Linux Magazine的August 2021目录

Tutorials, screencasts, or even training videos are becoming increasingly important in everyday life. Multimedia is particularly useful in the home office and for homeschooling. But not every device can handle every file format, and not every screen displays all resolutions. Conversion programs help to adjust the formats and modify the image resolutions for the best possible results. Linux offers a great variety of multimedia conversion tools. We decided to investigate a few of the top contenders. Note that we focused on active projects for this report and did not consider some of the alternatives that are still widely known but not in active development (see the box entitled “Out of the Running”). Containerized Audiovisual content can be stored with different parameters and image resolutions. Audio files can be saved in…

Over the years, a rich ecosystem of applications has grown around Debian package management. In fact, the available choices are so numerous that some are easy to overlook, especially since some scripts are not in the official repositories of any distribution. Finding compatible scripts can require a lot of searching, often resulting in frustration. Setting out to maximize download speed, I found several layers of scripts or tools: netselect [1] to find the quickest mirrors for my location, aria2 [2] or Axel [3] to serve as download managers, and apt-fast [4] to make the other scripts’ modifications easy to use by placing them in a single command. The procedure can take some time, but, considering that it can increase download speeds by more than 50 percent, the effort seems worthwhile.…

Over the past year, an increase in homeschooling has given an unprecedented boost to learning management, communication systems, and curriculum-based software. When using these online learning tools, a virtual whiteboard can help enhance learning. Xournal [1], a note-taking, sketching, and journaling app, can turn your device into a whiteboard, letting you visualize content via a stylus or tablet. Xournal’s workspace mimics a notebook page and offers a variety of tools, including a shape recognizer that recognizes geometric shapes as they are drawn. Not only can you take notes and make simple drawings, but you can also use Xournal for screencasts and real-time screen sharing during a video conference. Installation Xournal can be found in the repositories of all major distributions. For numerous Linux derivatives, there are packages for both 32-…

A majority of users rely on Google to find information on the Internet. Although convenient, Google can expose your personal information. Your searches result in companies tracking your online activities and then bombarding you with targeted advertising. The privacy concerns alone might make you want to consider an alternative search engine, but there are other reasons you might consider another option. What if you want to include a search service on your personal network or website? By integrating an alternative search engine into your network or website, you can make it easier for people to find your information, while maintaining your independence from the big search giants like Google. Luckily, there are several alternative search engines that give excellent results regardless of your motivation. Tracking When it come to privacy…

These days, there are too few purely C-coded utilities that are useful, modern, self-contained, compiled in seconds, and relatively easy to understand. However, diskgraph is an instantly compiled command-line tool that draws a chart in your terminal showing storage throughput for both input and output operations. Each measurement is represented by a character-sized square that represents a 500ms interval, with the y-axis showing an automatically scaled bandwidth (amount transferred over time) and the xaxis showing the time frame. The blocks will scroll from the right to the left as time progresses so you can more easily see fluctuating load conditions as you read and write files, allowing you to easily see periods of peak and low transfer and how your hardware is performing. It’s very simple, but it presents information…

Most of us agree that Git is wonderful, and it’s now being used everywhere, even in places not routinely handling code. Documentation, design, and even configuration files can often benefit from using Git, which can create a problem when non-technical people need to wrestle with some of Git’s more esoteric features. This is where a graphical interface can help by promoting best practices, safe-guarding from mistakes, and by simply visualizing normally abstract commands. The problem is, we’ve yet to find a Git GUI that’s able to do all of this without becoming more complex than the git command itself. But GitAhead is a very strong contender, especially in one area of Git’s functionality: commit history. Understanding and visualizing a Git repository’s commit history can help you to understand exactly what’s…

It’s been more than 20 years since IBM’s Deep Blue defeated a reigning (human) world chess champion, and chess has since been through various troughs and peaks in popularity. But thanks to recent circumstances, and a particularly popular episodic streaming production, the humble game of chess is going through a huge renaissance. It’s become difficult to even buy a decent chess board. Fortunately, there are plenty of computer chess engines and clients to choose from on Linux, including the widely regarded and ported PyChess with the Stockfish back end. But one of the most popular open source implementations has never had official support on Linux, until now. And that’s the brilliant Lucas Chess. What makes Lucas Chess so popular, despite its antiquated graphics and long development periods, is the quality…

openSUSE Leap 15.3 64-bit OpenSUSE Leap 15.3 includes increased build consistency and seamless migration to the commercial SUSE Linux Enterprise Server and the latest array of openSUSE’s developing set of artificial intelligence packages. Those working with containers may also want to check out Podman, a daemonless container engine for developing, managing, and running OCI Containers, and kubeadm, a tool for creating minimal, best-practices Kubernetes clusters. For everyday users, Leap 15.3 features the usual desktop environments. For KDE users, it includes the long-term support Plasma 5.18, whose new features include a builtin emoji picker, strong GTK support for those who like to mix their desktops and applications, and better support for public WiFi. Also supported is Gnome 3.34, which includes visual makeovers for icons, login, and the overview screen; sandboxed browsing;…

