Indholdsfortegnelse for December 2019 i Linux Format

“The words ‘amateur’ and ‘professional’ are often taken to mean ‘unpaid’ and ‘paid’ respectively. I’d like to suggest different definitions. The real difference between amateur and professional is attitude. There’s a sign hanging on the meeting room wall here, attributed to Henry Ford, that says, “Quality means doing it right when no one is looking”. I think that neatly defines professionalism, too. We’ve all been there. While working on one problem, we uncover a deeper or different problem. We know it will impact the reliability or security of the system. One response is, “If I ignore this, no one will know”. Those are the words of an amateur. By contrast, there are volunteers who work at the deepest level of the Linux kernel, yet they carry out this hugely complex…

“Recently, there was a post on the Linux Kernel Mailing List pondering the future of packet-writing support. This is a mechanism, implemented by a driver known as ‘pktcdvd’, used when writing data to rewriteable DVD and Blu-ray media in such a way that the disks can be treated as mountable filesystems. The poster was concerned that the driver was going away and was keen to point out that optical drives are still on sale and even used. My first reaction upon reading this was twofold. First, the inevitable question of when had I last used a physical CD, DVD or Blu-ray disk. That I couldn’t really remember, and that it wasn’t a big deal, alarmed me a little, in the same way that progress sometimes does. Secondly – and even…

Anti-ANSI help  Q You recommended the use of the script command to record terminal output. This has worked well for me, thank you, but there is one gotcha. If any program I run produces coloured output, the typescript file that script produces has ANSI codes splattered all over it. Is there a way to have script record only plain ASCII? Alternatively, is there a relatively easy way to remove these codes from the file? Suzette Blanchard A You cannot tell script to not record those codes as it is designed to produce a faithful record of the terminal session that can be viewed with script replay. For a quick way to view a clean version of the file, the less pager removes the majority of such codes. If you want…

SPECS CPU: 1.9GHz Intel Core i7-8650U (quad-core, 8MB cache, up to 4.2GHz boost) GPU: Intel UHD Graphics 620 RAM: 16GB DDR4 Display: 15.6-inch, 1920 x 1080, IPS HDD: 128GB SSD (eMMC) Ports: 2x USBC, 1x USB Comms: 802.11ac Wi-Fi, Bluetooth, HD webcam Weight: 1.95 kg Size: 36.6 x 24.9 x 1.8 cm (W x D x H) Premium Chromebooks aren’t a new notion. It was Google itself that defenestrated the assumption that laptops running its Chrome OS were automatically budget devices. The Google Pixelbook was a $1,000 system with build quality and features to match. So what makes this Acer premium? Highlights include all-metal construction, a powerful Intel quad-core CPU, 16GB of RAM, a 15.6-inch IPS touchscreen, a fairly beefy battery and a fingerprint reader. With UK pricing of £899…

When you first attempt to access the Gerbera web interface, you’ll likely face an error informing you that the UI is disabled and to check your configuration. The solution requires editing the /etc/gerbera/config.xml config file and changing <ui enabled=”no” show-tooltips=”yes”> under the <server> heading at the top of the file to <ui enabled=”yes” show-tooltips=”yes”> . Should you feel the need to make any other changes to its default configuration, you’ll have to similarly hack away at the config file manually. You can use Universal Media Server’s graphical administrative interface to configure various aspects of the server, and you don’t necessarily have to muck about with configuration files in a text editor. The different settings are split across intelligently named tabs such as General Settings, Navigation Settings, Shared Content and Transcoding…

Out of the box, most mainstream distros are bloated and chunky. In their quest to appeal to the tastes of a very large number of people, their developers stuff them with a long list of desktop productivity apps. The number of packages not only increases the size of the distro’s ISO image, but the bloat also taxes your computing resources. While it is true that on many recent computers the excess baggage wouldn’t make much of a difference, not everyone has machines with 8GB of RAM or an octa-core processor. That’s not to say that these hacks are only for older machines. They’ll be just as effective on modern machines and help you optimise your resource consumption for a much smoother desktop experience. Back in the good ol’ days, when…

