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Programming Leftovers

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  • Sin function in C

    In mathematics, the sine function is among three primary functions, others comprising cosine and tan. Techniques for executing basic mathematical operations, like the elementary exponential, logarithmic, square root, and mathematical operations, are included in the <math.h> header. You must include the header file <math.h> to utilize these functions. The sin function accepts an angle in radians and gives its sine value, which can be confirmed using a sine curve.

    You may use the law of sine to find any arbitrary angle in a triangle, as well as the length of a certain triangle side. This is a fundamental trigonometric notion. The sin function is used in the ANSI/ISO 9899-1990 versions of the C language. Sin () returns a result that is between 1 and -1.

    Now, let us start with a few examples of sin() function in the C programming language.

  • Dirk Eddelbuettel: RcppQuantuccia 0.0.4 on CRAN: Updated Calendar

    A new release of RcppQuantuccia arrived on CRAN earlier today. RcppQuantuccia brings the Quantuccia header-only subset / variant of QuantLib to R. At the current stage, it mostly offers date and calendaring functions.

    This release is the first in two years and brings a few internal updates (such as a swift to continuous integration to the trusted r-ci setup) along with a first update of the United States calendar. Which, just like RQuantLib, now knows about two new calendars LiborUpdate and FederalReserve.

  • System/Linux/DevOps Engineer Interview - Invidious

    An interview with a fellow Linux Engineer / System Engineer / DevOps Engineer / Programmer / Tech Person -- Craig has an interesting background, and some amazing advice for those of you breaking into the tech industry right now.

  • ninja Build system, and renamed files

    I've been hearing about ninja, I had looked at it some time in the past, and did some local basic benchmarking (using time), and didn't find a huge difference in build times, both from scratch and incrementally. I tried ninja again recently and found one feature that sells it pretty well to me, it can show the build progress on one line in the terminal.

  • The Return of the Unix Shell

    With about half a century of life, the Unix shell is pervasive and entrenched in our computing infrastructure—with recent virtualization and containerization trends only propelling its use. A fresh surge of academic research highlights show potential for tackling long-standing open problems that are central to the shell and enable further progress. A recent panel discussion at HotOS ’21 concluded that improvements and research on the shell can be impactful and identified several such research directions. Maybe it’s time for your research to be applied to the shell too?

  • Python CGI example

    CGI is abbreviated as Common Gateway Interface in Python, which is a block of benchmarks to explain the exchange of data among the web server and a script. A CGI program is written by an HTTP server as the user input is entered through the HTML . In other words, it is a collection of procedures that are used to build a dynamic interaction between the client and the server application. When a client uses any element or sends a request to the web browser, that CGI executes a particular request, and the result or the output is sent back to the webserver.

  • How do I check if a string contains another substring in Python

    Sometimes we need to find out whether a particular string is present in another string or not. So to know that there are some already pre-defined methods available in Python programming.

  • How to disable scrolling on a webpage with JavaScript

    JavaScript is a web language used for creating dynamic web pages and making them interactive for users. Through JavaScript we can perform various functions, change CSS of HTML elements, perform actions on each click and many more.JavaScript makes the page of our website more interactive and adds dynamic behaviors to it, we can create various menus, drop down menus, scroll bars etc. We can even enable and disable the behaviour of each of these components using JavaScript. In this article we’ll see how to disable scrolling on a webpage using JavaScript.

  • How to check if an array is empty in JavaScript

    Knowing how to check for an empty array is an important coding skill which can often come in handy. It can be helpful in a situation where you have to show or hide something on a web page depending on whether the array is empty or not.

    Similarly, there are many other places where you will find this skill helpful. The purpose of this post is to explain the code, the concept behind the code and the most common use cases of checking for empty arrays in JavaScript code.

  • OpenCL 3.0.9 Specification Released - Phoronix

    The Khronos Group's OpenCL working group did a quiet Friday evening tagging of OpenCL 3.0.9.

    Most notable with OpenCL 3.0.9 as this routine specification update are the specification sources now being included for the provisional extensions adding semaphores and external memory support to OpenCL. Those extensions were originally announced this spring as part of OpenCL 3.0.7 but the specification ASCII doc sources were not included until now.

  • Computer scientists at University of Edinburgh contemplate courses without 'Alice' and 'Bob' [Ed: This isn't the way to promote equality but to garner animosity towards those who claim to be promoting this cause]

    A working group in the School of Informatics at the University of Edinburgh in Scotland has proposed a series of steps to "decolonize" the Informatics curriculum, which includes trying "to avoid using predominantly Western names such as Alice/Bob (as is common in the computer security literature)."

    The names Alice and Bob were used to represent two users of a public key cryptography system, described in a 1978 paper by Ronald Rivest, Adi Shamir, and Leonard Adleman, "A Method for Obtaining Digital Signatures and Public-Key Cryptosystems." And since then, a variety of other mostly Western names like Eve – playing an eavesdropper intercepting communications – have been employed to illustrate computer security scenarios in related academic papers.

