/loop14 - 173 MB / 165 MiB (RO)
|
||||
Disk /dev/loop15 - 169 MB / 161 MiB (RO)
|
||||
>[Previous] [ Next ] [Proceed ] [ Quit ]
|
||||
```
|
||||
|
||||
In this example, the deleted file was in a home directory in **/dev/sdb**.
|
||||
|
||||
At this point, the partition type should already be selected by **testdisk**.
|
||||
|
||||
```
|
||||
Disk /dev/sdb - 500 GB / 465 GiB - SAMSUNG HE502HJ
|
||||
|
||||
Please select the partition table type, press Enter when done.
|
||||
[Intel ] Intel/PC partition
|
||||
>[EFI GPT] EFI GPT partition map (Mac i386, some x86_64...)
|
||||
[Humax ] Humax partition table
|
||||
[Mac ] Apple partition map (legacy)
|
||||
[None ] Non partitioned media
|
||||
[Sun ] Sun Solaris partition
|
||||
[XBox ] XBox partition
|
||||
[Return ] Return to disk selection
|
||||
```
|
||||
|
||||
In the next step, arrow down to “[ Advanced ] Filesystem Utils”.
|
||||
|
||||
```
|
||||
[ Analyse ] Analyse current partition structure and search for lost partitions
|
||||
>[ Advanced ] Filesystem Utils
|
||||
[ Geometry ] Change disk geometry
|
||||
[ Options ] Modify options
|
||||
[ Quit ] Return to disk selection
|
||||
```
|
||||
|
||||
Next, view the selected partition.
|
||||
|
||||
```
|
||||
Partition Start End Size in sectors
|
||||
> 1 P Linux filesys. data 2048 910155775 910153728 [drive2]
|
||||
```
|
||||
|
||||
Then press the right arrow to select **[ List ]** at the bottom and press enter.
|
||||
|
||||
```
|
||||
[ Type ] [Superblock] >[ List ] [Image Creation] [ Quit ]
|
||||
```
|
||||
|
||||
Notice that it looks as if we’re starting in **/**, but this is actually the base of the file system that we’re working in. In this example, that’s **/home**.
|
||||
|
||||
```
|
||||
Directory / <== starting point
|
||||
|
||||
>drwxr-xr-x 0 0 4096 23-Sep-2020 17:46 .
|
||||
drwxr-xr-x 0 0 4096 23-Sep-2020 17:46 ..
|
||||
drwx——— 0 0 16384 22-Sep-2020 11:30 lost+found
|
||||
drwxr-xr-x 1008 1008 4096 9-Jul-2019 14:10 dorothy
|
||||
drwxr-xr-x 1001 1001 4096 22-Sep-2020 12:12 nemo
|
||||
drwxr-xr-x 1005 1005 4096 19-Jan-2020 11:49 eel
|
||||
drwxrwxrwx 0 0 4096 25-Sep-2020 08:08 recovery
|
||||
...
|
||||
```
|
||||
|
||||
Next, we arrow down to the specific home directory.
|
||||
|
||||
```
|
||||
drwxr-xr-x 1016 1016 4096 17-Feb-2020 16:40 gino
|
||||
>drwxr-xr-x 1000 1000 20480 25-Sep-2020 08:00 shs
|
||||
```
|
||||
|
||||
Press enter to move into that directory and then arrow down to a subdirectory as needed. Note that you can choose **..** near the top of the list to back up if you picked the wrong one.
|
||||
|
||||
If you have trouble finding the file, you can press **/** (like when you start a search in **vi**) to be prompted to enter the file name or some portion of it.
|
||||
|
||||
```
|
||||
Directory /shs <== current location
|
||||
Previous
|
||||
...
|
||||
-rw-rw-r— 1000 1000 426 8-Apr-2019 19:09 2-min-topics
|
||||
>-rw-rw-r— 1000 1000 24667 8-Feb-2019 08:57 Up_on_the_Roof.pdf
|
||||
```
|
||||
|
||||
Once you’ve located the file that you need to restore, press “**c**” to select it.
|
||||
|
||||
NOTE: You will see helpful instructions at the bottom of your screen:
|
||||
|
||||
```
|
||||
Use Left arrow to go back, Right to change directory, h to hide deleted files
|
||||
q to quit, : to select the current file, a to select all files
|
||||
C to copy the selected files, c to copy the current file <==
|
||||
```
|
||||
|
||||
At this point, you’ll be ready to select where to restore that file within your starting directory (see earlier note about starting in a good place to check out the file before moving it back to its place of origin). In this case, the **/home/recovery** directory has no subdirectories, so this is our recovery spot.
|
||||
|
||||
NOTE: You will see helpful instructions at the bottom of the screen.
|
||||
|
||||
```
|
||||
Please select a destination where /shs/Up_on_the_Roof.pdf will be copied.
|
||||
Keys: Arrow keys to select another directory
|
||||
C when the destination is correct
|
||||
Q to quit
|
||||
Directory /home/recovery <== recovery location
|
||||
```
|
||||
|
||||
Once you see “**Copy done! 1 ok, 0 failed**” in green, you’ll know the file has been restored.
|
||||
|
||||
The file in this case was left in **/home/recovery/shs** (starting directory with the selected directory appended).
|
||||
|
||||
You should probably verify that the recovered file looks right before moving it back into its original location. Make sure you also restore the original owner and group since the file will be owned by root at this point.
|
||||
|
||||
**NOTE:** For many points in the file recovery process, you can use quit (**q** or **[ Quit ]**) to back up a step. You can select quit options all the way back to the first step in the process if you like or **^c** to exit immediately.
|
||||
|
||||
#### Recovery training
|
||||
|
||||
Recovering files using **testdisk** is relatively painless, but somewhat complicated. It’s probably a good idea to practice recovering files before panic time sets to give yourself a chance to get comfortable with the process.
|
||||
|
||||
Join the Network World communities on [Facebook][2] and [LinkedIn][3] to comment on topics that are top of mind.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://www.networkworld.com/article/3575524/recovering-deleted-files-on-linux-with-testdisk.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.cgsecurity.org/testdisk.pdf
|
||||
[2]: https://www.facebook.com/NetworkWorld/
|
||||
[3]: https://www.linkedin.com/company/network-world
|
||||
@ -0,0 +1,63 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (Akraino: An Open Source Project for the Edge)
|
||||
[#]: via: (https://www.linux.com/news/akraino-an-open-source-project-for-the-edge/)
|
||||
[#]: author: (Swapnil Bhartiya https://www.linux.com/author/swapnil/)
|
||||
|
||||
Akraino: An Open Source Project for the Edge
|
||||
======
|
||||
|
||||
Akraino is an open-source project designed for the Edge community to easily integrate open source components into their stack. It’s a set of open infrastructures and application blueprints spanning a broad variety of use cases, including 5G, AI, Edge IaaS/PaaS, IoT, for both provider and enterprise Edge domains. We sat down with Tina Tsou, TSC Co-Chair of the Akraino project to learn more about it and its community.
|
||||
|
||||
Here is a lightly edited transcript of the interview:
|
||||
|
||||
Swapnil Bhartiya: Today, we have with us Tina Tsou, TSC Co-Chair of the Akraino project. Tell us a bit about the Akraino project.
|
||||
|
||||
Tina Tsou: Yeah, I think Akraino is an Edge Stack project under Linux Foundation Edge. Before Akraino, the developers had to go to the upstream community to download the upstream software components and integrate in-store to test. With the blueprint ideas and concept, the developers can directly do the use-case base to blueprint, do all the integration, and [have it] ready for the end-to-end deployment for Edge.
|
||||
|
||||
Swapnil Bhartiya: The blueprints are the critical piece of it. What are these blueprints and how do they integrate with the whole framework?
|
||||
|
||||
Tina Tsou: Based on the certain use case, we do the community CI/CD ( continuous integration and continuous deployment). We also have proven security requirements. We do the community lab and we also do the life cycle management. And then we do the production quality, which is deployment-ready.
|
||||
|
||||
Swapnil Bhartiya: Can you explain what the Edge computing framework looks like?
|
||||
|
||||
Tina Tsou: We have four segments: Cloud, Telco, IoT, and Enterprise. When we do the framework, it’s like we have a framework of the Edge compute in general, but for each segment, they are slightly different. You will see in the lower level, you have the network, you have the gateway, you have the switches. In the upper of it, you have all kinds of FPGA and then the data plan. Then, you have the controllers and orchestration, like the Kubernetes stuff and all kinds of applications running on bare metal, virtual machines or the containers. By the way, we also have the orchestration on the site.
|
||||
|
||||
Swapnil Bhartiya: And how many blueprints are there? Can you talk about it more specifically?
|
||||
Tina Tsou: I think we have around 20-ish blueprints, but they are converged into blueprint families. We have a blueprint family for telco appliances, including Radio Edge Cloud, and SEBA that has enabled broadband access. We also have a blueprint for Network Cloud. We have a blueprint for Integrated Edge Cloud. We have a blueprint for Edge Lite IoT. So, in this case, the different blueprints in the same blueprint family can share the same software framework, which saves a lot of time. That means we can deploy it at a large scale.
|
||||
|
||||
Swapnil Bhartiya: The software components, which you already talked about in each blueprint, are they all in the Edge project or there are some components from external projects as well?
|
||||
|
||||
Tina Tsou: We have the philosophy of upstream first. If we can find it from the upstream community, we just directly take it from the upstream community and install and integrate it. If we find something that we need, we go to the upstream community to see whether it can be changed or updated there.
|
||||
|
||||
Swapnil Bhartiya: How challenging or easy it is to integrate these components together, to build the stack?
|
||||
|
||||
Tina Tsou: It depends on which group and family we are talking about. I think most of them at the middle level of middle are not too easy, not too complex. But the reference has to create the installation, like the YAML files configuration and for builds on ISO images, some parts may be more complex and some parts will be easy to download and integrate.
|
||||
|
||||
Swapnil Bhartiya: We have talked about the project. I want to talk about the community. So first of all, tell us what is the role of TSC?
|
||||
|
||||
Tina Tsou: We have a whole bunch of documentation on how TSA runs if you want to read. I think the role for TSC is more tactical steering. We have a chair and co-chair, and there are like 6-7 subcommittees for specific topics like security, technical community, CI and documentation process.
|
||||
|
||||
Swapnil Bhartiya: What kind of community is there around the Akraino project?
|
||||
|
||||
Tina Tsou: I think we have a pretty diverse community. We have the end-users like the telcos and the hyperscalers, the internet companies, and also enterprise companies. Then we have the OEM/ODM vendors, the chip makers or the SoC makers. Then have the IP companies and even some universities.
|
||||
|
||||
Swapnil Bhartiya: Tina, thank you so much for taking the time today to explain the Akraino project and also about the blueprints, the community, and the roadmap for the project. I look forward to seeing you again to get more updates about the project.
|
||||
|
||||
Tina Tsou: Thank you for your time. I appreciate it.
