Linux FormatNovember 2019的目錄

After years of hard work, the Librem 5 smartphone is finally being sent to customers. It’s a smartphone built by Purism (https://puri.sm) from the ground up to support and run open-source software and with a focus on privacy and security. Running the completely open-source PureOS (https://pureos.net), Librem 5 packs in some decent specs for $699 – see the full list at: https://shop.puri.sm/shop/librem-5/. Anyone who has pre-ordered the Librem 5 should receive an email about what shipping batch their order will be included in, along with a shipping date window. The team behind Librem 5 is rightly proud of reaching this important milestone, and anyone who has been patiently waiting for their order will hopefully soon have the smartphone in their hands. “This is a big moment… Not just for us…

“Not everyone is fascinated by technology – odd, isn’t it? Those of us who are can have conversations with the others in two ways. We can show off, name-drop, try to impress: “We’ll build you a three node Pacemaker cluster and we’ll run all your apps in containers. You can move to Kubernetes next year if the app takes off”. Or we can talk their language: “We’ll build you a system that is reliable, fault-tolerant and secure. If it needs to grow to deal with more users next year, that’ll be straightforward.” Our job, as technically competent people, is to help other people use the technology in a meaningful way. Talking to them about things they probably don’t understand (IPv6, Kubernetes, attack surfaces, idempotency) is just showing off. Instead, we…

Linus Torvalds announced the release of Linux 5.3. The new kernel includes support for AMD Navi GPUs among many other new features. As usual, the KernelNewbies site has a breakdown (https://kernelnewbies.org/Linux_5.3). In particular, the write-up of the work that Dave Taht (of ‘Bufferbloat’ fame) is doing to free up additional IPv4 addresses is worth following the links. You’re so random! One thing 5.3 did not include was a seemingly innocuous small change to the ext4 filesystem intended to improve performance. Ted Ts’o (ext4 maintainer) had pulled in the improvement, which “avoids a lot of small disk requests” when performing read-ahead (opportunistic prefetching) of certain data structures on disk. This change did improve performance, so much so that on some systems there would be far fewer disk accesses early in boot.…

Q Blocked user I’m running Ubuntu Server and once I’ve created a user, I cannot log in as that user. When I run: where roroot as a group set up for read-only access to all files. So it looks like the user has been created correctly – what could be wrong? R C Ellis A You need to also set a password for that user. There is a --password option to useradd , but it requires that you give the password in its encrypted form – useradd does not do the encryption for you. This would explain the authentication failure as you are trying to login with the ‘wrong’ password. You can add the password by specifying its plain-text form by running the passwd command after adding the user: Also…

Unpowered I’ve been using OpenSUSE for many years, starting with 6.1 Professional. The last version I used was 13.1 in failsafe mode – a graphic driver problem. I write software mainly in C for electronic (www.eocs.org.uk)music devices. Recently I had to replace my old system so had a local firm build me a new one. I specified no OS. I had a copy of OpenSUSE Leap 42.3 and started to install it. After about 60 per cent of the installation, the system just hung. I tried again – same result. A dodgy DVD, I thought, so I tried Leap 42.2 from the LXF220 DVD. Same result, so I started to worry about the DVD drive. Purely by chance I happened to knock the tower slightly while the system was hung.…

The open source server distribution landscape has changed considerably since the early days of Debian and Slackware dominating the space. In the decades since, RHEL and then CentOS have carved out a considerable chunk of the pie for themselves. However, recent years have seen the rise of yet another species of server distribution clamouring for dominance. Aimed at SMBs, these modern business distributions have brought the ease and simplicity of deploying and setting up a desktop to the world of Linux servers. Gone are the days of toiling through messy configuration files. The installation and configuration of most services is now reduced to little more than a bunch of mouse-clicks. But for experienced system administrators, ease of configuration can never be the sole criterion for deciding on a distribution. For…

Ensuring maximum uptime is of paramount importance in a production server. Ideally you want a distribution with a strong foundation, a large repository of packages and a steady, thoroughly vetted stream of updates and bug fixes. It’s also important for the distribution to invest resources in hosting an efficient system of bug reporting and fixing. Although it has spent a considerable part of its existence following a ship-when-ready schedule, Debian now strives for a new release every two years. It also continually pushes out updates and patches to ensure the system remains secure. NethServer and ClearOS are both built with CentOS as the base, which is itself based on RHEL. A new release of CentOS is made available within 48-72 hours of upstream RHEL release. The latest CentOS release, version…

