Inhaltsverzeichnis für No. 194 in Linux User & Developer

Welcome to the UK and North America’s No.1 Linux and open source magazine. I was chatting to Michael Meeks at the Collabora offices recently (see p12) and something struck me about his response to the GitHub acquisition. He was less interested in Microsoft as the buyer and more focused on the new CEO, Nat Friedman. Friedman has made serious contributions to the open source movement and he’s someone – along with Miguel de Icaza, a founder of GNOME – who’s attributed with encouraging Microsoft to open-source projects such as .NET. So maybe we need to give GitHub a chance? However, we know some of you are considering your Git hosting options, so flip to p34. Just to emphasise we’re not being mean, we’ve got a tutorial on Azure Powershell as…

Top 10 (Average hits per day, 30 days to 29 June 2018) This month Highlights Peppermint Based on Lubuntu, Peppermint is fast and lightweight, and uses a hybrid LXDE/Xfce desktop environment, mixing lxsession with Xfce’s panel. Deepin Formerly Linux Deepin, this distro is now Debian-based (replacing Ubuntu). The distro aims to be a good Windows alternative. Devuan GNU+Linux Forked from Debian, this project aims to be an alternative, without the issues surrounding systemd. Devuan GNU+Linux features the Xfce desktop. Latest distros available: filesilo.co.uk…

“The first prerequisite is having had a ‘Eureka!’ moment of how much containers change the way software releases work” There’s unquestionably a heap of confusion around getting started with the now-dominant container orchestrator, Kubernetes. It’s no longer a particularly new piece of software, but I think it’s safe to say that when it was first released it appeared relatively arcane. The confusion is certainly lessening and exists for a number of reasons. Don’t get me wrong; the Kubernetes community has done a great job in documenting the application, but the barriers to entry definitely still exist for some new users. I recently saw a how-to article offering people with minimum Docker experience a way into Kubernetes – and that leads me to issue number one. The first prerequisite is having…

A key feature of Collabora Office 6.0, which was released in June, is a new interoperability tool called COLEAT (Collabora OLE Automation Tool) which can be used as a drop-in replacement for legacy systems that use components such as VBA scripts. This is enabling many organisations to migrate to open source. As an example, Meeks says Ulster Hospital in Belfast, Northern Ireland, had a problem with a system called Patient Centre, created by Computer Services Corporation (CSC). The system was developed in Visual Basic 6, explained Meeks: “You can no longer really buy the compiler for VB6. You need a professional edition, and it’s hundreds of dollars on eBay as Microsoft doesn’t sell it any more. But this thing essentially screen-scrapes an HPUX mainframe service that sits at the back-end…

“The one networking skill that you must grasp firmly is tuning the firewall” Although administrators interact with real-world network hardware less frequently than they once did, familiarity with traditional networking still remains a crucial skill. In addition to grasping the underlying technology and the protocols at play, you must know how to configure your network peripherals and how to troubleshoot the connections. You should be familiar with the process of configuring networking in Linux and also have knowledge of the configuration files involved. The nature and composition of your organisation will heavily influence how you set up your network. A business that is starting out often has only one main server that pretty much provides all the networking infrastructure: a DNS, DHCP, file, mail and web server all rolled into…

“ The best work is work you don’t have to do. Eliminating work isn’t lazy, it’s smart ” As a savvy admin you should try to automate all your regular tasks, such as flushing caches and removing temp files, locking out idle accounts, backups and so on, using scripts. Scripts standardise these administrative chores and free up admins’ time for more pressing tasks. You should spend time hashing out a plan to perform repetitive tasks with as little involvement or intervention as possible. Bash and Python are two of the most popular scripting languages for automating system administration tasks. Generally speaking, lengthier scripts for important tasks such as backups and user resets are executed on a schedule. To that end, spend some time getting familiar with the time-based job scheduler,…