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://www.linux.com/news/akraino-an-open-source-project-for-the-edge/
|
||||
|
||||
作者：[Swapnil Bhartiya][a]
|
||||
选题：[lujun9972][b]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]: https://www.linux.com/author/swapnil/
|
||||
[b]: https://github.com/lujun9972
|
||||
101
sources/tech/20201001 Bringing COBOL to the Modern World.md
Normal file
101
sources/tech/20201001 Bringing COBOL to the Modern World.md
Normal file
@ -0,0 +1,101 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (Bringing COBOL to the Modern World)
|
||||
[#]: via: (https://www.linux.com/news/bringing-cobol-to-the-modern-world/)
|
||||
[#]: author: (Swapnil Bhartiya https://www.linux.com/author/swapnil/)
|
||||
|
||||
Bringing COBOL to the Modern World
|
||||
======
|
||||
|
||||
COBOL is powering most of the critical infrastructure that involves any kind of monetary transaction. In this special interview conducted during the recent Open Mainframe Summit, we talked about the relevance of COBOL today and the role of the new COBOL working group that was announced at the summit. Joining us were Cameron Seay, Adjunct Professor at East Carolina University and Derek Lisinski of the Application Modernizing Group at Micro Focus. Micro Focus recently joined the Open Mainframe Project and is now also involved with the working group.
|
||||
|
||||
Here is an edited version of the discussion:
|
||||
|
||||
Swapnil Bhartiya: First of all, Cam and Derek, welcome to the show. If you look at COBOL, it’s very old technology. Who is still using COBOL today? Cam, I would like to hear your insight first.
|
||||
|
||||
Cameron Seay: Every large commercial bank I know of uses COBOL. Every large insurance company, every large federal agency, every large retailer uses COBOL to some degree, and it processes a large percentage of the world’s financial transactions. For example, if you go to Walmart and you make a sale, that transaction is probably recorded using a COBOL program. So, it’s used a lot, a large percentage of the global business is still done in COBOL.
|
||||
|
||||
Swapnil Bhartiya: Micro Focus is I think one of the few companies that offer support around COBOL. Derek, please tell people the importance of COBOL in today’s modern world.
|
||||
|
||||
Derek Lisinski: Well, if we go back in time, there weren’t that many choices on the market. If you wanted robust technology to build your business systems, COBOL was one of the very few choices and so it’s surprising when there are so many choices around today and yet, many of the world’s largest industries, largest organizations still rely on COBOL. If COBOL wasn’t being used, so many of those systems that people trust and rely on — whether you’re moving money around, whether you’re running someone’s payroll, whether you’re getting insurance quotation, shipping a parcel, booking a holiday. All of these things are happening with COVID at the backend and the value you’re getting from that is not just that it’s carried on, but it runs with the same results again and again and again, without fail.
|
||||
|
||||
The importance of COBOL is not just its pervasiveness, which I think is significant and perhaps not that well understood, but also it’s reliability. And because it’s welded very closely to the mainframe environments and to CICS and some other core elements of the mainframe and other platforms as well. It uses and trusts a lot of technology that is unrivaled in terms of its reliability, scalability and its performance. That’s why it remains so important to the global economy and to so many industries. It does what it needs to do, which is business processing, so fantastically well.
|
||||
|
||||
Swapnil Bhartiya: Excellent, thanks for talking about that. Now, you guys recently joined the project and the foundation as well, so talk about why you joined the Open Mainframe Project and what are the projects that you will be involved with, of course. I know you’re involved with the working group, but talk about your involvement with the project.
|
||||
|
||||
Derek Lisinski: Well, our initial interest with the Open Mainframe Project goes back a couple of years. We’re longtime proponents of the mainframe platform, of course, here at Micro Focus. We’ve had a range of technologies that run on z/OS. But our interest in the wider mainframe community—and that would be the Open Mainframe Project—probably comes as a result of the time we’ve spent with the SHARE community and other IBM-sponsored communities, where the discussion was about the best way to embrace this trusted technology in the digital era. This is becoming a very topical conversation and that’s also true for COBOL, which I’m sure we’ll come back to.
|
||||
|
||||
Our interest in the OMP has been going on for the last couple of years and we were finally able to reach an agreement between both organizations to join the group this year, specifically because of a number of initiatives that we have going on at Micro Focus and that a number of our customers have talked to us about specifically in the area of mainframe DevOps. As vital as the mainframe platform is, there’s a growing desire to use it to deliver greater and greater value to the business, which typically means trying to accelerate delivery cycles and get more done.
|
||||
|
||||
Of course, now the mainframe is so inextricably connected with other parts of the IT ecosystem that those points of connection and the number of moving parts have to be handled, integrated with, and managed as part of a delivery process. It’s an important part of our customers’ roadmap and, therefore, our roadmap to ensure that they get the very best of technology in the mainframe world. Whether it’s tried-and-trusted technology, whether it’s new emerging vendor technology, or whether in many cases, it becomes open source technology. We wanted to play our part in those kinds of projects and a number of initiatives around.
|
||||
|
||||
Swapnil Bhartiya: Is there an increase in interest in COBOL that we are seeing there now that there is a dedicated working group? And if you can also talk a bit about what will be the role of this group.
|
||||
|
||||
Cameron Seay: If your question was, is there an increased interest in working in COBOL because of the working group, the working group actually came as a result of a renewed interest in the written new discovery in COBOL. The governor of New Jersey made a comment that their unemployment was not able to be processed because of COBOL’s obsolescence, or inefficiency, or inadequacy to some degree. And that sparked quite a furor in the mainframe world because it wasn’t COBOL at all. COBOL had nothing to do with the inability of New Jersey to deliver the unemployment checks. Further, we’re aware that New Jersey is just typical of every state. Every state that I know of—there may be some exceptions I’m not aware of, I know it’s certainly true for California and New York—is dependent upon COBOL to process their day-to-day business applications.
|
||||
|
||||
So, then Derek and some other people inside the OMP got together and started having some conversations, myself included, and said “We maybe need to form a COBOL working group to renew this interest in COBOL and establish the facts around COBOL.” So that’s kind of what the working group is trying to do, and we’re trying to increase that familiarity, visibility and interest in COBOL.
|
||||
|
||||
Swapnil Bhartiya: Derek, I want to bring the same question to you also. Is there any particular reason that we are seeing an increase in interest in COBOL and what is that reason?
|
||||
|
||||
Derek Lisinski: Yeah, that’s a great question and I think there are a few reasons. First of all, I think a really important milestone for COBOL was actually last year when it turned 60 years old. I think one of your earlier questions is related to COBOL’s age being 60. Of course, COBOL isn’t a 60-year-old language but the idea is 60 years old, for sure. If you drive a 2020 motor car, you’re driving a 2020 motor car, you’re not driving a hundred-year-old idea. No one thinks a modern telephone is an old idea, either. It’s not old technology, sorry.
|
||||
The idea might’ve been from a long time ago, but the technology has advanced, and the same thing is true in code. But when we celebrated COBOL’s 60th anniversary last year—a few of the vendors did and a number of organizations did, too—there was an outpouring of interest in the technology. A lot of times, COBOL just quietly goes about its business of running the world’s economy without any fuss. Like I said, it’s very, very reliable and it never really breaks. So, it was never anything to talk about. People were sort of pleasantly surprised, I think, to learn of its age, to learn of the age of the idea. Now, of course, Micro Focus and IBM and some of the other vendors continue to update and adapt COBOL so that it continues to evolve and be relevant today.
|
||||
|
||||
It’s actually a 2020 technology rather than a 1960 one, but that was the first one. Secondly, the pandemic caused a lot of businesses to have to change how they process core systems and how they interact with their customers. That put extra strain on certain organizations or certain government agencies and, in a couple of cases, COBOL was incorrectly made the scapegoat for some of the challenges that those organizations face, whether it was a skills issue or whether it was a technology issue. Under the cover, COBOL was working just fine. So the interest has been positive regarding the anniversary, but I think the reports have been inaccurate and perhaps a little unkind about COBOL. Those were the two reasons they came together.
|
||||
|
||||
I remember when I first spoke to Cam and to some of the other people on the working group, you said it was a very good idea once and for all that we told the truth about COBOL, that the industry finally understood how viable it is, how valuable it is, based on the facts behind COBOL’s usage. So one of the things we’re going to do is try to quantify and qualify as best we can, how widely COBOL is used, what do you use it for, who is using, and then present a more factual story about the technology so people can make a more informed decision about technical strategy. Rather than base it on hearsay or some reputation about something being a bit rusty and out-of-date, which is probably the reputation that’s being espoused by someone who would have you replace it with something else, and their motivation might be for different reasons. There’s nothing wrong with COBOL and it’s very, very viable and our job I think really is to tell that truth and make sure people understand it,
|
||||
|
||||
Swapnil Bhartiya: What other projects, efforts, or initiatives are going on there at the Linux Foundation or Open Mainframe Project around COBOL? Can you talk about that?
|
||||
|
||||
Cameron Seay: Well, certainly. There is currently a course being developed by folks in the community who have developed an online course in COBOL. It’s the rudiments of it. It’s for novices, but it’s great for a continuing education program. So, that’s one of the things going on around COBOL. Another thing is there’s a lot going on in mainframe development in the OMP now. There’s an application framework that has been developed called Zoe that will allow you to develop applications for z/OS. It’s interesting that the focus of the Open Mainframe Project when it first began was Linux on the mainframe, but actually the first real project that came out of it was a z/OS-based product, Zoe, and so we’re interested in that, too. Those are just a couple of peripheral projects that the COBOL working group is going to work with.
|
||||
|
||||
There are other things we want to do from a curriculum standpoint down the road, but fundamentally, we just want to be a fact-finding, fact-gathering operation first, and Derek Lisinski has been taking leadership and putting together a substantial reference list so that we can get the facts about COBOL. Then, we’re going to do other things, but that we want to get that right first.
|
||||
|
||||
Swapnil Bhartiya: So there are as you mentioned a couple of projects. Is there any overlap between these projects or how different they are? Do they all serve a different purpose? It looks like when you’re explaining the goal and role of the working group, it sounds like it’s also the training or education group with the same kind of activities. Let me rephrase it properly: what are some of the pressing needs you see for the COBOL community, how are these efforts/groups are trying to help them, and how are they not overlapping or stepping on each other’s toes?
