Linux FormatOctober 2015的目錄

Jonni Bidwell It’ll take a cataclysmic event to stop me using Arch, but I was really impressed with the latest elementary OS beta. It’s a slick combination of old and new desktop styles with all the good bits of Ubuntu under the hood. It won’t scare newbies, but meddlers will be well served by the tweak tool. Les Pounder My favourite distribution of 2015 has to be Mageia. As a long time Debian user I was truly surprised at just how good it was. Mageia has the right balance of power features and manages a gentle learning curve for new users. Download the image and take it for a spin! Nick Peers I chose Minibian to power my Raspberry Pi 2, it’s a minimalist version of the official Raspbian distro,…

Linux 4.2 is out, with Linus Torvalds marking the occasion with a rather brief message that somewhat explained the delay: “So judging by how little happened this week, it wouldn’t have been a mistake to release 4.2 last week after all, but hey, there’s certainly a few fixes here, and it’s not like delaying 4.2 for a week should have caused any problems either” Despite the brief message (which you can read here: http://bit.ly/Linux4_2Out), Linux 4.2 is one of the biggest kernel releases ever – at least in terms of contributors, with kernel developer Jonathan Corbet announcing at LinuxCon that 1,569 developers contributed code and 277 of those were making their first-ever contribution. So what’s new with Linux 4.2? The new AMDGPU kernel driver is now mainlined, and brings support…

“The last few months’ progress on LibreOffice has been brisk. We released a new major version, 5.0, that includes all manner of important interoperability and functionality improvements. I was particularly encouraged by the Calc features – finally being able to import formulae that use newish Excel table referencing. Calc also added new scientific and engineering number formats, whole column references, new spreadsheet functions, improved interoperability and more. Another good thing to see out in the wild is PDF signing and time-stamping, a crowd-funded feature implemented by Collabora. From an interoperability perspective there are fixes across the board to the Microsoft Office filters, as well as being able to rescue Apple Pages files from poor recovering iPad users, thanks to the Document Liberation Project. There are many more features, fixes and…

I accepted your challenge in LXF199 to build my own system, having ascertained the cost would be comparable to a ready-built appropriate for my basic needs. Thanks to the motherboard manual it was straightforward to switch off Secure Boot and streamline the boot process. Transferring OpenSUSE from a USB flash stick took just a few minutes. The suggested partitions put everything on the hard drive, so I had to modify manually the allocation to put swap and root onto the SSD and leave home on the HD. The new machine boots up in around 10 seconds, so a good result thanks to your article. Leslie Swan, via email. Neil says: Excellent news! There’s something really satisfying about powering up your first self-made PC. It also gives you the confidence to…

Piwars The battle is back for 2015! This year sees a slightly different series of challenges for robots to tackle. This event will see robots from around the UK converge on Cambridge on December 5 to complete a series of challenges that test both the robots and the teams that create them. The teams have already been chosen for 2015 but spectators (kids under 16 go free) are welcome to enjoy the event. http://piwars.org Thinking Digital Manchester This is a two-day conference (November 2 and 3) full of inspirational talks lead by big names in the tech industry. Normally this event takes place in Newcastle Upon Tyne, but this year it’s shifting to Manchester. Thinking Digital attracts entrepreneurs, creatives and innovators who will discuss their specialist area of the technology…

A common issue with SSD drives in Linux is TRIM support. Trimming enables an SSD to handle garbage collection overhead, which would otherwise significantly slow down future write operations and lead to accelerated SSD wear. XFS, ext4 and btrfs are known to support TRIM, but sometimes you need to take a few extra steps to make it work correctly, eg ext4, XFS and btrfs enable TRIM after adding discard to their mount options in /etc/fstab (many recent distros automatically use discard with SSD). You can also apply discard on-demand on btrfs via the fstrim command. ZFS doesn’t benefit much from running the whole pool on SSD drive, but an SSD can improve a pool’s performance in a real-life ZFS implementation with multiple physical drives. ZFS uses a logging mechanism to…

Although some mainstream vendors – such as Dell and Lenovo – have joined the ranks of region-specific vendors, – such as System76 and ZaReason – in offering pre-installed Linux computers, for the majority of users a distro’s installation process is still their first encounter with Linux. A few releases ago, the Fedora project overhauled its Anaconda installer, which now employs a ‘hub and spoke’ model instead of a linear wizard. It isn’t the most intuitive installer in the business and it’s taken a few releases to stabilise but can even be used with disks with complex layouts now. Advanced users can use the Anaconda to create a LVM partition scheme but unlike some other installers it doesn’t offer an option to upgrade to a new release. However, the distro’s new…

Ubuntu, Mint and Fedora produce installable live CDs only, while Mageia and OpenSUSE also have install-only DVDs. All these distros support multiple desktop environments (DE) in different live CDs. However, none of the live CDs allow package selection. OpenSUSE and Mageia lead the others for flexibility as they both offer multiple DEs. Mageia offers the most options, although they both default to KDE. Once you’ve picked the DE, both distros enable you to select groups of software for various desktop functions, such as office, multimedia and gaming etc. Furthermore, both distros allow you to install server-specific packages for a web server, database server or a firewall gateway. Finally, you can use both the installers to fine-tune the package selection and even choose individual packages for installation. Beyond package selection, all…

These days all the top distros offer polished versions of multiple mainstream desktops. Ubuntu is somewhat of an exception in that it only includes and supports its own Unity desktop in the main Ubuntu release and offers other non-Unity desktop as officially supported spins. While the Unity desktop has had numerous usability tweaks and improvements, the desktop still looks different and disorientating to first-time users. If you’re willing to adjust, you’ll find Unity is well put together and is integrated nicely into Ubuntu. Fedora, in many respects is Gnome’s flagship desktop and the main Workstation release ships with this desktop. The Gnome 3 desktop is even more disorienting than Unity and you’ll most surely have to tweak it before use. Unlike some other Gnome-based distros, Fedora ships with an unmodified…