“VirtualBox’s VBoxManage CLI can be used to automate essential VM tasks” Perhaps the one biggest reason for the move towards computing in the cloud is convenience. You get technically superior access without the overhead of maintenance and upkeep. Cloud computing offers several other advantages to the modern IT infrastructure, and like any other resource on the network, it has to be looked after by the system administrator. There are various models of cloud services. Of these, Infrastructure-as-a-Service (IaaS) is the most pertinent to system administrators. IaaS enables businesses to purchase resources on demand, as and when required, instead of having to buy hardware outright. These are typically delivered in the form of virtual private servers (VPS) that are made up of virtualised peripherals. You should have the skills to evaluate…

One of the least interesting part of an admin’s job is to scroll through logs in order to spot potential issues. This is where log filtering tools like Logwatch come in. It parses, analyses and filters logs, and then generates daily reports on your system’s log activity. The utility is available in the official repositories of all popular server distributions, including CentOS and Debian.…

Once he’d stopped shaking his fist at Equifax, Laurent Gil (right) presented a case study of stopping a nasty botnet attack on “a very famous media site in the UK” using Machine Learning. AI is good at identifying attacks through similarities, but this attack “was almost impossible to identify, as they were burying a single request within millions of requests,” explained Gil. First, they got lucky spotting an early-morning attack, but they wanted to see if they were any patterns to what was inside the packets. Traditional techniques didn’t work in this case, such as limiting the number of requests by IP address or geolocation, as the IPs were spread across different addresses and countries. “We couldn’t even look at user agents as the guys were very smart and using…

You’re not required to have one central remote repository you push to as Git is decentralised. In fact, for some projects, it might be preferable to have no centralised repository at all; in this setup, each collaborator has their own copy of the repository, and they use tools such as Git’s e-mail support to transfer commits around. At the other end of the scale, it might make sense to use multiple remote repositories. We can use git remote add/remove to give them all descriptive names.…

PowerShell, a command-line shell and associated scripting language once exclusively for the domain of Windows Server administrators and programmers, can now run on a variety of Linux distros. The flagship of this transformation is PowerShell Core, an open source project that uses .NET Core to achieve cross-platform OS support for Linux distros such as CentOS, Debian and openSUSE, as well as macOS. PowerShell’s new features and cross-platform capabilities have enabled other PowerShell ‘cmdlet’-based libraries, namely Azure PowerShell, to become cross-platform capable. Azure PowerShell provides a broad array of cmdlets to manage a variety of Microsoft Azure cloud resources including virtual machines, app services, SQL databases, storage and networking, now with the ability to run from the Linux context. This article briefly introduces Azure PowerShell along with cmdlets to create Linux-based…

Over the previous issues, we’ve looked at a lot of different ways that you could use your Raspberry Pi. But, while we’ve developed code that was specific for each project – such as how to talk to Bluetooth devices or communicate over the GPIO bus – we haven’t really covered how to interact with people. This issue, therefore, we’ll take a look at Kivy, which is ideal for creating graphical displays and dashboards to make it easier for your users to interact with your apps. Kivy is a multi-platform library for Python that gives you the tools you need to build a GUI for your Python projects. As well as the Pi, Kivy is available on Linux, Windows, macOS and even Android – so you could take the examples given…

Go is unusual in that the names of functions and variables have a distinct syntactic meaning. Specifically, if an identifier begins with a capital letter, it’s visible to other packages that import the package it lives in. If it begins with a lower case letter, it’s only visible in its own package. This is exactly the same as the public and private keywords in C++, except that now we can tell at a glance whether something is public or private without going to its definition.…

Plasmoids (aka Plasma 5 Widgets) provide a powerful way to expand KDE Plasma. These are our favourites: 1 AlphaBlack Control is a useful widget to control the desktop theme’s accent colour, panel opacity, and the style of the taskbar’s window buttons. 2 Event Calendar is based on the Event Flow Calendar for Android, with daily weather forecasts and the ability to display events from Google Calendar. It also includes a timer and 24-hour weather forecast graph. 3 Redshift Control is a tool for enabling and disabling the redshift process, which adjusts the colour temperature of your screen according to environment. It also enables you to access the advanced settings and provides manual mouse-wheel screen-temperature control. 4 Simple Menu is an intentionally minimal launcher widget powered by the same powerful back-end…

