Linux FormatOctober 2016的目錄

Jonni Bidwell I have built up a series of false identities between which I alternate depending on the corner of the internet I’m visiting. There’s Pirate Jo (a scurvy seadog with a penchant for correcting people’s grammar), Sloop John B (a die-hard Beach Boys Fan) and Long John Bidwell (don’t ask). Neil Bothwick Apart from the obligatory tin foil hat and matching (and very uncomfortable) underwear, I always have a browser tab open and spoofing as IE6. That should keep the script kiddies so busy they don’t see the important stuff, although it does slow down my network connection a little. Nick Peers LastPass, the popular password manager, would be my response if that was allowed in this case, but it’s neither open source or (in the way I use…

We don’t like starting a news story with the line ‘Google is up to something’, but Google isup to something. It’s been revealed that a project known as Fuscia could be a completely new operating system that the search giant is working on. Code has been added to Google Git (https://fuchsia.googlesource.com), which highlights some interesting features of the OS. One thing that’s missing is any reference to the Linux kernel, which means that this operating system could be a complete departure from Android and Chrome OS, Google’s other operating systems that are based on Linux. Instead, the OS uses the Magenta kernel, which is based on LittleKernel (https://github.com/littlekernel/lk), which is designed for embedded systems, so there’s a possibility that Google’s OS could be aimed at Internet of Things and other…

“It started innocently enough. There I was, setting up myVPSwith Docker,getting my blog and other services running. Eventually, it came timeformetoinstall OwnCloud,soIheadedoverto Docker Hub to look for the right container to pull. I looked at the most popular container that wasn’t the official one providedbyOwnCloud,whichturnouttobeNextCloud. There have been a few famous forks to note. LibreOfficeandMariaDBforkedfromOpenOfficeand MySQL respectively, after Oracle acquired those two. Morerecently,theChromiumteamstartedBlink.Plexis aproprietaryforkofKodi.EventhepopularWordPressis aforkfrom b2/CafeLog. Fear the fork? Forking a project can create a lot of strife, as developers are often forced to choose sides by deciding which project they will contribute code to. Users are faced with problems whenever there‘s a fork, too. Users of the old software have to choose whether to continue with the current product or switch to the new one. Compatibility becomes an issue…

Having doubts over Windows and its download shenanigans and its unpredictable behaviour, I decided after some thought I would try Linux. We have two Lenovo tablets, an HP laptop and a Dell Optiplex 745 desktop donated free from my sister, so I purchased your magazine with the 16.04 disc, tried the disc, that did not work on the laptop, so I went on the Linux Mint website and proceeded to download Mint 17.3 Cinnamon 64-bit as recommended, but as the website runs at walking pace here, some of the data was missing… Off I went to work and decided to try a download on my work computer. As I was doing this, an IT friend asked what was up and instead he did two discs: one Cinnamon and one Ubuntu…

Four out of five of our printers are FFF (Fused filament fabrication), which means that there’s a huge variety of materials and colours that they can use and print, whereas the SLA (Stereolithography apparatus) is limited with less than ten options. The FormLabs Form 2 is a bit of a surprise, as although you only have a choice of five materials (standard, castable, flexible, tough and dental) each resin is aimed at a practical use. You don’t get a choice of colours but you do get materials that will enable you to cast, prototype working devices and print yourself a set of new teeth! The Lulzbot Taz 6 takes most filament materials at 2.85mm and the hot end will reach scorching temperatures of up to 300 degrees. The list of…

“If credentials fall into the wrong hands then things can get ugly quickly.” Whether it’s pesky nation states taking an interest in Auntie Ethel’s dark web browsing, ad networks tracking users’ daily surfing routines or hackers in Eastern Europe hijacking Amazon accounts and ordering bulk confectioneries, there’s plenty to be wary of online. With so much of our lives lived online, if systems are compromised or credentials fall into the wrong hands then things can get ugly pretty quickly. Most banks will act quickly to cancel cards when fraudulent transactions are detected, and generally they will provide refunds, though the process is tedious. But there are other risks as well, chief among them is identity theft. Convincing someone that the person that’s claiming to be you was not, in fact,…

We mentioned uploading your key to a public key server earlier. If you have someone’s public key, then you know that only the holder of the associated private key can read any encrypted messages you send them. The trouble is, unless you conducted the key exchange in person, there is no guarantee that the public key belongs to whom you think it belongs, it could well belong to an imposter. Thus it makes sense to advertise your key as much as possible: Put it on several keyservers, your website, your email signature. Conversely, do a background check before trusting a random public key. All of those things could potentially be hacked, though, so there’s another way. If you have met someone in person, or are otherwise sure of the authenticity…