The three distros we’ve compared on this page, above, all work to reduce the pain of building your system from scratch, which would normally be required by their base distros. However, both Gentoo and Arch are wonderful rolling release distros that give pervasive control to their users for building a system from the grounds up. Sabayon is perhaps the best Gentoo-based rolling release distro that allows inexperienced users to test the powers of its venerable base. Sabayon’s strongest feature is the Rigo Application Browser, which is a wonderful graphical front-end to Gentoo’s entropy package management system. While fleshing out the distro isn’t a tedious job, the distro loses out because of its odd package selection. If you are looking for a rolling release distro, irrespective of its base, both Antergos…

Freely licensed open source software (FLOSS) is largely running the internet, as well as all the hard working LXF writers’ machines (and maybe some of their brains too). Free software was relatively common throughout the ‘60s and early ‘70s too: programmers (rarer and even hairier than today’s species) typically worked on leased mainframes that came with source code provided (although IBM eventually put the kybosh to this practice). Academicians co-opted one another’s code in the name of not re-inventing the wheel, and likely never gave credence to the idea of privatising or monetising their programs. Bill Gates’ 1976 Open Letter to Hobbyists, (http://go2.pt/jAGeja) besides making people feel bad for pirating BASIC, engendered the idea that all software should be paid for, and its source code kept from prying eyes. The…

This month I found myself in the darkest depths of Cornwall. Well, not too far from the A39 to be honest, but deep and dark enough to have no phone signal, let alone the 4G I’ve become accustomed to. This was a working holiday (the blessing and curse of working for yourself). So Wi-Fi was a must when booking and the farm we planned to stay at assured us it was available, albeit shared between properties. Turns out this meant there was a small wooden ‘office’ at the end of the garden where the router sat. This could be visited when needed, making it the internet equivalent of an outside toilet. Unfortunately, the router’s weedy Wi-Fi signal couldn’t penetrate the walls of the farmhouse we were in (which were thick…

The Linux-verse is populated with thousands of software titles and most of them are small projects led by a handful of people, who are doing it out of personal interest or as coding study. Large projects run by one person, on the other hand, are rare and easier to count; Kdenlive is definitely one of them. Since 2002 the project has had ups and downs, but has grown steadily into a professional video-editing application. By 2011, the codebase was in need of refactoring and the team decided to create a new branch for the next version. However, the changes were so vast that in 2013, the project leader Jean-Baptiste Mardelle abruptly disappeared, prompting much speculation (including that he’d been kidnapped by a gnome). The reality was simply that he’d taken…

On Saturday 5 December, 32 teams will gather at the Cambridge Computer Laboratory to take part in this year’s Pi Wars, the Raspberry Pi challenge-based robotics competition. The teams will build Pi-powered robots and then pit themselves against our (non-destructive) courses. A few of the challenges have been changed this year. Our obstacle course has been changed: the Sumo battle has been replaced with a robot vs robot duel called ‘Pi Noon’ and Golf has been replaced with Skittles. Returning to the competition are: the Line Follower course; the distance-sensor challenge Proximity Alert; the Speed Test and the autonomous Three Point Turn challenge. As well as these main challenges, we will be looking at the aesthetics of the robots, build quality, code quality and sheer blinkiness! All of the challenges…

Before the Pi, before the Amiga, and before the IBM PC there was the DEC PDP-8/I a (just about) desktop-sized business computer that was the first commercially successful machine of its type. Launched in 1968 these were used until the IBM PC in 1981 made them obsolete. A fan has recreated a faithful Pi-powered copy. It’s mad, it’s pointless but it sure is clever. It’s also open source hardware so you’re free to create your own! http://bit.ly/LXFpipd.…

We set up an SSH server on our Raspberry Pi at the start of this project, so now let’s use it to remotely control our robot. On Linux we can run the ssh command from the terminal. To SSH into our robot we need to know its IP address, which we wrote down earlier, and the name of the user; typically pi for a Raspberry Pi. We then type the following into a terminal to proceed: $ ssh pi@IP ADDRESS . Replace IP ADDRESS with your Pi’s IP. You will be prompted for the Pi password, which is typically raspberry, and once logged in any command entered will output on your Pi. Navigate to the directory where you saved the robot.py and test.py files. To run the test code in…

Although the Raspberry Pi 2 packs quite a punch, there are some tweaks you can do in OpenELEC that result in smoother playback. For starters, you can turn down the video playback resolution to 720p, especially if your HTPC isn’t connected to a Full HDTV. Head to Settings > System > Video Output, and change the Resolution option to 720p. Another trick is to replace the default skin, which was designed for desktop computers, to a lightweight skin, such as Aeon Nox, which makes navigating the menus snappier. To change the skin, head to Settings > Skins. Also make sure that hardware acceleration is turned on. Go to System > Video > Acceleration and check that the Decoding Method is set to ‘Hardware’ and not ‘Software. While you’re here, also…

1 Tweak the taskbar The Cinnamon’s taskbar is called the panel and is split into three sections: menu button, app shortcuts and applets. You can pin app shortcuts to it by clicking ‘Menu’, right-clicking the app shortcut and choosing ‘Pin to panel’. Right-clicking the panel reveals more options, like adding new applets or adding a second panel (choose ‘Modify panel…’). 2 Customise look and feel Click the ‘Menu’ button and select the ‘System Settings’ button to change the way Cinnamon looks. In the Appearance section, you can change the background and system font (you’ll see options from other desktops you’ve installed too). Selecting Themes and clicking ‘Add/remove desktop themes…’ you can download more themes to pick from. 3 Change behaviour Hot Corners enable you to specify actions that occur when…