One of the best things about KDE Plasma is that it’s instantly accessible, yet has a huge number of powerful features. Window Rules are a great example of this: not something you’d immediately think of as being useful, but a must-have when you get used to having them! Window Rules, also known as Window-Specific settings, can be access from the ‘Window Management’ section of the revamped System Settings application. They enable you to select a window using a whole host of options including application, role, type, title or even machine, then apply a vast number of custom attributes including size and position, activity, maximum or minimum size and priority above other windows. The title bar and frame can be disabled, the colour scheme changed, and opacity applied. Windows can be…

DNA replicates itself in cell division via the polymerase chain reaction which is also key to some DNA-computing architectures. Replication starts with the double helix starting to unzip itself by breaking the hydrogen bonds that keep the two strands together. As the two strands start to separate, the now un-bonded bases are free to bond to bases in other nucleotides. So long as there are free nucleotides around, this is exactly what happens – but only nucleotides with the complementary bases can create new hydrogen bonds. So As and Ts attract each other, as do Cs and Gs and, in so doing, both strands of the original DNA bond to the nucleotides necessary to replace the missing complementary strand. In time, this process produces two DNA molecules identical to the…

While they’re not a necessity by any means, we find it’s always quite handy to have a GPIO label board to hand for these types of projects. Pop the board over your GPIO pins and you can instantly see which BCM is which, without needing to refer back to a print-out or website diagram. The GPIO label board you’ll see in our photographs is available for a whopping 38p online, so they’re not exactly going to break the bank. One side is designed for the Raspberry Pi, Pi 2 and Pi 3, the other for Pi Zero models. Pop one on your keyring and you’re always prepared for some Pi modding.…

Crystal is a fairly new language which was developed to offer a Ruby-inspired syntax with a fast compiler that produces efficient native code. It seems to working too, because according to benchmarks by one programmer (https://github.com/kostya/benchmarks) Crystal is an order of magnitude faster than Ruby. Unlike Ruby, though, Crystal is a compiled language. Programmers will appreciate this because it helps them catch errors at compile time instead of causing issues when the code is put into production. This also means that Crystal enables you to ship binaries – so if the target has limited storage space, you can avoid copying the whole repository and just use the pre-compiled binary instead. Programmers will also appreciate the fact that Crystal is statically typed. Most languages don’t do any kind of type checking,…

“Netcetera is one of Europe’s leading Web Hosting service providers, with customers in over 75 countries worldwide” About us Formed in 1996, Netcetera is one of Europe’s leading web hosting service providers, with customers in over 75 countries worldwide. It is a leading IT infrastructure provider offering co-location, dedicated servers and managed infrastructure services to businesses worldwide. What we offer Managed Hosting A full range of solutions for a cost-effective, reliable, secure host Dedicated Servers Single server through to a full racks with FREE setup and a generous bandwidth allowance Cloud Hosting Linux, Windows, hybrid and private cloud solutions with support and scaleability features Datacentre co-location from quad-core up to smart servers, with quick setup and full customisation Featured host: www.netcetera.co.uk03330 439780 Five tips from the pros 01 Optimise your…

LibreOffice appears in some surprising places – that’s something you learn when you spend time with Michael. While we’re queuing up for lunch, Meeks casually mentions that D-Wave Systems, the world’s first quantum computing company, uses LibreOffice to run its training programme. It turns out that teaching people a radical new way to model problems on a quantum computer isn’t that easy. Meeks tells us that the company uses a simulator fronted by an XLSM (an Excel Macro-Enabled Workbook file) that dynamically generates elements in the document, and this uses VBA scripts. As LibreOffice now supports VBA, the suite turned out to be the quickest and most efficient way to get the job done.…