Most users have a select bunch of apps that they use frequently. Preload is an adaptive read-ahead daemon that runs in the background and analyses and monitors the apps that you use. Based on this ongoing analysis, Preload determines the apps you use frequently and fetches all the binaries and relevant dependencies into memory beforehand. This means that when you launch the app, it starts almost instantaneously since it’s already in the memory. For example, if you always launch your browser and your email client soon after booting into the distro, Preload will automatically load them both into memory when your computer boots up. When you log in and call on these apps, you’ll be amazed by their launch times. Its biggest downside is that the act of preloading the…

You don’t have to be inexperienced to accidentally lose data. From what we have seen here at LXF Towers, the more experienced users make the most severe mistakes. So while amateurs curse themselves for accidentally zapping the wrong files, the pros usually mess up their partition tables, wipe the MBR and even format the wrong partition (haha, never <cough> – Ed). If that makes you feel bad about data loss, then get this: there’s a good chance that your data loss is reversible. There are lots of tools that’ll help you out of a sticky situation and help carve data out of failing or dead disks. There are tools that will not only help restore deleted files but also entire partitions. Remember, however, that the success of the tools depends…

Everyone loves new releases of software, new features, news tools to play with, and of course new bugs! So when Ubuntu 19.10 rolled off the compiler onto the download servers everyone scrambled to grab their new images and install the update on their Raspberry Pi 4 – only to discover they couldn’t type in their passwords… Initially there were mixed reports that a Pi firmware update fixing the issue, but it seemed this was only for units with less than 4GB of memory. Users with 4GB models could limit memory to less than 3GB (or use the 32-bit build) and get their USB ports back, but understandably this is hardly ideal. Bluetooth was also nobbled in 19.10 – Canonical developer Dave Jones admitted that Bluetooth wasn’t tested under Eoan, with…

The Internet of Things (IoT) is a weird and wonderful place, and in this tutorial we will make it a little weirder by creating a tool that reads the sentiment of our tweets and rates them according to a list of positive and negative words. If the tweet is positive, a green LED will light up; if it’s negative a red LED will light. Neutral will see a yellow LED light. This is a fun introduction to learning how we can measure the mood of a tweet and create novel outputs. We’ve kept components for this project simple. We have three LEDs (red, yellow and green) connected to pins GPIO17, 27 and 22 via their long leg, and connected to GND via their short leg and a 330 ohm resistor.…

We discovered an anomaly in the BlueZ installation during the final testing for this tutorial. The tarball file from the official site has an additional software requirement when compared to the software pulled from the mirror site. The tarball from the official site has a json-c software requirement that is not present in the mirror site’s software installation. In addition, the ./configure attribute -enable-experimental from the official sites results in a failure error when used with the official site software release. In order to work it has be be changed to -enable-mesh to succeed. There is a Developer Study Guide: Deploying BlueZ v5.50 on Raspberry Pi3 available at www.bluetooth.com/ bluetoothresources that provides the details on the json-c requirements. The installation for this tutorial used the tarball found on the Mirror…

The Raspberry Pi 4 can get quite hot very quickly. Children should not directly touch the CPU as they may get a small burn. If using the Pi 4 with children, ensure that it’s in a case, and that it has adequate cooling. Passive cooling relies on a large surface area to which heat is transferred and then released into the air via convection. This means that the heatsink will often get very hot, so take precautions. Active cooling can be as simple or elaborate as you require. If you have spare 5V PC fans, you can make your own active cooling unit. But take care not to pull too much current from the 5V pin as it is directly connected to the 5V power supply.…

Put simply, rows break up the height of the WTF interface into different elements. Similarly, columns break the width of the interface into different elements. Our tests revealed that columns that are less than 30 characters in width are unsuitable for most types of information modules in WTF. With that in mind, let’s create a layout using four columns of uniform width 35, and also three rows: The different columns and rows are numbered from 0 starting from the left. So, the first widget will have top and left positions set at 0. The second widget in the first row will have top set to 0 but left set to 1, and so on. Similarly, the third widget in the second row will have top set to 1, but left…

These days most of our raw video footage sits on our phones. The easiest way to transfer this to your PC is via a cloud provider. Simply upload to the cloud, wait for it to sync, then get ready to edit. It’s possible to edit clips directly on the timeline. Simply position the play-head at the point where you’d like to split your clip, right-click the clip and choose ‘Slice > Keep Left Side’ to end the clip at that point. Choose ‘Keep Right Side’ to start the clip at the play-head point, and ‘Keep Both Sides’ to split the clip in two. If your exported movie experiences playback issues, try exporting again using different presets. Still no luck? Scale back the number of effects in your movie or investigate…