You may be scratching your head here, wondering if I’d forgotten about you guys. However fear not! There’s only one major change that you will need to make, which is simply to switch out the yum command with the apt-get (the Ubuntu/Debian equivalent) command whenever you come across it in the tutorial. Yum, being a command-line package handler tool that works with Red hat Package Manager (RPM), is different from its Debian/Ubuntu counterpart, the Advanced Packaging Tool (APT). However both the Yum and apt-gettools are very similar in that they access software repositories (which are basically large sets of software packages) to get their information, which are either located locally of over the network. Ubuntu and Debian both support SSH protocol of course, and the subsequent steps for accessing and…

Our expert Mihalis Tsoukalos is a Unix admin, programmer, mathematician and DBA, who, as you might imagine, enjoys learning new things then writing about them for LXF. Networking Learn about netstat, netcat and lsof for network troubleshooting This article is about three command line tools that are related to networking: netstat, netcat and lsof. Netcat (nc) is a powerful and very useful Unix utility that reads and writes data across network connections, using either TCPor UDP[see page 84 for a full explanation]. The majority of its command line options don’t require root privileges to operate, which is very useful when you don’t have administrative privileges on a machine. You can easily install netcat on a Debian system by executing $ apt-get install netcat-traditional as root. There’s a slightly different netcat…

The utility netcat enables you to specify a range of ports when doing port scanning. The next command tells netcat to scan the 192.168.2.1 address using a range of port numbers from 20 to 40: The –n option tells netcat to disable DNS lookup for the given IP address, whereas the –z option tells netcat to send zero data, which makes netcat close the connection as soon as it opens it without sending any data. Please note that you cannot use a port range to make netcat listen to multiple port numbers with just one command – in order to make netcat listen to multiple ports, you should run many netcat processes. The following script will do the trick: Note: please run this script with a great amount of caution…

For services that use a simple line-byline text-based protocol, you can use telnet as the client for initial testing. Normally telnet will connect to port 23 and begin the telnet DO/DON’T WILL/ WON’T protocol negotiation. However, if you specify a port number on the command line it will simply connect to that port and ferry lines of text back and forth to the server. That’s essentially all our rot13 client is doing. We’ve used telnetin the past to verify operation of several services such as smtp and http. There’s also a nc (netcat see p80!) which is a general-purpose TCP tool that can be persuaded to act as either a client or a server and even to do simple port scanning. Comparing the two, telnetis designed for interactive use whereas…

Elixir supports two types of strings: single-quoted and double-quoted which mainly differ in their internal representation. Double-quoted strings are what is usually called a string whereas you can think of single-quoted strings as a list of characters. Therefore, libraries and functions that work with strings expect to work with double-quoted strings only. In Elixir terminology, double-quoted strings are binaries, which are sequence of bits. Double-quoted strings are stored as a consecutive sequence of bytes in the UTF-8 encoding. You can escape special characters with a backslash which is a common practice in Unix. Here’s a list of useful string-related functions: length() finds the length of a string. lstrip() removes leading space. rstrip() removes trailing space. strip() removes leading and trailing spaces. printable?() finds out if a string contains only printable…

We often give a solution as commands to type in a terminal. While it is usually possible to do the same with a distro’s graphical tools, the differences between these mean that such solutions are very specific. The terminal commands are more flexible and, most importantly, can be used with all distributions. System configuration commands often have to be run as the superuser, often called root. There are two main ways of doing this, depending on your distro. Many, especially Ubuntu and its derivatives, prefix the command with sudo , which asks for the user password and sets up root privileges for the duration of the command only. Other distros use su , which requires the root password and gives full root access until you type logout. If your distro…

It’s that time of the year when we feel it’s right to look back and smash all the best distros together and see which is left standing! This year there’s a big shadow over the distro world cast by the new Canonical IP policy. We’ve asked for a licence and were told we don’t need one to distribute vanilla Ubuntu images, which is lovely but what if we don’t? So no more megamixes. It’s an important issue, not just for us, as it could ultimately entirely change the distro landscape as we know it. As we’ve looked at in the past, Ubuntu is responsible for more distros than any other. Technically they’re all fathered by Debian, but Ubuntu brings so much to the party it is fair to say many…

Not long after the announcement of the Linux Kernel 4.2 (see above), the Ubuntu kernel team announced that Ubuntu 15.10 will be based on it, with packages being pushed throughout September and a kernel freeze planned for October 8. Although Ubuntu 15.10 will stick to the Deb packaging system, the new version will use Snappy technology for packaging as well. The Serverwatch website posted a video interview with the head of Canonical, Mark Shuttleworth (http://bit.ly/ShuttleworthOn15_10), where he explained some of the upcoming features of Ubuntu 15.10, including the thinking behind supporting both snappy and Deb packaging schemes, and how the two will work together. OpenStack Liberty will also be shipped with Ubuntu 15.10, but with OpenStack 2015 2.0 (Liberty) releasing just before 15.10 (on October 15), Canonical has enough time…