“Mastering rsync is one of those evergreen skills that’ll never go out of vogue” Data is one of the most critical parts of any business, which means managing it is one of the core responsibilities of any system administator. The key to a good storage management policy is that it should strike the right balance between keeping the data safe yet accessible. Before you can design a storage policy for an organisation, you need to understand how Linux deals with storage and familiarise yourself with the tools at your disposal. All it takes is a couple of clicks to add storage to a cloud server; provision a drive and then attach the disk to an existing VM. In the real world however, you’ll first to decide on the type of…

Webmin (www.webmin.com) is a configuration tool that can be used to control all aspects of your remote server, such as setting up a cron job, reading logs and managing running processes. Using it you can dispense your admin duties from a web interface. Instead of manually editing configuration files and fiddling with command line switches, Webmin helps you configure different aspects of your system, which then automatically update the relevant underlying config files. Webmin can manage network services as well as the host system. For instance, you can use the tool’s interface to create and configure virtual hosts for the Apache Web server, and set up a Samba file-sharing server just as easily as you can create and manage user accounts and set up disk quotas. Webmin’s intuitive dashboard contains…

1 Define a function Enter these lines in a file called fabfile.py and then call the function with fab uptime. You can also run functions on multiple remote servers with fab -H localhost,192.168.0.100 2 Change context Fabric’s context managers are used with Python’s with statement. You can use the settings context manager if you temporarily need to run a command as a different user, such as with settings (sudo_user='mysql'):. 3 Update several machines The env.hosts variable lists all computers in your network. When you call the function with fab upgrade_all it’ll connect to the remote machines, refresh their repos and install any updates. 4 Download remote logs The get command is useful for downloading logs from a remote system. This example saves them to the local PC with a timestamped…

The Virtual Machine Manager is the open source graphical front-end for creating KVM-based VMs, and is available as virt-manager in the repositories of most distributions. The app uses the qemukvm hypervisor, which is a version of the QEMU machine emulator modified by the KVM developers. The virt-manager app is written in Python and is very intuitive to operate. You can use the app to easily create new VMs, monitor them and make configuration changes. virt-manager also includes a VNC and SPICE client that displays a full graphical console to the running VM.…

1 Check on users You can use osquery to keep an eye on the users logged into your servers with the first command shown above, while the second shows the list of previous logins. Look for logins from unknown IP addresses, and even more so if there are multiple users logging in from an unfamiliar host, which should be a red flag. 2 Check firewall These queries help keep an eye on the firewall. If the first one doesn’t produce any output it means there’s no firewall – which isn’t a good thing, especially on a server. The second lists all the listening ports and will help you find back-doors on the server. 3 Check kernel You’ll also want to run these queries periodically and compare their output against older…

So far, we’ve been using the GitHub.com  site to host our Git repositories. GitHub is a great site, and it’s a very quick and easy way to get a project up and running with Git. It’s no surprise that it’s used to host a whole range of repositories, from simple personal projects to the code for Git itself and the Linux kernel. Nevertheless, Git is not tied to GitHub, and there are a number of reasons you might decide you want to host a Git repository on your own server. One reason is if you want to make a repository private. By default, repositories hosted on GitHub are public, so anyone can see the code. You can make a repository private, but only if you pay $7 per…

Savannah (https://savannah.gnu.org) is a version control site developed by the GNU foundation. As you can see from Figure 7 the site interface is a bit different from GitHub and Gitea. To get started, you’ll need to go to https://savannah.nongnu.org/account/register.php. Creating your own project and hosting it on Savannah is a bit harder. Being so closely linked to the Free Software community, Savannah is committed to hosting only software projects that are free, depend only on free software and run on free operating systems. Unlike GitHub, the software that Savannah runs on is itself free software, as are all its components. This means that if you want to create a project on Savannah, you’ll need to satisfy the Savannah team that your project is free software from top to toe. There’s…