Creating a proper HDR image requires several exposures but, if you only have the one, you might be able to go some way to replicating the effect. This is possible when some tonal differences are present in areas that look ostensibly uniform. The most intuitive way of finding out if this is the case in GIMP is to select Colors > Brightness-Contrast and try adjusting the Brightness slider to the left. If the result is that a uniform white sky simply becomes a uniform grey, then there is no detail in the sky, so it’s game over. Conversely, moving the Brightness slider to the right will reveal if there’s any hidden detail in apparently uniform dark areas. If you discover hidden detail in the light and dark areas, first reduce…

Practice in a virtual machine, as any experiments with GRUB can make your system unbootable. Most features will behave the same in a VM as on your real machine. Repeat this in your head: “The system will become unbootable several times before I get this right”. Create a recovery stick before you try anything in this tutorial, then decide how to proceed. If you want a really small and fast boot, cut out everything, even GRUB. The systemd-boot is text-only, only offers very few options but the boot is very fast.…

This issue sees the last in our series of Minecraft Python coding tutorials. Over the last six issues, we’ve looked at integrating Python code into Minecraft, giving us the creative freedom to produce all kinds of wonderful monstrosities. We’ve looked at how to move our character around the world (see LXF252) using code, building blocks with code and automatically building prefabricated creations. We experimented with Turtle graphics (see LXF255), pixel art and vector graphics (see LXF256) in Minecraft. We even designed our own graphical user interface, with buttons to spawn buildings (see LXF254) in our Minecraft worlds. Minecraft could be considered one of the most creative video games of our time, with virtual environments spanning acres of procedurally generated random biomes. The world and its contents are left to the…

You may not be surprised that some developers have criticised Electron (see tutorials LXF256), mostly regarding the memory usage of its final binaries. The initial binary is over 100MB, because a major chunk of code from Chrome is embedded. When you create a small piece of code, this is a horrible waste. With Proton Native the binary is compiled with the bare essentials, making the binary a few kilobytes in size. That’s a very big win for small utilities. Until now Proton Native hasn’t been in much use with bigger projects. However, it may become popular thanks to the potential for more efficient and smaller binaries compared to Electron. Since it supports Node.js, developers can create pretty much everything that they can with Electron. Environment and compilers Under the bonnet,…

As an alternative to this, you could use the regular React Native and add a new target. This is what the React Native Desktop team has done. To use it, you need to download it from GitHub or run a modification script that adds the ‘desktop’ option: http://bit.ly/ lxf257native. This package modifies the react-native-cli by adding the react-native-desktop version. You can do this for one project or globally with react-native init MyDesktopApp --version status-im/ react-native-desktop . Either way, you have the full development environment ready to make mobile and desktop applications. Once you have done that, you have a development server available and you can program as if you were making mobile applications. This package compiles using C++ to Qt, making the final binary a native application. While you are…

The tenth month of the year arrives and so does a new Ubuntu 19.10 (Eoan Ermine) update. Is it a portent that this is the 31st release of Ubuntu and with the 32nd release next year, 32-bit x86 Ubuntu builds will end? It shouldn’t come as a surprise to anyone. It’s been discussed for literally years, and access to x86 builds has been slowly decreasing; the net build was still an option for 19.xx, but with 20.04, x86 builds will be 64-bit only. Sure, Arm still has 32-bit builds for those vital embedded devices. The more worrying concern was support for 32-bit software: hardware eventually dies, but software lives on for as long as it can be stored. Thankfully, the community outcry made Canonical see sense here and 32-bit library…

One of the best features of Sony’s PlayStation 4 console is the ability to stream games from the console to PCs and laptops. However, only Windows and macOS are officially supported. The good news is that there’s now a way for Linux users to stream their PS4 games to their PCs, with the release of Chiaki, a free and open source PS4 Remote Play client for Linux (and also macOS and Windows). It comes with pretty much all the features that the official client has, including congestion control to ensure the best possible streaming quality and experience depending on network conditions, bitrate control, Touchpad support for the DualShock 4 controller, configurable key bindings and remote wakeup of the console. So far, it’s been getting very positive word of mouth from…