ROBOLINUX 8.1 “XFCE RAPTOR” Robolinux 8.1, the user-friendly operating system that’s based on the ‘rock-solid’ Debian 8 stable source code and 3.16 Linux kernel, has been released and comes with updated versions of Tor browser, i2P, Firefox, Thunderbird, Kazam screencaster, Google Chrome, Google Earth, Skypeand VirtualBox 4.30. The distro only needs 185MB of RAM for the 32-bit version, and boots up noticeably faster than the previous version based on Debian 7. Find out more details and download the operating system head to: www.robolinux.org/downloads. LINUX LITE 2.6 The beginner-friendly distribution Linux Lite has had another substantial update, with version 2.6 Final bringing a brand new Linux Lite Control Center, which aims to collect everything the user needs to tweak and configure their PC into one central location. There’s also a new…

Crafting the future Makers – the Craft Council needs you. Hackspaces and makerspaces are home to many different skills, many of which are based upon a craft, eg laser cutting is a form of wood work. In the UK we’re seeing a decline in the number of students who are taking up a craft during high school and this is leading to a drop in the number of apprenticeships in trades and crafts. But, in contrast, the maker movement is gaining ground with many more makers across the globe creating projects using code and electronics. Many of these projects also use 3D printers and laser cutters, so crafting skills are changing along with digital skills and using new technologies we’re now able to fabricate components at home but these devices…

Our selection Btrs Ext4 Reiser4 XFS ZFS By default most Linux distributions (distros) stick to ext4, a successor of ext3, which was, in turn, ext2 with a journaling feature. ext4 is very fast and stable, but there are other powerful players, such as ReiserFS. This filesystem was developed from scratch by a corporation called Namesys, and sponsored by DARPA, but after the project leader Hans Reiser dropped development – largely because he’d been found guilty of murdering his wife – the future of ReiserFS became uncertain. The current situation is that we have the latest Reiser4 code as a patch to Linux kernel, but it’s not included in the mainline kernel by most Linux distros. Another rival is XFS, a high-performance 64-bit journaling filesystem that excels in the execution of…

Of course, the five participants of this Roundup aren’t the complete and final list of all filesystems available in Linux. The variety available is very impressive, as you may have come to expect from Linux, and, in fact, Linux is the most flexible OS in terms of supported filesystems. The classic stack of ext2/3/4 remains the most popular choice but you can also use a more niche filesystem, such as JFS from IBM, which both perform slower than ext4, but resists fragmentation or you could try classic Reiserfs (v3), which is still supported in Linux out of the box. For a more exotic filesystem you could try GlusterFS, which is a scalable FUSE-based distributed filesystem, which unites remote devices under one logical entity and is best to try with CentOS/Scientific…

While a distro might ship with many applications, sooner or later you’ll need to call on the distro’s package manager, and virtually every distro has both a command-line package manager and a graphical front-end. Version 22 of Fedora marked the arrival of DNF, which replaces the ageing Yum. On the desktop, it relies on Gnome’s Software Tool. Ubuntu has been leading the pack in graphical package management. The distro’s Software Center is one of the best tools for fleshing out the distro. Like most package managers, it lists, by default, only packages in official repos. But the distro includes the Software & Updates tool, which you can easily enable and add or remove additional repos, and even control how the package manager handles updates. Mint doesn’t borrow much from Ubuntu,…

elementary OS “Freya” This distro has little in common with its base distro, Ubuntu. It ships with its own home-brew Pantheon desktop and has several custom apps, including a Mac OS X-inspired dock. The distro places great emphasis on design and its Apple fixation is evident from the tools it supplies, such as Snap, a webcam app, which is similar to Apple’s Photo Booth. The distro supplies a number of custom tools, such as the GearyMail, Scratchtext editor and Audience video player, which are designed to assist inexperienced users. The distro even uses its own custom window and compositing manager called Gala, which consumes less resources than some of its peers. However, elementary OS doesn’t offer many apps out of the box and doesn’t include proprietary codecs or ship any…

Deploying and configuring a server is an involved process. The three server distros we’ve covered, above, offer convenience and flexibility, and let you build complex server installations using a point-and-click interface in a fraction of the time it would require you to set them up manually. All three have low barriers to entry and an expansive list of supported servers. In a pinch they are all relatively similar and, ignoring minor usability differences, all offer pretty much the same user experience when it comes to deploying and configuring various servers and their components. The real contest is the number of servers and services each of them offers. Zentyal brings up the rear since it offers the fewest server options, followed by NethServer and is pipped to the post by our…

Porteus 3.1 Porteus is unique in that it doesn’t offer a singular download but rather asks its users to build one via its web-based builder. The distro enables you to pick a desktop from KDE 4, Mate, LXDE and Xfce together with a host of popular software, including web browsers (there’s Firefox, Chrome, Opera), word processors (LibreOffice, AbiWord), VoIPclient (Skype), graphics drivers for Nvidia and AMD Radeon etc. Advanced users can also define and customise boot parameters, such as the tmpfs partition, and enable kernel modules, such as zram. You can use the Porteus installer to install Porteus to a removable USB drive or a fixed hard disk. Porteus is based on Slackware and includes the graphical Unified Slackware Package Manager to help users install apps. Slacko Puppy 5.7 Puppy…

A quick visit to http://distrowatch.com will inform you of the immense number of choices on offer. PCLinuxOS and Chakra Linux are two popular semi-rolling releases designed for desktop users, and both use the KDE desktop. However, Chakra is usually one of the first distros to roll out the newest KDE releases. If you like Ubuntu but not Unity, there’s Ubuntu Gnome, Kubuntu and Ubuntu Mate spins. KDE-loving Ubuntu users should also take a look at the Kubuntu-based Netrunner distro. For older hardware you may want to consider Lubuntu and Xubuntu based on LXDE and Xfce desktops respectively. Mageia’s late parent, Mandriva, has also spawned two similar distros with different objectives. There’s the OpenMandriva distro that’s two-releases old and focuses solely on the KDE desktop, and the ROSA Desktop Fresh with…