During our conversations we were joined by Mani Srinivasan, Sr. Product Director at DataStax, in charge of the DataStax Insights performance management tool that was unveiled at the conference. LXF: You know what NoSQL and Cassandra are good at. What’s the one thing it isn’t good at? Mani Srinivasan: Jonathan alluded to it this morning: ease of use and configuration. LXF: But that problem you’ve solved. What’s something that you haven’t? MS: Well, what we’d like to do is make the lives of the operators a lot simpler than what it is today. So we throw a bunch of metrics, we throw a bunch of things and let people interpret whatever they would want to do. What we’d like to do is to solve that problem altogether by removing the…

In most cases this is not an issue because your Linux distribution normally has only one GCC version. However, some distros like openSUSE support installing more than one version. Others, like OpenMandriva, use LLVM/Clang by default and provide GCC as an alternative. We won’t dive too deeply into comparing which compiler is better and why, but instead we’ll see how you can choose between them. The quick way is to explicitly declare which one you want before compiling: Check if you are using the right version of the compiler: For permanent effect add the first line to your ~/.bashrc, or use the alternative mechanism that most Linux distros support. The latter allows for system-wide compiler version management and selection. Let’s assume that we have the old GCC 4.9 for building…

When you import the bookmark.html file into another existing Buku database, on another machine for instance, Buku will only import unique URLs and leave all other bookmarks in the existing database untouched. In this fashion, you can easily sync the bookmarks across different devices without worrying about creating duplicate entries. You can perform keyword searches through the database with Buku. The default search options matches any of the specified keywords in the URL, title or tags and displays the results. You can alternatively run the buku -S keyword1 keyword2 command. You can also search for bookmarks using multiple tags with the buku --stag tag1, tag2, tag3 command. The tool will display all bookmarks which match any of the specified tags. The command buku --stag tag1 + tag2 will similarly display…

To improve a program’s chances of correctly identifying your media whether it’s tagged or not, you need to adopt a certain file and folder naming convention. For example, music files are traditionally stored with the folder structure Artist > Album > 01-track name.mp3. Things get more complicated when you start trying to organise your TV shows and films. Films are simpler; it’s more about the naming convention: film title (year).mp4. TV shows require organising in the same way as music: Show title > Series 1 > show title – S01E01.mp4. The good news is that these conventions should fit for most music players and media servers; the bad news comes if you’ve not named them correctly. There are variations on the standards listed above, but it helps to be consistent.…

Over the past couple of issues we’ve seen how Linux and Android get along. In the first part, we explored the ‘under the bonnet’ Linux that makes up the foundation of Android (LXF253). Then we installed Termux to set up a capable, if small, Linux shell environment. This enabled us to install some additional software, and offered a great selection of tools. But this was still only a subset of what a real Linux distribution would provide. So in this article we’re going for the full monty: installing a fully featured Linux environment, complete with graphical desktop, onto your Android device. As with Termux, one of the key technologies many of these systems employ is pRoot (https://proot-me. github.io ). In case you missed the previous instalment in this series, pRoot…

If you happen to own a Samsung phone, you’re in luck. In addition to the above options, you have an additional one that’s not only compatible with your device and not just supported, but developed by the manufacturer themselves. That’s precisely what Samsung’s (www.linuxondex.com) Linux on DeX is. Still in beta at the time of writing, this application enables you to install Linux to be used in ‘DeX mode’. What is this, you might ask? Well, Samsung offers this feature on newer phone models that enable users to plug them into a monitor – and, by extension, a keyboard and mouse. When it’s connected this way, the phone’s UI switches over to something that more closely resembles a traditional desktop. There’s a taskbar, movable windows and so on – but…