Make sure to start Icedove whenTailsinforms you that Tor is ready. If you’re privacy conscious it’s probably best to create a new email address to be used exclusively with Tails. If you’re feeling lazy you can just enter the details of a common mail provider such as Gmail and Icedove will do the rest. If, however, you want to keep all your email traffic inside the Tor network, it’s best to make sure you and your contacts use a mail provider that offers a dark web (.onion) address. A few providers that do this include Mail2Tor, Riseup and OnionMail. Just click ‘manual config’ and enter the server settings from the relevant website. Once thisissetup. Select Enigmail from the Icedove MenuandstarttheSetupWizard. Choose the ‘extended’ set up for Advanced Users and choose…

Mayhem reigns The DARPA Grand Cyber Challenge plays out in Las Vegas as machines battle each other for prizes. Back in 2013, DARPA (the US defence agency which had a vital role in the research which led to the internet) announced its intention to hold a ‘Cyber Grand Challenge’, consisting of teams creating automated systems that could compete against each other to evaluate software, test for vulnerabilities, generate security patches and apply them to protected computers on a network. In a press release, the agency pointed out that the process of finding and countering bugs, hacks, and other attack vectors “is still effectively artisanal”, with professional bug hunters and other security professionals dedicating a huge amount of effort searching millions of lines of code to find and fix vulnerabilities that…

My Raspberry Pi is amazing, however, like many others I’ve found that the initial set up of the SD card can be a challenge. Depending on which operating system you use, the process ranges from tricky to break-out-the-command-line, which isn’t something you really want from a computer that’s designed to be used by people of all ages and skills. To try and solve this, I created PiBakery, a blocks-based, easy to use setup tool for the Pi. Put simply, PiBakery enables you to easily create customised SD cards for Raspberry Pi, using a Scratch inspired interface. If you’ve ever used Scratch before, you’llknow how to use PiBakery! With Scratch, you drag blocks out to make your sprites do things. In PiBakery, the idea is the same, except that the blocks…

The Pi Foundation’s blog has an amazing story outlining how the Pi – and a lot of person power – has brought computer education to Togo, West Africa. Dominique Laloux has worked on a number of projects in Africa and his latest is refitting a schoolroom with power and network. The classroom was kitted out with 21 Pis: one for each student, the teacher and another for driving the LED projector. http://bit.ly/LabsInWestAfrica…

This isn’t our first project using Python Sonic, in LXF211 we dipped our toe into what was a very bleeding edge library. Thankfully now the library has matured and is even being used by the Raspberry Pi Foundation as part of their Picademy training courses. Installation has been improved thanks to being packaged for the pip Python package manager, which handles installation and dependencies. Now that the installation has been improved the project loses some of its experimental status, but it is still in heavy beta, so it is prone to a few bugs along the way. The team behind Python Sonic are still working hard to improve the library and have provided an extensive reference guide via their Github page: https://github.com/gkvoelkl/ python-sonic…

It’s best before sending any private information with an OTP to send a Challenge-Response message first. Technically you could agree on two code words to use with your recipient: one could indicate that it’s you and you’re able to talk freely – for example, “Everest” – and another could disclose that you’re talking under duress – for instance, “Sparrow”. This means however that the same text is being encrypted each time, making messages easier to crack. A better system is to choose from a list of prearranged words or phrases. One way to do this would be to agree on a book – directories and almanacs are perfect types of book for this – and in your “challenge” message you could send an arbitrary page and line. For example you…

Many commands output to your screen, which is fine in many cases but awkward in others. You can instruct a command to send its output to a file rather than the screen using the > operator: This will list all the processes running on your PC in a newly created processes.txt file. Repeat the command, though, and the file will be overwritten. If you’d rather append the information on to an existing file, use >> instead: You can also pass the output of a command to another command for additional processing too. This requires the | separator, and is commonly used with the grep search tool for filtering output to include specific search terms. To filter your command history, for example, try the following: Replace ‘command’ with your search term…

You can make practically any Bash script a one-liner, even though it would be hard to read it. But there are a lot of useful yet short Bash scripts created by the people from around the world. Even if you feel like you don’t need any more practice at writing scripts looking at other’s best practices will not hurt. A one-liner means that you can use it directly as a command. The first example script we’re going to show off is for music lovers, and it converts all .flac files that it finds in the current directory to MP3 files at a good quality setting (320 kbps) using FFmpeg. Another tip is to copy something to the X.org clipboard from the command line. First make sure you have the xclip…

The Pi’s IOs generate 0V on a low and 3.3V on a high. The specified DPST relays need a DC coil voltage of 5.0V in order to switch, meaning that a driver circuit will be needed to boost the voltage of the Pi’s output up to 5.0V and drive the coil to switch the relay. Building a driver circuit is straightforward. First, grab a general purpose transistor such as a 2N3904. Then, create a circuit for the transistor that will allow it to run in the saturation region of operation during an ON (GPIO high). To do this, calculate the correct resistor value to obtain the saturation current needed and hook it up in series with the GPIO of the Pi’s output to the transistor’s base. Hook up the transistor’s…