    The School of Informatics' working group reflects the University of Edinburgh's commitment to diversity, equity, and inclusion and to meet specific obligations spelled out in Scottish regulations like the Equality Act 2010 and the Public Sector Equalities Duty.

    The naming recommendation was reported last month by The Telegraph, which cited internal university documents. The Register filed a Freedom of Information Request with the University to obtain the documents, which were added to the University's website following the Telegraph report.

    [...]

    Examples cited in the document include "to avoid using master/slave to represent computing agents and instead use coordinator or workers" – a decision taken by numerous open source projects and companies in recent years – and to avoid using off-putting stereotypes during instruction.

More in Tux Machines

Videos/Shows: Deepin, Free Software, GTK, KDE, and More

Ubuntu: Internet of Things (IoT), CyberDog, ZeroDown, and OVS (Open vSwitch)

  • Ubuntu Blog: Embedded systems: the advent of the Internet of Things – Part II

    This is the second part of the two-part blog series covering embedded Linux systems and the challenges brought about by the proliferation of Internet of Things (IoT) devices. In Part I, we surveyed the embedded ecosystem and the role Linux plays within that space. This blog takes you on the next step in the journey, where we explore the most demanding challenges facing manufacturers of tightly embedded IoT devices.

  • CyberDog: a four legged robot revolution with Ubuntu

    Late this year, Chinese tech giant Xiaomi unveiled CyberDog: a quadrupedal, experimental, open-source robot that the firm claims will improve the robot development environment and promote the development of the robot industry. Today, Canonical dives into the specifications of this four legged robot and discover how Ubuntu is helping the device become an open source technological platform. Xiaomi has a clear vision for its product. As Huang Changjiang, PM at Xiaomi, explains, “CyberDog is developers’ technological partner from the future. It equips inhouse-made high-performance servo motors, high computing ability, with built-in AI for visual detection system and voice interaction system, supporting a variety of bionic motion gestures.”

  • ZeroDown® Software Targets Open Source with New Canonical Partnership

    As businesses around the world and in every major industry define and accelerate their cloud strategies, the lack of open, flexible and complete high availability has become a major concern. The ZeroDown platform, built upon Canonical’s industry-leading operating system, Ubuntu, aims at integrating into Canonical’s broader Charmed OpenStack platform with its ZeroDown Ultra High-Availability TM Software, eliminating downtime and data loss for its customers, running seamlessly through planned or unplanned downtime events.

  • Data centre networking: what is OVS? | Ubuntu

    In one of our preceding blogs, we spoke about Software-Defined Networking (SDN) and the key drivers behind it. Virtualisation is one of the fundamental aspects that characterises SDN, and has influenced the architecture of network switching in the data centre. OVS (Open vSwitch) is a fundamental component of modern and open data centre SDNs, where it aggregates all the virtual machines at the server hypervisor layer. It represents the ingress point for all the traffic exiting VMs, and can be used to forward traffic between multiple virtual network functions in the form of service chains. Let’s take a closer look in order to understand what OVS is.

Compact edge AI boxes offer choice of Jetson Nano, TX2 NX, and Xavier NX

All three systems ship with the Ubuntu 18.04 with Nvidia JetPack 4.5.1. They also support Advantech’s Edge AI Suite and FaceView applications, which are available on its earlier AIR systems. Read more

today's howtos

  1. Collaborate on a file using Linux diff and patch

    I edit a lot of text files. Sometimes it's code. Other times it's the written word for role-playing games (RPGs), programming books, or general correspondence. Sometimes it's nice to make a change, but for my collaborator to compare my change with what they originally had written. Many people default to office suites, like LibreOffice, using comments or change tracking features. Sometimes a simpler tool makes more sense, though, and for that, you can look at programming history for tools like diff and patch, which provide standardized formatting for tracking and applying changes to shared files.

  2. Best ways to destroy Microsoft Windows - blackMORE Ops

    OK, like seriously don’t do it unless you’re doing it in a practice Virtual machine or have permission to do so.. I take no responsibility for these collection of best ways to destroy Microsoft Windows!

  3. Quickemu- Run Windows 11 on Ubuntu 20.04 LTS Linux in few clicks

    o you want to install Windows 10 or 11 on your Ubuntu 20.04 or 22.04 LTS Linux using QEMU-KVM virtual machine? Then here is a tutorial to do that using the command terminal and Quickemu + Quickgui. Although we all have a simple solution that is a virtual box to run Windows 11 virtual machine, what about KVM? Some will say it is not easy to operate because of the command line but no there are few open-source GUI programs to give KVM an easy interface. However, another thing is downloading ISO images of various operating systems including Windows 10 or 11 to use with Virtualbox can be a headache. Hence, to solve all of this, there is a project called QuickEMU with a GUI interface known as QuickGUI. QickEMU uses QEMU_KVM on Linux operating system to run a virtual machine and can easily download all popular operating system Images to install including macOS. Whereas it can be operated via CLI but for ease of usage users can install QuickGUI to download, create, and manage operating systems virtual machines.