Are you on the lookout for a Linux-powered laptop that can go the distance and exceed your needs for power, size, and battery life? If that sounds like the perfect machine to fill your dance card, and you’re not looking for the most brilliant display on the market, Entroware has the laptop for you. The Proteus 15.6-inch is a redesign of the original mobile workstation and includes something few other Linux laptops can match – a 73 Wh battery that can be charged via USB Type-C cable (so you don’t have to carry around so many cables). The original Proteus included a 62.16 Wh battery, so this is a good jump in battery life. Although there is no claim about battery life to be found on the Proteus page (https://www.entroware.com/store/proteus),…

Smartphones are getting more and more powerful. Is it time to start thinking of a smartphone as something more like a tablet or a real computer? Is it possible to set up an Android phone with a full version of Linux – connected to a monitor, keyboard, and mouse? Android OS is based on a modified version of the Linux kernel. In theory, a hardware-compatible Linux should be able to run on systems that Android OS runs on, but the Android developers at Google have added lots of proprietary drivers and bits. Additionally, the complexity of the communication hardware means that Android has drifted quite a distance from what we think of as a conventional Linux. Still, the power of the GPL means that Android OS is available to the…

One day, during one of my company’s cloud project meetings, a developer colleague said, “I need to find a way to quickly access logs for debugging and troubleshooting.” I already had some experience with the Grafana-Prometheus, so I said I would help find a solution. It turns out, the solution we settled on was Loki [1], from Grafana Labs. The Grafana Labs website describes Loki as “…a horizontally scalable, highly available, multi-tenant log aggregation system inspired by Prometheus.” Loki is designed to aggregate logs efficiently, extracting metrics and alerts – all without requiring a massive indexing configuration. Once you have extracted the information you need, you can then use Grafana to visualize the data. This workshop offers a quick look at how to access log data using Loki. In this…

IRCNow, a communication platform built on free and open source software and open standards, transforms Internet Relay Chat (IRC) into a user-controlled social network. IRCNow strives to give users as much control of the software stack as possible, with the goal of being vendor independent. With 13 active servers at the time of writing, IRCNow functions as a federation of self-governing servers. Aaron Lin (Figure 1), who has directed IRCNow [1] since its creation in 2019, recruits and trains volunteers and teaches them how to run the network. In this interview, he provides the back story on IRCNow and reveals what the future holds for the network. Linux Magazine: What is IRCNow, and why is it important? Aaron Lin: IRCNow aims to be a social network that the users control.…

During the COVID-19 lockdown, many activities like pools, gyms, and golf courses required people to sign in to websites before they could access these activities. These precautions helped to maintain a safe environment; however, the booking process was awkward, and it was easy to miss an activity if you weren’t signed up early enough. Luckily, some great Linux tools can automate web logins. In this article, I share two techniques to create automated web logins. The first technique uses command-line tools like xte and xdotool. This approach allows simple Bash scripts to replicate how you would use keystrokes to access web pages. The second technique uses the Selenium Python library. The Selenium API allows you to tackle more complex projects by giving you access to the full Document Object Model…

There was a time, many years ago, when managing web browser bookmarks was incredibly important. This was before Google got good, and you could seldom find the site you’d previously found or remember how you got there. Instead, you’d fruitlessly hunt through your browser history trying to remember the train of thought that led you to the site you wanted to revisit. If you had the foresight to bookmark the site, the problem was solved until you bookmarked too many sites and failed to organize them, leading you back to the rapidly improving Google. But bookmarks haven’t gone away, especially now with many of us experimenting with other search providers and trying to keep as much personal preference off the Internet as possible. Consequently, it can still be a good…

Maybe it’s because many of us have been dreaming about traveling and experiencing other cultures, but there’s been a resurgence in high-quality desktop Internet radio applications. We recently looked at the fantastic Shortwave, for example, which made tuning into a global network of radio stations easy, and here we have the equally wonderful Tuner. Tuner isn’t designed specifically for global radio, but it can access a huge library of available stations through its search function, along with quick access to a variety of genres, trending stations, and a discovery tab. It describes itself as a “minimalistic” Internet radio application, so it’s fitting that Tuner makes such brilliant use of the GTK3+ toolkit and its human interface guidelines to reduce the screen clutter to only those buttons you need. The top…

Smartphones, iPads, and Android tablets have rekindled popularity for all kinds of old-fashioned games, and in particular, games that involve drawing, coloring, and finding things. The weirdly named mki3dgame is a finding game, but rather than constraining itself to the limitations of a two-dimensional plane, mki3dgame hides objects for you to find within a 3D realm. Its name actually comes from the MKI 3D Rapid Modeler, a web-based, open source, and keyboard-driven 3D modeling tool, which was used to create all the 3D shapes in the game. The idea behind the game itself is to find and frame multiple red tokens hidden within the 3D environment using the targeting reticule to center the token and the direction keys to move toward the token so that you collide to collect it.…