Cassandra is a consistent, distributed key-value store. Being a Distributed key-value store essentially means that Cassandra fetches its data from multiple locations, which improves the software's performance. Cassandra offers an interactive shell called cqlsh. Executing cqlsh will show the following information: You should use CQL (Cassandra Query Language) to interact with a Cassandra database, which allows you to insert data, make queries and define schemas. However, software such as Cassandra is usually used in combination with other kinds of software, such as Spark, because Cassandra doesn't have much in the way of processing capabilities.…

The NTP configuration file options are using type 20 reference clock drivers. www.eecis.udel.edu/~mills/ntp/html/refclock.html#list. The mode switch tells the driver what NMEA sentence is being used for time. In the example mode 0x11 is data-type sentence $GPRMC with line speed of 9600. It is recommended that only one NMEA sentence per second be used. GPRMC or GPGGA are used most often. Don’t enable both, because doing so can cause problems with the driver. The option flag 1 1 enables PPS signal processing. By default PPS is disabled (set to 0). PPS is supported for NTP in the NMEA type 20 reference clock driver.…

PostgreSQL is a capable DBMS that can serve a large variety of applications. PostgreSQL offers psq , which allows you to interact with it from a terminal and perform most tasks. If you execute psql without any parameters you will most likely get an error message similar to the following: You can list all available PostgreSQL databases as follows, which is usually the first command you will need to execute: Then, you can specify the database you want to connect to as follows: You can find the version of PostgreSQL you’re using by executing this command under psq : You can create a new PostgreSQL user called “LXF” as follows: Alternatively, you can use the createuser command line utility, which is provided by PostgreSQL, to create a new PostgreSQL user.…

1 Slow upgrade Q You were kind enough to advise me on upgrading from Ubuntu 14.04 to 16.04 in LXF206. In the event I decided to wait for the official release of 16.04 LTS. I have now done the upgrade, which has prompted some further questions. The upgrade took a bit over three hours, which surprised me. Is this normal? Internet connection here is very slow, which doesn’t help. Now when I boot up, Lubuntu on the splash screen has changed to Kubuntu, which eventually disappears to leave a blank screen for what seems like ages. The boot process is very slow. Is this normal, or is there a way to speed it up? Peter Ratcliffe A First of all, the version of Ubuntu 16.04 on the LXFDVD was the…

String bashing Q Using Bash, I am trying to parse a string of undefined length to check whether the last five characters are correct, in particular whether the value of NAME does not yet have the dot extension “.epub” appended. It needs to cope if the string is shorter than the extension. Trying variations on the following –– the endless variations on dollar prefixes, enclosing quotes, white space and double-equals in the Bash documentation are driving me mental. Can you explain what is the correct way to do this and why? guy A This is Linux! There is generally more than one correct way to do something, but several approaches, each with its own merits. You cannot use filename wildcards like this; they are interpreted by the shell when referring…

“Please, come into my home nameless government agent. Yes, I have no issues with you looking through my letters, my computers, my phone, my messages, my photos and my emails. You want to store copies on your own servers forever? Fine, fine, take what you want, what a wonderful use of my tax money!” That’s effectively the situation that’s happening every second of the day while you’re online. Without being told, or warned, or asked, it appears all of our internet traffic has been stored away by government agencies in a number of secret programmes around the globe. It’s all done to protect us, you understand, despite the documented misuse of this information – and that’s only the leaked cases we know about – and the almost zero documented cases…

Thanks to a number of high-profile news stories, not least involving Edward Snowden,theTornetwork(see p34) became the go-to solution for many people seeking anonymity on the internet. Sadly, Tor’s increased popularity has also meant that government agencies, such as the NSA and GCHQ, have also taken a keen interest in discovering ways to de-anonymise Tor users and it looks like their attempts to crack it are making headway. A study that was undertaken at the US Naval Research Laboratory found that 80% of Tor users were at risk of being de-anonymised in the next six months, (http://bit.ly/ UsersIetRouted) as Tor is vulnerable to traffic analysis attacks that can see traffic entering and leaving the Tor network, which can lead to users being identified. While the Tor project is looking at ways to…

AryALInuX 2016.08 The latest release of the AryaLinux distro, which was built with the Linux From Scratch, is now available for download, and comes with Mate 1.15, KDE and LXQt desktopsupportand Qt 5. The GCC hasbeenupdatedto version 6 and the latest Linux kernel – version 4.7 – is also present and correct. As a source-based distro it uses source/ports package management with a custom package manager known as ALPS (Arya Linux Packaging System). To find out more about this version head to http://bit.ly/AryaLinux2016_08. Av LInuX 2016.8.30 AV Linux 2016.8.30 has been released and offers a Debian-based project (it doesn’t consider itself a Linux distro in the proper sense) aimed at users working with audio and video formats. There are big changes, including fixes and improved support for AMD video cards,…

