development Archives

Configuring the wireless interface on Ubuntu Linux

Setup Wireless interface on Ubuntu

14 May 2021 by Luke Reynolds

Setting up the wireless interface on Ubuntu Linux is likely one of the first things you’ll need to do after installing the operating system and booting into it for the first time. As long as you have the proper hardware, Ubuntu can easily connect to Wi-Fi networks configured with various types of security like WEP, WPA, and WPA2.

In this guide, we will cover the step by step instructions to connect to a Wi-Fi network from the GNOME GUI (the default desktop environment) on Ubuntu. We will also show how to connect to Wi-Fi from command line, which is handy in the case of headless servers or those running without a desktop environment. Follow along with us below to find out how.

In this tutorial you will learn:

How to connect to Wi-Fi network in GNOME GUI
How to connect to Wi-Fi network via command line
How to enable or disable the system’s Wi-Fi adapter

How to install and use ZSTD compression tool on Linux

13 April 2021 by Korbin Brown

Zstandard, often abbreviated as zstd, is a relatively new compression tool that premiered in 2015. It was created by engineers at Facebook, looking to improve on the speed and compression ratio of longstanding tools like gzip. It’s quickly becoming a standard compression tool on many Linux distros, so now’s a perfect time to learn about using it.

In this guide, we’ll go over the instructions to install and use zstd on Linux, with command line examples that show you how to compress files as well as open archives that use zstd.

In this tutorial you will learn:

How to install Zstandard on major Linux distros
How to use Zstandard through command line examples

Compressing a file with zstd on Linux

How to setup FTP/SFTP server and client on AlmaLinux

10 April 2021 by Korbin Brown

FTP and SFTP are great protocols for downloading files from a remote or local server, or uploading files onto the server. FTP will suffice for some situations, but for connections over the internet, SFTP is recommended. In other words, FTP is not secure to use over an internet connection, since your credentials and data are transmitted without encryption. The ‘S’ in SFTP stands for ‘Secure’ and tunnels the FTP protocol through SSH, providing the encryption needed to establish a secure connection.

In this guide, we’ll go over the step by step instructions to setup an FTP server through VSFTP software or SFTP server through OpenSSH on AlmaLinux. Then, we’ll see how to connect to the server from a client AlmaLinux system. Setting up FTP/SFTP is a common step after installing AlmaLinux or migrating from CentOS to AlmaLinux.

In this tutorial you will learn:

How to setup an FTP server through VSFTPD
How to setup an SFTP server through OpenSSH
How to setup FTP and SFTP user accounts
How to allow FTP and SFTP through firewalld
How to connect to an FTP/SFTP server via command line
How to connect to an FTP/SFTP server via GNOME GUI

How to setup an FTP/SFTP server on AlmaLinux

How to run command in background on Linux

10 April 2021 by Korbin Brown

Running commands or processes in the background on a Linux system becomes a common task if you need to free up your terminal or disconnect from an SSH session. This is especially true of commands that run for a long time, either to listen for events or complete their lengthy task.

We have a few options on Linux for running commands in the background. In this guide, we’ll cover a few different methods and show you how to use them through examples.

In this tutorial you will learn:

How to put a running command into the background
How to start a command in the background
How to close terminal and keep background job running
How to use the screen command

Putting a process into the background and moving it to the foreground

How to work with the Woocommerce REST API with Python

30 March 2021 by Egidio Docile

WordPress is probably the most used CMS in the world (it is estimated that almost 40% of all websites are built using the platform): it is very easy to install and use, and allows even non-developers to create website in few minutes.
Wordpress has a very large plugin ecosystem; one of the most famous is Woocommerce, which allows us to turn a website into an online store in few steps. The plugin makes use of the WordPress REST API infrastructure; in this tutorial we will see how to interact with the Woocommerce API using the Python programming language, showing how to list, create, update and delete products and categories.

In this tutorial you will learn:

How to generate Woocommerce REST API credentials and enable pretty permalinks
How to interact with the Woocommerce REST API using Python and the woocommerce package
How to get information about the existing Woocommerce categories, create, update and delete them
How to get information about the existing Woocommerce products
How to create simple and a variable products with variations
How to update and delete a product

How to Discover, From Inside a Bash Script, the Path the Script Is In

23 March 2021 by Roel Van de Paar

When you develop complex Bash scripts and start putting various scripts into a folder, where one script interacts with another by, for example, starting it, it quickly becomes necessary to ensure we know the path the script was started from, so we can start the other scripts with a fully qualified pathname. This is important because the first script may have been started from outside the script’s directory. We could have also done so by using a relative path, so even – somehow – reading the command that started the current script will not work.