Linus Torvalds announced the release of Linux 5.4-rc5, which should have been smaller than it was given that the current development cycle is coming to a close. Still, he wasn’t too concerned about the slight bloat. If things continue to plan, the final release of 5.4 should be featured in our summary next issue. Is hibernation usable? Linux has supported hibernation (suspending to disk) for many years. This differs from the typical ‘suspend’ (closing the lid on your laptop) in that the latter relies upon special hardware support maintaining the contents of RAM while effectively shutting down almost everything else. This allows for a very fast suspend, while limiting power draw sufficiently to last a few days. With hibernation, the machine is actually fully powered-down and can maintain a suspended…

Build Brighton Thursday evening is open night. http://buildbrighton.com Cornwall Tech Jam Second Saturday of the month, alternating between Bodmin and Camborne. www.cornwalltechjam.uk Thingqbator An IoT-focused makerspace, meeting weekly at The Shed MMU. mcr.thingqbator.org Leeds Hackspace Open night every Tuesday 7pm-late. Open day second Saturday of the month, 11am-4pm. http://leedshackspace.org.uk Huddersfield Raspberry Jam Meet every month at Huddersfield Library, typically the fourth Saturday of each month. Huddersfieldraspberryjam.co.uk rLab Reading Hackspace Unit C1, Weldale St, Reading, open sessions Wednesday from 7pm. http://rlab.org.uk Horsham Raspberry Jam Park Side, Chart Way, Horsham. www.facebook.com/hackhorsham Medway Makers Meet every 3-4 weeks on a Sunday. Full details at: http://meetup.com/Medway-Makers Maidstone Hackspace We hold open evenings every Wednesday from 5.30pm-8pm. https://maidstone-hackspace.org.uk Glasgow Makers and Hardware Hackers Mitchell Library, Glasgow. www.facebook.com/groups/115303729096198…

We’d love to try and answer any questions you send to lxf.answers@futurenet.com, no matter what the level. We’ve all been stuck before, so don’t be shy. However, we’re only human (although many suspect Jonni is a robot), so it’s important that you include as much information as you can. If something works on one distro but not another, then tell us. If you get an error message, please tell us the exact message and precisely what you did to invoke it. If you have, or suspect, a hardware problem, let us know about the hardware. Consider installing hardinfo or lshw. These programs list the hardware on your machine, so send us their output. If you’re unwilling, or unable, to install these, run the following commands in a root terminal and…

Send your thoughts to the Linux Format dungeon server at linuxformat@futurenet.com, be picked as Letter Of The Month and win* a 32GB Nitrokey Storage 2! The Nitrokey is worth a cool €149, has 32GB of hardware-encrypted storage, supports hidden volumes, secures your online accounts with onetime passwords, can encrypt emails, files and hard drives and is an open source, open hardware solution. Protected with AES-256 and RSA keys up to 4,096! Learn more at www.nitrokey.com.…

Just as a file server acts as a central repository doling out files to connected devices on a network, the role of a media server is to provide centralised access to your collection of videos, music and pictures. The modern solutions, such as the ones featured in this Roundup, are also capable of serving podcasts, connecting to live TV and even schedule recordings of your favourite programmes – and more. Many of the modern media servers feature a ‘10-foot’ user interface, making them ideal for connecting to large-screen displays and projectors. In addition to providing an intuitive display, these interfaces can also be controlled using remote devices, and many even have apps for Android devices that can be used for the same purpose. These projects can play multimedia in virtually…

You can use Kodi’s web interface to stream media from a Kodi installation over the network to Chromecast, AirPlay and other UPnP devices, in addition to devices such as Intel NUC and Odroid among others. Gerbera similarly is visible to all DLNA clients, including desktop applications such as VLC, once the server is up and running. The less-than-a-year-old Jellyfin doesn’t support as many devices as Plex. Still, it works on most popular web browsers, and even supports Chromecast when using Google Chrome. The apps for Android, Android TV and Fire TV are still in beta, with more apps and support for other devices and platforms to come. Plex works with various devices such as tablets and smart TVs from popular manufacturers such as LG, Roku TV, Samsung and Sony. It…