DLSS stands for Deep Learning Super Sampling and is a temporal image upscaling technology developed by NVidia for NVidia graphics cards. This technology makes it possible to upscale lower-resolution images into higher-resolution images so they can be better displayed on higher-resolution displays. This technology would greatly enhance the Linux gaming experience but isn’t available yet for the open source platform. Both NVidia and Valve are working to change that. By using Tensor Cores on RTX GPUs to accelerate performance for supported games, NVidia is making an effort to bring DLSS to Steam Proton on Linux. This means games such as Call of Duty, Cyberpunk 2077, Fortnite, and Rainbow Six Siege could soon be playable on Linux, via Steam. This technology will require supported graphics cards, such as the GeForce RTX…

DistroWatch lists 278 active distributions, but these numbers are misleading. Many distributions are minor variations of a half dozen major distributions, distinguished by their default software selection or oriented to a particular task. A notable exception is Void Linux [1], a small project organized more like the distributions of two decades ago, with every part of its structure carefully considered. The result is one of the more original distributions available today. To learn more, I contacted Michael Aldridge, who answered my questions after consulting with other core members of the development team. Originally released in 2008 by Juan Romero Pardines, Void Linux served as a testbed for the XBPS Package Manager. Since then, Void has changed direction several times. Currently, Void Linux is a rolling release distribution with an emphasis…

There are very few commands that you type more often than ls when working in the shell. As experienced Linux users will know, the shorter a command is, the more important it is. Even the often expressed suspicion that the shortest commands have the longest man pages is something that ls cannot really refute. You would think that there is little to improve with ls, but the exa developers beg to differ. Instead of a one-to-one replacement, exa [1] seeks to be the better ls. It gets by with far fewer parameters and is correspondingly less powerful. But if you use only the most common options – for me, that would be -l, -a, -t, -h, and --sort=size – you won’t miss anything. That’s because exa comes with sensible defaults…

If you’ve decided to learn Python [1] and have any experience with other programming languages, you’ll quickly notice that the ubiquitous switch statement is nowhere to be found. Soon, though, that will no longer be the case (sort of). Python 3.10 is slated to be released in October 2021 and includes the new match command [2] [3]. Switcheroo The function of switch is akin to trying to find a particular office in an office building. As you walk down the hallway, you look at each door to see if it displays the number or name in which you are interested. When you find it, you stop searching and go inside. In C (and indeed many other languages) switch allows you to compare a value against a set of others (Listing…

In this article, I discuss the design of a compact and portable workshop balance for various single-load-cell weighing applications constructed with a small load cell, an instrumentation amplifier, an excitation supply, a microcontroller, a display, and a serial port for debugging. Throughout, I used Linux and open source software, and I provide code samples, with directions for finding the complete code online. History Ancient civilizations used simple balances to compare weights for trading in precious metals, spices, salt, and the like. Today’s civilization is no less dependent on knowing the weight of objects. It is hard to imagine a day in which the knowledge of weight does not take part: from the morning visit to the bathroom scales, a trip to the supermarket, baking a cake, to weighing baggage at…

If you’ve ever had the pleasure of using Microsoft Windows, you might have run a Microsoft tool called Process Manager (ProcMon) to find out why your system is running slowly. Unlike other monitoring tools that might show you which processes were consuming the most resources, ProcMon focuses on which system calls (syscalls) a process is currently working on, enabling you to perform some analysis on what is going on behind a simple process name. Syscalls represent the functions that an application or process has requested to be run by the operating system or kernel, such as reading or writing data, allocating memory, waiting (polling) for an interrupt or a message, or opening a device. Monitoring which syscalls a process is running is a great way to troubleshoot your own projects…

Even though we’re used to the idea of a tool that can listen to music and identify it, especially on a smartphone, the reality is often different from the idea. Background noise, poor recording quality, and limited access to the clip you want to identify all inhibit the ability of these tools to do their job. As a result, there was a genuine “jaw-dropping” moment when we first tested out Music Radar on a piece of music. The piece was a rather obscure ambient track from 2020 by the artist Helios entitled “One And The Same.” It has no drums, no melody, no repeating sections, no verse, and no chorus. It consists mainly of textured soft clusters of droning synthesizer chords and, at times, sounds almost identical to Brian Eno’s…

The original Arduino IDE started life in 2005, before the launch of Twitter and before Facebook dropped its university-only invite policy. This text editor based IDE has since become synonymous with Arduino devices, being used for everything from uploading simple sketches (really, C files) to device management and fully fledged application development. At its heart, however, it was always a text editor with a lower panel for debug and compilation output, with few features to help with larger projects. This is why some projects created their own makefiles to automate the build, and partly why the arduino-cli tool was developed to unshackle the build process from the editor. More recently, arduino-cli has led to some excellent integration with Visual Studio (VS) Code, which can now develop, debug, build, and flash…