Sinclair BASIC was unusual because the instructions didn’t have to be typed in full. Instead, a system of multiple-level shifts and context awareness allowed common commands to be entered via keystrokes. We’ve seen that program instructions in BASIC are entered with a line numbers for execution later, while commands like LIST and RUN are entered with no line number so they execute immediately. Any instruction can be executed immediately, though, by omitting the line number. This means that you can use BASIC as a calculator, for example by typing PRINT COS(0) . The ZX80 was cheap at £99.95, but it was cheaper still if you bought it as a kit. Comprising the case, a printed circuit board and the electronic components, it cost just £79.95. The downside was that you…

If you’re frustrated with pure mic audio and want to make your soundtrack more flashy, you can use clever tricks to add positional sound. For instance, if you have multiple people taking turns to speak, or perhaps sound effects like tyres squealing or gunshots, you can isolate these sounds by copying them into a new track and muting their presence in the original source. Then in the new track, you can simply use the pan slider to assign their position within the stereo landscape. Techniques like these can even create stereo tracks out of old mono sound sources. This can get tricky when multiple sounds play at once, but clever use of EQ and techniques like vocal isolation (or vocal removal) can help cut out other noises and focus on…

This issue we’ll take our Minecraft pixel art into the third dimension, by building Pyramids with Python loops. We previously built some pixel art in Minecraft with two dimensions, so now we’re going to take a look at building 3D pixel art. Technically, everything in Minecraft is 3D, but our previous pixel art was ‘flat’; this time we’re adding another axis to build upwards/outwards. We’re then going to hack our pixel art into another player’s game. We’re going to start by building a pyramid using while loops and for loops in Python. The idea is that the loops will save us typing lots of similar lines of code, which will make life easier for us to create our prefabricated designs. Spawning in our coded creations is so much faster than…

If you start writing code with new packages, you are bound to get lost in the documentation for most of the time. A faster way to learn is to have samples and documentation mixed. This is the idea behind Electron Fiddle. To add Fiddle to your system, you can pick up a DEB, RPM or setup file from https://electronjs.org/fiddle. The creators of this package expect the user to use an editor for projects while getting started with new concepts using Fiddle. For this reason, there are several ways to export the code to a text file. The simplest is to save all the files in a directory, which is the standard way. The result also contains a .gitignore file so you can easily start to version-control it. Even easier is…

We’re officially too big for eight bits to contain: it’s the 0x100th issue of Linux Format, or 256 to you decimal types. Management has given the LXF dungeon server a couple of minutes downtime to celebrate and a free round of tea for the suffering staff. Are we doing anything special to celebrate? Every issue is special, but we did send Jonni off for recalibration (which he’s calling a sabbatical) and to buy a boat to live on. No, it does not run Arch. So we’ve been cast adrift on the high-sea of open source, Jonniless, like a rudderless boat, and as many other have been, we’re being pulled into the Google Chrome privacy-consuming eco-system whirlpool of despair. Thankfully Mayank Sharma has sailed to our rescue, throwing us a Nextcloud…

Could the German government be thinking of moving to open-source software? It appears so, with the Federal Minister of the Interior, Horst Seehofer, releasing an official statement (in German at http://bit.ly/LXF256GermanyIt suggests that the Federal Ministry of the Interior – Bundesministerium des Innern or BMI – is looking at some of the commercial software the government relies on – products from Microsoft, but also Oracle and SAP. The BMI has commissioned a strategic market analysis from PwC that recently published its findings (http://bit.ly/ LXF256PwC, again in German), with one of the key areas of concern being data security. With services such as Windows Server and Office 365, Microsoft is collecting telemetry data which its users have little knowledge and control over. Some of this data could include personal information, and…

“Recently I decided to purchase a new laptop, not for any good reason other than Dell had released the latest version of its excellent XPS series (the 7390) and it had been long enough since I’d picked up my last one. There are other great laptops out there (Lenovo, HP, even a few still trying to use Mac hardware like I used to for many years), but Dell has truly captured the mindshare of many open source devs in the community. This isn’t all that surprising when you consider that this is a laptop you can purchase with Ubuntu pre-installed. Sadly, however, in 2019 this still contains patches that aren’t in the upstream kernel on day one. Even now, if you were to run anything less recent than a 5.4…

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 Maidstone Hackspace We hold open evenings every Wednesday from 5:30pm to 8:00pm. https://maidstone-hackspace.org.uk Glasgow Makers and Hardware Hackers Mitchell Library, Glasgow. www.facebook.com/groups/115303729096198…