|
||||
|
||||
Cameron Seay: That’s an ongoing thing. Susharshna and I really work hard to make sure that we’re not working at either across purposes or there’s duplication of effort. We’re kind of clear about our roles. For the world at large, for the public at large, the working group—and Derek may have a different view on this because we all don’t think alike, we all don’t see this thing exactly the same—but I see it as information first. We want people to get accurate current information about COBOL.
|
||||
|
||||
Then, we want to provide some vehicle that COBOL can be reintroduced back into the general academic curriculum because it used to be. I studied COBOL at a four-year university. Most people did when they took programming in the ’80s and the ’90s, they took COBOL, but that’s not true anymore. Our COBOL course at East Carolina this semester is the only COBOL course in the entire USC system. That’s got to change. So information, exposure, accurate information exposure, and some kind of return to the general curriculum, those are the three things that we we can provide to the community at large.
|
||||
|
||||
Swapnil Bhartiya: If you look at Micro Focus, you are working in the industry, you are actually solving the problem for your customers. What role do these groups or other efforts that are going on there play for the whole ecosystem?
|
||||
|
||||
Derek Lisinski: Well, I think if we go back to Cam’s answer, I think he’s absolutely right that the industry, if you project forward another generation in 25 years’ time who are going to be managing these core business systems that currently still need to run the world’s largest organizations. I know we’re in a digital era and I know that things are changing at an unprecedented pace, but most of the world’s largest organizations, successful organizations still want to be in those positions in generations to come. So who is it? Who are those practitioners that are coming through the education system right now, who are going to be leaders in those organizations’ IT departments in the future?
|
||||
|
||||
And there is a concern not just for COBOL, but actually, many IT skills across the board. Is there going to be enough talent to actually run the organizations of the future? And that’s true, it’s a true question mark about COBOL. So Micro Focus, which has its own academic initiative and its own training program as does IBM as do many of the other vendors, we all applaud the work of all community groups. The OMP is obviously a fabulous example because it is genuinely an open group. Genuinely, it’s a meritocracy of people with good ideas coming together to try to do the right thing. We applaud the efforts to ensure that there continues to be enough supply of talented IT professionals in the future to meet the growing and growing demand. IT is not going away. It’s going to become strategically more and more important to these organizations.
|
||||
|
||||
Our part to play in Micro Focus is really to work shoulder-to-shoulder with organizations like the OMP because between us, we will create enough groundswell of training and opportunity for that next generation. Many people will tell you there just isn’t enough of that training going on and there aren’t enough of those opportunities available, even though one survey that Micro Focus ran last year on the back of the COBOL’s 60th anniversary suggests that around 92% of all application owners of COBOL systems confirmed that those applications remain strategic to their organization. So, if the applications are not going anywhere, who’s going to be looking after them in the next generation? And that’s the real challenge that I think the industry faces as a whole, which is why Micro Focus is so committed to get behind the wheel of making sure that we can make a difference.
|
||||
|
||||
Swapnil Bhartiya: We discussed that the interest in COBOL is increasing as COBOL is playing a very critical role in the modern economy. What kind of future do you see for COBOL and where do you see it going? I mean, it’s been around for 60 years, so it knows how to survive through times. Still, where do you see it go? Cam, I would love to start with you.
|
||||
|
||||
Cameron Seay: Yeah, absolutely. We are trying to estimate how much COBOL is actually in use. That estimate is running into hundreds of billions of lines of code. I know that, for example, Bank of America admits to at least 50 million lines of COBOL code. That’s a lot of COBOL, and you’re not going to replace it over time, there’s no reason to. So the solution to this problem, and this is what we’re going to do, is we’re going to figure out a way to teach people COBOL. It’s not a complex language to learn. Any organization that sees lack of COBOL skills as an impediment and justification to move to another platform is [employing] a ridiculous solution, that solution is not feasible. If they try to do that, they’re going to fail because there’s too much risk and, most of all, too much expense.
|
||||
|
||||
So, we’re going to figure out a way to begin to teach people COBOL again. I do it, a COBOL class at East Carolina. That is a solution to this problem because the code’s not going anywhere nor is there a reason for it to go anywhere, it works! It’s a simple language, it’s as fast as it needs to be, it’s as secure as it needs to be, and no one that I’ve talked to, computer scientists all over the world, no one can give me any application, that any language is going to work better than COBOL. There may be some that work as good or nearly as good, but you’re going to have to migrate them, but there’s nothing, there’s no improvement that you can make on these applications from a performance standpoint and from a security standpoint. The applications are going to stay where they are, and we’re just going to have to teach people COBOL. That’s the solution, that’s what’s going to happen. How and when, I don’t know, but that’s what’s going to happen.
|
||||
|
||||
Swapnil Bhartiya: If you look at the crisis that we were going through, almost everything, every business is moving online to the cloud. All those transactions that people are already doing in person are all moving online, so it has become critical. From your perspective, what kind of future do you see?
|
||||
|
||||
Derek Lisinski: Well, that’s a great question because the world is a very, very different place to how architecture was designed however long ago. Companies of today are not using that architecture. So there is some question mark there about what’s COBOL’s future. I agree with Cam. Anyone that has COBOL is not necessarily going to be able to throw that away anytime soon because, frankly, it might be difficult. It might be easy, but that’s not really the question, is it? Is it a good business decision? The answer is it’s a terrible business decision to throw it away.
|
||||
|
||||
In addition to that, I would contend that there are a number of modern-day digital use cases where actually the usage of COBOL is going to increase rather than decrease. We see this all the time with our larger organizations who are using it for pretty much the whole of the backend of their core business. So, whether it’s a banking organization or an insurer or a logistics company, what they’re trying to do obviously is find new and exciting business opportunities.
|
||||
|
||||
But, upon which they will be basing their core business systems that already run most of the business today, and then trying to use that to adapt, to enhance, to innovate. There are insurers who are selling the insurance quotation system to other smaller insurances as a service. Now, of course, their insurance quotation system is probably the version that isn’t quite as quick as the one that runs on their mainframe, but they’re making that available as a service to other organizations. Banking organizations are doing much the same thing with a range of banking services, maybe payment systems. These are all services that can be provided to other organizations.
|
||||
|
||||
The same is true in the ISB market where really, really robust COBOL-based financial services, packages, ERP systems, which are COBOL based, and they have been made available as cloud-based as-a-service packages or upon other platforms to meet new market needs. The thing about COBOL that few people understand is not only is it easy to learn, but it’s easy to move to somewhere else. So, if your client is now running Linux and it says, “Well, now I want it to run these core COBOL business systems there, too.” Well, maybe they’ve taken a move to AIX to a Power system, but the same COBOL system can be reused, replicated as necessary, which is a little known secret about the language.
|
||||
|
||||
This goes back to the original design, of course. Back in the day, there was no such thing as the “standard platform” in 1960. There wasn’t a single platform that you could reasonably rely on that would give you a decent answer, not very quickly anyway. So, in order for us to know that COBOL works, we have to have the same results compiled about running on different machines. It needs to be the same result running at the same speed, and from that point, that’s when the portability of the system came to life. That’s what they set out to do, built that way by design.
|
||||
|
||||
Swapnil Bhartiya: Cam, Derek, thank you so much for taking the time out today to talk about COBOL, how important it is in today’s world. I’m pretty sure that when we spend our whole day, some of the activities that we have done online touch COBOL or are powered by COBOL.
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://www.linux.com/news/bringing-cobol-to-the-modern-world/
|
||||
|
||||
作者：[Swapnil Bhartiya][a]
|
||||
选题：[lujun9972][b]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]: https://www.linux.com/author/swapnil/
|
||||
[b]: https://github.com/lujun9972
|
||||
@ -0,0 +1,89 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (How open source underpins blockchain technology)
|
||||
[#]: via: (https://opensource.com/article/20/10/open-source-blockchain)
|
||||
[#]: author: (Matt Shealy https://opensource.com/users/mshealy)
|
||||
|
||||
How open source underpins blockchain technology
|
||||
======
|
||||
Openness, not regulation, is what creates blockchain's security and
|
||||
reliability.
|
||||
![cubes coming together to create a larger cube][1]
|
||||
|
||||
People are often surprised when they find out that blockchain technology, which is known for its security, is built on open source software code. In fact, this openness is what creates its security and reliability.
|
||||
|
||||
One of the core values of building anything as open source is gaining efficiency. Creating a community of developers with different perspectives and skillsets, all working on the same code base, can exponentially increase the number and complexity of applications built.
|
||||
|
||||
### Open source: more common than people think
|
||||
|
||||
One of the more popular operating systems, Linux, is open source. Linux powers the servers for many of the services we feel comfortable sharing personal information on every day. This includes Google, Facebook, and thousands of major websites. When you're interacting with these services, you're doing so on computer networks that are running Linux. Chromebooks are using Linux. Android phones use an operating system based on Linux.
|
||||
|
||||
Linux is not owned by a corporation. It's free to use and created by collaborative efforts. More than 20,000 developers from more than 1,700 companies [have contributed to the code][2] since its origins in 2005.
|
||||
|
||||
That's how open source software works. Tons of people contribute and constantly add, modify, or build off the open source codebase to create new apps and platforms. Much of the software code for blockchain and cryptocurrency has been developed using open source software. Open source software is built by passionate users that are constantly on guard for bugs, glitches, or flaws. When a problem is discovered, a community of developers works separately and together on the fix.
|
||||
|
||||
### Blockchain and open source
|
||||
|
||||
An entire community of open source blockchain developers is constantly adding to and refining the codebase.
|
||||
|
||||
Here are the fundamental ways blockchain performs:
|
||||
|
||||
* Blockchain platforms have a transactional database that allows peers to transact with each other at any time.
|
||||
* User-identification labels are attached that facilitate the transactions.
|
||||
* The platforms must have a secure way to verify transactions before they become approved.
|
||||
* Transactions that cannot be verified will not take place.
|
||||
|
||||
|
||||
|
||||
Open source software allows developers to create these platforms in a [decentralized application (Dapp)][3], which is key to the safety, security, and variability of transactions in the blockchain.
|
||||
|
||||
This decentralized approach means there is no central authority to mediate transactions. That means no one person controls what happens. Direct peer-to-peer interactions can happen quickly and securely. As transactions are recorded in the ledger, they are distributed across the ecosystem.
|
||||
|
||||
Blockchain uses cryptography to keep things secure. Each transaction carries information connecting it with previous transactions to verify its authenticity. This prevents threat actors from tampering with the data because once it's added to the public ledger, it can't be changed by other users.