Wuthering Bytes Walking a thin between passion and terror. The picturesque surrounds of the Upper Calder Valley, Hebden Bridge plays host to Wuthering Bytes for one week a year in September. This event is a celebration of maker culture and encompasses many facets of the movement. We were lucky enough to pop along for the Open Source User Group meeting, which showcases new and interesting projects. To open the event, we heard from Dr Tim Drysdale who has been part of the LabRTC team at the Open University to enable real-time control of hardware over an internet connection. The goal of the project is to enable anyone to have real-time access to expensive laboratory equipment, no matter their location. Next up was Ken Boak, an ex-BBC R&D engineer who is…

We have to face the fact that 3D printers just aren’t very quick currently, not even moderately so, and although speed should be taken into consideration when choosing your printer, you shouldn’t base your purchase on it. More important are the print quality options, and all our printers offer different preset quality settings and these can vary the print time from a low of one hour to well over eight. Three of the printers: LulzBot Taz 6, Ooznest Prusa i3 and the Ultimaker 2 Extended all manage to produce prints using PLA at the lowest settings in around one hour and at the top settings the times stretch out to around four hours. The Ultimaker has one higher quality setting that increased the printing time to six hours. The XYZ…

This year, the Facebook-owned Whatsapp messaging app rolled out so-called end to end encryption for all its users. This means that the key required to decrypt messages as they pass throughthe Whatsapp networkisonlyever known to the sender and receiver of those messages. The underlying technology used by WhatsApp is the same as that used in Open Whisper Systems privacy-centric messenger client, Signal. Theopensource SignalProtocol was designed by privacy activist and well-known hacker, Moxie Marlinspike. That protocol will also be rolled out to Facebook Messenger shortly, although secure messages will only be available on one device, otherwise key distribution becomes problematic. As this kind of ‘strong encryption’ becomes more prevalent, those depending on it will see increased attacks on the endpoints themselves, namely devices used by the communicating parties. The woeful…

Apart from short keys (the original WEP specified 40- or 104-bit keys and early routers were forced into choosing the former), the protocol itself is vulnerable to a statistical attack. Besides the 40-bit key, a 24-bit initialisation vector (IV) is used to encrypt the data packet. The most practical attack against WEP involves collecting many IVs and their associated packets and doing some number crunching to derive the key. For a 40-bit key, we can get away with as few as 5,000 packets. If the network (or rather the nodes of it within earshot of our wireless device) is busy, this will not be a problem. If not we can use a sneaky trick to get the router to generate some. Specifically, we can listen for ARP request packets (used…

This month, I’m writing this column whilst on holiday sans electricity. The owner of the property we’re renting cheerfully warned me that the power would be out for a few hours one day during our stay for maintenance work. We brushed it off, assuming we’d be out at the beach anyway. Unfortunately, we didn’t take into account the British weather and today coincided with the type of rain and wind that made the dog look at me as though I was insane when I tried to take her out this morning. So we’re sat in our temporary home watching it lash down. Of course, everyone ignored my warnings to charge up devices overnight, so they sit silent drained of power. Even if they are useable, there’s no internet and phone…

Lumina EncryptPad Qt5-Fsarchiver Fontforge Museeks Tor Browser Pitivi Bovo Blobwars: Blob Metal Solid Krop Clementine “You get multi-monitor support, a fast and responsive interface.” Desktop environment Lumina Version: 1.0 Web: https://lumina-desktop.org Many Linux users will be accustomed to the fact that KDE Plasma is the most configurable of the Linux desktop environments, although it‘s quite a heavyweight. Those who like lighter solutions often stick to LxQt and enjoy snappier performance, but LxQt development has stalled lately and for some users this has become quite a problem. Luckily, we have another more robust, light and feature-rich Qt-based desktop that we can turn to and it’s called Lumina. This desktop environment was initially developed to complement the user-friendly PC-BSD operating system—the BSD flavour that’s aimed at desktop users. Recently, a shiny new…

Our expert Nate Drake Nate is a freelance journalist specialising in cybersecurity and retro tech. His girlfriend won’t let him buy a kitten, so he has to make do with photos of kittens. Quantum Computers. Microphones so sensitive that they can record your keystrokes from yards away. Networks of zombie computers working round the clock to brute-force passwords. Government designed backdoors in code. It has never been harder to be entirely certain that any message you send can be transmitted or received in absolute secrecy. This holy grail of cryptography has long frustrated security experts, and most people are willing to settle for using encryption programs like gpg, which while theoretically breakable will resist all cracking attempts long after you’re pushing up the daisies. What if, however, there were a…