If you were to benchmark your laptop’s performance you’d get different results with the same distro. This is because laptops are designed to tweak their performance based on power usage. When running on battery power, laptops will try to extend battery life by turning down their performance. You can get better control over this process with the TLP tool, this is an advanced power management command line tool for Linux that tries to apply various tweaks to conserve battery while maximising performance. You can install TLP and its associated utilities with sudo apt install tlp tlp-rdw tlpui . Once installed, start TLP with sudo tlp start . Although it works in the background, you can use the tlpui graphical frontend to change settings and override the default behaviour. Furthermore, you…

Whether or not you are recovering data from a dying disk, it’s much more convenient to work with raw images of the disk rather than the physical hardware. Although we can use the venerable dd command to make the copy, it won’t always be a good idea. That’s because dd is designed to quit as soon as it encounters any errors, and wouldn’t be of much help on a malfunctioning disk. So instead we’ll use GNU ddrescue. It works like dd and makes block-level copies of a disk. Unlike dd however, GNU ddrescue skips over the bad blocks and copies the good blocks first. It goes without saying to make sure you create the mirror image on a healthy drive – it could be an external USB drive or an…

Retro-gaming is a passion of mine. I love to reminisce about old games, delve into their history and learn more about the game and the team behind it. With the Raspberry Pi we can experience retro-gaming from two different viewpoints. We can use an emulation platform such as Lakka, reviewed on page 49, and play the games from the ‘golden years’ of gaming – this is subjective, but for me it was the SNES/Mega Drive era – and experience the thrill of gaming with these classic machines. But with a Raspberry Pi we can also create our own ‘retro-style’ games using one of many coding tools. If you’re new to coding then Scratch is the place to start and you can follow one of the many tutorials to create your…

There are many thousands of programming languages in existence and they are used across a diverse number of platforms and projects. But what if you cannot code, or need a language that can be quickly understood with the minimal of training? Well, Node-RED is an ideal candidate. Developed originally by Nick O’Leary and Dave Conway-Jones at IBM, this flowbased visual programming tool uses connected nodes to perform tasks. It can read content from websites and Twitter, and via libraries it can also be connected to hardware such as the Raspberry Pi and Arduino (Arduino User anyone?–Ed). Rather than focus on loops which constantly run code, Node-RED reacts to inputs and events and the flow of the code is controlled by the nodes. For example, in our tutorial we used a…

In 1997 Jim Kardach, an engineer from Intel, proposed the name Bluetooth for the system he had developed that enabled cellular devices to communicate with computers using a short-range wireless link. Bluetooth was taken from the name of the second king of Denmark, Harald Bluetooth, who reined from c. 958-986. The king was credited with uniting different Scandinavian tribes into a single kingdom. King Harald united the Danish counties in the same way that Bluetooth unites multiple devices through one universal standard communication protocol. The idea for Bluetooth protocol originated with the Ericsson cellphone company. Ericsson engineers were developing a wireless method of attaching other devices to the cellphones. The original Bluetooth Special Interest Group (SIG) was formed by Ericsson, Intel, IBM, Nokia and Toshiba in 1996. Other companies such…

The 486 and early Pentium chips ushered in cooling, and the heat generated from a CPU needed to be removed as quickly as possible. Thermally conductive materials were required, and with this the thermal pad was factory-applied. We remember attaching the cooling to our first 1GHz AMD Athlon CPU and playing a game… but we forgot the thermal pad, and the CPU quickly cooked itself to death. Thermal pads enabled anyone to simply place the cooling unit on the CPU and get on with building the PC. But if you need to pull more heat from a CPU, we can use a thermally conductive liquid: a paste. Thermal paste is available in many different combinations and various cooling claims, but typically it’s cheap and offers better conductivity than a pad.…

Click Effects on the Project Files pane to apply one of 14 different special effects to your video clips. Just drag the effect onto your clip and you’ll see a small letter appear next to the filename or clip name; right-click this and choose Properties to configure it. The Chroma Key effect is a rough and ready way to introduce greenscreen effects such as removing backgrounds. Just select your Key Color from the effect’s Properties and use the Fuzz property to refine the edges. If your background isn’t as clean as you’d like, or you’d like to add a greenscreen effect to an image, you’ll need to do a little more work by creating a simple black (areas to keep)/white (areas to erase) mask in an image editor. Save this…