You won’t spend long using Linux before you come across a TAR file. These files, usually referred to as tarballs, are archives of one of more files. They fulfil a similar function to the ZIP files commonly used on Windows. The TAR format was originally designed for tape drives (the name is a contraction of Tape ArRchive), so TAR archives themselves are not compressed, as tape drives generally have built-in compression. However, it is normal to see tarballs with a TAR.GZ, TAR.BZ2 or TAR.XZ extension, meaning they have been compressed with Gzip, Bzip2 or xz. It is not necessary to worry about the type of compression applied to a tarball; tar will recognise it (even if the file is named incorrectly) and handle it internally. To unpack a tarball to…

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.…

Perhaps more than anything else, Linux distributions are popular for server deployments because of their stability. We’re testing these server distributions from a SMB or SOHO point of view. This is why, in addition to stability, we’ll also be looking at the support options on offer with these distributions, to assist in deployments across different use cases. Apart from the traditional roles of running web, mail or file servers, we’re interested in distributions that offer services such as VPN, control internet access, share resources among users on a network and so on. There are bonus points if the installation is straightforward and its control and configuration are a breeze. Another important factor when settling on a distribution for the server is its release cycle and update policy. Some of the…

In recent years, server distributions based on Ubuntu and Fedora have gained a hold. These are primarily adopted by administrators who don’t want to work with different systems on their servers and desktops. While these and many other distributions don’t provide a web-based admin interface, you can try your hands at Webmin. It’s a distro-neutral solution that enables you to perform routine admin tasks such as tweaking config files. Another viable option is to start with a desktop distribution you’re already familiar with. Tack on all the additional functionality you need using the software repositories. For additional security, you can then remove the desktop packages, and all the other bells and whistles that are normally part of a desktop distribution, but is out of place on a server. More than…

Since our cloud is accessible from the internet, we’ll err on the side of caution and set up two-factor authentication (2FA) for another layer of security. Once set up, it’ll prompt you for an additional authentication code in addition to the usual credentials before giving you access to your Nextcloud account. First up, install any Time-based One-time Password (TOTP) client from your mobile’s official app store. Then log into your Nextcloud server, head to Nextcloud’s Apps store and install the Two Factor TOTP Provider app listed under the Security category. After it’s installed, log out of the administrator user and log back in as a regular user. The rest of the steps will have to be repeated by all users who want to enable two-factor authentication for their account. After…

The Cassandra project doesn’t have a Benevolent Dictator For Life, but if it did that title would surely go to Jonathan Ellis. The co-founder of DataStax, Jonathan has been involved with Cassandra since the time it was open-sourced by Facebook. Once the project graduated from the incubator at the Apache Software Foundation (ASF), he served as its first Project Chair for the next six years. It was difficult to tear Jonathan from his fans at DataStax’s Accelerate conference in Washington, but Mayank Sharma lured him by disguising himself as one as well. Linux Format: You’ve always been a database guy… How did you find your way to Apache Cassandra? Jonathan Ellis: It’s true that I’ve always been interested in database technology, but I initially thought that the database space was…

Telegram is an encrypted, private messaging service with an open API that is really easy to use. In this tutorial we shall build a Telegram Bot, code that reacts to commands issued by the user from inside Telegram. Our bot will give us the latest CPU temperature, CPU usage and current available RAM for a Raspberry Pi. Software setup Before any code can be written, we first need to sign up for a Telegram account. There are many clients for Windows, Linux and mobile devices. For this tutorial it would be prudent to install the desktop client, but if you are completing the tutorial on a Pi, you can use the web version. With the account created and Telegram installed we can now start to create a bot that will…

With a Raspberry Pi Zero bodycam set up and running, you’ll probably have an eye on the limits of storage. After all, standard high definition video is going to fill up most microSD cards within a few hours. While timelapse is an alternative, it can’t be streamed – you’ll have to upload the combined video file later. A smart option, therefore, is to build the project with a Raspberry Pi Zero W (or the pre-soldered GPIO model, the Raspberry Pi Zero HW) and use your mobile device to stream footage directly to YouTube if you’re heading out. You’ll need a YouTube account to set this up, along with a channel stream key. You can find this in the Go Live option on YouTube; add it to your avconv command. It…

