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Programming Leftovers

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  • Godot Engine - Fog Volumes arrive in Godot 4.0

    On top of the existing non-volumetric fog, Godot 4.0 introduces a new type of fog: Volumetric Fog. For the 4.0 release, we decided to take Volumetric Fog one step further with the addition of FogVolumes. These allow users to dynamically place fog and control complex fog effects with shaders.

    This post starts off with a high-level description of what FogVolumes are and how to use them, and then includes some technical details about what is going on under the hood and how we get them to render so fast.

  • Commercial add-on: Qt VNC Server

    "VNC" (or Virtual Network Computing) compatibility has a long history in Qt, and we are now improving this story with Qt 6.4.

  • Gitly is an Open Source GitHub and GitLab Alternative

    GitHub and GitLab are free web-based version control system and collaboration platforms for developers. While, they are free on certain aspects, many developers and companies like to have their own version control system self-hosted on their servers.


    Gitly is released under the GPL-3.0 License.

  • 3 steps to create an awesome UX in a CLI application

    As I was sitting in a meeting room, speaking with one of my teammates, our manager walked in with the rest of the dev team. The door slammed shut and our manager revealed that he had a big announcement. What unfolded before our eyes was the next project we were going to develop—an open source CLI (command line interface) application.

    In this article, I'd like to share what I learned during our development process, and specifically what I wish I had known before we began developing Datree's CLI. Perhaps the next person can use these tips to create a great CLI application faster.

    My name is Noaa Barki. I've been a full-stack developer for over six years, and I'll let you in on a little secret—I have a superpower: My interest and expertise are evenly split between back-end and front-end development. I simply cannot choose one without the other.


    Use CLI commands that are named in a SINGLE form and VERB-NOUN format. This allows the command to be read like an imperative or request, for example: Computer, start app!

    Minimize with the total number of commands you use, and don't rush to introduce new verbs to new commands. This makes it easier for users to remember command names.

  • SQL Like Multiple Values

    “The SQL LIKE operator allows performing logical evaluation for any matching records. Using the LIKE operator, you can specify single or multiple conditions. This allows you to perform an action such as select, delete, and updating any columns or records that match the specified conditions. It is mainly paired with a where clause to set the conditions.

    In this tutorial, we will look at the workings of the LIKE clause and how we can use it to specify multiple conditions.”

  • JSON Multi-Line String

    “JSON is a popular data-interchange format that has been widely adopted across the development community. However, JSON has strict schema and formatting tools.
    JSON does not natively support multi-line strings. This can be quite frustrating when looking for flexibility and storing large texts.

    Let us discuss a simple workaround and how we can use multiline strings.”

  • PostgreSQL Cascade Delete

    “When working with PostgreSQL databases, you will encounter instances where you must drop records from a table. Before running a delete query, it is important to ensure that the table does not leave any incomplete relationships between tables.

    In PostgreSQL, we can use the CASCADE DELETE feature to accomplish this. This feature allows a delete operation to remove the specified records and any foreign keys that reference them.

    Using this article, we will review how to perform a cascade delete in PostgreSQL.”

  • Kibana Server Not Ready Yet

    “Kibana is a free and open-source analytics and visualization platform for Elasticsearch. It provides a browser-based graphical interface for interacting with your Elasticsearch database.

    It is very simple and intuitive. You can perform operations such as search, view, update, delete and query all the indices in your Elasticsearch cluster. When it comes to visualization, it offers a wide range of options, including charts, tables, maps, etc.

    However, Elasticsearch and Kibana have a notorious reputation for being difficult to set up and configure, especially when getting started.

  • TOTP with Perl and Authen::OATH | Lester Hightower []

    I wrote this post after seeing Flavio Poletti's blog post entitled OATH Toolkit. I have been a fan of time-based one time passwords (TOTP) for many years. In fact, I used Mobile-OTP in commercial applications for several years before the Initiative for Open Authentication (OATH) and OATH/TOTP were codified in RFC6238.