Our expert Alexander Tolstoy is our resident picker of hot things and has been a freelance writer for many Linux publications since 2006. Bash Bash Learn about commands and attributes to make some handy scripts For many Linux users a command-line interface is still something that’s best to be avoided. Why drop to the command-line shell when virtually all activities can be performed perfectly well in a graphical desktop environment, after all? Well, it depends. While modern Linux distributions (distros) are very user-friendly and in many areas outperform Windows and OS X, there’s a huge amount of power hidden away in Bash (Bourne Again Shell). The shell is a cornerstone of the GNU Project and has been with us since 1989. It’s also been a standard Unix shell in many…

Our expert Dan Smith Half man, half caffeinated beverage. With brew running through his veins, he takes you on a quest to find the holy grail of the perfect espresso. Kivy Pi and /Python coffee Build a Raspberry Pi touchscreen espresso coffee machine Coffee snobs are everywhere, especially in the software industry! Coffee fuels those long nights of gaming, coding and programming. No wonder they called it Java! You might have started drinking coffee at university because the cheap and nasty coffee machines gave a more financially sustainable caffeine hit than Red Bull. Fast forward ten years, and the majority of graduates morph into full-blown coffee snobs who don’t skimp when it comes to quality. If you are one of these people, you will most likely have a beautiful home…

Our expert Mihalis Tsoukalos (@mactsouk) has an M.Sc. in IT from UCL and a B.Sc. in Mathematics. He’s a DB-admining, software-coding, Unix-using, mathematical machine. You can reach him at www.mtsoukalos.eu. Cassandra Xxxx ssandra Use the database for large data processing with Sparks and Python Cassandra is a database server created by the Apache Software Foundation and Spark is an engine for large-scale data processing that‘s also created by Apache. This tutorial will teach you how to use Spark shell to talk to Cassandra; how to use the Cassandra shell to insert data; how to use Python to insert data into Cassandra and how to talk to Spark using Python. But first, you’ll learn how to install Cassandra and Spark because there are some subtle points in their installation process. Although…

Our expert Sean D Conway had formal training in electronics and half a career spent in aviation, so he really knows where he is with implementing a GPS receiver on a Pi. GPS Nxxx Configure and GPS a GPS HAT to provide time synchronisation for NTP Here at LXF, we’re always trying to keep up with the times. Last issue we showed you how to add GPS capabilities to your Raspberry Pi by pairing it with an Adafruit Ultimate Global Positioning System (GPS) HAT (www.adafruit.com/products/2324), enabling you to be up-to-the-minute in knowing precisely where you are. As it happens, GPS receivers are useful for more than simply finding your location. (Who’d have thought it?) In fact, GPS receivers can be used by the NTP daemon for ultra precise time synchronisation.…

Our expert Mihalis Tsoukalos (@mactsouk) is a Unix administrator, a programmer, a DBA and a mathematician who enjoys writing articles and learning new things. You can reach him at www.mtsoukalos.eu. Phoenix is a Web Framework written in Elixir that works similarly to Rails but is faster and more scalable than Rails. This tutorial will show you how to create a simple blog site using Phoenix and some Elixir code. You can find more about Phoenix at www.phoenixframework.org but don’t spend too much time on reading because the correct way to learn Phoenix is by writing applications! Before installing Phoenix you will need to install some additional packages to create a proper development environment and make your life easier: The first command installs Hex, which is the package manager of Elixir.…

Our expert Ramanathan Muthaiah began his career, in the mid-90s, flirting with legacy Unix systems. After assembling a PC on a shoestring budget running Slackware on a 486 processor and getting very excited, the Unix fever has never gone away. Continuous integration (CI), to quote Martin Fowler (http://bit.ly/CIMartinFowler), is a “. . . software development practice where members of a team integrate their work frequently . . . leading to multiple integrations per day. Each integration is verified by an automated build (including test) to detect integration errors as quickly as possible” Substantiating how or why this practice helps, he further adds, “Many teams find that this approach leads to significantly reduced integration problems and allows a team to develop cohesive software more rapidly” Various CI tools are available in…

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 as much as the competition, and as for the best, well… that’s a subjective claim, but we do sell way more copies than any other Linux mag in the UK. As we like giving things to our readers, each issue the Star Question will win a copy or two 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…

fsck You have mentioned fsck in response to a couple of questions this month. Assuming it’s not an expletive, what is it? Fsck is a filesystem check and repair tool. It scans a filesystem for errors and optionally fixes them if it can. Sounds useful, but which filesystems does it support? Each type of filesystem comes with its own set of tools, usually including an fsck program. For example the ext2/3/4 tools include fsck.ext. So I have to use the one for my particular filesystem? That’s not what you said in the answers. There is a general fsck program that looks at the filesystem, determines its type and runs the corresponding fsck.filesystem with the arguments you gave it. That’s the one you use – let it decide what to run…