|
||||
|
||||
### Is blockchain open source?
|
||||
|
||||
Although blockchain itself may not technically be open source, blockchain _systems_ are typically implemented with open source software using a concept that embodies an open culture because no government authority regulates it. Proprietary software developed by a private company to handle financial transactions is likely regulated by [government agencies][4]. In the US, that might include the Securities and Exchange Commission (SEC), the Federal Reserve Board, and the Federal Deposit Insurance Corporation (FDIC). Blockchain technology doesn't require government oversight when it's used in an open environment. In effect, the community of users is what verifies transactions.
|
||||
|
||||
You might call it an extreme form of crowdsourcing, both for developing the open source software that's used to build the blockchain platforms and for verifying transactions. That's one of the reasons blockchain has gotten so much attention: It has the potential to disrupt entire industries because it acts as an authoritative intermediary to handle and verify transactions.
|
||||
|
||||
### Bitcoin, Ethereum, and other cryptocurrencies
|
||||
|
||||
As of June 2020, more than [50 million people have blockchain wallets][5]. Most are used for financial transactions, such as trading Bitcoin, Ethereum, and other cryptocurrencies. It's become mainstream for many to [check cryptocurrency prices][6] the same way traders watch stock prices.
|
||||
|
||||
Cryptocurrency platforms also use open source software. The [Ethereum project][7] developed free and open source software that anyone can use, and a large community of developers contributes to the code. The Bitcoin reference client was developed by more than 450 developers and engineers that have made more than 150,000 contributions to the code-writing effort.
|
||||
|
||||
A cryptocurrency blockchain is a continuously growing record. Each record is linked together in a sequence, and the records are called blocks. When linked together, they form a chain. Each block has its own [unique marker called a hash][8]. A block contains its hash and a cryptographic hash from a previous block. In essence, each block is linked to the previous block, forming long chains that are impossible to break, with each containing information about other blocks that are used to verify transactions.
|
||||
|
||||
There's no central bank in financial or cryptocurrency blockchains. The blocks are distributed throughout the internet, creating a robust audit trail that can be tracked. Anyone with access to the chain can verify a transaction but cannot change the records.
|
||||
|
||||
### An unbreakable chain
|
||||
|
||||
While blockchains are not regulated by any government or agency, the distributed network keeps them secure. As chains grow, each transaction makes it more difficult to fake. Blocks are distributed all over the world in networks using trust markers that can't be changed. The chain becomes virtually unbreakable.
|
||||
|
||||
The code behind this decentralized network is open source and is one of the reasons users trust each other in transactions rather than having to use an intermediary such as a bank or broker. The software underpinning cryptocurrency platforms is open to anyone and free to use, created by consortiums of developers that are independent of each other. This has created one of the world's largest check-and-balance systems.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/20/10/open-source-blockchain
|
||||
|
||||
作者：[Matt Shealy][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/mshealy
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/cube_innovation_process_block_container.png?itok=vkPYmSRQ (cubes coming together to create a larger cube)
|
||||
[2]: https://www.linuxfoundation.org/wp-content/uploads/2020/08/2020_kernel_history_report_082720.pdf
|
||||
[3]: https://www.freecodecamp.org/news/what-is-a-dapp-a-guide-to-ethereum-dapps/
|
||||
[4]: https://www.investopedia.com/ask/answers/063015/what-are-some-major-regulatory-agencies-responsible-overseeing-financial-institutions-us.asp
|
||||
[5]: https://www.statista.com/statistics/647374/worldwide-blockchain-wallet-users/
|
||||
[6]: https://www.okex.com/markets
|
||||
[7]: https://ethereum.org/en/
|
||||
[8]: https://opensource.com/article/18/7/bitcoin-blockchain-and-open-source
|
||||
@ -0,0 +1,368 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (Level up your shell history with Loki and fzf)
|
||||
[#]: via: (https://opensource.com/article/20/10/shell-history-loki-fzf)
|
||||
[#]: author: (Ed Welch https://opensource.com/users/ewelch)
|
||||
|
||||
Level up your shell history with Loki and fzf
|
||||
======
|
||||
Loki expands the model Prometheus uses for metrics for monitoring and
|
||||
log aggregation.
|
||||
![Gears above purple clouds][1]
|
||||
|
||||
[Loki][2] is an Apache 2.0-licensed open source log-aggregation framework designed by Grafana Labs and built with tremendous support from a growing community. It is also the project I work on every day. In this article, rather than just talking about how Loki works, I will provide a hands-on introduction to solving real problems with it.
|
||||
|
||||
### The problem: a durable centralized shell history
|
||||
|
||||
I love my shell history and have always been a fanatical CTRL+R user. About a year ago, my terminal life changed forever when my peer Dieter Plaetinck introduced me to the command-line fuzzy finder **[fzf][3]**.
|
||||
|
||||
Suddenly, searching through commands went from this:
|
||||
|
||||
![Before Loki and fzf][4]
|
||||
|
||||
(Ed Welch, [CC BY-SA 4.0][5])
|
||||
|
||||
To this:
|
||||
|
||||
![After Loki and fzf][6]
|
||||
|
||||
(Ed Welch, [CC BY-SA 4.0][5])
|
||||
|
||||
While fzf significantly improved my quality of life, there were still some pieces missing around my shell history:
|
||||
|
||||
* Losing shell history when terminals close abruptly, computers crash, computers die, whole disk encryption keys are forgotten
|
||||
* Having access to my shell history _from_ all my computers _on_ all my computers
|
||||
|
||||
|
||||
|
||||
I think of my shell history as documentation: it's an important story I don't want to lose. Combining Loki with my shell history helps solve these problems and more.
|
||||
|
||||
### About Loki
|
||||
|
||||
Loki takes the intuitive label model that the open source [Prometheus][7] project uses for metrics and expands it into the world of log aggregation. This enables developers and operators to seamlessly pivot between their metrics and logs using the same set of labels. Even if you're not using Prometheus, there are still plenty of reasons Loki might be a good fit for your log-storage needs:
|
||||
|
||||
* **Low overhead:** Loki does not do full-text log indexing; it only creates an index of the labels you put on your logs. Keeping a small index substantially reduces Loki's operating requirements. I'm running my loki-shell project, which uses Loki to store shell history, on a [Raspberry Pi][8] using just a little over 50MB of memory.
|
||||
* **Low cost:** The log content is compressed and stored in object stores like Amazon S3, Google Cloud Storage, Azure Blob, or even directly on a filesystem. The goal is to use storage that is inexpensive and durable.
|
||||
* **Flexibility:** Loki is available in a single binary that can be downloaded and run directly or as a Docker image to run in any container environment. A [Helm chart][9] is available to get started quickly in Kubernetes. If you demand a lot from your logging tools, take a look at the [production setup][10] running at Grafana Labs. It uses open source [Jsonnet][11] and [Tanka][12] to deploy the same Loki image as discrete building blocks to enable massive horizontal scaling, high availability, replication, separate scaling of read and write paths, highly parallelizable querying, and more.
|
||||
|
||||
|
||||
|
||||
In summary, Loki's approach is to keep a small index of metadata about your logs (labels) and store the unindexed and compressed log content in inexpensive object stores to make operating easier and cheaper. The application is built to run as a single process and easily evolve into a highly available distributed system. You can obtain high query performance on larger logging workloads through parallelization and sharding of queries—a bit like MapReduce for your logs.
|
||||
|
||||
In addition, this functionality is available for anyone to use for free. As with its [Grafana][13] open observability platform, Grafana Labs is committed to making Loki a fully featured, fully open log-aggregation software anyone can use.
|
||||
|
||||
### Get started
|
||||
|
||||
I'm running Loki on a Raspberry Pi on my home network and storing my shell history offsite in an S3 bucket.
|
||||
|
||||
When I hit CTRL+R, Loki's [LogCLI][14] command-line interface makes several batching requests that are streamed into fzf. Here is an example—the top part shows the Loki server logs on the Pi.
|
||||
|
||||
![Logs of the Loki server on Raspberry Pi][15]
|
||||
|
||||
(Ed Welch, [CC BY-SA 4.0][5])
|
||||
|
||||
Ready to give it a try? The following guide will help you set up and run Loki to be integrated with your shell history. Since this tutorial aims to keep things simple, this setup will run Loki locally on your computer and store all the files on the filesystem.
|
||||
|
||||
You can find all of this, plus information about how to set up a more elaborate installation, in the [loki-shell GitHub repository][16].
|
||||
|
||||
Note that this tutorial will not change any existing behaviors around your history, so _your existing shell history command and history settings will be untouched._ Instead, this duplicates the command history to Loki with `$PROMPT_COMMAND` in Bash and `precmd` in Zsh. On the CTRL+R side of things, it overloads the function that fzf uses to access the CTRL+R command. Trying this is safe, and if you decide you don't like it, just follow the [uninstall steps][17] in the GitHub repo to remove all traces. Your shell history will be untouched.
|
||||
|
||||
#### Step 1: Install fzf
|
||||
|
||||
There are several ways to install fzf, but I prefer [the Git method][18]:
|
||||
|
||||
|
||||
```
|
||||
git clone --depth 1 <https://github.com/junegunn/fzf.git> ~/.fzf
|
||||
~/.fzf/install
|
||||
```
|
||||
|
||||
Say yes to all the question prompts.
|
||||
|
||||
If you already have fzf installed, make sure you have the key bindings enabled (i.e., make sure when you type CTRL+R, fzf pops up). You can rerun the fzf installation to enable key bindings if necessary.
|
||||
|
||||
#### Step 2: Install loki-shell
|
||||
|
||||
Like fzf, loki-shell also has a Git repo and install script:
|
||||
|
||||
|
||||
```
|
||||
git clone --depth 1 <https://github.com/slim-bean/loki-shell.git> ~/.loki-shell
|
||||
~/.loki-shell/install
|
||||
```
|
||||
|
||||
First, the script creates the `~/.loki-shell` directory where all files will be kept (including Loki data). Next, it will download binaries for [Promtail][19], LogCLI, and Loki.
|
||||
|
||||
Then it will ask:
|
||||
|
||||
```
|
||||
Do you want to install Loki? ([y]/n)
|
||||
```
|
||||
|
||||
|
||||
If you already have a centralized Loki running for loki-shell, you could answer n; however, for this tutorial, answer y or press Enter.
|
||||
|
||||
|
||||
There are two options available for running Loki locally: as a Docker image or as a single binary (with support for adding a systemd service). I recommend using Docker if it's available, as I think it simplifies operations a bit, but both work just fine.
|
||||
|
||||
```
|
||||
#### Running with Docker
|
||||
```
|
||||
|
||||
|
||||
To run Loki as a Docker image:
|
||||
|
||||
[code]
|
||||
|
||||
```
|
||||
[y] to run Loki in Docker, [n] to run Loki as a binary ([y]/n) y
|
||||
Error: No such object: loki-shell
|
||||
Error response from daemon: No such container: loki-shell
|
||||
Error: No such container: loki-shell
|
||||
54843ff3392f198f5cac51a6a5071036f67842bbc23452de8c3efa392c0c2e1e
|
||||
```
|
||||
|
||||
|
||||
```
|
||||
If this is the first time you're running the installation, you can disregard the error messages. This script will stop and replace a running Loki container if the version does not match, which allows you to rerun this script to upgrade Loki.
