Linux User & DeveloperNo. 185的目錄

Welcome to the UK and North America’s favourite Linux and FOSS magazine. I discovered recently that ‘aardvark’ means ‘earthpig’ in its original Afrikaans. You’re either going to view the release of Ubuntu ‘Artful Aardvark’ 17.10 as a grounded and pragmatic approach to moving to the GNOME Shell or as more like putting lipstick (in the form of extensions) on a pig. Send us an email and tell us what you think! In the meantime, there’s still a lot to unpack in Ubuntu 17.10, so dive into our feature (see p18). This issue we’ve got a little automation theme running, with a feature on generative artists who use, for example, autonomous programs to capture brainwaves to paint pictures from a person’s emotional state. We’ve also got a guide to the machine…

“Risk is inherent regardless of the overall quality of the software” All software has bugs. This applies to widely used open source software (OSS) like the Linux kernel, Apache httpd, or OpenSSL. And while we know how transformative collective collaboration can be when developing software, we rarely talk about the risks associated with the consumption of OSS. We’ve already proven that the quality of OSS is on a par if not better than commercially developed software in regard to defects per lines of code, but this has not reduced the impact to the users who consume and rely on the OSS the community produces. Why? The increasing complexity of the software we develop and the fact that programming is a largely human endeavour guarantee imperfection. These combined refute one of…

“Everything feels polished, stable and ready for prime-time, despite the obvious challenges of the last six months” Ubuntu 17.10 ‘Artful Aardvark’ succeeds ‘Zesty Zapus’ and marks not only a new beginning as the alphabet name convention begins to be recycled, but also a new era for Ubuntu as a product. In April, Canonical announced that its ‘Unity’ project was dead, and with it the dreams of a unified desktop, server, tablet and phone distribution. Long delayed, Unity was expected to finally reach a solid state of maturity in 17.10 ahead of a full LTS release next year in 18.04. Instead, Artful serves as a bedding-in period for Ubuntu with GNOME, an approach fans of the environment have long dreamed of and advocates of the Unity project have just as long…

Dr Bowman has designed a cheap 3D-printable yet high-quality, open source OpenFlexure microscope and stage that’s being used in a water-testing kit by WaterScope. This kit is intended to speed up water tests, by using time-lapse microscopy, and improve record-keeping, through digital verification of results, in developing countries. What inspires Richard? Most recently, he’s been inspired by Public Lab, who use (mostly) open hardware and software to enable community-driven science, mostly environmental monitoring and balloon mapping. “For me, it is one of the nicest examples of taking science out of the lab and making it accessible to people.” It helps, he thinks, that they are addressing problems that matter to the people taking the measurements, such as air and water pollution, for example.…

“The reason grep is so powerful is that it is built to work with regular expressions” Regular expressions are a common feature of many programming languages, providing a concise way of performing string matching – the process by which filter strings based on whether or not they match a particular pattern. Languages such as Perl and Java have extensive support for regular expressions built in, but they originate from UNIX command-line utilities such as the ones we have met in this series. When we first met the grep command, it seemed useful, but fairly limited in scope. In this article, we will see that it is in fact a very sophisticated and powerful tool, that can be used to perform all sorts of tasks to do with filtering text. The…

“Complex data-types can be identified by reading the code and looking for common code patterns generated by compilers” Reverse engineering is a daunting task indeed. Static, dynamic and symbolic analysis of binaries are used heavily to reverse-engineer firmwares and malware. In a world full of new threats, a non-expert on reverse engineering is at a loss. And yet, there is hope. Enter Radare2 ESIL, an intermediate language capable of abstracting architecture specifics into an evaluable strings representation. ESIL is mainly used in Radare2 for describing the behaviour of assembly instructions and for emulation. ESIL has its own registers, stack and instruction set, so you can emulate a bunch of well-known architectures within Radare2 without worrying about executing dangerous code. Naturally, it has some drawbacks (see ESIL Shortcomings box), but has…

