Egidio Docile

How to compile vanilla Linux kernel from source on Fedora

30 May 2019 by Egidio Docile

The kernel is the most important component of an operating system: among the other things, it provides support for different types of hardware and manages resource allocations.

Linux is a monolithic kernel: although its functionalities can be included statically or built and loaded as separate modules, it always runs as a “single piece” in the same address space. In this tutorial we will see how to download, compile and install a vanilla Linux kernel. The instructions provided should work on all Linux distributions, however this guide is focused on compiling the kernel on a Fedora system.

In this tutorial you will learn:

How to configure, compile and install a vanilla Linux kernel
How to package the compiled kernel and its modules

The ncurses-based configuration menu for the Linux kernel

Introduction to the JavaScript Fetch API

3 June 2020 by Egidio Docile

Compared to XMLHttpRequest and the libraries built around it, like JQuery.ajax, the fetch API defines a more modern and cleaner way of performing asynchronous requests, based on the use of promises. In this article we will see some of the interfaces provided by the API, like Request and Response, and we will learn how to use the fetch method to perform various types of asynchronous requests.

In this tutorial you will learn:

How to send asynchronous requests using the fetch method
How to work with the Request and Response objects provided by the fetch API

How to configure network interface bonding on RHEL 8 / CentOS 8 Linux

25 September 2019 by Egidio Docile

Network interface bonding consists in the aggregation of two or more physical network interfaces, called slaves, under one logical interface called master or bond interface. Depending on the bonding mode, such setup can be useful to achieve fault tolerance and/or load balancing. In this tutorial we will learn what the available bonding modes are and how to create a network bonding on RHEL 8 / CentOS 8.

In this tutorial you will learn:

What is network interface bonding
How to configure network interface bonding on RHEL 8 / CentOS 8
What are the different bonding modes

The Bond status as seen by the Linux kernel

How to combine the results of multiple SQL queries using the UNION statement

3 June 2020 by Egidio Docile

In a previous article we talked about the various type of JOIN we can use in a MariaDB/MySQL database. This time, instead, we take a look at the UNION statement: how it works, how we can use it to combine the result of queries run on different tables, and what are its peculiarities.

In this tutorial you will learn:

How to use the UNION statement in a MariaDB/MySQL server
What are the properties of the UNION statement

How to install node.js on RHEL 8 / CentOS 8 Linux

8 June 2019 by Egidio Docile

Node.js is a Javascript runtime environment based on the V8 open source engine made by Google and originally used in Chrome. Thanks to Node.js we can run Javascript outside of the browser context, and use it also like a server-side scripting language, thus creating an entire web application around it. In this tutorial we will see how to install Node.js in the RHEL 8 / CentOS 8 distribution.

In this tutorial you will learn:

How to list the available Node.js versions on RHEL 8 / CentOS 8
How to install a specific version of Node.js
How to switch between Node.js versions on RHEL 8 / CentOS 8

The Node.js – RHEL 8

How to perform HTTP requests with python

3 June 2020 by Egidio Docile

In this series of article about python and HTTP protocol, we work with HTTP requests and responses. In the first article we explore standard library functions such as urllib.request.urlopen or urllib.request.urlretrieve. In the second part we focus on the external “requests” library, which let us perform complex operations, writing less code.

How to perform HTTP requests with python – Part 2 – The request Library

3 June 2020 by Egidio Docile

In the previous article we saw how to perform basic HTTP requests using the python3 standard library. When requests become more complex, or we just want to use less code, and we don’t mind adding a dependency to our project, it’s possible (and sometimes even recommended) to use the external requests module. The library, which adopted the “HTTP for Humans” motto, will be the focus of this article.

In this tutorial you will learn:

How to perform HTTP requests with python3 and the ‘requests’ library
How to manage server responses
How to work with sessions

How to perform HTTP requests with python – Part 1: The standard Library

3 June 2020 by Egidio Docile

HTTP is the protocol used by the World Wide Web, that’s why being able to interact with it programmatically is essential: scraping a web page, communicating with a service APIs, or even simply downloading a file, are all tasks based on this interaction. Python makes such operations very easy: some useful functions are already provided in the standard library, and for more complex tasks it’s possible (and even recommended) to use the external requests module. In this first article of the series we will focus on the built-in modules. We will use python3 and mostly work inside the python interactive shell: the needed libraries will be imported only once to avoid repetitions.

In this tutorial you will learn:

How to perform HTTP requests with python3 and the urllib.request library
How to work with server responses
How to download a file using the urlopen or the urlretrieve functions

How to configure a static IP address on RHEL 8 / CentOS 8 Linux

13 June 2019 by Egidio Docile

There are many cases in which we may want to set a static IP for a network interface. In RHEL 8 / CentOS 8, the network connections are managed by the NetworkManager daemon, so in this tutorial we see how we can perform such task by editing an interface file directly, by using a command line utility, nmcli, or via a text user interface, nmtui.

In this tutorial you will learn:

How to set a static IP address by directly editing an interface file
How to set a static IP address using the nmcli utility
How to set a static IP address using nmtui

The edited network interface file

How to install phpMyAdmin on RHEL 8 / CentOS 8

14 June 2019 by Egidio Docile

PhpMyAdmin is a php web application which let us manage a MariaDB/MySQL database from an intuitive graphical interface. The application is not provided in the RHEL 8 / CentOS 8 official repositories, and is usually installed from third party sources like EPEL. Epel-8 is, however, not yet available, so in this tutorial we will see how to fetch the upstream phpMyAdmin code and install it on our system “manually”.

In this tutorial you will learn:

How to download and install phpMyAdmin from source
How to verify the downloaded archive
How to access the phpMyAdmin configuration wizard

The phpMyAdmin login page

How to install packages on RHEL 8 / CentOS 8 Linux System

21 September 2019 by Egidio Docile

All modern linux distributions organize software in packages which contain applications binaries, files, metadata and information about the package dependencies, possible conflicts with other packages etc. The core Rhel package manager is called rpm itself, and it is the tool used also by dnf, the higher level package manager, which is capable to manage dependencies. A relatively recent technology , flatpak, let us install also sandboxed applications together with their runtimes.

In this tutorial you will learn:

The three main ways to install a package using rpm
How to install packages using dnf
How to install applications graphically from the gnome-software utility
How to install sandboxed applications with flatpak

The rpm package manager manual

How to install php on RHEL 8 / CentOS 8 Linux

15 June 2019 by Egidio Docile

In the RHEL 8 / CentOS 8 Linux systems, the way software is organized has changed: critical packages are now contained in the BaseOs repository, while the AppStream one contains multiple versions of some of the most common used applications and programming languages which are organized in modules, and updated independently of the distribution release cycle. This strategy has been adopted in order to avoid the problem of being stuck with a certain, too outdated or too recent release of a certain software.

In this tutorial you will learn:

How to install PHP on RHEL 8 / CentOS 8
What are software modules in RHEL 8 / CentOS 8
How to install and switch between different versions of the PHP module

Available php modules on RHEL 8