Linux User & Developer 172 - Take Charge of the Command Line Interface

100 Pages·2016·18.328 MB·English

by  April Madden

WITH 3 LIVE BOOTING DISTROS
FREE DVD
www.linuxuser.co.uk
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TAKE CHARGE OF THE
COMMAND LINE
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INTERFACE
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IN
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IN MASTERCLASS
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F Discover how shell scripts can be integrated
A Protect your servers and find
C into Sun’s popular cross-platform language
E exploits before the hackers do
HOW TO MANAGE PROCESSES
Take control of everything your Ubuntu box is doing
ASP.NET CODING EXPLAINED
Microservice architecture with ASP.NET and Docker
TEST YOUR DISC
MISSING?
ASK YOUR
GO PROGRAMS RETAILER
PPIIXXEELL
DISCOVER
w
w Introducing the Pi’s new desktop
w Learn about profiling and use the runtime package
.lin
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u LOCATE PHONES NEXTCLOUD BOX
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e ISSUE I1S72S N 2041-327P0RINTED IN THE UK £5.99
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.u How to use your Pi to seek & How does Nextcloud’s
k identify Bluetooth devices private cloud shape up? 9 772041 327002
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Welcome
THE MAGAZINE FOR
THE GNU GENERATION
to issue 172 of Linux User & Developer
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Editorial
Editor April Madden
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☎ 01202 586218 » Take charge of the command line interface
Senior Art Editor Stephen Williams
Designer Rebekka Hearl » Protect your servers
Editor in Chief Dave Harfi eld
Photographer James Sheppard » Discover Pixel
Contributors
Dan Aldred, Joey Bernard, Toni Castillo Girona, Christian » Confi gure your desktop
Cawley, Sanne De Boer, Nate Drake, Gareth Halfscree, Tam
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Contents
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Subscribe
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on page 65
Reviews
81 IRC clients
Which multi-network chat client is
best for Linux users?
18 Take charge of the command line interface
Learn to use the most powerful Linux commands like a pro
WeeChat Quassel
OpenSource Tutorials
08 News 34 Bash masterclass: Make Bash
T he biggest stories from work with Java HexChat Konversation
the open source world Shell scripts can be integrated into Sun’s
cross-platform language
12 Interview 86 Nextcloud Box
Qin Wei discusses the world’s 38 Realise a microservice architecture This provate cloud is powered by a
smallest router with ASP.NET Core and Docker Raspberry Pi 2
Learn how you can use ASP.NET Core to deliver
16 Kernel column .NET-based microservices in Linux 88 Chapeau 24
The latest on the Linux Does Chapeau’s latest release do
kernel with Jon Masters 42 Manage processes in Ubuntu enough to stand out?
Take a deeper look at process management
90 Free software
on Ubuntu systems
Richard Smedley recommends some
46 Learn how to test your Go software excellent FOSS packages for you to try
Master testing in Go and use profiling and the
runtime package
52 Use OSINT techniques to
protect your servers
Find out if your servers are exposing sensitive
information to attackers
Features
18 Take charge of the
command line 67 Practical Raspberry Pi
interface
Use your Pi to locate and identify Bluetooth
Master the CLI today devices, install and explore the new Pixel
96 Free downloads
desktop, discover how the pi-topCEED is
56 Configure your desktop Find out what we’ve uploaded to our digital changing education, and more!
Give your Linux a new look content hub FileSilo for you this month
Join us online for more Linux news, opinion and reviews www.linuxuser.co.uk
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Open Source
On the disc
On your free
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Load DVD
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To access software and tutorial
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Welcome to the Linux User & Developer take the KDE Plasma Desktop for a whirl. your computer and double-click
DVD. This issue, transform your desktop Plus there’s Conky and Cairo-Dock to switch the icon.
with a range of tools. Live boot Apricity OS up essential parts of your Linux interface, Live boot
‘Aspen’ and discover its beautiful Cinnamon and all the essential tutorial fi les you need
and GNOME environments, take a look to follow along with the tutorials in this issue. To live-boot into the distros
at Elementary OS ‘Loki’ and its stunning Please note that all the distros on this disc are supplied on this disc, insert the
Pantheon desktop, or fi re up KDE neon to designed for 64-bit architecture. disc into your disc drive and
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booting from disc – check your
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case on your PC.
Apricity OS ‘Aspen’ Check out all of the latest KDE software, including the • Live-booting distros are read
KDE Plasma Desktop, built on a stable LTS Ubuntu from the disc: they will not be
Live boot the stunning GNOME interface of Apricity release. Make your desktop your own! installed permanently on your
OS. Once installed, to switch to the Cinnamon computer unless you choose
version while running Apricity OS GNOME, open the to do so.