|
||||
|
||||
|
||||
That's it! Loki is now running as a Docker container.
|
||||
|
||||
|
||||
Data from Loki will be stored in ~/.loki-shell/data.
|
||||
|
||||
|
||||
The image runs with --restart=unless-stopped, so it will restart at reboot but will stay stopped if you run docker stop loki-shell.
|
||||
|
||||
|
||||
(If you're using Docker, you can skip down to Shell integration.)
|
||||
```
|
||||
|
||||
##### Running as binary
|
||||
|
||||
```
|
||||
There are many ways to run a binary on a Linux system. This script can install a systemd service. If you don't have systemd, you can still use the binary install:
|
||||
|
||||
[code]
|
||||
```
|
||||
|
||||
[y] to run Loki in Docker, [n] to run Loki as a binary ([y]/n) n
|
||||
|
||||
Run Loki with systemd? ([y]/n) n
|
||||
|
||||
This is as far as this script can take you
|
||||
You will need to setup an auto-start for Loki
|
||||
It can be run with this command: /home/username/.loki-shell/bin/loki -config.file=/home/username/.loki-shell/config/loki-binary-config.yaml
|
||||
|
||||
```
|
||||
|
||||
```
|
||||
|
||||
|
||||
The script will spit out the command you need to use to run Loki, and you will be on your own to set up an init script or another method of auto-starting it.
|
||||
|
||||
|
||||
You can run the command directly, if you want, and run Loki from your current shell.
|
||||
|
||||
|
||||
If you do have systemd, you have the option of letting the script install the systemd service or showing you the commands to run it yourself:
|
||||
|
||||
[code]
|
||||
|
||||
```
|
||||
Run Loki with systemd? ([y]/n) y
|
||||
|
||||
Installing the systemd service requires root permissions.
|
||||
[y] to run these commands with sudo [n] to print out the commands and you can run them yourself. ([y]/n) n
|
||||
sudo cp /home/ed/.loki-shell/config/loki-shell.service /etc/systemd/system/loki-shell.service
|
||||
sudo systemctl daemon-reload
|
||||
sudo systemctl enable loki-shell
|
||||
sudo systemctl start loki-shell
|
||||
Copy these commands and run them when the script finishes. (press enter to continue)
|
||||
```
|
||||
|
||||
|
||||
```
|
||||
|
||||
```
|
||||
|
||||
##### Shell integration
|
||||
|
||||
```
|
||||
Regardless of how you installed Loki, you should now see a prompt:
|
||||
|
||||
[code]Enter the URL for your Loki server or press enter for default (http://localhost:4100)
|
||||
```
|
||||
|
||||
|
||||
If you had set up a centralized Loki, you would enter that URL here. However, this demo just uses the default, so you can press Enter.
|
||||
|
||||
|
||||
A lot of text will spit out explaining all the entries added to your ~.bashrc or ~.zshrc (or both).
|
||||
|
||||
|
||||
That's it!
|
||||
|
||||
[code]
|
||||
|
||||
```
|
||||
Finished. Restart your shell or reload config file.
|
||||
source ~/.bashrc # bash
|
||||
source ~/.zshrc # zsh
|
||||
```
|
||||
|
||||
|
||||
```
|
||||
|
||||
```
|
||||
|
||||
#### Step 3: Try it out!
|
||||
|
||||
```
|
||||
Start using your shell, and use CTRL+R to see your commands.
|
||||
|
||||
|
||||
Open multiple terminal windows, type a command in one and CTRL+R in another, and you'll see your commands available immediately.
|
||||
|
||||
|
||||
Also, notice that when you switch between terminals and enter commands, they are available immediately with CTRL+R, but the Up arrow's operation is not affected between terminals. (This may not be true if you have Oh My Zsh installed, as it automatically appends all commands to the history.)
|
||||
|
||||
|
||||
Use CTRL+R multiple times to toggle between sorting by time and by relevance.
|
||||
|
||||
|
||||
Note that this configuration will show only the current hosts' query history, even if you are sending shell data from multiple hosts to Loki. I think by default this makes the most sense. There is a lot you can tweak if you want this behavior to change; see the loki-shell repo to learn more.
|
||||
|
||||
|
||||
It also installed an alias called hist:
|
||||
|
||||
[code]alias hist="$HOME/.loki-shell/bin/logcli --addr=$LOKI_URL"
|
||||
```
|
||||
|
||||
|
||||
LogCLI can be used to query and search your history directly in Loki, including allowing you to search other hosts. Check out the getting started guide for LogCLI to learn more about querying.
|
||||
|
||||
|
||||
Loki's log query language (LogQL) provides metric queries that allow you to do some interesting things; for example, I can see how many times I issued the kc command (my alias for kubectl) in the last 30 days:
|
||||
|
||||
|
||||
```
|
||||
![Counting use of a command][20]
|
||||
|
||||
(Ed Welch, [CC BY-SA 4.0][5])
|
||||
```
|
||||
|
||||
```
|
||||
## Extra credit
|
||||
```
|
||||
|
||||
|
||||
Install Grafana and play around with your shell history:
|
||||
|
||||
[code]docker run -d -p 3000:3000 --name=grafana grafana/grafana
|
||||
```
|
||||
Open a web browser at http://localhost:3000 and log in using the default admin/admin username and password.
|
||||
|
||||
|
||||
On the left, navigate to Configuration -> Datasources, click the Add Datasource button, and select Loki.
|
||||
|
||||
|
||||
For the URL, you should be able to use http://localhost:4100 (however, on my WSL2 machine, I had to use the computer's actual IP address).
|
||||
|
||||
|
||||
Click Save and Test. You should see Data source connected and labels found.
|
||||
|
||||
|
||||
Click on the Explore icon on the left, make sure the Loki data source is selected, and try out a query:
|
||||
|
||||
[code]{job="shell"}
|
||||
```
|
||||
|
||||
|
||||
If you have more hosts sending shell commands, you can limit the results to a certain host using the hostname label:
|
||||
|
||||
[code]{job="shell", hostname="myhost"}.
|
||||
```
|
||||
You can also look for specific commands with filter expressions:
|
||||
|
||||
[code]{job="shell"} |= "docker"
|
||||
```
|
||||
|
||||
|
||||
Or you can start exploring the world of metrics from logs to see how often you are using your shell:
|
||||
|
||||
[code]rate({job="shell"}[1m])
|
||||
```
|
||||
|
||||
```
|
||||
|
||||
![Counting use of the shell over previous 20 days][21]
|
||||
|
||||
(Ed Welch, [CC BY-SA 4.0][5])
|
||||
|
||||
```
|
||||
Want to reconstruct a timeline from an incident? You can filter by a specific command and see when it ran.
|
||||
```
|
||||
|
||||
![Counting use of a command][22]
|
||||
|
||||
(Ed Welch, [CC BY-SA 4.0][5])
|
||||
|
||||
```
|
||||
To see what else you can do and learn more about Loki's query language, check out the LogQL guide.
|
||||
```
|
||||
|
||||
### Final thoughts
|
||||
|
||||
```
|
||||
For more ideas, troubleshooting, and updates, follow the GitHub repo. This is still a work in progress, so please report any issues there.
|
||||
|
||||
|
||||
To learn more about Loki, check out the documentation, blog posts, and GitHub repo, or try it in Grafana Cloud.
|
||||
```
|
||||
|
||||
* * *
|
||||
|
||||
```
|
||||
A special thanks to my colleague Jack Baldry for planting the seed for this idea. I had the Loki knowledge to make this happen, but if it weren't for his suggestion, I don't think I ever would have made it here.
|
||||
```
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/20/10/shell-history-loki-fzf
|
||||
|
||||
作者：[Ed Welch][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/ewelch
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/chaos_engineer_monster_scary_devops_gear_kubernetes.png?itok=GPYLvfVh (Gears above purple clouds)
|
||||
[2]: https://github.com/grafana/loki
|
||||
[3]: https://github.com/junegunn/fzf
|
||||
[4]: https://opensource.com/sites/default/files/uploads/before.gif (Before Loki and fzf)
|
||||
[5]: https://creativecommons.org/licenses/by-sa/4.0/
|
||||
[6]: https://opensource.com/sites/default/files/uploads/with_fzf.gif (After Loki and fzf)
|
||||
[7]: https://prometheus.io/
|
||||
[8]: https://www.raspberrypi.org/
|
||||
[9]: https://helm.sh/docs/topics/charts/
|
||||
[10]: https://grafana.com/docs/loki/latest/installation/tanka/
|
||||
[11]: https://jsonnet.org
|
||||
[12]: https://tanka.dev/
|
||||
[13]: https://grafana.com/
|
||||
[14]: https://grafana.com/docs/loki/latest/getting-started/logcli/
|
||||
[15]: https://opensource.com/sites/default/files/uploads/example_logcli.gif (Logs of the Loki server on Raspberry Pi)
|
||||
[16]: https://github.com/slim-bean/loki-shell
|
||||
[17]: https://github.com/slim-bean/loki-shell/blob/master/uninstall
|
||||
[18]: https://github.com/junegunn/fzf#using-git
|
||||
[19]: https://grafana.com/docs/loki/latest/clients/promtail/
|
||||
[20]: https://opensource.com/sites/default/files/uploads/count_kc.png (Counting use of a command)
|
||||
[21]: https://opensource.com/sites/default/files/uploads/last_20.png (Counting use of the shell over previous 20 days)
|
||||
[22]: https://opensource.com/sites/default/files/uploads/command_hist.png (Counting use of a command)
|
||||
126
sources/tech/20201001 Navigating your Linux files with ranger.md
Normal file
126
sources/tech/20201001 Navigating your Linux files with ranger.md
Normal file
@ -0,0 +1,126 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (Navigating your Linux files with ranger)
|
||||
[#]: via: (https://www.networkworld.com/article/3583890/navigating-your-linux-files-with-ranger.html)
|
||||
[#]: author: (Sandra Henry-Stocker https://www.networkworld.com/author/Sandra-Henry_Stocker/)
|
||||
|
||||
Navigating your Linux files with ranger
|
||||
======
|
||||
Ranger is a great tool for providing a multi-level view of your Linux files and allowing you to both browse and make changes using arrow keys and some handy commands.
