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Whois is a simple, yet powerful, tool that allows you to see information about a specific domain name or IP address. You can use it to see things like contact information, nameservers, and domain registration information. Whois is an older core Unix utility, so it's available on every distribution.

TrueCrypt was known as a gold standard in filesystem encryption. It was known for providing excellent encryption options, including hidden encrypted volumes. That's something the LUKS can't do. TrueCrypt has been abandoned, but it's been forked into VeraCrypt.

KVM is the Linux kernel's own answer to virtualization. As a result, it's the lightest, most stable, and most universal virtualization option for Linux systems. While, KVM isn't as simple to set up as packaged solutions like VirtualBox, it's ultimately more efficient and flexible.

Web scraping is a technique which consist in the extraction of data from a web site through the use of dedicated software. In this tutorial we will see how to perform a basic web scraping using python and the Beautiful Soup library. We will use python3 targeting the homepage of Rotten Tomatoes, the famous aggregator of reviews and news for films and tv shows, as a source of information for our exercise.

MySQL/MariaDB triggers are stored programs associated with a table in a database, and used to automatically perform some actions when an INSERT, DELETE or UPDATE event is performed on the table. A trigger can be set to perform an action either before or after the event it is associated to. In this tutorial, we will see how to create and manage a trigger.

Server-sent events is an HTML5 technology which allows a client to automatically monitor event notifications from a server, and react as needed. This technology is very useful to notify live events, to implement, for example, a live messaging application or a news feed. In this tutorial we will see how to implement this technology using PHP and javascript.

Remembering Passwords is awful. It's not something anyone likes, and with people needing more online accounts than ever, it's becoming entirely unmanageable. Remember, using the same password twice is a BAD IDEA.

FreeIPA is mainly a directory service, where you can store information about your users, and their rights regarding login, become root, or just run a specific command as root on your systems that are joined your FreeIPA domain, and many more. Although this is the main feature of the service, there are optional components that can be very useful, like DNS and PKI - this makes FreeIPA an essential infrastructural part of a Linux-based system. It has a nice web-based GUI, and powerful command line interface.

One of the core feature of any Linux system is that they are built for automation. If a task may need to be executed more than one time - even with some part of it changing on next run - a sysadmin is provided with countless tools to automate it, from simple shell scripts run by hand on demand (thus eliminating typo errors, or only save some keyboard hits) to complex scripted systems where tasks run from cron at a specified time, interacting with each other, working with the result of another script, maybe controlled by a central management system etc.

PostgreSQL is an open source RDBMS (Relational DataBase Management System), and with any databases, the need may arise to scale and provide HA (High Availability). A single system providing a service is always a possible single point of failure - and even with virtual systems, there may be a time when you can't add more resources to a single machine to cope with the ever-increasing load. There also may be a need to another copy of the database contents that can be queried for long-running analytics, that are not fit to be run on the highly transaction-intensive production database. This copy could be a simple restore from the most recent backup on another machine, but the data would be outdated as soon as it is restored.

RPM, which stands for Red Hat Package Manager, is a well-known and mature package manager used by all Red Hat flavor distributions, as well as SuSE. With RPM the packager can define relations between packages, and even with versions of packages - for example, an Apache Tomcat server needs proper Java environment present to be able to run.

The objective is to install Tor on Ubuntu 18.04 Bionic Beaver. This guide will also provide you with some basic configuration and usage of Tor network in order to conceal your identity.

Packages to be installed with RPM package manager have the .rpm extension and are basically archives which contain the files provided by a library or an application plus information needed for the package to be installed and run correctly, such as its dependencies. In this tutorial we will learn how to use rpmrebuild, a very powerful tool which let us modify an existing rpm package without having to rebuild it from source code.

You many have heard of Owncloud. It was the primary solution for open source self hosted cloud storage for quite some time. Unfortunately, due to internal struggles, Owncloud split. Owncloud still remains, but it is currently owned by the people that caused the split. Nextcloud, on the other hand, is run by the original founder and the people who wanted to continue to work with the open source community.

Most likely, your are at the moment sitting in front of your computer, have a terminal window opened and wondering: "What should I do with this thing? Well, the terminal window in front of you contains shell, and shell allows you by use of commands to interact with your computer, hence retrieve or store data, process information and various other simple or even extremely complex tasks.

The objective is to create an offline digital and paper bitcoin wallet using Linux operating system, VirtualBox and Electrum Bitcoin wallet. The outcome of this tutorial will be a paper with written keywords which can be used to access your bitcoins. We will also create an encrypted version of virtual machine as a digital backup to be stored digitally on a secure medium which will provide a convenient access to your bitcoins if necessary.

During the administration of a system, being able to schedule a task for a later execution it's one crucial ability: to perform a backup of a database for example, or perhaps to run a maintenance script. Less known than cron or anacron, the at program let us do this in a pretty easy way: in this tutorial we will learn how to use it and how it is different from the programs mentioned above.

Lynis is a tool for performing an automated audit of your system. It's not a virus scanner or an antivirus. Instead, it checks certain criteria on your system to see how it's configured. By evaluating the system configuration, Lynis can give you an idea what areas are reasonably secure, and which ones need additional hardening.

It's important to regularly test any public-facing server to see which information it's making available. That information is important to attackers. They can use it to put together a picture of your server, what's running on it, and which exploits might work against it.

In a GNU/Linux system, while devices low level support is handled at the kernel level, the management of events related to them is managed in userspace by udev, and more precisely by the udevd daemon. Learning how to write rules to be applied on the occurring of those events can be really useful to modify the behavior of the system and adapt it to our needs.