For many people the name ‘PowerShell’ will take you back to when you had to use Windows, as it’s the command-line shell for Microsoft’s operating system. It looks like PowerShell may once again be a part of your life, Microsoft is open-sourcing the command line shell and is looking to bring it to Linux and Mac OS X. This follows on from previous news that Microsoft has open-sourced its .NET framework, and shows that the company finally recognises that people like to choose their own operating systems (which, shock, horror, may not be Windows), while still wanting to use its cloud platforms, such as Azure. Stellar animation studio, Pixar has recently revealed that it uses open source software, namely Red Hat Enterprise Linux and OpenGL, when animating its films, and…

Fan boy! I recently re-subbed for two more years as Linux Format has become my favourite Linux magazine. I hope the recent vote on EU membership won’t impact you guys negatively. I’d love to know what folks at the magazine favoured and why? I have wondered if Britain, Canada and America shouldn’t be forming an AU (Anglo Union) that unlike the EU was just based on free trade (especially that favoured small- and medium-sized businesses) and exchange of culture… and of course that supported free software and hardware. Thanks so much for the tutorials on Rust. I think it just might be capable of replacing C for me. I also enjoyed the firewall Roundup. I saw in a video that Linus Torvalds said they now use three separate hardware firewalls…

Make:Shift:Do The UK Crafts Council are once again asking for maker/hack spaces to open their doors to the public and demonstrate their skills. On October 28-29, venues around the UK will hold events where the public can get hands on with technologies, such as 3D printers, CNC machinery and laser cutters. The events are free to attend and vary in scope dependant on the services provided by the venue. For more information head over to www.craftscouncil.org.uk/what-we-do/makeshiftdo Linux Presentation Day October is becoming a busy month. The first Linux Presentation Day was held on April 30 this year and had LUGs reach out to their communities and explain the benefits of running Linux on all forms of hardware. The second Linux Presentation Day is taking place on October 22 in venues…

Each of the printers either ships with its own software or uses Cura by Ultimaker. The ease of use of the software, even when it’s the same Cura package, varies greatly between printers and not all manufacturers offer software that’s compatible with Linux. However, with the use of Wine or a 3D print package compatible with your printer, such as Simply3D, all the 3D printers can be made to work with Linux. The three machines that use Cura have the greatest platform compatibility with versions of Cura available for Windows, OSX and several varieties of Cura are available for different versions of Linux—in our case, we used the Ubuntu version. This isn’t just handy if you need to swap machines, but it also means that when it comes to configuring…

Print resolution is really what gets 3D printer enthusiasts excited. For many, it’s all about microns which represent the minimum layer height, but consistency of flow and reliability is far more important. All the printers proved exceptionally accurate showing both holes in flat material, model heights and widths that were exactly what they should be. More revealing is the difference in overall print quality and resolutions, the FormLabs Form 2 at the lowest resolution of 100 microns produces a print that’s visually the same quality as the best print from any of the other printers. Increasing the quality to its minimum layer height of 25 microns, and it’s so close to a injection-moulded print that it’s difficult to tell that it has been 3D printed. The LulzBot Taz 6 supplies…

The initial outlay for a 3D printer isn’t cheap, even if you build your own with a Prusa i3 kit you’re still looking at £400. If you’re not sure about printing but still want to print out some models or products that you have designed there are other ways to do it. The first is to find one of the many maker clubs and hackspaces around the country. They often have a selection of printers that you can use, and the organisers will have loads of advice about which printers will suit the type of work you’re wanting to do, they might even print it for you. If the prospect of going to one of these clubs seems a little daunting then why not give www.3dhubs.com a go. This site…

Recently offered for sale (by a collective going by the handle the Shadow Brokers) was a collection of high-powered hacking tools and exploits. To whet potential buyers’ appetites, a free sample of the material was released. The asking price for the rest was a cool $1 million, to be paid in bitcoins. The auctioneers claimed, and subsequent analysis of the freebies corroborated, that the malware originated from the revered Equation Group, said to be a Tailored Access Operations (TAO) unit within the NSA. The most interesting parts of the cache exploited vulnerabilities in enterprise-grade networking appliances. Cisco and Fortinet released emergency patches, suggesting that the dump included prized ‘zero-day’ exploits (those of which the manufacturer is not aware and no security patch exists). It’s hard to overstate the (predisclosure) value…