|
||||
[Heidi Sandstrom][1] [(CC0)][2]
|
||||
|
||||
Ranger is a unique and very handy file system navigator that allows you to move around in your Linux file system, go in and out of subdirectories, view text-file contents and even make changes to files without leaving the tool.
|
||||
|
||||
It runs in a terminal window and lets you navigate by pressing arrow keys. It provides a multi-level file display that makes it easy to see where you are, move around the file system and select particular files.
|
||||
|
||||
To install ranger, use your standard install command (e.g., **sudo apt install ranger**). To start it, simply type “ranger”. It comes with a lengthy, very detailed man page, but getting started with ranger is very simple.
|
||||
|
||||
[[Get regularly scheduled insights by signing up for Network World newsletters.]][3]
|
||||
|
||||
### The ranger display
|
||||
|
||||
One of the most important things you need to get used to right away is ranger’s way of displaying files. Once you start ranger, you will see four columns of data. The first column is one level up from wherever you started ranger. If you start from your home directory, for example, ranger will list all of the home directories in column 1. The second column will show the first screenful of directories and files in your home directory (or whatever directory you start it from).
|
||||
|
||||
The key here is moving past any inclination you might have to see the details in each line of the display as related. All the entries in column 2 relate to a single entry in column 1 and content in column 4 relates to the selected file or directory in column 2.
|
||||
|
||||
Unlike your normal command-line view, directories will be listed first (alphanumerically) and files will be listed second (also alphanumerically). Starting in your home directory, the display might look something like this:
|
||||
|
||||
```
|
||||
shs@dragonfly /home/shs/backups <== current selection
|
||||
bugfarm backups 0 empty
|
||||
dory bin 59
|
||||
eel Buttons 15
|
||||
nemo Desktop 0
|
||||
shark Documents 0
|
||||
shs Downloads 1
|
||||
^ ^ ^ ^
|
||||
| | | |
|
||||
homes directories # files listing
|
||||
in selected in each of files in
|
||||
home directory selected directory
|
||||
```
|
||||
|
||||
The top line in ranger's display tells you where you are. In the abive example, the current directory is **/home/shs/backups**. We see the highlighted word "empty" because there are no files in this directory. If we press the down arrow key to select **bin** instead, we'll see a list of files:
|
||||
|
||||
```
|
||||
shs@dragonfly /home/shs/bin <== current selection
|
||||
bugfarm backups 0 append
|
||||
dory bin 59 calcPower
|
||||
eel Buttons 15 cap
|
||||
nemo Desktop 0 extract
|
||||
shark Documents 0 finddups
|
||||
shs Downloads 1 fix
|
||||
^ ^ ^ ^
|
||||
| | | |
|
||||
homes directories # files listing
|
||||
in selected in each of files in
|
||||
home directory selected directory
|
||||
```
|
||||
|
||||
The highlighted entries in each column show the current selections. Use the right arrow to move into deeper directories or view file content.
|
||||
|
||||
If you continue pressing the down arrow key to move to the file portion of the listing, you will note that the third column will show file sizes (instead of the numbers of files). The "current selection" line will also display the currently selected file name while the rightmost column displays the file content when possible.
|
||||
|
||||
```
|
||||
shs@dragonfly /home/shs/busy_wait.c <== current selection
|
||||
bugfarm BushyRidge.zip 170 K /*
|
||||
dory busy_wait.c 338 B * program that does a busy wait
|
||||
eel camper.jpg 5.55 M * it's used to show ASLR, and that's it
|
||||
nemo check_lockscreen 80 B */
|
||||
shark chkrootkit-output 438 B #include <stdio.h>
|
||||
^ ^ ^ ^
|
||||
| | | |
|
||||
homes files sizes file content
|
||||
```
|
||||
|
||||
The bottom line of the display will show some file and directory details:
|
||||
|
||||
```
|
||||
-rw-rw-r—- shs shs 338B 2019-01-05 14:44 1.52G, 365G free 67/488 11%
|
||||
```
|
||||
|
||||
If you select a directory and press enter, you will move into that directory. The leftmost column in your display will then be a listing of the contents of your home directory, and the second column will be a file listing of the directory contents. You can then examine the contents of subdirectories and the contents of files.
|
||||
|
||||
Press the left arrow key to move back up a level.
|
||||
|
||||
Quit ranger by pressing "q".
|
||||
|
||||
### Making changes
|
||||
|
||||
You can press **?** to bring up a help line at the bottom of your screen. It should look like this:
|
||||
|
||||
```
|
||||
View [m]an page, [k]ey bindings, [c]commands or [s]ettings? (press q to abort)
|
||||
```
|
||||
|
||||
Press **c** and ranger will provide information on commands that you can use within the tool. For example, you can change permissions on the current file by entering **:chmod** followed by the intended permissions. For example, once a file is selected, you can type **:chmod 700** to set permissions to **rwx------**.
|
||||
|
||||
Typing **:edit** instead would open the file in **nano** and allow you to make changes and then save the file using **nano** commands.
|
||||
|
||||
### Wrap-Up
|
||||
|
||||
There are more ways to use **ranger** than are described in this post. The tool provides a very different way to list and interact with files on a Linux system and is easy to navigate once you get used to its multi-tiered way of listing directories and files and using arrow keys in place of **cd** commands to move around.
|
||||
|
||||
Join the Network World communities on [Facebook][4] and [LinkedIn][5] to comment on topics that are top of mind.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://www.networkworld.com/article/3583890/navigating-your-linux-files-with-ranger.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://unsplash.com/photos/mHC0qJ7l-ls
|
||||
[2]: https://creativecommons.org/publicdomain/zero/1.0/
|
||||
[3]: https://www.networkworld.com/newsletters/signup.html
|
||||
[4]: https://www.facebook.com/NetworkWorld/
|
||||
[5]: https://www.linkedin.com/company/network-world
|
||||
@ -0,0 +1,173 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: ( )
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (How to Free Up Space in /boot Partition on Ubuntu Linux?)
|
||||
[#]: via: (https://itsfoss.com/free-boot-partition-ubuntu/)
|
||||
[#]: author: (Ankush Das https://itsfoss.com/author/ankush/)
|
||||
|
||||
How to Free Up Space in /boot Partition on Ubuntu Linux?
|
||||
======
|
||||
|
||||
The other day, I got a warning that boot partition is almost full or has no space left. Yes, I have a separate boot partition, not many people do that these days, I believe.
|
||||
|
||||
This was the first time I saw such an error and it left me confused. Now, there are several [ways to free up space on Ubuntu][1] (or Ubuntu-based distros) but not all of them are useful in this case.
|
||||
|
||||
This is why I decided to write about the steps I followed to free some space in the /boot partition.
|
||||
|
||||
### Free up space in /boot partition on Ubuntu (if your boot partition is running out of space)
|
||||
|
||||
![][2]
|
||||
|
||||
I’d advise you to carefully read through the solutions and follow the one best suited for your situation. It’s easy but you need to be cautious about performing some of these on your production systems.
|
||||
|
||||
#### Method 1: Using apt autoremove
|
||||
|
||||
You don’t have to be a terminal expert to do this, it’s just one command and you will be removing unused kernels to free up space in the /boot partition.
|
||||
|
||||
All you have to do is, type in:
|
||||
|
||||
```
|
||||
sudo apt autoremove
|
||||
```
|
||||
|
||||
This will not just remove unused kernels but also get rid of the dependencies that you don’t need or isn’t needed by any of the tools installed.
|
||||
|
||||
Once you enter the command, it will list the things that will be removed and you just have to confirm the action. If you’re curious, you can go through it carefully and see what it actually removes.
|
||||
|
||||
Here’s how it will look like:
|
||||
|
||||
![][3]
|
||||
|
||||
You have to press **Y** to proceed.
|
||||
|
||||
_**It’s worth noting that this method will only work if you’ve a tiny bit of space left and you get the warning. But, if your /boot partition is full, APT may not even work.**_
|
||||
|
||||
In the next method, I’ll highlight two different ways by which you can remove old kernels to free up space using a GUI and also the terminal.
|
||||
|
||||
#### Method 2: Remove Unused Kernel Manually (if apt autoremove didn’t work)
|
||||
|
||||
Before you try to [remove any older kernels][4] to free up space, you need to identify the current active kernel and make sure that you don’t delete that.
|
||||
|
||||
To [check your kernel version][5], type in the following command in the terminal:
|
||||
|
||||
```
|
||||
uname -r
|
||||
```
|
||||
|
||||
The [uname command is generally used to get Linux system information][6]. Here, this command displays the current Linux kernel being used. It should look like this:
|
||||
|
||||
![][7]
|
||||
|
||||
Now, that you know what your current Linux Kernel is, you just have to remove the ones that do not match this version. You should note it down somewhere so that you ensure you do not remove it accidentally.
|
||||
|
||||
Next, to remove it, you can either utilize the terminal or the GUI.
|
||||
|
||||
Warning!
|
||||
|
||||
Be extra careful while deleting kernels. Identify and delete old kernels only, not the current one you are using otherwise you’ll have a broken system.
|
||||
|
||||
##### Using a GUI tool to remove old Linux kernels
|
||||
|
||||
You can use the [Synaptic Package Manager][8] or a tool like [Stacer][9] to get started. Personally, when I encountered a full /boot partition with apt broken, I used [Stacer][6] to get rid of older kernels. So, let me show you how that looks.
|
||||
|
||||
First, you need to launch “**Stacer**” and then navigate your way to the package uninstaller as shown in the screenshot below.
|
||||
|
||||
![][10]
|
||||
|
||||
Here, search for “**image**” and you will find the images for the Linux Kernels you have. You just have to delete the old kernel versions and not your current kernel image.
|
||||
|
||||
I’ve pointed out my current kernel and old kernels in my case in the screenshot above, so you have to be careful with your kernel version on your system.
|
||||
|
||||
You don’t have to delete anything else, just the ones that are the older kernel versions.
|
||||
|
||||
Similarly, just search for “**headers**” in the list of packages and delete the old ones as shown below.
|
||||
|
||||
![][11]
|
||||
|
||||
Just to warn you, you **don’t want to remove “linux-headers-generic”**. Only focus on the ones that have version numbers with them.
|
||||
|
||||
And, that’s it, you’ll be done and apt will be working again and you have successfully freed up some space from your /boot partition. Similarly, you can do this using any other package manager you’re comfortable with.
|
||||
|
||||
#### Using the command-line to remove old kernels
|
||||
|
||||
It’s the same thing but just using the terminal. So, if you don’t have the option to use a GUI (if it’s a remote machine/server) or if you’re just comfortable with the terminal, you can follow the steps below.