In this tutorial, you will learn:

What the pwd command is, and what it does
How to discover from inside a Bash script what path that same script is in

How to check Kernel version on Linux

22 March 2021 by Korbin Brown

Every Linux system is running a Linux kernel, which serves as the foundation for a fully packaged operating system. As technology evolves, the Linux kernel receives updates to accommodate new hardware, features, and security patches.

Keeping your Linux kernel up to date is an important task for administrators and users alike. Do you know what kernel version your Linux distribution is running? In this guide, we’ll show you how to find the Linux kernel version through various command line utilities.

In this tutorial you will learn:

How to check kernel version with uname, hostnamectl, and /proc/version

Multiple commands showing the kernel version of a Linux system

$Computer Math Basics: Binary, Decimal, Hexadecimal, Octal$

Computer Math Basics: Binary, Decimal, Hexadecimal, Octal

2 March 2021 by Roel Van de Paar

How we express a number depends on whether we are a computer or a human. If we are human, we are likely to express numbers using our familiar 10-base decimal system. If we are a computer, we are likely, at our core, to express numbers as 2-base or binary.

So what is up with all the many ways of expressing numbers, and why do they exists? This article will go into some detail and hopefully by the end you’ll be counting octal on your fingers. Which works fine by the way, as long as you use only 8 fingers, after all… octal is 8-base.

In this tutorial you will learn:

How to do simple counting in up non-decimal systems like binary, hexadecimal and octal.
What the terms 2-base, 10-base etc. stand for and how to understand them more easily.
The connection between these various methods of expressing numbers

How to install Swift on Ubuntu 20.04

2 March 2021 by Justin Chapin

Swift is a modern open source high-performing programming language with a focus on safety. It was developed by Apple and released in 2014. Swift was designed as a replacement for the older Objective-C language. Although, the language was originally proprietary, in 2015 Apple open-sourced the language and made it available for GNU/Linux systems. Although Swift is most well known for being the language used in iOS app development, there is an uptick in using it for server-side programming on Linux. Additionally, the fact that it is a young open source general-purpose programming language may lead to increased use in other domains over time.

Special Bash Variables with examples

16 February 2021 by Roel Van de Paar

Bash is a great coding language, which allows you to do complex things like Big Data Manipulation, or simply create sever or desktop management scripts.

The entry level skill required to use the Bash language is quite low, and one-liner scripts (an often used jargon, which indicates multiple commands executed at the command line, forming a mini-script), as well as regular scripts, can grow in complexity (and how well written they are) as the Bash developer learns more.

Learning to use special variables in Bash is one part of this learning curve. Whereas originally the special variables may look cryptic: $$, $?, $*, \$0, $1, etc., once you understand them and use them in your own scripts, things will soon become clearer and easier to remember.

In this tutorial you will learn:

How to use special variables in Bash
How to correctly quote variables, even special ones
Examples using special variables from the command line and scripts

ERROR: Unable to find the kernel source tree for the currently running kernel error message on CentOS / RHEL

ERROR: Unable to find the kernel source tree for the currently running kernel – CentOS / RHEL / AlmaLinux

5 February 2021 by Lubos Rendek

This article will provide you with an information on how to install kernel source on CentOS/RHEL Linux system. Alternatively it will guide you through a simple troubleshootng process in case you have already installed kernel sources/headers and yest still receiving the bellow error message:

  ERROR: Unable to find the kernel source tree for the currently running kernel.  Please make sure you have installed the kernel     
         source files for your kernel and that they are properly configured; on Red Hat Linux systems, for example, be sure you have 
         the 'kernel-source' or 'kernel-devel' RPM installed.  If you know the correct kernel source files are installed, you may    
         specify the kernel source path with the '--kernel-source-path' command line option.

In this tutorial you will learn:

How to install kernel-headers
How to install kernel-devel
How to check kernel version
How to check for installed kernel-devel version

Using a hex editor to view binary file on Kali Linux

How to install and use Hex editor on Kali Linux

25 January 2021 by Korbin Brown

Once a program has been compiled, it’s tough to get a peek at the source code or to manipulate its behavior. But there is one thing we can do, which is to edit the hexadecimal values inside the binary files. This will sometimes reveal information about a file, or allow us to modify its behavior if we can edit the right bit.

A classic example is video game hacks. When playing a game, let’s say your character has a health value of 100. Chances are that a certain bit can be edited to make it 9999. This works more reliably in older, basic games, but it illustrates how hex editors can modify a compiled binary file.

In this guide, we’ll show how to install hex editors on Kali Linux, and give some examples so you can see how to use them on your own system.

In this tutorial you will learn:

List of hex editors for Kali
How to use hex editors on Kali