Terminal and type
For best results:
freezedry --load /etc/freezedry/cinnamon.
toml This disc has been optimised
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Elementary OS ‘Loki’
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by selecting your username and clicking ‘Log out’ in recommend you use:
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extended and themed to your preferences. and can be added to with plugins, applets and scripts. software companies.
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08 News & opinion | 12 interview | 96 Filesilo
Below There’s plenty of customisations users can apply to Ubuntu 16.10
Distro
Ubuntu 16.10 cleans up performance
Yakkety Yak update boosts cloud, container & package management
Ubuntu is far and away the most popular Shuttleworth, who leads Canonical’s product those who like to experiment with virtual
Debian-based operating system, and if the team and oversees the Ubuntu project. “Our machines, you’re in luck, as the new Unity Low
latest update from Canonical is anything to go focus is to enable true hybrid cloud operations, Graphics Mode dramatically improves Ubuntu
by, it’s going to continue going from strength to and this release further enhances the tools and 16.10’s performance when used in a VM.
strength. Ubuntu 16.10 delivers a plethora of new platform that most companies depend on to Ubuntu’s ever-popular Nautilus ile
features, with some major improvements going operate effectively across all major public clouds manager has undergone major UI and UX
on under the hood. At its core is a new hybrid and in one’s own data centre, from bare metal to changes as well. It now includes a built-in
cloud operation system, alongside improved cloud container.” ile transfer progress widget, and a series
bare-metal cloud performance. Users will also In order to help take container and package of pop-over bubbles when renaming iles.
be to take advantage of world-leading process- management to the next level, Canonical has Smaller improvements are also numerous;
container coordination through Kubernates, also introduced a new Linux package which is including setting icon orders, zoom levels and
while there’s also full container support in named Snaps. Snaps in Ubuntu 16.10 merge streamlined transfer speeds. As you’d expect,
OpenStack. container and packaging technology together all native Ubuntu applications have been
“The world’s fastest hypervisor, LXD, and into a single format, enabling developers to updated for this release. Among them is the
the world’s best cloud operating system, format and distribute their apps and services latest version of Mozilla’s Thunderbird email
Ubuntu, together with the latest OpenStack and from cloud to IoT. As well as working on Ubuntu client, as well as the Rhythmbox music player
Kubernetes make for the world’s fastest and 16.10, Snaps will also work in later 16.04 and the 49th release of Mozilla Firefox.
best private cloud infrastructure” said Mark releases and across a range of alternate Linux For those interested in getting their hands on
operating systems. the latest update, the Ubuntu 16.10 installation
Core desktop functions Eagle eyed users will also be able to ind a image is a hefty 1.5GB, noticeably larger than
number of small improvements to the Unity previous updates. Oficial word from Canonical
have been streamlined,
desktop, and in particular the Compiz window is that the extra size is needed due to additional
helping everything work manager that acts as its central hub. Core language packs being included. Downloads of
desktop functions have been streamlined, Ubuntu 16.10 (Yakkety Yak) can be found over
that little bit smoother
helping everything work more smoothly. For at www.ubuntu.com.
8
008-011_LUD172.indd 8 02/11/2016 14:46
top five
Niche
Linux distros
1 C.A.IN.E
Despite its odd name, C.A.iN.e is the distro of
choice for those needing to perform computer
forensics, aiding detectives throughout their
investigations. it focuses on a user-friendly front-
end, and can be installed on a hard drive, or run
from a live CD.
2 Gentoo
RASpBERRY pI
The reason Gentoo has a small, but loyal, following,
is because it’s one of the few distros that enable
Raspberry Pi reveals
users to modify and recompile source code to their
exact needs. it isn’t for the faint-hearted, and is
reputed to be one of the hardest distros to master.
a brand new interface
Getting to grips with Raspbian’s latest desktop
Raspbian has long been the operating system Changes are immediately noticeable, with
of choice for many users who have invested a new splash screen on hand that displays the
in a Raspberry pi unit. it has proven to be a image version for quicker identification. The splash
great OS of choice for those starting off in the screen now covers up most of the initialisation
3 Ubuntu Studio
world of developing for the first time, and even text when booting up the operating system. On the
more so when it is used in conjunction with the desktop, application icons have been refreshed, for all you media enthusiasts out there, look no
Raspbian Desktop. with the Pi team wanting “something that looked further than Ubuntu Studio. it comes with a plethora
After nearly two years of development, the businesslike enough to be appropriate for those of media editing programs readily available to you,
Raspberry Pi foundation has announced the people who use the Pi desktop for serious work, complete with worklows to help you manage your
various projects.