|
||||
|
||||
First, list all your kernels installed using the command below:
|
||||
|
||||
```
|
||||
ls -l /boot
|
||||
```
|
||||
|
||||
It should look something like this:
|
||||
|
||||
![][12]
|
||||
|
||||
The ones that are mentioned as “**old**” or the ones that do not match your current kernel version are the unused kernels that you can delete.
|
||||
|
||||
Now, you can use the **rm** command to remove the specific kernels from the boot partition using the command below (a single command for each):
|
||||
|
||||
```
|
||||
sudo rm /boot/vmlinuz-5.4.0-7634-generic
|
||||
```
|
||||
|
||||
Make sure to check the version for your system — it may be different for your system.
|
||||
|
||||
If you have a lot of unused kernels, this will take time. So, you can also get rid of multiple kernels using the following command:
|
||||
|
||||
```
|
||||
sudo rm /boot/*-5.4.0-{7634}-*
|
||||
```
|
||||
|
||||
To clarify, you need to write the last part/code of the Kernel versions separated by commas to delete them all at once.
|
||||
|
||||
Suppose, I have two old kernels 5.4.0-7634-generic and 5.4.0-7624, the command will be:
|
||||
|
||||
```
|
||||
sudo rm /boot/*-5.4.0-{7634,7624}-*
|
||||
```
|
||||
|
||||
If you don’t want to see the old kernel version in the grub boot menu, you can simply [update grub][13] using the following command:
|
||||
|
||||
```
|
||||
sudo update-grub
|
||||
```
|
||||
|
||||
That’s it. You’re done. You’ve freed up space and also potentially fixed the broken APT if it was an issue after your /boot partition filled up.
|
||||
|
||||
In some cases, you may need to enter these commands to fix the broken apt (as I’ve noticed in the forums):
|
||||
|
||||
```
|
||||
sudo dpkg --configure -a
|
||||
sudo apt install -f
|
||||
```
|
||||
|
||||
Do note that you don’t need to enter the above commands unless you find APT broken. Personally, I didn’t need these commands but I found them handy for some on the forums.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://itsfoss.com/free-boot-partition-ubuntu/
|
||||
|
||||
作者：[Ankush Das][a]
|
||||
选题：[lujun9972][b]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]: https://itsfoss.com/author/ankush/
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://itsfoss.com/free-up-space-ubuntu-linux/
|
||||
[2]: https://i1.wp.com/itsfoss.com/wp-content/uploads/2020/10/free-boot-space-ubuntu-linux.jpg?resize=800%2C450&ssl=1
|
||||
[3]: https://i1.wp.com/itsfoss.com/wp-content/uploads/2020/09/apt-autoremove-screenshot.jpg?resize=800%2C415&ssl=1
|
||||
[4]: https://itsfoss.com/remove-old-kernels-ubuntu/
|
||||
[5]: https://itsfoss.com/find-which-kernel-version-is-running-in-ubuntu/
|
||||
[6]: https://linuxhandbook.com/uname/
|
||||
[7]: https://i2.wp.com/itsfoss.com/wp-content/uploads/2020/09/uname-r-screenshot.jpg?resize=800%2C198&ssl=1
|
||||
[8]: https://itsfoss.com/synaptic-package-manager/
|
||||
[9]: https://itsfoss.com/optimize-ubuntu-stacer/
|
||||
[10]: https://i2.wp.com/itsfoss.com/wp-content/uploads/2020/09/stacer-remove-kernel.jpg?resize=800%2C562&ssl=1
|
||||
[11]: https://i0.wp.com/itsfoss.com/wp-content/uploads/2020/09/stacer-remove-kernel-header.png?resize=800%2C576&ssl=1
|
||||
[12]: https://i1.wp.com/itsfoss.com/wp-content/uploads/2020/09/command-kernel-list.png?resize=800%2C432&ssl=1
|
||||
[13]: https://itsfoss.com/update-grub/
|
||||
273
translated/tech/20200901 Create a mobile app with Flutter.md
Normal file
273
translated/tech/20200901 Create a mobile app with Flutter.md
Normal file
@ -0,0 +1,273 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: (gxlct008)
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (Create a mobile app with Flutter)
|
||||
[#]: via: (https://opensource.com/article/20/9/mobile-app-flutter)
|
||||
[#]: author: (Vitaly Kuprenko https://opensource.com/users/kooper)
|
||||
|
||||
使用 Flutter 创建 App
|
||||
======
|
||||
|
||||
使用流行的 Flutter 框架开始您的跨平台开发之旅。
|
||||
![A person looking at a phone][1]
|
||||
|
||||
[Flutter][2] 是一个深受全球移动开发者欢迎的项目。该框架有一个庞大的、友好的发烧友社区，随着 Flutter 帮助程序员将他们的项目带入移动领域，这个社区还在继续增长。
|
||||
|
||||
本教程旨在帮助您开始使用 Flutter 进行移动开发。阅读之后，您将了解如何快速安装和设置框架，以便开始为智能手机、平板电脑和其他平台编码。
|
||||
|
||||
本操作指南假定您已在计算机上安装了 [Android Studio][3]，并且具有一定的使用经验。
|
||||
|
||||
### 什么是 Flutter ？
|
||||
|
||||
Flutter 使得开发人员能够为多个平台构建应用程序，包括：
|
||||
|
||||
* Android
|
||||
* iOS
|
||||
* Web (测试版)
|
||||
* macOS (正在开发中)
|
||||
* Linux (正在开发中)
|
||||
|
||||
对 macOS 和 Linux 的支持还处于早期开发阶段，而 Web 支持预计很快就会发布。这意味着您可以立即试用其功能（如下所述）。
|
||||
|
||||
### 安装 Flutter
|
||||
|
||||
我使用的是 Ubuntu18.04，但安装过程与其他 Linux 发行版类似，比如 Arch 或 Mint。
|
||||
|
||||
#### 使用 snapd 安装
|
||||
|
||||
要使用 [Snapd][4] 在 Ubuntu 或类似发行版上安装 Flutter，请在终端中输入以下内容：
|
||||
|
||||
```
|
||||
$ sudo snap install flutter --classic
|
||||
|
||||
$ sudo snap install flutter –classic
|
||||
flutter 0+git.142868f from flutter Team/ installed
|
||||
```
|
||||
|
||||
然后使用 `flutter` 命令启动它。 首次启动时，该框架会下载到您的计算机上：
|
||||
|
||||
```
|
||||
$ flutter
|
||||
Initializing Flutter
|
||||
Downloading <https://storage.googleapis.com/flutter\_infra\[...\]>
|
||||
```
|
||||
|
||||
下载完成后，您会看到一条消息，告诉您 Flutter 已初始化：
|
||||
|
||||
![Flutter initialized][5]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
#### 手动安装
|
||||
|
||||
如果您没有安装 Snapd，或者您的发行版不是 Ubuntu，那么安装过程会略有不同。 在这种情况下，请[下载] [7] 为您的操作系统推荐的 Flutter 版本。
|
||||
|
||||
![Install Flutter manually][8]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
然后将其解压缩到您的主目录。
|
||||
|
||||
在您喜欢的文本编辑器中打开主目录中的 `.bashrc` 文件 (如果您使用 [Z shell][9]，则打开 `.zshc`)。因为它是隐藏文件，所以您必须首先在文件管理器中启用显示隐藏文件，或者使用以下命令从终端打开它：
|
||||
|
||||
```
|
||||
$ gedit ~/.bashrc &
|
||||
```
|
||||
|
||||
将以下行添加到文件末尾：
|
||||
|
||||
```
|
||||
export PATH="$PATH:~/flutter/bin"
|
||||
```
|
||||
|
||||
保存并关闭文件。 请记住，如果将 Flutter 提取到您的主目录之外的其他位置，则 [Flutter SDK 的路径][10] 将有所不同。
|
||||
|
||||
关闭您的终端，然后再次打开，以便加载新配置。 或者，您可以通过以下命令使配置立即生效：
|
||||
|
||||
```
|
||||
$ . ~/.bashrc
|
||||
```
|
||||
|
||||
如果您没有看到错误，那说明一切都是正常的。
|
||||
|
||||
这种安装方法比使用 `snap`命令稍微困难一些，但是它非常通用，可以让您在几乎所有的发行版上安装框架。
|
||||
|
||||
|
||||
#### 检查安装结果
|
||||
|
||||
要检查结果，请在终端中输入以下内容：
|
||||
|
||||
```
|
||||
flutter doctor -v
|
||||
```
|
||||
|
||||
您将看到有关已安装组件的信息。 如果看到错误，请不要担心。 您尚未安装任何用于 Flutter SDK 的 IDE 插件。
|
||||
|
||||
![Checking Flutter installation with the doctor command][11]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
### 安装 IDE 插件
|
||||
|
||||
您应该在您的 [集成开发环境 (IDE)][12] 中安装插件，以帮助它与 Flutter SDK 接口、与设备交互并构建代码。
|
||||
|
||||
Flutter 开发中常用的三个主要 IDE 工具是 IntelliJ IDEA (社区版)、Android Studio 和 VS Code (或 [VSCodium][13])。我在本教程中使用的是 Android Studio，但步骤与它们在 IntelliJ Idea (社区版)上的工作方式相似，因为它们构建在相同的平台上。
|
||||
|
||||
首先，启动 **Android Studio**。打开 **Settings**，进入 **Plugins** 窗格，选择 **Marketplace** 选项卡。在搜索行中输入 **Flutter**，然后单击 **Install**。
|
||||
|
||||
![Flutter plugins][14]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
您可能会看到一个安装 **Dart** 插件的选项；同意它。如果看不到 Dart 选项，请通过重复上述步骤手动安装。我还建议使用 **Rainbow Brackets** 插件，它可以让代码导航更简单。
|
||||
|
||||
就这样！您已经安装了所需的所有插件。您可以在终端中输入一个熟悉的命令进行检查：
|
||||
|
||||
```
|
||||
flutter doctor -v
|
||||
```
|
||||
|
||||
![Checking Flutter plugins with the doctor command][15]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
### 构建您的 “Hello World” 应用程序
|
||||
|
||||
要启动新项目，请创建一个 Flutter 项目：
|
||||
|
||||
1. 选择 **New -> New Flutter project**.
