today's howtos

posted by Roy Schestowitz on Sep 10, 2022

• Use Apt or Apt-Get Command to Install a Specific Version of a Package on Ubuntu - TREND OCEANS

  Do you want to install a specific version of a package using the apt or apt-get command without using modern sandboxing tools like Snap or Flatpak?

  Then check your package for all available versions that you want to install by using the below command.

• cURL – How to display request headers and response headers - TecAdmin

  The request headers contain the information about the resource that is required to be fetched. The response headers contain information about the response sent by the server. It’s something like server details and other information.

  cURL is a command line utility used to transmit data over the different-2 protocols. It is a quick tool for developers to view the request header and response header values of a website.

• MAX7219 LED Matrix with Arduino

  To control the dot matrix with MAX7219 using Arduino and display different patterns/characters on a dot matrix

  In this tutorial, we will learn how to interface MAX7219 LED Dot matrix display with Arduino. We will familiarize you with the MAX7219 dot matrix display and program Arduino to show various demonstrations of displaying texts and symbols.

• Tried implementing FUSE cpiofs.

  Tried implementing FUSE cpiofs. I thought it might be fun to implement a file system that can mount initrd file systems. I've implemented symlinks and regular files handling and then I realized that it is kind of annoying that I need to implement hard links.

• The history of sending signals to Unix process groups

  All (Unix) processes are members of some process group. Process groups go very far back in Unix; they're present at least as far back as Fourth Edition (V4) Unix. However, they aren't really "process groups" in the modern sense, as we can see from the relevant proc struct field being called p_ttyp. Instead they were used primarily to send signals to your terminal processes when various things happened (see dmr/tty.c and dmr/dc.c), and the 'process group number' was the address of the 'struct tty' for your terminal.

  In V7, h/proc.h changed the p_ttyp field to p_pgrp and now called it the 'process group leader'. However, there's (still) no way to send a signal to a process group from user code, although various tools know about the idea of process groups and will report them to user level (for example pstat.1m, which gets this information in the traditional Unix approach of reading kernel memory, per cmd/pstat.c). V7 is also where the 'process group' number becomes the process ID of the first process to open a (serial) tty after it's been closed.

• Install or Uninstall add-ons on Mozilla Firefox - Here is How?

  Want to install add-ons like Adblocker in Mozilla Firefox? Here is this tutorial where we will learn how to install the extensions for this open-source browser on Windows, Linux, or macOS.

  To extend the functionality and feature of the browser we use extensions and the same goes for FireFox as well. For example, if you want to block advertisements in FireFox completely, then we can use extensions such as Adblocker that need to be installed separately in Mozilla Firefox. The so-called add-ons/extensions make it easier for us to surf or enable you to use new functions.