Data breaches, malware, malicious URLs, unknown IP addresses brute-forcing our services… Ours is a hell of a job indeed. Facing these threats alone would be suicidal, so that’s why we have public APIs. These APIs are front-ends to massive databases holding vast amounts of valuable data, from cracked passwords to exposed SCADA (supervisory control and data acquisition) devices. Using these APIs is easy: more often than not all you need is a tool like curl to query them, or some basic knowledge of Bash, Python or whatever script language you fancy, in case you need more complex data-parsing. Some of these APIs have even been integrated into some open source and commercial software, too. For example, WordPress has some plug-ins to find out whether a user password has been pwned…

Until about ten years ago, nearly all of Google’s server code was written in C++. While C++ programs run extremely quickly, they are also prone to a number of problems, such as the lack of built-in support for concurrency and slow build times caused in part by the way C++ handles dependencies between modules. Google released the Go language in 2009. It was intended to resolve some of the problems it was having with C++ code, speeding up build times and leading to a more readable and testable code base. It has had a lot of success on this front: in 2012, Brad Fitzpatrick (the creator of LiveJournal and now a Google employee) decided to rewrite the dl.google.com server – from which users download Google Chrome – in Go, expecting…

Like other languages (even C), Go allows us to pass functions around as arguments to other functions. The way functions are declared means that the syntax is often easier to understand than it is in C, where such declarations are notoriously difficult to understand. For example, the equivalent of the C declaration int f(int (*g)(char c), char *p) in Go is func f(func g(c byte) uint8, p *byte) uint8. It’s easier to see what’s going on in the Go version, and becomes easier for more complicated examples. Go also enables us to use anonymous function literals, in much the same way as JavaScript. For example, we could call the above function f as f(func (c byte) { return 6 }, nil). Function-passing makes error-handling code less repetitive. For example, our…

1 Install Plasma add-ons The Software Centre has an entire section dedicated to Plasma add-ons, sorted by category, so make the most of it! Window Manager scripts provide useful inspiration for how to use Window Rules, and Plasma widgets are perfect for customising your various activities. 2 Make the most of KRunner There’s no need to manually dive through the application menu every time you want to launch an application. Provided the desktop has focus or after pressing the super key, just start typing the name of the app you want to open and hit Return when the list is suitably refined. 3 Use jump lists Jump lists enable you to launch an application directly to a specific section or feature. You can see this in action by adding the…

Terran’s first publicly released project uses a server – essentially any old desktop you might have spare – and Raspberry Pi-powered guns to create a fun infrared laser tag game for three players. Terran says the project relies heavily on Wi-Fi, which is why he decided to use the Raspberry Pi Zero W for the 3D-printed guns. What inspired you to make your own laser tag game? During the past year or two, I have been more and more interested in home-automation projects. I first created a simple infrared-relay module using an Arduino to control a fan in my house. I then began realising how easy it was to send information through infrared and wanted to take it to the next level. If I could turn on a fan using…

The Pimoroni Inky pHAT is a beautiful 212x104-pixel, three-colour ePaper (eInk/EPD) display for your Raspberry Pi, and costs a very reasonable price as well at £22 ($25). These types of display are designed to emulate traditional ink on paper. Unlike conventional back-lit flat-panel displays that emit light, electronic paper displays reflect light. In addition, the Inky pHAT maintains the image and text when the electricity is removed, thus acting as a static display. Best of all, because it’s like paper, it’s readable in bright sunlight which makes it suitable for outdoor use. It uses three colours – red, black and white – and is ideal for displaying simple graphics and crisply rendered text. The Inky pHAT can be employed as a cute little clock, it can display tweets, updates from…

Specs CPUAny AMD, VIA or Intel processor Graphics 1024x768 resolution RAM 1GB RAM Storage 15GB disk space for minimal install Licence GPL Available from https://linuxmint.com Originally based on Debian, but now built on Ubuntu’s LTS releases, Mint follows a ‘release when ready’ cycle, instead of a fixed schedule as preferred by Fedora, Ubuntu and many others. Codenamed Tara, the latest release of Linux Mint ships after nearly a month spent fixing the myriad bugs reported in the beta release. In a blog post, the Mint Team expressed gratitude to the community for the steady stream of bug reports on the beta, which helped the developers take corrective measures. This nearly zealot-like community involvement and the tireless efforts by the developers are the reason for Mint’s soaring popularity, and has helped…

