today's howtos

posted by Roy Schestowitz on Dec 03, 2022

• Day 50: :has(:not()) vs. :not(:has())

  Something I was tripping over when I began learning about :has() was the combination with :not().

  Let me show you what I got wrong by using an example. Let's say we have two cards, each with a heading and some text. One of them also contains an image.

• Day 49: layering entire style sheets

  You can use @import to load entire style sheets into a cascade layer.

• Installing Mastodon on the Raspberry Pi

  Mastodon is a free and open-source software that allows you to self-host your own social network on your Raspberry Pi.

  This software is a microblogging platform that is very much like Twitter However, unlike Twitter, it is possible to use Mastodon to run a private social network.

  Please note that Mastodon is a relatively heavy piece of software. You will have the best experience using a Raspberry Pi 4 with at least 2GB of memory.

  Additionally, you must be using a 64-bit operating system due to the newer release of PostgreSQL we will be utilizing.

• The Sidecar For Psion - A PPP Modem And Linux Terminal For RS232 Devices

  Creating the PiRS232 and playing with the Pi over serial has been leading towards an idea - I wanted to create a small, battery powered device, a sidecar that I could carry with my Psion and use as portable Linux terminal. I also managed to turn it into an Internet gateway, leading to some interesting experiences.

  The idea was straightforward: take a Pi Zero, add an RS232 board that already handles the null modem side, add a Lipo battery, power management and charging, and print a case for it. It’s taken a few months from initial idea to final design, but I’m happy the result, it’s usable and practical, and you can build one too.

• Personal Server Backups

  Services like Linode or DigitalOcean offer backup services for your VPS. Save your money, you don’t need it. Here’s how to backup your data safely, and with no extra costs…

• Apache 2.4's event MPM and oddities with ServerLimit

  I mentioned recently that we were hopefully going to move away from the Apache prefork MPM when we upgraded our primary web server from Ubuntu 18.04 to Ubuntu 22.04. We had tried to switch over to the event MPM back in 18.04, but had run into problems and had reverted to the prefork MPM as a quick fix. Specifically, we had run into Apache stopping serving requests and reporting the following in the error log: [...]

• Authentication gateway with SSH on OpenBSD

  A neat feature in OpenBSD is the program authpf, an authenticating gateway using SSH.

  Basically, it allows to dynamically configure the local firewall PF by connecting/disconnecting into a user account over SSH, either to toggle an IP into a table or rules through a PF anchor.

• How To Install Nessus Scanner on Rocky Linux 9 - idroot

  In this tutorial, we will show you how to install Nessus Scanner on Rocky Linux 9. For those of you who didn’t know, Nessus is an open-source network vulnerability scanner for vulnerability assessments and penetration testing. With the help of this web-based GUI scanner, you can stay apprised of any issues that might arise on your network servers. Nessus does a fantastic job of checking for vulnerabilities and breaches in your company’s infrastructure.

  This article assumes you have at least basic knowledge of Linux, know how to use the shell, and most importantly, you host your site on your own VPS. The installation is quite simple and assumes you are running in the root account, if not you may need to add ‘sudo‘ to the commands to get root privileges. I will show you the step-by-step installation of the Nessus Security Scanner on Rocky Linux. 9.