Any movement between exposures is potentially a problem. Clouds moving in the sky is a common example, although a city scene with moving people and vehicles is clearly much more of a challenge. While the two methods we’ve looked at here don’t produce exactly the same sort of HDR effect, the presence of movement might influence your choice of which of them to use. Unlike some other HDR software, Luminance HDR claims to handle movement. However, there’s a limit to how well this can work, and the result might not be entirely satisfactory. Nevertheless, in the case of scenes that contain large moving objects, there might well be no alternative. With the case of movement of clouds in the sky, the method of combining two images in GIMP may well…

rEFInd is a boot manager only, as opposed to GRUB, which manages and loads the OS. This is not a problem when you run Linux since the kernel can act as a boot loader. The feature ‘EFI Stub Loader’ enables this and most distributions deliver kernels with this feature active. You can use rEFInd in the same way as you use GRUB – the differences are few. However rEFInd has a few more features; it detects kernels on its own, for example. Thanks to this and a few other features, rEFInd has a simpler configuration than GRUB. Most people have no problems because the distribution has created scripts that write the configuration. When you want to install rEFInd, you need to use a separate file. Most distributions include GRUB; rEFInd…

DOCUMENT MANAGER Paperwork Version: 1.3.0 Web: https://gitlab.gnome.org/World/OpenPaperwork/paperwork The amount of paper people use for bills, official documents, mailing, marketing materials and advertising is huge. Even though eco-friendly initiatives like ‘print less’ (LXF is a paperless office! Management won’t pay for paper… – Ed) or ‘use double-sided printing’ are welcome, the situation is still pretty bad. Why not help save the planet by using the power of open source? Let Paperwork help. This user-friendly GTK3-based personal document manager helps collect and sort any type of printed material. Paperwork will be a best friend to your Linux-connected flatbed document scanner. This application combines features of a SANE-compatible scanner GUI with a Shotwell-like image library manager – but it differs from both. The purpose of Paperwork is to help you scan your papers…

Using Python, we can hook directly into Minecraft’s API to perform complex calculations, alter the location of our player character, and spawn blocks into the game world to create all kinds of creations, both 2D and 3D. We can do pretty much anything from creating prefabricated pixel-art to communicating directly with the player. Now, with this issue’s tutorial, we can do all of that over the network with our friends. By hacking into our friend’s Minecraft, we can manipulate their game world and their player character to our heart’s content. We’ll also do some reading and writing directly to text files in order to create a kind of non-player character script that can be printed to the chat display in-game. We’re essentially further advancing our Minecraft API projects from the…

The most common way to install and manage packages from node.js is the npm package handler. However, npx is also available, with new capabilities. Granted, npx is now included in npm but which to use and when? In general, npm manage your packages locally or globally, and npx executes the package you want to use. Ordinarily, you would run npm and set up your package.json file so you can run your application. This is the best and most organised way to run and develop a project. If you see a package that has exciting goals and you want to see how it works, you can use npx instead. You can also use npx to create a new project. Many of the scripts that make a project template you will only…

When you want to package your application, you can use electron-builder. This does not mean that we make a full Electron application with a Chrome binary built in, it just helps us make packages to distribute. With this system, you get features to handle all your packaging needs. You can make packages for macOS, Windows and of course Linux. You also have several package formats available. For Linux it supports snap, Appimage, DEB, pacman and RPM. On top of that you can create for FreeBSD systems. If you use this, make sure you have two package.json files. One file should be for development and one for deployment. This way you can have a small binary for production even though you have full debugging capabilities while developing. In the case of…

USING THE LXFDVD Using Linux for the first time can be very confusing. It’ll be unlike anything that you’ve likely operated before, especially if you’re used to Microsoft Windows or Apple macOS. Generally our DVDs are designed to be run directly, which is to say that when you first power on your PC (or Mac) it should ‘boot’ from the DVD – so before Windows or macOS even starts to load – with Linux running directly from the DVD. This trick is known as a Live Disc. It enables you to try out the various versions of Linux without having to install or change anything on your PC. Just remove the DVD, restart your PC and it’ll be exactly as you left it. While many systems will boot from a…