Anyone who used the earlier versions of Kali Linux will see that 2.0 no longer bundles Metasploit commercial versions in its install. This is at the request of Rapid7, who own the overall project and provide support for these versions. Kali does include the free/open source Metasploit Framework, however. Rapid7 said in a statement that this is due to the project not yet officially supporting Kali 2.0 as an install target, but that this will be forthcoming in the near future. However, Metasploit’s software can be installed via its GitHub hosted software for people wanting to try it out (without support from the vendor). Metasploit is a very powerful framework for developing and discovering vulnerabilities. Indeed, publicly disclosed issues are often accompanied by Metasploit modules which demonstrate how they can…

Whonix took part in our recent Privacy Distros Roundup in [p28, LXF196] and performed decently, though it didn’t win due to the many extra steps required to set it up. To refresh your memory, Whonix is an anonymising distro solution that’s delivered in the form of two Linux-based virtual clients: one for the gateway and another for actual computing. The idea of such a design is to separate the user system from a potentially dangerous internet connection and related vulnerabilities. The gateway component goes online and uses a set of privacy-aware tools, of which Tor is the keystone. Whonix also brings up another network interface, which is used by the workstation component for a secure connection. Both parts are based on Debian/GNU Linux and available as bootable images for different…

By the time you read this the Astro-Pi will have been on sale for a number of weeks and we understand has already sold-out its initial production run. If you’re excited as us you’ll be wanting to run the same space tests on your own Astro-Pi and we’ll have a full guide next issue. In the mean time the Astro-Pi is still on track for a December 2015 blast off in the Russian Soyuz-45S rocket. In preparation for the launch the European Space Agency has been putting the Astro-Pi through its rigorous test regime. The tests cover everything from its electrical power draw, vacuum exposure tests to vibration testing it in launch conditions and adding a protective coating to stop ‘tin whiskers’ breaking off solder joints. The complete set of…

In this project we bought a robot chassis kit from eBay that included two DC motors. These motors come assembled but require soldering two wires to the terminals for power. Soldering is an essential maker skill and it is really easy to learn, though adult supervision is essential for our younger would-be solders out there. There are many YouTube tutorial videos, but the best is from Carrie Anne Philbin (http://bit.ly/ LXF203_Solder). Soldering irons sets can be bought for around £10, but a good example is the Antex XS25 for around £25, which is a great starter to intermediate soldering iron. Soldering should be undertaken in a spacious, well-ventilated room with a clear workspace. Soldering is great fun and your local hackspace/LUG can help you to learn in a safe manner.…

Seeing as you’ve spent a considerable amount of time setting up your HTPC, it would be a shame to lose it all because of a corrupted card. To prevent this happening, you can back up all your customisations and information about your library. Kodi includes a backup utility, but we’ll use an add-on that enables us to back up files to a custom location, including Dropbox. Head to Programs > Get More and install the Backup add-on. Once installed, launch it from under Program > Backup. The program asks you to select one of two modes – ‘Backup’ or ‘Restore. When you select ‘Backup, it throws an error because we haven’t configured it yet. Click ‘OK’ to bring up the Settings window. If you wish to back up to Dropbox,…

Our expert Nick Peers has over 20 years of experience writing for various platforms, and has been dabbling with Linux for the best part of a decade. Desktop Install multiple desktop environments and switch between them One of Linux’s great strengths is its versatility, and unlike other operating systems that ability to customise extends to your desktop environment (DE). Each distribution (distro) of Linux ships with its own DE, and while they share superficial similarities – specifically the point-and-click WIMP (Windows, Icons, Menus, Pointer) interface – there can be some quite radical differences in functionality as well as their look and feel. The good news is that you’re not locked into your distro’s choice of desktop. Whether you’re planning to switch to a different distro, but are put off by…

You can install as many desktop environments as you like – aside from taking up space on your hard drive, they don’t consume any resources unless you’re actually running one. But there may come a time when you’ve finished experimenting with desktops, settled on your favourite (or favourites) and want to remove the rest. It goes without saying you shouldn’t be logged into the DE that you’re planning to remove. With that prerequisite out of the way, removing the desktop is best done from the Terminal, particularly if you plan to remove all the software the DE installed alongside itself. Here’s the two commands you’ll need: Replace ‘packagename’ with the desktop’s package name, which will be one of the following: cinnamon, plasma-desktop (KDE Plasma 5), gnome, lxde or xfce4 (Xfce).…

Answering the question of which tool to use is a rather difficult to answer. The best advice is to use the tool that you know best, provided that it is able to solve your problem. The main advantage of netstat is that most of its command line options don’t need root privileges to run. What should be clear by now is the fact that netcat does a completely different job from the other two tools. It’s a tool that can help you test network connections between two machines, as well as the quality of a connection. On the other hand, both lsofand netstatdisplay information about open ports, established connections etc on the local machine only. Each tool has its advantages and disadvantages and it’s your job as a Linux or…

Our expert Dr. Chris Brown provides Linux training, authoring and consultancy. He finds his Ph.D. in particle physics to be of no help in this work at all. For the final two parts of this series on system coding we’re going to spread our wings a little and start reaching out across the network. Specifically we’re going to write clients and servers using the so-called ‘Berkeley Sockets’ API which was originally released into 4.2BSD Unix in 1983 to provide a way to interact with the (then new) TCP/IP protocol suite. This API has remained (with very few changes) the standard for network programming. Before we get into any code, we’d like to provide a little background. First, we’ll examine the difference (from a programmer’s viewpoint) between the TCP and UDP…