release of the new and drastically improved but with just a touch of playfulness.” A series of 16
PiXeL desktop for Raspbian users. in an official all-new wallpapers can also be found with their 4 MuLinux
statement from Simon Long, senior principal eXif information as an added bonus.
engineer at Raspberry Pi, he said: “i think the Desktop windows now sport thinner frames MuLinux is a tiny distro, requiring just 20MB of HD
desktop has reached the point where it’s a and rounded corners, with subtle improvements space and 4MB of RAM to run it at a decent level.
complete product in its own right and should also made to the default Roboto font. Perhaps the While not tailor-made for newer machines, it’s the
perfect accompaniment to an aging desktop that
have its own name. So today, we’re announcing biggest addition is a series of new applications
needs saving from the scrapheap.
the release of the PiXeL desktop, which will ship making their debut on the desktop. Both the vNC
with the foundation’s Raspbian image from now view and vNC Server applications have been 5 Yellow Dog
on. The latest set of changes are almost entirely integrated into the operating system, as well as an
to do with the appearance of the desktop; there initial version of Chromium browser, instead of the Despite being originally developed for Apple
computers in the late Nineties, under new ownership,
are some functional changes and a few new aging epiphany. for those looking to download the
Yellow Dog is now one of the better distros for high-
applications... but this is mostly about making latest version of Raspbian with the PiXeL desktop,
performance, multicore computing. it’s even been
things look nicer.” head across to the official Raspberry Pi blog. used in development for the PlayStation Network.
www.linuxuser.co.uk 9
008-011_LUD172.indd 9 02/11/2016 14:46
OpenSource
Your source of Linux news & views
KERNEL
Linux kernel
4.7.10 will be
last in series
Existing 4.7 users need to
make the move over to 4.8
Despite the Linux 4.8 kernel being around for
some time now, there are still plenty of users
yet to make the move across to the newer
4.8 update. In a recent announcement, kernel
maintainer Greg Kroah-Hartman has said that
the latest 4.7.10 kernel update will be the last in
the series. “I’m announcing the release of the
4.7.10 kernel. All users of the 4.7 kernel series
must upgrade. This is the LAST 4.7 stable kernel
to be released, it is now end-of-life, please use 4.8
instead at this point in time.”
For those still looking to keep faith with the Above It’s time for users to move over to the 4.8 kernel branch
4.7 kernel, the .10 update introduces some enhancements to the Broadcom b43 and to the 4.7.9 update, namely to counter the ‘Dirty
improvements. There have been noticeable brcm80211 wireless drivers, and an overhaul to COW’ bug that’s been circling as of late.
the kernel’s cryptography framework and ARC While the 4.7.10 update is entirely usable, it’s
You will fi nd that
architecture. File systems have also gone under important to note that it’ll be the last .7 release
migrating over to the 4.8 the scope, with noticeable improvements to to get any sort of security maintenance. You will
the ReiserFS, Btrfs, EXT4, Debugfs and FUSE fi nd that migrating over to the 4.8 kernel branch
kernel branch couldn’t be
fi lesystems. In total, there are 49 changed couldn’t be made any easier and is relatively
made any easier and is fi les, 411 insertions and a surprisingly low 172 simple. Those interested should head across
deletions. Alongside the announcement of the to the kernel.org blog for further details. Linux
relatively simple
4.7.10 release, further patches have been added kernel 4.7.10 sources are available to download.
SECURITY
‘Dirty COW’ security fl aw putting millions at risk
Network security has seen multiple exploits V3 that the exploit is actually becoming more The kernel fl aw, dubbed ‘Dirty COW’, is
appear in recent years, but one to come into widely used and at a rather alarming rate. actually an 11-year-old bug that has had
focus in the past few weeks has actually “The exploit in the wild is trivial to execute, multiple patches attempted by Linus Torvalds
been in the wild for a number of years. This never fails and has probably been around for himself. Unfortunately, his efforts have yet
follows on from a warning from Red Hat, years – the version I obtained was compiled to fully fi x the issue. The exploit itself can be
which indicates that the fl aw is now being with gcc 4.8,” he also said. “An unprivileged used to gain root server access, potentially
exploited on multiple desktops worldwide. local user could use this fl aw to gain write enabling someone to gain access to a Linux
Phil Oester, a Linux security researcher access to otherwise read-only memory machine via an executable fi le.
who was the one to initially uncover the fl aw, mappings and thus increase their privileges At the time of writing, there’s little
has explained in a very recent interview with on the system.” information on how to protect yourself from
the Dirty COW exploit. It’s advisable, however,
It’s advisable, however, to make sure to upgrade the
to make sure to upgrade the security strength
security strength of the systems used and to keep a close of the systems used and to keep a close eye
on your network server access. A potential fi x
eye on your network server access
should be available in 2017.
10
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