THE LXF LIBRARY Advanced Bash Scripting Guide Go further with shell scripting. Bash Guide for Beginners Get to grips with the basics of Bash scripting. Bourne Shell Scripting First steps in shell scripting. The Cathedral and the Bazaar Eric S. Raymond’s classic text explains the advantages of open development. The Debian Book Essential guide for sysadmins. Dive Into Python Everything you need to know. Introduction to Linux A handy guide full of pointers for new Linux users. Linux Dictionary The A-Z of everything to do with Linux. Linux Kernel in a Nutshell An introduction to the kernel written by master hacker Greg Kroah-Hartman. The Linux System Administrator’s Guide Take control of your system. Tools Summary Overview of GNU tools. GNU Emacs Manual Six hundred pages of essential information! Producing Open…

“Well, I’m told the last couple of months’ payment anomalies have been resolved, so perhaps by Samhain I’ll be able to eat again. Meanwhile, it seems I was remiss in my distro selections for LXF256. Off went the disc to the replicators, and then a couple of weeks later CodeLinSoft announced that the Condres OS project was shutting up shop. Even if we had time, there’s no way the higher-ups would authorise the costs of making a replacement disc, so we had no choice but to run with it. It’s hard work maintaining a Linux distro, and this sort of thing happens a lot with ‘one-person distros’, but we really thought Condres had a future. “Beware of that which claims to make Arch easy” is the moral of the story.…

Blender (www.blender.org), the open source 3D creation suite, is going from strength to strength, and has received a major boost with two high-profile companies, AMD and Nvidia, joining the Blender Foundation Development Fund at the patron level. The money from AMD will go to investment in general development, Vulkan migration and supporting AMD technology, while Nvidia’s investment will enable two more developers to work on core Blender development, and to help support Nvidia technology. Nvidia and AMD are the two biggest names in graphics card technology, so to have their support is a huge win for Blender. We’re not just talking in the financial sense either, as being associated with those two companies shows how respected Blender has become. In LXF253, we reported on how Epic and Ubisoft, two other…

“Announced last month at the Open Source Summit in Lyon, the Kernel CI project, which powers kernelci.org with automated testing for the upstream Linux kernel, has joined the Linux Foundation. This is a new home for a project that has sailed through uncharted waters for over five years. Given the huge scale at which the Linux kernel is being used, achieving comprehensive test coverage for it is an incredibly challenging goal. Based on the open source philosophy principles, Kernel CI’s distributed architecture makes this possible by enabling the whole kernel community to collaborate around a single upstream CI system. Becoming part of the Linux Foundation will let the project flourish and become in turn an integral part of the Linux kernel development workflo in general. One thing we can be…

Dmitry Safonov posted ‘kernel: Introduce Time Namespace’, a patch series that adds a new namespace for managing the perceived time as seen by processes. A typical use case will be to apply a time namespace to a cgroup containing the running tasks of a container, allowing a system administrator to alter time seen by applications. More importantly, it will allow container orchestration tooling to adjust the time seen by applications, particularly during migration. When moving containers from one host to another, the two hosts may not agree or be sychronised to the same time, which could otherwise have a devastating impact on applications not expecting discontinuity. Jessica Yu (maintainer of in-kernel module loading support) let everyone know that a new feature merged in Linux 5.3 may be the cause of…

When using the command line, there are often occasions when you need to run several commands in sequence – this can also happen when using a GUI, but the solution is nowhere near as simple. The classic example of this is the standard method of compiling software from source, this requires you to run ./configure (possibly with some arguments) followed by make then make install . Each of these steps can take anywhere from a few seconds to many hours, depending on the complexity of the code and speed of your machine. Waiting for one to complete before running the next is inefficient, so instead you could do: ./configure; make; make install The semicolons cause the commands to be executed in sequence, as if you had run each one individually.…

With any one of the projects featured in this Roundup, you could easily turn your old machine into a media server. More importantly, media servers don’t necessarily need vast amounts of RAM or computing prowess. These are needed only your media files are in a non-standard file format, and require on-the-fly transcoding. While a graphics card is an added bonus, the lack of one, or reliance on a lesser graphics card, wouldn’t be a bother if you have a 2GHz dual-core machine with 4GB RAM. We’re looking for a project that doesn’t make users want to perform a ritual sacrifice to complete installation. It’s also important to have a friendly user interface and plenty of documentation to help make sense of just how to set up a server. We’ll also…