Our expert Mihalis Tsoukalos is a Unix admin, a programmer and DBA. He’s a man of many hats but his favourite has ‘I heart maths’ printed on it because he’s also a mathematician. The Elixir functional programming language is built on top of Erlang VM; just as Scala is built on top of Java VM. As you can imagine, José Valim, the creator of Elixir and a former member of the Ruby on Rails core team, has tried to take advantage of the good parts of Erlang while improving or removing the less interesting and elegant parts of Erlang. As Elixir is based on Erlang VM, an Elixir program can call any Erlang function with no runtime cost. Elixir also offers a command-line utility to compile your projects as well…

When it comes to devices that could be putting our privacy at risk, the fridge that sits in the corner of your kitchen probably isn’t high up on your list of potential culprits,it’s emerged, however, that if you have a Samsung RF28HMELBSR ‘smart fridge’ you could be putting your Gmail account at risk. The fridge has a built-in display that allows the owner to view their online calendar, and that requires signing in with their Google account. At the recent DEF CON hacking conference it was found that the fridge doesn’t validate SSL security certificates when a user logs in, opening the door to man-in-the-middle attacks and potentially access to a user’s personal information. Organisers of the DEF CON event created an Internet of Things village, which included the fridge,…

Mozilla has announced that a new extension API, called WebExtensions, is to be included in upcoming version of Firefox, which will make it easier for developers of Chromeand Opera extensions to port them over to Firefox. All third-party extensions will now need to validated and signed by Mozilla, beginning with Firefox 41 while XPCOM- and XULbased add ons will be deprecated. http://bit.ly/LXFffchrome AMD is keen to catch up with its rival Nvidia, which continues its lead in the graphics hardware stakes, helped by big name games such as the Linux version of Middle-earth: Shadow of Mordor only officially supporting Nvidia graphics cards. AMD is now looking to unify its open source Radeon drivers with its closed source Catalyst ones, creating a new open source AMDGPU driver, which is included in…

Bristol and Bath LUG Meets on the 4th Saturday of each month at the Knights Templar (near Temple Meads Station) at 12.30pm until 4pm. www.bristol.lug.org.uk Blackpool Makerspace Meets every Saturday, 10am to 2pm. At Crossways Hotel Tyldesley Road, FY1 5DF http://blackpool.lug.org.uk Edinburgh LUG Meets on the first Thursday of the month at the Southsider pub, West Richmond St. www.edlug.org.uk Hull LUG Meets at 8pm in Hartleys Bar, Newland Ave, 1st Tuesday every month. http://hulllug.org Lincoln LUG Meets on the third Wednesday of the month at 7.00pm, Lincoln Bowl, Washingborough Road, Lincoln, LN4 1EF. www.lincoln.lug.org.uk Liverpool LUG Meets on the first Wednesday of the month from 7pm onwards at the DoES Liverpool, Gostins Building, Hanover Street, Liverpool. L1 4LN http://liv.lug.org.uk/wiki Manchester Hackspace Open night every Wednesday at its space at 42…

In addition to games you can download other content from both the GoG and Steam stores. GoG offers over 50 feature-length game-related films that are in true GoG-style DRM-free. While a couple of them are free, most are priced between $4.99 and $9.99 (about £3–£6). Once you’ve paid for them you can download these movies in multiple resolution, including 1080p, 720p and lower. Virtually all movies ship with additional goodies like subtitles, posters and some even offer music tracks, commentaries and more. All movies include a trailer and are flush with user reviews. On the Steam store, in addition to games, you can also buy software. The store hosts software for Animation & Modeling, Design & Illustration, Photo editing and more. In addition to software you need to purchase before…

Our filesystem contenders have significant differences when it comes to their general usage. First of all, ext4 and XFS are part of the mainline Linux kernel, which means that to use them we only need system utilities and in this case the e2fsprogs package. This package comes with every Linux distribution (distro) nowadays, so if you want to format a partition with Ext4, simply issue $ sudo mkfs.ext4 /dev/<xxx> where <xxx> is the name of your partition (eg sdc1). Our second contender, btrfs has been considered stable since 2013 and is also part of Linux kernel. The filesystem isn’t used as widely as ext4, but many distros already offer it, and some (eg OpenSUSE) recommend it as the default filesystem. The userspace utilities for btrfs are jammed into the btrfs-progs…

No filesystem can guarantee 100% protection from data corruption or loss (eg in case of outage), but our contenders differ in stability and reliability. By default, ext4 uses write barriers, which helps maintain a consistent on-disk structure even if the filesystem isn’t correctly unmounted. XFS is no less mature and reliable than ext4. It was notable for having some major bugs, eg where a user’s files would get filled with zeros after an outage, but these were fixed some years ago. The reliability of btrfs is still under question, even though the situation is constantly improving, we’d generally advise you to use the latest kernel version with btrfs. Even given the fact that some enterprise developers consider btrfs stable, it doesn’t mean that it’s ready for production. Reiser4 knocked us…

There’s a lot of very informative documentation for ext4 (http://bit.ly/Ext4Docs), which explains legacy, new and proposed feature of the filesystem and also covers all available mounting options. There’s also a comprehensive wiki (https://ext4.wiki.kernel.org) with lots of goodies of which the most compelling is the Development section. XFS is historically very different from ext4, it was developed by Silicon Graphics in 1994 as a journaling filesystem from the outset. So XFS has collected a solid library of user guides, specifications, FAQs and notes at the dedicated http://xfs.org website. Red Hat promotes XFS for its RHEL product and offers the Storage Administration Guide (http://red.ht/1MT6LOq), which means XFS has premier enterprise-level support as well. Although a relatively young project, since 2012, btrfs’ inclusion in the Linux kernel has created a superb portal (https://btrfs.wiki.kernel.org)…