    Now-a-days, OATH/TOTP is the best choice for time-based one time passwords, and has been for at least a decade.

  • ERROR: 'flock' trapped by operation mask at /usr/lib64/perl5/vendor_perl/

More in Tux Machines

today's howtos

  • How to Change Comment Color in Vim – Fix Unreadable Blue Color

    Are you annoyed about the comment color in vim? The dark blue color of the comment is often hard to read. In this tutorial, we learn how to change the comment color in Vim. There are few methods we can use to look vim comment very readable.

  • How to Add Repository to Debian

    APT checks the health of all the packages, and dependencies of the package before installing it. APT fetches packages from one or more repositories. A repository (package source) is basically a network server. The term "package" refers to an individual file with a .deb extension that contains either all or part of an application. The normal installation comes with default repositories configured, but these contain only a few packages out of an ocean of free software available. In this tutorial, we learn how to add the package repository to Debian.

  • Making a Video of a Single Window

    I recently wanted to send someone a video of a program doing some interesting things in a single X11 window. Recording the whole desktop is easy (some readers may remember my post on Aeschylus which does just that) but it will include irrelevant (and possibly unwanted) parts of the screen, leading to unnecessarily large files. I couldn't immediately find a tool which did what I wanted on OpenBSD [1] but through a combination of xwininfo, FFmpeg, and hk I was able to put together exactly what I needed in short order. Even better, I was able to easily post-process the video to shrink its file size, speed it up, and contort it to the dimension requirements of various platforms. Here's a video straight out of the little script I put together: [...]

  • Things You Can And Can’t Do

    And it got me thinking about what you can and can’t do — what you do and don’t have control over.

  • allow-new-zones in BIND 9.16 on CentOS 8 Stream under SELinux

    We run these training systems with SELinux enabled (I wouldn’t, but my colleague likes it :-), and that’s the reason I aborted the lab: I couldn’t tell students how to solve the cause other than by disabling SELinux entirely, but there wasn’t enough time for that.

  • Will the IndieWeb Ever Become Mainstream?

    This is an interesting question, thanks for asking it, Jeremy. I do have some history with the IndieWeb, and some opinions, so let’s dive in.

    The short answer to the question is a resounding no, and it all boils down to the fact that the IndieWeb is really complicated to implement, so it will only ever appeal to developers.

  • How to Install CUPS Print Server on Ubuntu 22.04

    If your business has multiple personal computers in the network which need to print, then we need a device called a print server. Print server act intermediate between PC and printers which accept print jobs from PC and send them to respective printers. CUPS is the primary mechanism in the Unix-like operating system for printing and print services. It can allow a computer to act as a Print server. In this tutorial, we learn how to set up CUPS print server on Ubuntu 22.04.

Open Hardware: XON/XOFF and Raspberry Pi Pico

  • From XON/XOFF to Forward Incremental Search

    In the olden days of computing, software flow control with control codes XON and XOFF was a necessary feature that dumb terminals needed to support. When a terminal received more data than it could display, there needed to be a way for the terminal to tell the remote host to pause sending more data. The control code 19 was chosen for this. The control code 17 was chosen to tell the remote host to resume transmission of data.

  • Raspberry Pi Pico Used in Plug and Play System Monitor | Tom's Hardware

    Dmytro Panin is at it again, creating a teeny system monitor for his MacBook from scratch with help from our favorite microcontroller, the Raspberry Pi Pico. This plug-and-play system monitor (opens in new tab) lets him keep a close eye on resource usage without having to close any windows or launch any third-party programs. The device is Pico-powered and plugs right into the MacBook to function. It has a display screen that showcases a custom GUI featuring four bar graphs that update in real-time to show the performance of different components, including the CPU, GPU, memory, and SSD usage. It makes it possible to see how hard your PC is running at a glance.

Security Leftovers

How to Apply Accent Colour in Ubuntu Desktop

A step-by-step tutorial on how to apply accent colour in Ubuntu desktop (GNOME) with tips for Kubuntu and others. Read more