If you decide that the benefits of persistence outweigh the downsides then this is very simple to set up. Go to Applications > Tails > Configure Persistent Volume. Needless to say this can only be done if Tails is installed on a USB stick. Once you’ve chosen a passphrase, click on ‘Create’ and wait for the volume to be ready. You’ll then be presented with options as to what data you’d like to preserve. You can enable the following list of options: GnuPG (Stores all OpenPGP keys), SSH keys (both public and private), Pidgin settings (accounts, chats and OTR keys etc.), Icedove configuration and emails, Gnome Keyring, Network Connections, Browser Bookmarks, Printers, Electrum Bitcoin Client settings, APT Packages and APT Lists (enables installation of additional software). Finally, you will also…

While I can’t shake off associating the word Falco with the Austrian singer from the 80s, this spinofffromthemainsysdigprojectisworth investigating (probably worth a column on its own). It’s a behavioural activity monitor designed to “detect anomalous activity in your applications” according to the website. Runningasa daemon, Falco uses sysdigto watch a system for behaviour matching a set of predefined (open source) rules. This makes it similarto Snort, thepopularintrusion prevention system, albeit it at the system call level rather than at the network. As with the rest of the project, much emphasis is placed on the ability to use it with containers (which is fair enough, given the marketplace at the moment). It can be run inside a container itself, of course. Examples of the types of things it can detect are…

The son of a Japanese cucumber farmer has decided to combine the power of Arduino, the Raspberry Pi 3 and Google Cloud TensorFlow to enable deep-learning AI to sort their family’s crop of spikey cucumbers – an arduous process, for his poor mother, that’s currently done manually. While the system still has some way to go from its 70% accuracy, it’s another example of how disparate technologies can come together for novel solutions. http://bit.ly/DeepCucumber…

Our expert Les Pounder is a maker who specialises in the Raspberry Pi and works with the Raspberry Pi Foundation to deliver their Picademy teacher training. He has a blog at http://bigl.es You will need Any model of Raspberry Pi A USB dance mat An Internet connection for your Raspberry Pi All of the code for this tutorial can be downloaded from https://github.com/lesp/ LXF216-SonicPi-Dancemat/archive/master. zip For our tutorial this month we delve into our loft and dust off the USB dance mat that we bought in the 2000s. The goal of this project is to use the dance mat as a method of input for Sonic Pi. Now, we can’t just plug in and go; we first need to write some Python code that will talk to Sonic Pi’s server…

In order to proceed, you’ll need to have your Adafruit Printer set up and working. Fortunately the website has an excellent guide to this available at https://learn.adafruit.com/mini-thermal-receipt-printer. First install rng-tools as indicated in Step 1 of the walkthrough on p63. You’ll also need to edit /etc/default/rng-tools in your favourite text editor. Remove the # at the beginning of the line HRNGDEVICE=/dev/hwrng. Save and exit. Use sudo /etc/init.d/rng-tools restart to be certain the Pi is using only the hardware RNG now. Next, download the otp-gen software: you you can go opt-gen/ folder and run off a sample pad to see what it looks like: Next we need to make sure the software starts automatically when the machine starts: Scroll to the bottom of this file and insert the following three…

Our expert Nick Peers estimates that by following the tips he’s uncovered in this tutorial, he may actually reduce his typing in the Terminal by up to 50 per cent. Terminal Handy shortcuts and time-savers for command line users Transitioning from a graphical user interface to the Terminal? Then you’ll want to speed things up. The good news is that the Terminal is packed full of time-saving commands and shortcuts; the trickier part is actually finding them. Never fear, because this issue we’ve dug out a collection of handy command-line tricks that will transform the way you interact with the Terminal going forward. Repeat previous commands One of the first time-saving tips you’ll learn is that pressing the up and down arrow keys at the command line cycles you through…

The more time you spend in Bash, the more you may feel that some aspects of it could have been much better optimised. However, this isn’t entirely true. Bash has been used in system administration for 27 years, and it can be excellent when it comes to optimisation as long as you’re willing to put in a little effort to make it your own. Remember that Bash stores its settings in the ~/.bashrc file (individually for each user), which you can populate with your own features. Let’s start by automating mkdir $dir and cd $dir with a single command. Add the following to .bashrc: And then don’t forget to run $ source .bashrc to apply changes. After that when you run, say, $ mkcd build , you will immediately enter…

Hardware required for the Silvia-Pi build includes: 1x Raspberry Pi 2 1x Raspberry Pi 7-inch touchscreen 1x Rancilio Silvia (or any coffee machine that could do with better temperature control) 1x Solid State Relay (SSR) 2x Double Pole Single Throw (DPST) relays 2x transistors & diodes (for the driver circuits on the DPST relays) 1x integrated power supply (your country’s input V AC in, 5 V DC out) 1x k-type thermocouple 1x thermocouple amplifier (1-wire MAX31850K) Why are you using an SSR? Why don’t you use a mechanical relay to control the boiler? Well… This is because of the potentially high switching rate of the controller. In actual practice the switching rate is relatively low, and some low-end machines do use mechanical relays. However, mechanical relays typically fail open. SSRs…