It is fast approaching the winter holidays. Decorations, egg-nog, carols, Home Alone and, of course, Christmas is not Christmas unless you don't celebrate Christmas of course, without a festive jumper (or sweater to our US readers). The gaudier the better and extra points if it is knitted. So, how about augmenting your jumper with LEDs so that while you make small talk at the office party or throw some shapes on the dance floor, your fellow colleagues can trigger the LEDs via social media? Each time they do, your jumper will light up with all the joy of the season and send them a confirmation tweet with suitable festive image to thank them. In this tutorial, we’ll take some Christmas lights or old LEDs and write…

ABOUT Eating Robots Taken from the new book Eating Robots by Stephen Oram: near-future science-fiction exploring the collision of utopian dreams and twisted realities as humanity and technology become ever more intertwined. Sometimes funny and often unsettling, these 30 sci-fi shorts will stay with you long after you’ve turned the final page. http://stephenoram.net The broken doll had been dumped in the cellar. Thrown away without a thought for her feelings, no longer held and caressed by her owner. She may be damaged and only a doll, but it was humiliating to be discarded so easily. She’d been a part of the Internet of Things. Things – that said it all. She was intelligent. Okay, she couldn’t fly a spaceship or predict the future, but she was conscious. She felt stuff.…

“Despite making millions of euros, he is believed to have contributed less than 0.25% of code in the kernel” It seems that the GPL has a loophole. Ambiguities in the GNU Public License 2.0 have resulted in a developer with slight contributions to GPL-licensed software winning multiple copyright enforcement lawsuits. The result: a few million euros in his pocket. Patrick McHardy was once involved with Netfilter, a networking project that adds various networking benefits to Linux (such as NAT). However, in 2016 McHardy was suspended from his role for “consistent allegations from various trusted sources” concerning “the style of his licence enforcement activities on parts of the […] software he wrote.” Later, the Software Freedom Conservancy noted that “the most common criticism that we hear from those who have been…

Netplan is a handy utility used to define network configs from desktop and servers through to very complicated setups. Over time, network configuration has become fragmented between NetworkManager and ifupdown et al., but netplan has been introduced in 17.10 as the standard declarative YAML syntax for configuring interfaces. It’s backwards compatible and will enable interfaces to continue to be NetworkManager, while providing an overview of the entire system in a single place.…

“Wayland introduces a much more controlled graphics stack, which will ultimately be better performing, more efficient and more maintainable” Ubuntu 11.04 ‘Natty Narwhal’ was released, in April 2011, becoming the first version to use Unity by default, although the previously default GNOME was still available as an option. The move to Unity was hugely controversial, not least because fans of the GNOME environment feared that the change would deal a crushing blow to the project, even jeopardising its future entirely. The 11.10 ‘Oneiric’ release took things a step further, no longer including GNOME even as a fallback. In July 2012, Canonical founder Mark Shuttleworth spoke of the desire for Unity to provide a unified interface across multiple devices – laptops, tablets, phones and even TVs. Over the following five years,…

Whether your Linux laptop previously had a proprietary operating system installed, or is set up to dual-boot, you’ve probably noticed something. A niggling inconvenience that you don’t want to admit. But it’s true: your laptop battery doesn’t last as long under Linux. There are several practical solutions to this, such as keeping the device plugged in whenever possible or employing a portable battery pack, but software, behavioural changes, and tweaking settings can all contribute to improved battery life. The end result will be a laptop that keeps its charge far longer in Linux. Open your distribution’s built-in power settings to get started. The exact location for this will differ between distro and desktop environment. For instance, in Ubuntu, you’ll need to open System Settings > Power. Here, switch to the…