Linux has no end of good FTP servers, but uftpd has carved a niche for itself by shipping with sensible defaults which work for most users. It’s designed for home users and developers who need a simple FTP server, but aren’t too particular about being secure. In fact the documentation of the project advises against using the server if security is a deciding factor. On the other hand, uftpd isn’t totally insecure and its author has implemented some common security best-practices (though not all of them, in the interests of keeping the program more user-friendly). Combined with users taking adequate precautions and defining strict permissions, uftpd is as secure as any of its peers. While uftpd supports both FTP and TFTP, uftpd’s author points to research that deems the latter…

Canonical has revealed that 67 per cent of users opted-in to the collection of desktop metrics when installing Ubuntu 18.04 LTS. Controversial upon its announcement, the Ubuntu Report tool was integrated into setup to record hardware and localisation options. Intended to help Canonical understand what systems are running Ubuntu – and how it can improve the OS – the decision to include the tool has reportedly turned long-term Ubuntu users away from the distro. That’s despite assertions from Canonical that the reporting is not an actual privacy breach (no user-identifiable information is shared), and the fact that all data is available to review by the user before it’s even sent. While some of the information revealed is a little dry, Canonical has been able to get an idea of the…

M eeks is a mild-mannered heavyweight of the open source world, who has worked tirelessly for the GNOME project for many years and was an early employee of Nat Friedman and Miguel de Icaza (one of the founders of the GNOME project) when they set up Ximian to develop the Ximian Desktop. We interviewed Meeks in Collabora’s Cambridge offices. For Meeks, Collabora is the culmination of a number of moves in the open source software business which saw him join Novell when Ximian was acquired in 2003, and work at SUSE until Collabora was formed. Tell us about your background and how you got into open source… Sure. My mother taught me to program when I was very small, which was fun. It was a BBC Micro and I got…

Linus Torvalds has announced Linux 4.18-rc4, noting that things “look pretty normal here, and size-wise this looks good too”. Release Candidate 4 (rc4) represents about the mid-way point of a kernel development cycle, which typically lasts a couple of months during which the RCs come weekly. These follow the closing of the ‘merge window’, a period of time during which disruptive changes are merged that are subsequently soak-tested prior to final release. The 4.18 merge brought in a number of new features, including Mathieu Desnoyers’ ‘Restartable Sequences’ (which we’ll cover in more detail next issue) and some additional Spectre security fixes for the Arm architecture. One important removal in 4.18 is support for the Lustre filesystem. Lustre had been a part of the ‘staging’ subtree maintained by Greg Kroah-Hartman (Greg-KH).…

1 Install OMV Installing OMV is pretty straightforward. Download the ISO, transfer it to a USB disk and run through the basic steps. Since you have multiple disks connected to the NAS box, make sure you select the right installation target during the partitioning step. 2 The web interface When you’re done, reboot the computer, which will drop you to the login shell. Don’t log in but instead head to the web address displayed on the console. This brings up OMV’s web interface, from which you can manage all aspects of the NAS server. 3 Set up storage You’ll first need to format the drives before you can use them. Head to Storage > Disks to view all the attached disks. Select the drive and click the ‘Wipe’ button. After…

1 OpenLDAP www.openldap.org All companies need a directory server and OpenLDAP is the popular open source implementation of the Lightweight Directory Access Protocol (LDAP). Despite being lightweight, it’s a fully featured suite of apps and development tools. 2 Kolab www.kolab.org Kolab is an open source, unified communications, collaboration and groupware suite. It’s built with security, privacy and user control in mind and provides solutions for an email server, directory service, web service, Calendar, Tasks, address books and more. 3 Docker www.docker.com The shiny new and popular piece of tech for managing and running apps in virtual containers is also a boon for admins. You can use it to deploy conflict-free and production-like development environments for your users. 4 MariaDB https://mariadb.org Developed by the original authors of MySQL, MariaDB is one…