|
||||
|
||||
![Creating a new Flutter plugin][16]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
2. 在窗口中，选择所需的项目类型。 在这种情况下，您需要选择 **Flutter Application**。
|
||||
|
||||
3. 命名您的项目 **hello_world**。 请注意，您应该使用合并的名称，因此请使用下划线而不是空格。 您可能还需要指定 SDK 的路径。
|
||||
|
||||
![Naming a new Flutter plugin][17]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
4. 输入软件包名称。
|
||||
|
||||
您已经创建了一个项目！现在，您可以在设备上或使用模拟器启动它。
|
||||
|
||||
![Device options in Flutter][18]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
选择您想要的设备，然后按 **运行**。稍后，您将看到结果。
|
||||
|
||||
![Flutter demo on mobile device][19]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
现在你可以在一个 [中间项目][20] 上开始工作了。
|
||||
|
||||
### 尝试 Flutter for web
|
||||
|
||||
在安装 Flutter 的 Web 组件之前，您应该知道 Flutter 目前对 Web 应用程序的支持还很原始。 因此，将其用于复杂的项目并不是一个好主意。
|
||||
|
||||
默认情况下，基本 SDK 中不启用 Flutter for web。 要打开它，请转到 beta 频道。 为此，请在终端中输入以下命令：
|
||||
|
||||
```
|
||||
flutter channel beta
|
||||
```
|
||||
|
||||
![flutter channel beta output][21]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
接下来，使用以下命令根据 beta 分支升级 Flutter：
|
||||
|
||||
```
|
||||
flutter upgrade
|
||||
```
|
||||
|
||||
![flutter upgrade output][22]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
要使 Flutter for web 工作，请输入：
|
||||
|
||||
```
|
||||
flutter config --enable-web
|
||||
```
|
||||
|
||||
重新启动 IDE；这有助于 Android Studio 索引新的 IDE 并重新加载设备列表。您应该会看到几个新设备：
|
||||
|
||||
![Flutter for web device options][23]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
选择 **Chrome** 会在浏览器中启动一个应用程序， **Web Server** 会提供指向您的 Web 应用程序的链接，您可以在任何浏览器中打开它。
|
||||
|
||||
不过，现在还不是急于开发的时候，因为您当前的项目不支持Web。要改进它，请打开项目根目录下的终端，然后输入：
|
||||
|
||||
```
|
||||
flutter create
|
||||
```
|
||||
|
||||
此命令重新创建项目，并添加 Web 支持。 现有代码不会被删除。
|
||||
|
||||
请注意，目录树已更改，现在有了一个 "web" 目录：
|
||||
|
||||
![File tree with web directory][24]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
现在您可以开始工作了。 选择 **Chrome**，然后按 **Run**。 稍后，您会看到带有应用程序的浏览器窗口。
|
||||
|
||||
![Flutter web app demo][25]
|
||||
|
||||
(Vitaly Kuprenko, [CC BY-SA 4.0][6])
|
||||
|
||||
恭喜你！ 您刚刚为浏览器启动了一个项目，并且可以像其他任何网站一样继续使用它。
|
||||
|
||||
所有这些都来自同一代码库，因为 Flutter 使得几乎无需更改就可以为移动平台和 Web 编写代码。
|
||||
|
||||
### 用 Flutter 做更多的事情
|
||||
|
||||
Flutter 是用于移动开发的强大工具，而且它也是迈向跨平台开发的重要一步。 了解它，使用它，并将您的应用程序交付到所有平台！
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/20/9/mobile-app-flutter
|
||||
|
||||
作者：[Vitaly Kuprenko][a]
|
||||
选题：[lujun9972][b]
|
||||
译者：[译者ID](https://github.com/gxlct008)
|
||||
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/kooper
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/idea_innovation_mobile_phone.png?itok=RqVtvxkd (A person looking at a phone)
|
||||
[2]: https://flutter.dev/
|
||||
[3]: https://developer.android.com/studio
|
||||
[4]: https://snapcraft.io/docs/getting-started
|
||||
[5]: https://opensource.com/sites/default/files/uploads/flutter1_initialized.png (Flutter initialized)
|
||||
[6]: https://creativecommons.org/licenses/by-sa/4.0/
|
||||
[7]: https://flutter.dev/docs/get-started/install/linux
|
||||
[8]: https://opensource.com/sites/default/files/uploads/flutter2_manual-install.png (Install Flutter manually)
|
||||
[9]: https://opensource.com/article/19/9/getting-started-zsh
|
||||
[10]: https://opensource.com/article/17/6/set-path-linux
|
||||
[11]: https://opensource.com/sites/default/files/uploads/flutter3_doctor.png (Checking Flutter installation with the doctor command)
|
||||
[12]: https://www.redhat.com/en/topics/middleware/what-is-ide
|
||||
[13]: https://opensource.com/article/20/6/open-source-alternatives-vs-code
|
||||
[14]: https://opensource.com/sites/default/files/uploads/flutter4_plugins.png (Flutter plugins)
|
||||
[15]: https://opensource.com/sites/default/files/uploads/flutter5_plugincheck.png (Checking Flutter plugins with the doctor command)
|
||||
[16]: https://opensource.com/sites/default/files/uploads/flutter6_newproject.png (Creating a new Flutter plugin)
|
||||
[17]: https://opensource.com/sites/default/files/uploads/flutter7_projectname.png (Naming a new Flutter plugin)
|
||||
[18]: https://opensource.com/sites/default/files/uploads/flutter8_launchflutter.png (Device options in Flutter)
|
||||
[19]: https://opensource.com/sites/default/files/uploads/flutter9_demo.png (Flutter demo on mobile device)
|
||||
[20]: https://opensource.com/article/18/6/flutter
|
||||
[21]: https://opensource.com/sites/default/files/uploads/flutter10_beta.png (flutter channel beta output)
|
||||
[22]: https://opensource.com/sites/default/files/uploads/flutter11_upgrade.png (flutter upgrade output)
|
||||
[23]: https://opensource.com/sites/default/files/uploads/flutter12_new-devices.png (Flutter for web device options)
|
||||
[24]: https://opensource.com/sites/default/files/uploads/flutter13_tree.png (File tree with web directory)
|
||||
[25]: https://opensource.com/sites/default/files/uploads/flutter14_webapp.png (Flutter web app demo)
|
||||
78
translated/tech/20200928 Create template files in GNOME.md
Normal file
78
translated/tech/20200928 Create template files in GNOME.md
Normal file
@ -0,0 +1,78 @@
|
||||
[#]: collector: (lujun9972)
|
||||
[#]: translator: (rakino)
|
||||
[#]: reviewer: ( )
|
||||
[#]: publisher: ( )
|
||||
[#]: url: ( )
|
||||
[#]: subject: (Create template files in GNOME)
|
||||
[#]: via: (https://opensource.com/article/20/9/gnome-templates)
|
||||
[#]: author: (Alan Formy-Duval https://opensource.com/users/alanfdoss)
|
||||
|
||||
在 GNOME 中创建文档模板
|
||||
======
|
||||
|
||||
![Digital images of a computer desktop][1]
|
||||
|
||||
制作模板可以让你更快地开始写作新的文档。
|
||||
|
||||
我偶然发现了 [GNOME][2] 的一个新功能（对我来说是的）：创建文档模版。模版（template）也被称作样版文件（boilerplate），一般是有着特定格式的空文档，例如律师事务所的信笺，在其顶部有着律所的名称和地址；另一个例子是银行以及保险公司的保函，在其底部页脚包含着某些免责声明。由于这类信息很少改变，你可以把它们添加到空文档中作为模板使用。
|
||||
|
||||
一天，在浏览我的 Linux 系统文件的时候，我点击了**模板**（Templates）文件夹，然后刚好发现窗口的上方有一条消息写着：“将文件放入此文件夹并用作新文档的模板”，以及一个**获取详情……** 的链接，指向了 [GNOME 指南（GNOME help）][3]中的模板页面。
|
||||
|
||||
![Message at top of Templates folder in GNOME Desktop][4]
|
||||
|
||||
(Alan Formy-Duval, [CC BY-SA 4.0][5])
|
||||
|
||||
### 创建模板
|
||||
|
||||
在 GNOME 中创建模板非常简单。有几种方法可以把文件放进模板文件夹里：你既可以通过图形用户界面（GUI）或是命令行界面（CLI）从另一个位置复制或移动文件，也可以创建一个全新的文件；我选择了后者，实际上我也创建了两个文件。
|
||||
|
||||
![My first two GNOME templates][6]
|
||||
|
||||
(Alan Formy-Duval, [CC BY-SA 4.0][5])
|
||||
|
||||
我的第一份模板是为 Opensource.com 的文章准备的，它有一个输入标题的位置以及关于我的名字和文章使用的许可证的几行。我的文章使用 Markdown 格式，所以我将模板创建为了一个新的 Markdown 文档——**Opensource.com Article.md**：
|
||||
|
||||
````
|
||||
# Title
|
||||
```
|
||||
An article for Opensource.com
|
||||
by: Alan Formy-Duval
|
||||
Creative Commons BY-SA 4.0
|
||||
```
|
||||
|
||||
````
|
||||
|
||||
我将这份文档保存在了 `/home/alan/Templates` 文件夹内，现在 GNOME 就可以将这个文件识别为模板，并在我要创建新文档的时候提供建议了。
|
||||
|
||||
### 使用模板
|
||||
|
||||
每当我有了新文章的灵感的时候，我只需要在我计划用来组织内容的文件夹里单击右键，然后从**新建文档**（New Document）列表中选择我想要的模板就可以开始了。
|
||||
|
||||
![Select the template by name][7]
|
||||
|
||||
(Alan Formy-Duval, [CC BY-SA 4.0][5])
|
||||
|
||||
你可以为各种文档或文件制作模板。我写这篇文章时使用了我为 Opensource.com 的文章创建的模板。程序员可能会把模板用于软件代码，这样的话也许你想要只包含 `main()` 的模板。
|
||||
|
||||
GNOME 桌面环境为 Linux 及相关操作系统的用户提供了一个非常实用、功能丰富的界面。你最喜欢的 GNOME 功能是什么，你又是怎样使用它们的呢？请在评论中分享～
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/20/9/gnome-templates
|
||||
|
||||
作者：[Alan Formy-Duval][a]
|
||||
选题：[lujun9972][b]
|
||||
译者：[rakino](https://github.com/rakino)
|
||||
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/alanfdoss
|
||||
[b]: https://github.com/lujun9972
|
||||
[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/computer_desk_home_laptop_browser.png?itok=Y3UVpY0l (Digital images of a computer desktop)
|
||||
[2]: https://www.gnome.org/
|
||||
[3]: https://help.gnome.org/users/gnome-help/stable/files-templates.html.en
|
||||
[4]: https://opensource.com/sites/default/files/uploads/gnome-message_at_top_border.png (Message at top of Templates folder in GNOME Desktop)
|
||||
[5]: https://creativecommons.org/licenses/by-sa/4.0/
|
||||
[6]: https://opensource.com/sites/default/files/uploads/gnome-first_two_templates_border.png (My first two GNOME templates)
|
||||
[7]: https://opensource.com/sites/default/files/uploads/gnome-new_document_menu_border.png (Select the template by name)
|
||||
Loading…
Reference in New Issue
Block a user