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Programming Leftovers

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Development
  • Understanding jq's SQL style operators JOIN and INDEX

    In this post I explore a couple of new (to me) operators in jq's arsenal: JOIN and INDEX, based on an answer to a question that I came across on Stack Overflow.

    The answer was in response to a question (JQ: How to join arrays by key?) about how to merge two arrays of related information. I found it interesting and it also introduced me to a couple of operators in jq that I'd hitherto not come across. There's a section in the manual titled SQL-Style Operators that describe them.

  • Migrating Rails cookies to the new JSON serializer

    How to move from Marshal to the new Rails 7 default JSON serializer.

    I was recently upgrading Phrase to Rails 7. Big upgrades like that are usually being done with the most minimal changes, and this one wasn’t an exception. However, every major and minor version of Rails brings some new defaults that can accumulate over time, leaving you with some debt to pay.

  • gfldex: Sinking Errors

    I was looking for a way to output debug messages that can also carry additional values, when not output to the screen. That is easy. The tricky part is golfing the interface. After quite a bit of struggle. I ended up with the following.

  • Friday is an Open-source Virtual Assistant

    Virtual assistant technology defines as an application program that uses semantic and deep learning. It can also call an AI assistant or digital assistant. It helps users or enterprises to assist people or automate tasks.

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