If the idea of running a media server on top of your existing Linux distribution doesn’t appeal to you, OpenELEC is a viable alternative. Built around Kodi with the ‘just enough operating system’ principle, the distribution can easily be run off a pen drive or Raspberry Pi and helps you serve media from a dedicated server. If you want a home theatre setup without going through the trouble of installing and configuring a Linux distribution and a media server on top, this is your best bet. Meanwhile, if you’re not averse to spending money for the right feature-set in much the same way as Plex, Emby is another viable choice. It boasts a vast array of plug-ins, not unlike Kodi, and supports a great many different devices. Finally, OSMC will…

It might sound like a lazy approach to speeding up machines, but a little amount of newer hardware can sometimes lead to a big performance boost. Our best advice to anyone looking for a speed bump is to install more RAM. Use the free -m command to display the total and available amounts of RAM. Low figures in both the column might be the issue for your dismal performance. Before you go shopping, figure out the type of RAM installed in your machine and its clock speed with the sudo lshw -c memory command. Also remember that your computer has a certain number of RAM slots or banks into which you can insert chips. Another piece of hardware that’ll have a significant impact on the performance of your installation is…

While we don’t expect many distros to bring back the package selection section in their installation process, it was nice of Ubiquity to offer a minimal installation option. It’s been a permanent fixture since the Ubuntu 18.04 release. When toggled, the minimal install option only copies the bare essentials, giving you the flexibility to build your system yourself. You can avoid installing over 80 packages of bloat: all you get is the GNOME Desktop, Firefox and some core utilities. Once inside the installation, you can use the package manager to pull-in lightweight, responsive apps instead of their heavyweight and lethargic defaults. While the minimal install comes with the GNOME desktop, it’s a good idea to replace it with a snappier alternative to speed up your installation. Xfce is a popular…

Since this interview, EdgeX Foundry has become part of LF Edge (https:// lfedge.org), Linux Foundation’s umbrella organisation which aims to further the Edge unification and interoperability about which Jason spoke so eloquently in this interview. LF Edge is supported by key industry players including Arm, AT&T, Dell EMC, IBM, Intel and Zededa. Besides EdgeX, other LF Edge-hosted projects include Akraino (mentioned), Baetyl (for connecting cloud-native applications), Fledge (for industrial edge applications) and Project EVE (The Edge Virtualization Engine). EVE connects a type-1 hypervisor with optimisations and hardening designed especially for running on edge and IoT devices. You can read more about it in a future issue when the transcription Jonnibot gets round to typing up the interview he just enjoyed in Lyon with none other than Erik Nordmark, cofounder of,…

While the tools covered in the feature work at a deeper level than the filesystem, there are a couple of handy utilities that are experts at recovering files from particular filesystems. First up is the extundelete tool that can hunt for files in ext3- and ext4-formatted partitions. You can use the tool to restore a single file. Assuming you know the name of the file you accidentally zapped (deletedfile.jpg), you can restore it with: The restored file will be kept in the RECOVERED_FILES directory. You can similarly restore all files inside a directory: Then there’s ntfsundelete, which is designed to recover files from an NTFS filesystem. Assuming /dev/sda5 is your NTFS-formatted partition, in a terminal enter: This will display a list of files it has found. You can also use…

Your camera or phone might have a built-in HDR mode, which does much what we’ve seen here but behind the scenes. For the best results, though, there’s no real alternative to investing some time and effort. We said the human eye has a dynamic range of a few thousand to one, but it can actually be larger. That figure refers to the range that can be perceived in a single scene, but it’s billions to one if we compare bright daylight and night-time scenes. Monitors with HDR capabilities are gradually becoming available, at a price. They might not be able to display as many tonal values as a proper HDR image contains, but they’re a step in the right direction.…

When you start your computer, GRUB flashes by too quickly for most users, so the look of its boot screen is plain. If you do want to have a nice screen (see the LXFDVD for an example), you can add a theme. The structure is simple: all files need to be put in /boot/grub/themes/<theme-name>. You need one file in this directory named theme.txt and all pictures you need for your theme. To use the theme, add GRUB_ THEME=/boot/grub/themes/<theme-name> to your /etc/default/ grub and GRUB will use it. The file itself points to your graphical resources; images and icons must be in PNG format. Most of the items are easy to understand, though you will probably need to experiment to make it look good. An alternative is the grub-customizer, a small…