Because audiobooks use the same tags as your music files, you need to ‘translate’ audiobook information to music-based tags. There’s no common standard for which tags to use, so much will depend on how your audiobook player translates those tags. Try the following tag scheme: Author (First name Last name) should be Artist, while Narrator (again First Name Last Name) should be Album Artist. Use Album Title to record the book’s title. If your audiobook is split across multiple files, use the Title field to record chapters or parts (for example, Chapter 1, Part 1); if not, record the book’s title here too. Don’t forget disc and track number information if relevant. Finally, use a single genre – Audiobook – to help filter your audiobooks in other programs. All this…

In some terminals you may see a path like ‘/data/data/tech.ula/ files’. This is because on your host Android device, it’s the default storage location for UserLAnd’s data. Once pRoot starts up and transfers you into the guest OS you’ll only see ‘/home/aaron’ when browsing in PCFileMan. You might already have Termux installed and only need a specific GUI application on your Android device. If so, before going through the effort of installing one of these systems check to make sure that Termux doesn’t offer it directly. While most desktops today use the 64-bit x86-64 architecture, phones use Arm-based processors. There are some packages that, for various reasons, won’t compile across the different architectures and so won’t be available in UserLAnd.…

If you check your desktop distro’s package manager, you may find that BusyBox is available for install. On Ubuntu, it’s as easy as: sudo apt install busybox But wait, doesn’t BusyBox replace lots of common Linux utilities? Won’t this overwrite them? Fortunately, it won’t. In fact, there’s a good chance it’s installed on your machine already. It’s there in the event a normal boot-up doesn’t work; many ‘safe mode’ environments use BusyBox instead of a full set of Linux utilities. But under normal circumstances, bear in mind that while BusyBox is used as a replacement for these utilities, it doesn’t need to overwrite them. It normally requires a number of symlinks to work properly, and on Ubuntu the package’s description notes that it won’t create any of the necessary symlinks…

BASIC is often criticised because it’s not block-structured, so the only methods of flow control are the FOR ... NEXT loop, GOSUB and the much-disparaged GOTO statement. The excessive use of GOTO , it was argued, leads to “spaghetti code”. Not only is spaghetti code difficult to follow, so that maintaining the code can be tricky, but it was also suggested that it gets people into bad habits. Another BASIC concept that has questionable value for beginners – although, strictly speaking not in the language itself, but in most implementations – is the fact that it’s interpreted. In not requiring code to be compiled, it allows programmers to see the results of their labours immediately. Unlike learning to program on a mainframe, where there could be several hours’ delay between…

If you’re having trouble keeping, er, track of which track is which, colour-coding them can help avoid mistakes. Just click the track menu and choose Wave Color > Instrument 1-4. If you’re drowning in tracks and only want to focus on a select few, at the bottom of each track control is a Collapse button, which squishes up any tracks you don’t want to focus on. You’ll be using the Silence function a lot, so it’s worth learning the hot-key: Ctrl+L (Ctrl+S was already taken!). Just highlight the audio with the selection tool and hit the hotkey.…

EMAIL CLIENT Thunderbird Version: 68 Web: https://thunderbird.net You’ve got new mail! One of the greatest open source e-mail clients, Thunderbird, has seen a big bold new release lately: 68, although the previous version was 60. Don’t worry, you haven’t missed anything – it’s just that the Thunderbird development team aligned the version numbering with Firefox ESR. Although the email client has long been uncoupled from Firefox, both still share a lot of code and are perceived as companion projects. The new release introduces plenty of small visual design improvements, of which the most catchy is the revamped in-app menu. Click the hamburger icon somewhere around the top-right corner and notice that the items in the drop-down menu have been rearranged, separators were added and new icons were introduced. So far,…

Play around with different blockIDs when building pyramids or other shapes. There are some great interactive lists for finding the right blockIDs online: http://bit.ly/ LXF256blocks, or try: https://opiu.ms, finally: www.minecraft info.com/idlist.htm. If you’re not familiar with GitHub, you can use Pip to install modules to be used in Python. ‘sudo pip install minecraftstuff’ installs the module we’re using for shapes. Save your Python file in ~/home/.minecraft/mcpipy/. You can then use F5 in Python IDLE to launch the script, or type the name of it directly into Minecraft chat: ‘python filename’.…