The Linux-verse is teeming with distros of all shapes and sizes, and each of them is a labour of love, but not all deserve a slice of your hard disk. On the face of it, all distros borrow from the same common pool of applications and libraries and you might think they would offer pretty much the same user experience. However, a Linux distribution (or distro) is more than the sum of its parts. The mainstream distros put in many hours working on open source components to tweak and polish them to suit their particular flavour of Linux. Things were much simpler in the good ol’ days when distro choices were governed by the choice of software or function: OpenSUSE was popular for its rendition of the KDE desktop; Gnome…

Since all the distros bundle almost the same collection of tools and apps, the one factor that makes or breaks a distro is the user experience. In addition to creating custom artwork, distro developers spend a lot of time tweaking various settings and components to ensure their users get a wonderful experience. All the leading distros spend a considerable amount of effort on making sure their final product is a cohesive unit rather than a loose conglomeration of its parts. They spend time homogenising software to help the applications blend with the rest of the desktop. While the main factor that has a strong bearing on the user experience is the default desktop environment, some distros make tweaks and adjustments to the default settings to deliver a polished product that…

All three of the desktop distros we’ve rated, above, have put in a great amount of effort to polish the underlying components of their base distro to a high finish. All three feature incredibly good-looking desktops that are intuitive and functional as well. Of the three, elementary OS has perhaps put in the most amount of effort into building custom tools and libraries. Everything from the window manager up to its apps is crafted to adhere to its design principles. The one disadvantage with the distro is that it isn’t as usable straight out-of-the-box as the others. Then there’s Korora which has turned the clean slate of its Fedora underpinnings into a fully functional smart-looking desktop. The distro is a wonderful starting point for anyone, and its strength lies in…

Antergos A rolling release distro based on Arch Linux, Antergos uses the official Arch repos along with its own custom ones and offers the option to enable the community supported Arch User Repository (AUR) too. Officially, Antergos uses a slightly modified but heavily themed version of the Gnome desktop but the distro’s custom installer means you can replace it with a number of desktops: KDE, Cinnamon, Mate, Openbox or LXDE. By default, Antergos ships with the Chromium browser equipped with Flash plugin. However, during install you can choose Firefox as well as some other software that isn’t installed by default, such as LibreOffice. The distro uses Arch’s pacman package manager and you can use the graphical Pamac front-end to interact with it. Manjaro 0.8.13.1 Another rolling-release distro, which is based…

If you need a distro to support older hardware like dial-up modems, look no further than Puppy Linux. But if you’re looking for a distro to revive an older machine that’s been unable to keep up with the demands of contemporary Linux desktops, then you’ve got a few options. Tiny Core Linux is the leanest of the lot. But since the distro doesn’t ship with any real applications, you’ll have to spend time with its quirky tools converting the basic installation into a usable desktop. Bear in mind that despite the availability of applications and conveniences like automated application installers, it still takes some doing to transform Tiny Core into a regular desktop. In fact, the first application you’ll have to download is the distro installer itself, which doesn’t ship…

John Sullivan has been working at the Free Software Foundation (FSF) since 2003 and since 2011 he’s been the foundation’s Executive Director. He’s worked on many of the FSF’s outreach efforts including Defective by Design, a campaign against DRM, and Bad Vista and Windows 7 Sins campaign aimed at steering users away from freedom-hating operating systems. He’s a former debate team instructor and a contributor to Emacs. Technically he’s also in the unique position of being Richard Stallman’s boss. We caught up with him at OSCON to talk about user freedoms, the GPL, Flash, GNU/ Linux and the perils of the cloud. Linux Format: For the benefit of our readers, what’s the mission of the FSF? John Sullivan: We work to protect computer user freedom by making sure that software…

Kali comes bundled with a free version of Burp Suite, (https://portswigger.net/index.html) a java application written by Portswigger Web Security. Putting the name to one side – which is memorable, at least – the software is an alternative to the likes of the better-known proprietary Nessus. It targets web applications and, like Kali itself, is geared towards easing the workflow around finding vulnerabilities. At its most basic, Burp consists of a local proxy (which intercepts both HTTP and HTTPS traffic via a man-in-the-middle type arrangement) which can be used to observe and manipulate traffic between a locally controlled clientanda remote target. Burp canperform automated scanning and spidering of a website and will flag up vulnerabilities it finds (handily presenting them in a nicely formatted report which includes a summary of the…

A quick look at the screenshot of 2048 (right) and it might look familiar… and that’s because we’ve covered n2048in the past [HotPicks, p60, LXF188]. Unlike n2048, this sliding tile game doesn’t run in ncurses but is a QMLversion of 2048that looks as smooth and fluid. The original single-player puzzle game was programmed by Gabriele Cirulli, a web developer who pulled an idea together over a weekend in 2014. The goal of the game is to slide numbered tiles on a grid to combine them together to create a tile with the highest number possible. Technically, the number 2,048 isn’t the limit; you can reach a tile with 131,072 and 3,932,100 points. The 2048 may look simple, but many new players max out at a 512- or 1,024-numbered tile after…

Every month a new Pi killer appears, missing the point that the Pi is a community based around the support of the Pi Foundation, not just low-cost hardware. This month, it’s the Orange Pi running the AllWinner H3 SoC a quad-core Cortex A7 1.6GHz chip. It’ll run Android 4.4, Ubuntu and Raspbian but the poor support from AllWinner means no hardware acceleration. It’s an impressive system but not if the software support isn’t there: www.orangepi.org.…