1 By reading a book: Practical Reverse Engineering, Wiley, April 2014 This book introduces to the reader two of the main architectures there are: x86 and ARM (think about Android), although it lacks a chapter on MIPS (think about IoT devices). The first two chapters are ideal to get acquainted with the instruction set of both architectures, with some code snippets and walkthroughs in order to apply what has been learned from the text. The sections about code patterns in order to identify certain data types (such as structures) or high-level code branching (if, switches and so on) in assembly code are simply great. Then, from chapter three onwards, the book focuses on Windows, malware reversing, anti-debugging and anti-disassembling techniques, and code obfuscation. 2 By attending conferences: Recon 2018 &…

01 Creat virtual environment The recommended first step is to create a virtual environment where you can install TensorFlow without complications from other Python modules. Use: 02 Activate it Next, activate the new virtual environment with: The CLI prompt prefix will change. Your path environment variable should now be set so that you’ll use the Python executable and other utilities stored in the bin directory. 03 Update pip In order to install TensorFlow, you need to have a very recent version of pip. You can be sure you have the latest version by using the command: Executing any pip commands will now use this latest version. 04 Install TensorFlow You can now install TensorFlow. The command: This installs the CPU-only version of TensorFlow. If you want the version that supports…

Components • Raspberry Pi Zero W with 40-pin header soldered in • microSD card • Pimoroni Unicorn pHAT • Right-angle header pins for the pHAT (8 used) • 3× 20cm female to female jumper leads • Heat shrink to disguise the three leads • Plastic box to chop up for the bracket • 1× M10 bolt to secure the bracket to the cylinder door • 1× 1930s Kodak Table Viewer • HDMI and USB adaptors (for access to monitor and keyboard) Light scripting The script on the Pi Zero W only looks for emails from a set address with specific words in the subject. Martin demonstrates how when the Pi receives a ‘redalert’ message, the script tells it to flash the LEDs red for 30 seconds. Power trim Martin realised…

The Raspberry Pi has found a cosy niche in several projects where it’s used as the computational core. This led to the Pi Foundation releasing the Compute Module, designed specifically for this use case. This month, we will build on this idea by looking at the Python project, Jupyter. Through its web-based interface, Jupyter provides a great front-end to the computational resources you have available through your Raspberry Pi. If you are using the stock Python installation, you can install Jupyter with the following commands. If you installed Berryconda, the Anaconda port for the Raspberry Pi, you can install it from there as well. Once you have it installed on your system, you will need to start it up. The assumption we’ll be making is that your Raspberry Pi is…

RAM 384MB minimum, 2GB advised Storage 16GB for full installation Specs 1GHz processor Available from: www.parrotsec.org There’s no dearth of specialised distributions that hand over a gazillion tools to the ethical hacker looking to prod the robustness of their network. Kali Linux has been the incumbent champion of this arena for quite some time now. While Kali has seen off challenges from quite a few projects over the years, the latest release of the Parrot Security OS poses a real threat to its dominance. For starters, Parrot Security has a much wider mandate than Kali Linux. In addition to the large number of pen-testing tools for performing security audits, the distro includes top-of-the line utilities to keep you anonymous and is also fully equipped to double up as a developmental…

For most of us, the download managers rolled into web browsers work just fine. But if you need more control over your downloads or want to grab multiple files or even a full website, you’ll want a dedicated download manager like HTTraQt. This intuitive app uses a wizard to create a download project which can clone an entire site, download individual files, follow links and pass authentication information. The app supports multiple modes for cloning websites. One mirrors the website as is with the default option, while the other prompts you before following links. There’s also an option that’ll create local mirrors of all websites in a page. You can pass your browser’s bookmark file to this option to mirror them all. Before downloading multiple websites, you can ask the…