1 MAAS www.ubuntu.com/server/maas Canonical’s MAAS is easy to set up and can provision Ubuntu, CentOS, RHEL and SUSE servers. It was designed to compliment Canonical’s service orchestration framework called Juju that enables you to easily deploy services with its charms architecture. 2 Foreman www.theforeman.org Foreman’s a popular choice for provisioning machines and can deploy lots of mainstream distributions. One of the reasons for Foreman’s popularity is interoperability; it can work with a host of popular application provisioning tools such as Puppet and Chef. 3 Fog https://fogproject.org With Fog you can image an installation and deploy it to other computers on the network. It also makes light of regular administration tasks such as installing software, and can manage large networks that may be spread over multiple locations.…

“ Syslog has been the standard Unix format for several years” Everything from databases to daemons keep logs of their activity and managing these is as important a function as deploying servers. It’s the responsibility of system administrators to gather actionable bits of information from this deluge of messages. Log data usually ends up in the /var/log directory in a variety of files usually placed by the syslog daemon. Syslog has been the standard Unix format for several years, but there have been a couple of replacements, with rsyslog being the most recent and popular one. Make sure you are fully versed with the configuration of the logging daemon on your servers. Another aspect of managing logs is to control their size and archive duration, which for some types files…

When creating a centralised Git repository on a remote server, the convention is to give the root directory the extension .git, as we’ve done here. When we clone the repository locally, Git automatically strips off the .git to give us the name for the repository. It’s not compulsory to use .git – Git works fine without it – but it’s widely used as a convention to distinguish between local repositories that are in active use and remote copies that exist only to be pushed to and pulled from.…

GitLab (www.gitlab.com) is a direct competitor to GitHub and a similar site in many ways. Unlike GitHub, the Community Edition is free and open source, and also enables you to create unlimited private repositories. GitLab has a web interface and its own hosting, like GitHub, but it is also possible to use it to self-host repositories, very similarly to what we did with Gitea in this article. If you’re interested in self-hosting with GitLab, there are very good instructions available at https://docs.gitlab.com/ce/install/README.html. We recommend the Omnibus installation if you’re using a compatible Linux distribution. We were impressed with the range of features available in GitLab, even in the free Community Edition, and we think that most developers will find that it gives them everything they need. It’s worth noting that…

1 Introducing MalTrail MalTrail is a malicious-traffic detection system that uses a bunch of publicly accessible blacklists, along with some static data from AV reports and custom user-defined lists to do its job.See http://bit.ly/lud_maltrail. 2 Install and start the sensor MalTrail needs Python Pcapy; install it first and then clone the repository: apt-get install python-pcapy && git clone https://github.com/stamparm/maltrail.git. Start the sensor: cd maltrail; sudo python sensor.py. It updates its data on first run. 3 Start the server You can install MalTrail on another computer to act as the server or you can use the same computer for both services. Start the server with sudo python server.py. Your computer will be listening on TCP port 8338. 4 Access the interface Open your browser and navigate to http://127.0.0.1:8338; make sure to…

In most programming languages, it is very difficult to keep track of which packages rely on which other ones. In C++, it is difficult to know when a particualr #include directive is necessary. We can delete the line, of course, but if the code then compiles it doesn’t necessarily mean that the module wasn’t used: it might be #included by some other header file. Go forces developers to tackle these problems early and often, so there is as little confusion as possible later on. In Go, for example, an unused import is not just wasteful, but will lead to the compiler rejecting the program outright. In that way, we ensure that the packages we import are precisely the ones we need to run our program, helping to keep binaries as…