  4. Steinar H. Gunderson: Commitcoin

    How do you get a git commit with an interesting commit ID (or “SHA”)? Of course, interesting is in the eye of the beholder, but let's define it as having many repeated hex nibbles, e.g. “000” in the commit would be somewhat interesting and “8888888888888888888888888” would be very interesting. This is pretty similar to the dreaded cryptocoin mining; we have no simple way of forcing a given SHA-1 hash unless someone manages a complete second-preimage break, so we must brute-force. (And hopefully without boiling the planet in the process; we'd have to settle for a bit shorter runs than in the example above.) Git commit IDs are SHA-1 checksums of what they contain; the tree object (“what does the commit contain”), the parents, the commit message and some dates. Of those, let's use the author date as the nonce (I chose to keep the committer date truthful, so as to not be accused of forging history too much). We can set up a shell script to commit with --amend, sweeping GIT_AUTHOR_DATE over the course of a day or so and having EDITOR=true in order not to have to close the editor all the time.

  5. How to Install Kuma on Ubuntu 20.04 | LinuxHostSupport

    Kuma is an open source monitoring tool like “Uptime Robot” written in Nodejs. In this article, we’ll learn how to install it on Ubuntu 20.04 so we can self-host our Uptime Bot. We’ll also set up a reverse proxy on Apache with a Let’s Encrypt SSL to secure our website. Kuma is easy to use and upgrade, and is powerful for traffic control, observability, service discovery, etc.

  6. How to Install SuiteCRM with Apache and free Let's Encrypt SSL on Debian 11

    SuiteCTM is an open-source Customer Relationship Management solution written in PHP. It is a fully-featured and highly-extensible CRM application that runs on any operating system. It became popular when SugarCRM decided to stop the development of its community edition. It is used for creating business strategies, actions, and decisions. It is an alternate CRM solution for other commercial CRM such as SugarCRM, Salesforce, and Microsoft. In this post, we will show you how to install SuiteCRM with Apache and Let's Encrypt SSL on Debian 11.

  7. How to Install Rudder System Configuration and Auditing Tool on Ubuntu 20.04 – VITUX

    Rudder is an open-source and user-friendly web-based system configuration and audit tool. It helps you to manage your IT infrastructure by automating system configurations while ensuring visibility and control of your infrastructure. Two main components of Rudder are: Root server and node. Root server defines the configurations for the systems it manages. The systems managed by Rudder are known as nodes. Rudder manages the nodes using the Rudder agent which is installed on these systems. In today’s post, we will install the Rudder root server and agent on Ubuntu 20.04 LTS. We will use two Ubuntu machines: one as the Rudder root server and the other one as the Rudder node. Note: You must be a root user or have sudo privileges on both machines in order to install the Rudder server and agent.

  8. How to check if packages in RHEL-based Linux distributions have been patched for specific CVEs - TechRepublic

    CVEs (Common Vulnerabilities and Exposures) are constantly being discovered and patched. When discovered, it means a new security flaw exists in either an operating system or a piece of software and should be patched as soon as possible. Fixing the vulnerabilities, of course, is up to the developers. Patching those vulnerabilities, however, is up to the admin (or user). Thing is, you might not know if you're using a piece of software that includes one or more CVEs. How do you uncover this information? Do you have to spend hours researching? Not really. In fact, all you need to know is the CVE you're looking for and the piece of software it affects. With those two bits of information in hand, you can quickly discover if what's installed on your Red Hat Enterprise Linux-based distribution contains that vulnerability. I'm going to show you how to do just that.

  9. How to Install and Configure Nginx on Ubuntu

    Web applications have gained wide popularity over the past few years as a means of providing services to different clients. With a web application, you can reach out to a wider audience regardless of the device or operating system they are using. Being able to install and configure a web server is a valuable skill to have both as a web developer and software engineer. A web server is a program responsible for delivering your web content to clients over the internet or a network. Let's take a look at how to install and configure the Nginx web server on Ubuntu.

  10. How to install Sublime Merge on a Chromebook

    Today we are looking at how to install Sublime Merge on a Chromebook. Please follow the video/audio guide as a tutorial where we explain the process step by step and use the commands below.

  11. How to Install OpenEMR on Ubuntu 20.04 With LAMP Stack

    OpenEMR is a popular open-source software for the healthcare industry. It offers electronic health records and medical practice management solutions. OpenEMR provides a fully integrated Workflow Management inside healthcare facilities. Any healthcare facility would be able to capture and control patient data using the following features in OpenEMR.

  12. Add current user to all groups on the system except “nobody/nogroup”