Our expert Les Pounder travels the UK working with the Raspberry Pi Foundation delivering its Picademy training. He can be found hacking new project and blogging about them all at http://bigl.es. Robotics is an exciting way to introduce people to programming but it can also be a little difficult sometimes for newcomers to get to grips with as well as being expensive. Enabling anyone to create an easy to build and cost-effective robot is a significant step in their learning. So in this tutorial we shall build our own robot and create a Python 3 library that enables anyone to control it. For this project you will need: any model of Raspberry Pi; Raspbian (www.raspberrypi.org/downloads), a Wi-Fi dongle and Pi connected to your home router; a USB battery pack, a…

Your desktop is the virtual environment in which you work, and provides a friendlier user interface with which to interact with your PC. The desktop consists of a number of different elements to produce the working environment you know and love – or hate, if you’re switching. The desktop typically contains icons, windows, toolbars, folders, wallpapers and – optionally – desktop widgets. Most of what you’ll see is provided by the window manager. As its name implies it determines how the desktop’s windowing system works by taking responsibility for the placement and appearance of windows and their component parts, such as menus, title bars and control buttons. The desktop’s graphical elements – buttons, scrollbars, icons etc – are stored in special libraries. These include the widget toolkit, which is also…

Our expert Afnan Rehman has been breaking things since 1996 and messing about – and fixing things – in the Linux-verse since 2009. SFTP Take control of your files and share them securely over your network Today’s heavily online world has seen offsite storage, or ‘cloud’ storage, become a pretty big deal. However, the threats to our cyber security grow every day and many users are heading towards creating their own servers from which they can download and access documents and media. Why, you ask? Why go through all that trouble when I can have free online storage from my ISP (Internet Service Provider) or use one of the numerous free cloud storage services? The answer is simple: security and convenience. By creating your own basic file server or network–attached…

Syncthing should not normally be run as root. [Should anything?! – Ed] If you want it started at boot, you may have to modify the init script to use -u, or use your desktop’s autostart feature to start it when you load the desktop. Life is easier for users with systemd, use: to respectively start the service and have it started automatically at boot. The @ notation is Systemd’s way of passing an argument to a service file, in this case the name of the user to run syncthing. If you are running as a normal user, turn off the ‘Automatic upgrades’ option in the settings. It will try and fail to upgrade and annoy you with messages about it, which until it does work is more annoying that useful.…

IPv6 was developed by IETF (Internet Engineering Task Force) and its purpose is to solve the looming problem of IPv4 address exhaustion. IPv6 uses 128-bit addresses whereas IP uses 32-bit addresses. IPv6 is already in use and will soon replace IPv4 and become the dominant Internet protocol, so it’s good to know that all presented tools support IPv6 with the help of specific command line parameters. The lsof utility can show IPv6 connections when combined with either -i6 or -i 6 . The netcat utility can work in IPv6 mode when used with the -6 command line parameter. Similarly netstat can work with IPv6 when used with the -6 parameter. Using netstat you can see the kernel IPv6 routing table by executing the netstat -6 -rn command. Its output is…

When computers exchange binary data, it’s fair to assume that the individual bytes of a message will be received in the same order that they were transmitted. But suppose you’re trying to transmit, say, a 32-bit integer. That’s 4 bytes. Which byte do you send first? It turns out that the ‘natural’ byte order depends on the architecture of the processor you’re running on. So-called ‘little-endian’ processors, which include the ubiquitous Intel family found on PCs, store the least significant byte first, so that if, eg, they wanted to transmit the integer 0x25543ED2 (we’ve deliberately written it in hex) they would send D2 first, then 3E and so on. Big-endian processors (such as SPARC and the Motorola 68000) do it the other way round, sending 25 first, then 54 and…

Functions are considered first class citizens in all functional programming languages and Elixir is no exception. A special class of functions are anonymous functions. You must create an anonymous function by using the fn keyword and you are allowed to pass an anonymous function as a parameter to other functions or get an anonymous function as the return value of another function. The following output shows you how to define an anonymous function, connect it with a variable and use it in other expressions inside the Elixir shell: The first line defines an anonymous function that starts with the fn keyword and finishes with the end keyword and binds it to the product variable. The second line uses the anonymous function with the product.(2,3) notation. As you already know you…

This month we answer questions on: 1 Running LXFDVDs from VirtualBox 2 Firewalling a Raspberry Pi 3 Running Mageia as root 4 Transferring files to a new computer 5 CD ripping › What Windows 10 really means for Linux 1 VB + LXFDVD != VM Q I’ve installed VirtualBox on my Linux PC. I’d really like to use one of the LXFDVDs as the source for my virtual Linux installation. However, I get an error message stating that VirtualBox doesn’t recognise the disc format. I believe that it’s due to the disc being a hybrid ISO file. Can I create a standard ISO disc image from the DVD to install Linux onto a VB Linux install? If so, how can I achieve this? GeordieJedi From the forums The hybrid ISO…

Linux Format is proud to produce the biggest and best magazine that we can. A rough word count of LXF193 showed it had 55,242 words. That’s a few thousand more than Animal Farm and Kafka’s The Metamorphosis combined, but with way more Linux, coding and free software (but hopefully less bugs). That’s more than most of our competitors, and as for the best, well… that’s a subjective claim, but we do sell way more copies than any of our competition in the UK. As we like giving things to our readers, each issue the Star Question will win a copy of one of our amazing Guru Guides or Made Simple books, discover the full range at: http://bit.ly/LXFspecials. For a chance to win, email a question to lxf.answers@futurenet.com, or post it…