Stellarium is an open source planetarium for your computer. You can use it to view 3D photo-realistic skies in real time. The software is capable of displaying stars, constellations, planets, nebulae, as well as other deep sky objects and can also simulate astronomical phenomena such as meteor showers and eclipses. Stellarium calculates the positions of the Sun and Moon, planets and stars, and draws the sky as per your location and time along with illustrative representation of the ground, landscape and atmosphere. Stellarium is available in the official repositories of most desktop distros. From its website you can grab the source tarball, and Ubuntu users can fetch the latest release from the official PPA repository. Stellarium requires 1GB RAM and a 3D graphics card that supports OpenGL 3.0 at the…

The way in which researchers monitor market share was called into question this month following the announcement that Linux had jumped to a 6.91% portion of the market. The news, based on figures from website NetMarketShare, was unfortunately inaccurate. While Linux use is certainly increasing (the share has doubled from 1.57% in October 2015 to a peak of 3.37% in August 2017), the initial 6.91% figure would have represented a stunning rise. It would also have meant a bigger share of the market than macOS! So, how did the error occur? At this point, it’s difficult to be sure. NetMarketShare conducts research by sampling data from 40,000 websites globally. The consensus is that NetMarketShare bundles Linux figures alongside those collected from Chromebooks and other Chrome OS devices. This can be…

“Rather than having to patch GNOME, we could implement our own stuff: take vanilla GNOME and add our stamp to it” “It’s strange – even six months after founder and returning CEO of Canonical, Mark Shuttleworth, announced that the Unity project was dead – to hear Unity 8 described as a “bad investment” by a Canonical employee. Will Cooke, desktop manager at Canonical, seemed quite comfortable with the new narrative when we spoke to him on release day, although he preferred to use the term ‘parked’ in relation to Unity 8 rather than closed, which would appear to open the possibility of Unity 8 being reversed out of its ‘parking bay’ in the future. His initial comment on Mir was quite open-ended as well: “Mir still exists, the display server…

Linus Torvalds announced Linux 4.14-rc7, the traditional release candidate (RC) kernel prior to 4.14 final. Except in this case, once again, Linus is likely to do an RC8. This is something he’s been pondering aloud for a few weeks, “considering the issues we’ve had”. While a delay would push the 4.15 ‘merge window’ (period of time during which disruptive changes are allowed) out into the US Thanksgiving holiday, Linus notes that “I’ll release 4.14 when it feels ready ready, not when convenient”. As we mentioned last issue, Greg Kroah-Hartman (‘Greg K-H’) announced that 4.14 will be an LTS (Long Term Support) kernel with support extended from two to six years. Thus, 4.14 will live a long life, which makes getting it right especially prudent. This is the kernel that is…

1 trying the live ISo Before you update your main installation, it’s a good idea to try the live-boot ISO and check everything’s working. Although hardware support is typically improved in new releases, there can be gotchas which mean you might want to wait before updating. You’ll notice that for the 17.10 release there are no longer 32-bit ISOs – this is unlikely to affect most users on modern hardware, however. 2 Back up your data Before upgrading, you should back up your data. We know it sounds obvious (and you have backups already, right?), but there’s always a chance that something might go wrong. Even if you just copy your most important files to a USB stick, it’s worth the effort. If you want to be ultra-efficient and give…

Within two minutes of talking to Dr Richard Bowman, in his lab at the University of Bath, he’s guiding me through the physics of tractor beams in Star Trek. He’s using it as a simile to explain the complicated subject of optical tweezers to a stupid person. He does so in a charming way, as someone familiar with explaining his complex field to journalists, but it’s clear why he’s a Prize Fellow and Royal Commission 1851 Research Fellow – his explanation ends with our imaginary tractor beam melting an object it’s trying to move before Bowman shrinks this entire sci-fi example down to demonstrate how he’s used laser beams in his past work to move tiny objects. On the face of it, Dr Bowman’s story is that he’s on a…