Electron is actually a browser packaged with node.js and a few APIs. Because it’s built on top of the Chromium browser, you have everything available from there to add to your application. GitHub developed it as part of the Atom editor; it was open-sourced in 2014 and is now popular with many open source developers. Electron is practical for building small (ish–Ed), simple desktop applications since it uses web technologies. This makes it very easy for web developers to make a desktop application. It has already been used for many productivity and development applications. The obvious use case is the Atom editor which GitHub developed in parallel. Other applications lift out web pages and social media and drop them into their own application. In this tutorial, you will learn how…

Once your code is ready and you want to bless the world with your creation, you need to publish it. Electron-Fiddle has a way to do this: it uses Electron-forge. To use it, you run electron-forge make . The make command only creates a package for your own platform. If you want people on other platforms to use your application, you need more tools. These tools are called makers. Makers require fakeroot and dpkg to run on Linux. For each platform you want to send to, you need a separate package. Unfortunately, building for a Windows target requires a Windows machine with the Windows 10 SDK – which involves downloading and installing a hefty amount of software. One alternative is to use the Squirrel Windows maker; this requires mono and…

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…

Richard Stallman has resigned from both his position at MIT and as president of the Free Software Foundation, the organisation he founded in 1985. It follows controversy surrounding comments Stallman made about Virginia Giuffre – a victim of Jeffery Epstein – in an email chain sent to the MIT Computer Science and Artificial Intelligence Laboratory (CSAIL) mailing list. These comments were shared on Medium (http://bit.ly/LXF256StallmanCommentsand appear to show him downplaying the severity of Giuffre’s abuse and arguing if it should be considered sexual assault at all. Many people were understandably upset, and the Free Software Foundation announced that “On September 16, 2019, Richard M. Stallman, founder and president of the Free Software Foundation, resigned as president and from its board of directors,” and that “The board will be conducting a…

“Oh my, this is odd. It seems that the great Future Towers database only allocated eight bits to store issue numbers. So this, my first (and not to sound too pessimistic, but very likely all of our last) power-of-two issue is now issue zero. Which is not a power of two in any sane magazine-indexing number system. All that uptime obliterated by the simple act of incrementing an integer. So I’ve been enjoying a nice break, swapping the vicissitudes of magazine life for the simple pleasure of just being. Just skipping along the precipice of bankruptcy, surviving largely on foraged acorns and mushrooms, plus the proceeds of making a LXFDVD around the time of the full moon.I recall a passage from my lost tome Zen and the Art of Linux…

Lennart Poettering, the inventor of Systemd, plans to reinvent home directories. The home directory should be familiar to any Linux user: /home is where personal documents and data is stored for each user. Users of a Linux system are identified by a username and user ID number, which is stored in the /etc/passwd text database. According to Poettering, the way the /home directory works isn’t ideal. For a start, he feels the user ID number is a state, not a configuration, so it should not be stored in /etc. There are also security considerations, as when the system is suspended, the decryption key for /etc/passwd is held in memory. Thus Poettering has suggested creating self-contained home folders. A system would assign a user ID automatically, and all user information would…

“Ongoing work on the reverse-engineered Panfrost OpenGL ES driver for Arm Mali GPUs has turned the ROCK Pi 4 RK3399 SoC into a very attractive platform to try out Wayland on Arm devices using open source drivers. It’s a versatile platform that is both affordable to buy and available in multiple form factors, including system-on-module (SoM) and single-board computer (SBC). Recent work to enable RK3399 support in upstream u-boot has included adding a GMAC (Gigabit Ethernet) driver for Rockchip devices, enabling other RK3399 boards such as the Ficus EE and Rock 960, and upstreaming patches that make it possible to derive a permanent MAC address from a CPU serial number. In addition, in the Linux 5.2 release cycle, various subsystems were optimized, such as the Panfrost DRM driver for Arm…