Spark, which is the successor to Hadoop, is an engine for large-scale data processing. The engine also includes an SQL engine and supports stream processing, machine learning as well as graph processing. Software such as Spark needs to get its data from other sources—the good thing is that Spark can access a plethora of data sources including Cassandra, HDFS, HBase and Hive as well as any Hadoop data source. You can use Spark interactively from the Python, R and Scala shells, which also allows you to test and try new things while getting instant feedback before moving your code onto a production system. You can try Spark using Python with the help of the pyspark executable and using Scala with the spark-shell executable. The fundamental data structure of Spark is…

The GPS chip needs to know time and the location of each satellite to establish a fix. The satellite sends information about its location and time in data sentences. In order for the GPS to retrieve the information, the satellite signal must be of a specific strength for a specific duration. If the signal is degraded because of obstructions while the unit is trying to get a fix, the data is lost and the GPS unit must start over. To assist the GPS receiver in locating satellites, the manufacturers make available ephemeris data from their FTP site. The data can be downloaded and then uploaded into the GPS unit’s flash memory. When the GPS unit starts it has information on the satellites that assists the receiver in establishing time to…

The Elixir tool for creating and maintaining projects is called mix. Each Elixir project created by mix, including projects that use Phoenix, contains a file named mix.exs that is used for configuring your project. The mix.exs file is divided into three parts, named “project”, “application” and “deps”, that are also valid Elixir functions. The “project” part is where you put all project-related information such as project name and version. The “application” part is for putting information that is used for describing the application you are developing. The “deps” part contains the most important information because it is where the dependencies of the project are listed – the mix tool will either download all dependencies based on the information found in the “deps” function or give you the details you need…

In the early months of 2011, Niels Heinen of the Google Security Team reported a ‘Redirect vulnerability in urllib/urllib2 (http://bugs.python.org/issue11662). The patch to fix this issue was committed within a month of it being reported. Post-commit, more details were shared about the nature of the issue and the fix in the official blog, Python Inside (see http://bit.ly/urllibSecVulFix). Another bug in urllib was reported in 2013, (http://bugs.python.org/issue17322); however, this bug’s category was ‘normal’ unlike ‘11662’ which was classed as a ‘release blocker’. However both are fixed now. It should be noted that when using urllib or urllib2, SSL verification isn’t possible when ‘urlopen’ is invoked. For anyone serious about security this is surely a concern. This is where the ‘requests’ module scores and stands apart from the others. The list of…

You’ve just bought a lovely new 1TB drive, partitioned and formatted it in GParted, but your desktop’s tools are reporting that it has a size of around 900GB. Have you been robbed? Where is the 1TB you paid for? There are two main factors here. The first is overhead – space is needed for the partition tables, and any filesystem also needs space for its own purposes. Ext4 also reserves 5 per cent (a default that can be changed) of the filesystem for the root user only, to prevent lowly users like us from filling up the drive and causing problems. The other factor is the way in which drive (and memory) capacity is measured. Memory works in powers of two, so the nearest to 1,000 is 1,024 – one…

This month’s features are about security, an area in which Linux has a good reputation. I’d go so far as to say that the main security flaw in Linux is its reputation for security. Windows users know their computers are at risk (that’s a polite way of saying ‘full of gaping security holes’) and act accordingly. They install virus checkers and outgoing firewalls to stop software doing the things it tries to do in the background. The trouble with Linux is that so many of its users think it’s secure, so they don’t have to worry about it. It’s true that it’s much harder to inadvertently introduce malware onto a Linux box; you can’t do it by carelessly clicking on an email attachment, but it’s still possible. Sticking to software…

System tools Essentials Checkinstall Install tarballs with your package manager. Coreutils The basic utilities that should exist on every operating system. HardInfo A system benchmarking tool. Kernel Source code for the latest stable kernel release, should you need it. Memtest86+ Check for faulty memory. Plop A simple manager for booting OSes, from CD, DVD and USB. RawWrite Create boot floppy disks under MS-DOS in Windows. Smart Boot Manager An OS-agnostic manager with an easy-to-use interface. WvDial Connect with a dial-up modem. Reading matter Bookshelf Advanced Bash-Scripting Guide Go further with shell scripting. Bash Guide for Beginners Get to grips with Bash scripting. Bourne Shell Scripting Guide Get started with shell scripting. The Cathedral and the Bazaar Eric S Raymond’s classic text explaining the advantages of open development. The Debian Administrator’s…