Egidio Docile

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Most common custom SSH Configurations of the OpenSSH Server

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The Openssh set of utilities let us create secure, encrypted connections between machines. In this tutorial we will take a look at some of the most useful options we can use to change the behavior of sshd, the Openssh daemon in order to make your Linux system administration job easier.

In this article we assume the existence of an already running and accessible server. If you want to know more about Openssh installation, you can take a look at this article on how to install SSH server on Ubuntu Linux.

In this tutorial you will learn:

  • How to customize the behavior of the sshd daemon by manipulating options in the main ssh config file /etc/ssh/sshd_config
  • How to change the default port(s) used by the server
  • How to change the address the server listens to
  • How to change the maximum SSH login time
  • How to allow or deny login as root
  • How to change the max login attempts and maximum number of session opened
  • How to display a message when user tries to authenticate to the server
  • How to Enable/Disable password and pubkey authentication
  • How to Enable/Disable HostBasedAuthentication
  • Enabling/Disabling X11 Forwarding

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MySQL workbench dashboard on Ubuntu Linux

Install and Configure MySQL Workbench on Ubuntu Linux

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MySQL workbench is a graphical application which let us manage data and perform administrative tasks on MySQL databases. In this tutorial we will see how to install the program on Ubuntu 18.04 (Bionic Beaver) and we will perform a brief tour of some of its most basic functionalities to make your Linux system administration job easier.

In this tutorial you will learn:

  • How to install and configure MySQL workbench
  • How to create a schema and a table via MySQL workbench
  • How to crate an E.R diagram by reverse-engineering an existing schema
  • How to execute SQL queries

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How dd command works in Linux with examples

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Dd is a very powerful and useful utility available on Unix and Unix-like operating systems. As stated in its manual, its purpose is to convert and copy files. On Unix and Unix-like operating systems like Linux, almost everything is treated as a file, even block devices: this makes dd useful, among the other things, to clone disks or wipe data. The dd utility is available out of the box even in the most minimal installation of all distributions. In this tutorial we will see how to use it and how we can modify its behavior by using some of the most commonly used options to make your Linux system administration job easier.

In this tutorial you will learn:

  • How to use dd
  • How to modify the program behavior by using some of the most commonly used options

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Introduction to MySQL/MariaDB database SQL views

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A database view is nothing but a virtual table, which does not contains data itself, but references data contained in other tables. Views are basically the result of stored queries which can vary on complexity and can be used, for example, to hide data from users, allowing access only on selected columns of a table, or simply to provide a different point of view on the existing data. In this tutorial we will see how to create, update, alter and drop a view on a MySQL, MariaDB database.

In this tutorial you will learn:

  • What is a view
  • How to create a view
  • How to update a view
  • How to alter a view
  • How to drop a view

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php-curl

How to perform web requests with PHP using the cURL extension

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The open source libcurl is client-side URL transfer library which supports a lot of protocols like FTP, HTTP, HTTPS  and works on a multitude of platforms. The PHP cURL module let us access the functionalities provided by the library from the PHP programming language. In this tutorial we will see how to install the module and how to use it to perform simple requests.

In this tutorial you will learn:

  • How to install the cURL module
  • The basic steps to follow to initialiaze a cURL session and perform a request
  • How to perform a GET request with PHP cURL
  • How to perform a POST request with PHP cURL

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How to use graphical widgets in bash scripts with zenity

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Zenity is a very useful utility which let us create graphical user interfaces for our shell scripts. Several widgets exists, and can be used by invoking the program with the respective options. The widgets are based on the GTK toolkit, and return the result of the user interaction either on the standard output or as a return code.

In this tutorial you will learn:

  • What are the general zenity options
  • What are the some of the most useful available widgets and how to use them

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How fstab works – introduction to the /etc/fstab file on Linux

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The /etc/fstab file is one of the most important files in a Linux-based system, since it stores static information about filesystems, their mountpoints and mount options. In this tutorial we will learn to know its structure in details, and the syntax we can use to specify each entry in the file.

In this tutorial you will learn:

  • How to use the fstab file to provide static filesystem information
  • How the fstab file is structured
  • What is the purpose of each entry field in the file

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How to extend the GNOME Nautilus file manager with custom scripts

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Although GNOME, in its 3.x iteration has been the object of many debates, due to its non-traditional desktop paradigm, it is probably the most used desktop on Linux. The default file manager included in GNOME is Nautilus (the application new name is “Files”). In this tutorial we will see how we can extend the file manager with functionalities provided by custom scripts.

In this tutorial you will learn:

  • How to use custom scripts to extend Nautilus functionalities

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How to setup AMule and control it via web interface on a Raspberry Pi

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AMule is a p2p, open source client for the  eD2k network. Released under the GPL license, it supports a lot of platforms and operating systems. In this tutorial we will see how to install a minimal, headless version of AMule on Raspbian “Stretch”, the latest version of the official Raspberry Pi OS. We will see how to setup the amule-daemon and adjust the firewall rules in order to control it via web interface.

In this tutorial you will learn:

  • How to install and configure the amule-daemon
  • How to configure and access the amule web interface

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How to Reuse PHP Code Effectively – Introduction to PHP traits

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Originally developed by Rasmus Lerdorf in 1994, PHP is one of the most used general-purpose programming languages. Originally born as a template language, during the years it evolved into a fully-featured language with proper OOP (Object Oriented Programming) support. Its latest incarnation, 7.x, introduced new features like return type declaration for functions and huge performance improvements. PHP is a single inheritance language: this means that a class can inherit only for one parent or base class. To overcome this problem a feature was introduced in the language: traits. In this article we will see how to use it and how it works.

In this tutorial you will learn:

  • How to use traits in Php

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How to create, package and sign a Firefox web extension

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Firefox is one of the most used web browser in the world: it’s a free and open source software built by the Mozilla foundation, and it’s available for all the major operating systems. The browser has all the features that nowadays are considered standard: tabbed browsing, private navigation, a synchronization system and its functionalities can be extended using third party addons written in Javascript. In this tutorial we will see how to create, build and sign a simple web extension.

In this tutorial you will learn:

  • How to build and test a simple Firefox web extension
  • How to package and sign an extension

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Introduction to Bash Shell Parameter Expansions

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A shell is a crucial part of an Unix-based operating system and is the main interface we can use to interact with the system itself. Bash is without doubt the most used shell on the majority of Linux distributions: it was born as thefree software replacement for the Bourne shell (bash is the acronym for Bourne-again shell) inside the GNU project. In this tutorial we will learn how some of the most useful bash expansions works.

In case you are not familiar with Bash yet, or you simply need to refresh your memory, then you are recommended to visit our Bash Scripting Tutorial for Beginners, before you dive into the Bash Shell expansions concept below.

In this tutorial you will learn:

  • How to use various bash parameter expansions

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