The kernel is gaining a new set of documentation around “embargoed hardware issues” which describe how the kernel community expects to engage with CPU vendors and other hardware manufacturers in the mitigation of future vulnerabilities such as Spectre. Roman Gushchin posted a patch series titled “The new slab memory controller” that aims to clean up how Linux manages memory allocations within cgroups; Cgroups are used particularly by containers to isolate groups of processes from one another. SLABs on the other hand are used by the kernel to dole out small memory allocations in an efficient manner. The two technologies normally interact well, but there is a “serious flaw” that leads to low slab utilisation. Roman reworks the allocator to share slabs between multiple memory cgroups, reducing overhead. Lu Baolu posted…

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 visiting deity testing out Arch Linux), 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…

Unlike desktop Linux, where you’re ready to muck about with the system post-installation, server distributions require a greater degree of tweaking before they are ready for deployment. Not only must administrators contend with getting the different services to gel, they must also ensure the system is properly configured, or risk a security breach. This is why proper documentation is integral to a production server. All the distributions boast a sizeable user community and the usual host of aids that come with it, such as mailing lists, forums and so on. The CentOS wiki is home to a great number of useful Tips & Tricks as well as how-tos on a variety of topics such as installation, encryption and more. Debian, one of the oldest continuously developed Linux distributions, is also…

Even before they had a decent interface or useful features, it’s the convenience that online services offered that tricked the majority of us to entrust them with all sorts of data. So much so that the Internet giants that hosted them could create a ‘virtual identity’, even if depersonalised, from our correspondence and reading, browsing and watching habits. Slowly however, under the garb of showing us better advertisements or weeding out irrelevant content, the free of cost services started imposing them elsewhere: down-rating, shadow-banning and censoring content and competition, abusing their reach to tear the neutral fabric of the web. Many believe Google has been abusing its monopoly on the web long before it dropped the “Don’t be evil” phrase from its corporate code of conduct sometime in 2018. The…

Replace: Google Search With: Startpage (www.startpage.com) Fetches results from Google Search without passing any identifying information about the user. Replace: Gmail With: Tutanota (https://tutanota.com) Online service with open source code that offers end-to-end encryption and 1GB of free storage. Replace: Google Maps With: Openstreetmap (www.openstreetmap.org) A very usable Maps alternative based on crowdsourced data, now powering many online services. Replace: YouTube With: PeerTube (https://joinpeertube.org/en) A decentralised video platform built on free software. Replace: Google Photos With: Cryptee (https://crypt.ee) An open source, cross-platform encrypted storage silo with 100MB of free storage and affordable plans for more data. Replace: Chrome With: Tor Browser (www.torproject.org) There’s no better option if you want to avoid tracking, surveillance and censorship. Replace: Google Drive With: Syncthing (https://syncthing.net) Cross platform peer-to-peer app for syncing files between computers…

As we’ve already mentioned, the official Nextcloud virtual machine is available with various preset hard disk sizes. Other important settings that impact its performance, including the size of RAM and number of CPUs, are editable. In terms of software, the VM runs Nextcloud on a 64-bit installation of Ubuntu Server 18.04.3 LTS. Other important software includes the Apache Web Server v2.4 and PostgreSQL database v10. The developers have also made several customisation to the software inside the VM. For instance, they’ve defined virtual hosts for both HTTP and HTTPS access. The VM will also help you fetch a certificate from Let’s Encrypt during the initial setup. They’ve also tweaked PHP to allow uploads up to 1,000MB in size. Note, however, that this restriction applies only when using the web interface…

There are always practical reasons for building an application from its source code, and these include the following: 1 You could re-compile the Linux kernel to make it smaller by throwing away unneeded modules, or using custom compiler flags for better performance. 2 Compile a piping-hot fresh app that has not been yet packaged for your distribution (and for which there are no Snaps or Flatpak either). Or maybe you’re just stuck with an older Linux distribution with no newer software. 3 Compile an application with a different UI toolkit if you know there are several available options. Many GTK apps can be built with either GTK2 or GTK3 support, whereas in the Qt world you can often pick Qt4 or Qt5. A good example is the game Freeciv, which…