Arduinos are perhaps the perfect device for someone wanting to control pieces of hardware quickly but, quite frankly, they suck at doing large amounts of computation – the clock speeds are slow, the programs have a maximum size, and the RAM isn’t all that large either. In this tutorial, we are going to make a robot sentry which detects when someone (or something) enters the room by analysing before and after photos and then takes aim at it. However, tasks such as image processing, for example, are entirely unsuited to an Arduino – it’s going to need a helping hand. Therefore to construct this device, we are going to interface an Arduino with a Raspberry Pi, with each device sharing the workload, in order to detect and target an intruder.…

In the last issue, we modified our game to work according to a client-server pattern, where a server program, that hosted the game, and a client program, used by the player, could communicate with each other over a network. One advantage of creating a networked game is that we can convert it into a multiplayer version, in which multiple client programs connect to the same server. As we will see, the concept behind this is simple, but it introduces a number of tricky problems. In order to communicate with several client programs at once, the server needs to run multiple threads, modifying the shared game data concurrently. We will examine how this can lead to problems, and how we can solve them. A different problem is that individual programs must…

01 Install CUDA libraries The first step is to be sure that the CUDA libraries are installed on your system. You will need to visit Nvidia’s website to get the drivers and libraries for your particular hardware and operating system. You will also need the libcupti-dev package, which in Ubuntu is available with the command: 02 Device labelling Available devices are labelled by type and number. For example, the CPU of your machine will be labelled as /cpu:0, whereas the first GPU card will be labelled as /gpu:0. If you have multiple cards, the second card would be labeled as /gpu:1. This is how they are displayed in logging information, as well as how you refer to them in configuration calls. 03 Check device usage Since TensorFlow does a lot…

The Pi Hut’s latest add-on, the Status Board is simple yet powerful, like the Pi itself and with a board, you can monitor anything you want at a glance. The Status Board has five customisable strips, each with a green and red LED. The options are almost limitless. Do you want to be able to quickly check if your home server is online? Or perhaps you’d prefeer to monitor a value, such as your whether your investments have gone up or down? Each strip can be written on with a dry-wipe marker, so you can keep reassigning them. In this guide, we’ll focus on basic setup of your Status Board, along with some example scripts coded by LU&D and the folks at the Pi Hut. These sample scripts can be…

If you have a whole mini-cluster of Raspberry Pis, you can tie them all into Jupyter so that you can run work on them from a single interface. The first step is to install ipyparallel with the following command. If using Berryconda, you will instead need to use: You will need to do this on each Pi that is going to take part in the cluster. On the one Raspberry Pi that will be hosting the Jupyter server, you will also need to run the following command. This will enable the ‘Cluster’ tab in the Jupyter dashboard, where you can see any available clusters. You can start a new cluster on the the main Raspberry Pi, start another tab in tmux and enter the following command. This will create a…

The web is a virtual minefield laced with privacy-invading cookies and trackers. While popular browsers can be equipped to thwart information leaks, Brave ships with privacy-strengthening features built right into its core. Headed by Mozilla co-founder Brendan Eich, the Brave project promises two improvements over the competition: privacy and speed. One of them is achieved by blocking ads and trackers, which has the pleasant side effect of improving the browsing speed since the browser doesn’t have to spend time loading all the extra tracking and advertising information. But as you know, blocking ads robs many quality websites of their only source of revenue. So Brave allows you to set up micropayments for the sites you care about. It can also replace the default ads that threaten your privacy with its…

The Phoronix Test Suite (PTS) is arguably the most comprehensive testing and benchmarking platform available for Linux. It’s fairly intuitive to use and allows anyone to effortlessly stress-test a wide range of peripherals connected to their Linux computer. PTS can help you gauge the performance of graphics cards, hard disk drives, solid-state drives, monitors, processors, RAM, sound cards, and many other devices and components. You can then upload the results to OpenBenchmarking.com and also compare the performance of your devices with others via the existing crowdsourced results on the website. The PTS website hosts pre-packaged binaries for DEB-based distributions such as Ubuntu. If you use another distribution such as Fedora, you should instead grab and extract the tarball from the project’s website. While you can run PTS straight from the…

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