Application overview hot corner Moving your pointer to the top left of the screen (and continuing to head in that direction) activates an overview of an activity’s apps The application launcher icon This launcher icon opens a menu with five useful tabs: favourites, applications, computer, history and leave Plasmoids & widgets A powerful widget system runs throughout Plasma, with the ability to easily add items to the desktop or panels Activities and apps Activities and your currently running apps are displayed at the bottom of the screen The toolkit button The button at the top right of the screen is for the toolkit. This provides useful system options such as activity and widget management The Dolphin file manager Dolphin is the KDE Plasma file management utility and a stand-out feature,…

By default, the first time you fire up KDE Plasma you’ll be greeted with a single activity. The activity switcher won’t be visible, as it only shows when you have more than one active, but if you don’t make the most of Activities, you’re missing out. To get started, press the toolkit button at the top right of the screen and select Activities. You’ll be presented with your current activities (likely only ‘default’) and a ‘Create activity’ button to add more. These are groups of applications and a unique desktop where you can add widgets. You can control how an activity is displayed, with a text name or an icon, a keyboard shortcut can be configured, and activity tracking can be disabled if you don’t want the apps to appear…

The Raspberry Pi is such a versatile little computer. Having access to the GPIO pins enables us to interface directly with any number of hardware peripherals, and in this case, create our own. Using some basic bits of tech, including a breadboard, some jumper wires and tactile push buttons, we’re going to build our own prototype video games controller that’ll work with third-party Pi games, but could also come in handy if you’re coding games of your own. Our prototype won’t be pretty, but there’s nothing to say you couldn’t 3D-print a case and turn the controller into a legitimate-looking gadget. The beauty of a project like this is that you don’t need to be an electrical engineer; in fact, you don’t need to know much more than the basics…

The Inky pHAT is ideal for displaying information or data in real time. For example, why not create a Twitter display that notifies you of your incoming tweets, mentions and hashtags? If you’re an avid surfer, sailor or just generally like the sea then why not build a tide display. This project pulls down tide data from the Met Office and presents it in a good-looking way: http://bit.ly/lud_tides. Finally, if you like your art then consider making some graphics of your favourite game, film or anime character: see http://bit.ly/lud_art for a tutorial. You could probably even create digital Inky pHAT versions of some classic paintings such as the Mona Lisa, The Starry Night or The Scream.…

Cinnamon is the shell or user interface of the popular Cinnamon desktop. This component is responsible for the various elements you see in the desktop environment, including panels, menus, hot corners and such. Cinnamon’s user interface is written in JavaScript and its core libraries are written in C. The Cinnamon project is headed by Linux Mint, but the desktop is developed separately from the distribution. One of the main reasons for the desktop’s popularity is that it adheres to the traditional desktop metaphor with a single panel located at the bottom of the screen, a design reminiscent of GNOME 2. The desktop environment is made of several components such as the Muffin window manager, the Cinnamon Control Center and the Cinnamon shell. Most of the work in this minor new…

System monitoring is an essential task for any user. Although you’ll find several system monitors in distribution repositories, Stacer offers the added benefit of an attractive user interface that’s intuitive to navigate. Besides monitoring, you can also use the app to optimise and fine-tune several aspects of your installation – much like Bleachbit, but with a much nicer interface. Stacer has a PPA repository for Ubuntu and also hosts precompiled RPM and DEB files in addition to an AppImage for other distributions. The app’s dashboard displays information about the system and has dials to depict the activity levels of the processor, memory and disk, along with bars for download and upload speeds. You can also configure the app to alert you in case the readings on any of the dials…

It’s embarrassing,’ said Nialle as he put his empty coffee cup down. She picked up his cup and put it in the sink. ‘Yeah, but it’s a seriously cool jacket,’ she said. He shrugged and lifted the wearable tech jacket from its hook. He turned to kiss her goodbye, brushing the hair from in front of her face and kissing her hand by mistake as she also tried to brush it away. She chuckled. ‘You’ll be glad of it once you’re on that crowded train.’ She was right, as always, and he knew it. But, that didn’t make him cringe any less at the thought of using it. He shouted as he closed the front door, ‘See you tonight.’ She shouted something back, but he didn’t catch it. At the…