Just recently the Scratch Conference Europe 2019 took place for the first time in the UK – Cambridge, to be exact. Hosted by the Raspberry Pi Foundation, this conference had the singular goal of showcasing the benefits of the child-friendly programming language via a plethora of talks and workshops from experts. Just in case you didn’t know, Scratch is a block-based language that enables anyone to write code. It is mainly aimed at children, but is of benefit to everyone. Scratch has advanced so much since I first used it in 2010. Back then it was still a capable platform for coding, but in recent years there have been updates that have brought Raspberry Pi GPIO access, creating sprites from the official Pi camera, use of the Astro Pi project…

In the tutorial we created a function that would react to a command from the user and post data to Telegram. We can also use Telegram to control the GPIO of a Raspberry Pi. The code remains very similar to the tutorial code, but we use the GPIO Zero library and import the LED class, then we set GPIO 17 as the pin for our LED. We then change the message handler to look for /led-on . If that command is issued it runs the GPIO Zero code to turn on the LED. The code to turn off the LED is very similar to turning it on. Run the code and you can control an LED over Telegram! We’ve made a video demonstrating for more go see this: http://bit.ly/lxf256telegram2…

You’ll notice that the solutions in this article, as well as Termux, rely on pRoot to host the Linux distributions that run on Android. It may make it seem like pRoot itself is an Android utility, but it isn’t. It’s a general userspace implementation of chroot. What this means is that you can use pRoot to install ‘jailed’ Linux distributions on any compatible host OS. You can most likely install it from your distro’s repositories ( sudo apt install proot will work on Ubuntu), or download it from the project’s website https:// prootme.github.io. Once it’s installed, you’ll need to find a compatible root filesystem for the pRoot. The Downloads section of the site has some places where you can download these, while the Examples section shows some common command options.…

Bywater BASIC is similarly basic to Sinclair BASIC, but the two certainly aren’t the same. Perhaps most importantly, the first version of Sinclair BASIC supported only integers. This major limitation set it aside from most other dialects of BASIC, and also from later versions of Sinclair BASIC that shipped with the ZX81 and the ZX Spectrum. Bywater BASIC is also one step ahead of Sinclair BASIC in taking the first few steps towards structured programming. Interestingly, though, Sinclair BASIC had a few additional instructions of its own. While Bywater BASIC supports pixel graphics, Sinclair BASIC was able to display primitive graphics by writing characters from a special character set to specific screen locations. Because some of Sinclair BASIC’s extensions related to aspects of the ZX80 hardware, for example screen modes…

After you’ve imported a video clip in Kdenlive (Project > Add Clip), extract the audio by choosing Project > Extract Audio > Wav 48000Hz. This will export your current audio into lossless wave audio for editing with something like Audacity. Once you’ve finished with Audacity import your audio by clicking Project > Add Clip again. Any added clips will be added to the Project Bin panel. These clips can be dragged onto the main editing field, and placed on any audio or video track you like – by default, a new track will have multiple audio and video tracks ready to use. To piece together your final product, first drag your video clip onto a video track and mute the audio by clicking ‘Disable audio’ in the control bar on…

Just in case you don’t have last issue to hand, here are some handy tips for downloading and installing Minecraft and the relevant mods to get this tutorial working. Ensure you have the appropriate version of Minecraft for your distro of choice. Mojang offers pre-packaged solutions for Debian/ Ubuntu and Arch (DEB and AUR respectively), and a generic Java version for everyone else, at: www.minecraft.net/en-us/download/alternative. Next you’ll want to make sure you’ve got Python installed. sudo apt-get install python should suffice for any Debian-based distro (after a sudo apt-get update , of course). Before installing McPiFoMo it’s always best to backup your Minecraft folder first; in fact that’s a good rule of thumb to follow before making any changes. It can be found hidden in your /home as .minecraft ’.…

You can get the Electron-todo code from its own GitHub repository. There are also several other repositories that are there to help you explore all the capabilities of Electron. The whole project uses https:// github.com/electron/ as its home on the web. When you want your application to look good, pick a CSS framework that works for you. In this example spectre.css is used, but you can choose any other. All you need to do is change the class names and reference to the style sheet. To create your first Electron project on GitHub, open the website from your own account and find the template https://github. com/electron/electron-quick-start. You have several others to choose from!…

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…