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Bash, the Bourne Again Shell, it's the default shell on practically all major linux distributions: it is really powerful and can be also considered as a programming language, although not as sophisticated or feature-reach as python or other "proper" languages. In this tutorial we will see how to use bash arrays and perform fundamental operations on them.

Keeping the system up to date is an every day task for a sysadmin, as well as a desktop user. By applying the latest (stable) available software on the system we can take advantage of the latest features, and will be more protected from security issues and hopefully suffer less from bugs. To update the system you will need configured yum repositories that act as the source of the updated software.

Variables expansion is one of the most common feature used in the shell: when a variable exists and is part of a command, it is "expanded", so that is substituted by its value. The expansion of empty variables, is one of those things, that if not well managed, could cause serious damage to a system.

Manually mounting and unmounting devices such as external USB drives or remote NFS or Samba shares can be tedious tasks to perform when administering a machine. The autofs daemon can help us automatically mounting a filesystem when needed and umounting it after a specified period of time. In this tutorial we will see the basic concept related to the automounter, and how to configure it.

Using Apache httpd as a proxy to an Apache Tomcat application container is a common setup. It comes with many use cases, the most trivial is serving static content from httpd, while providing services implementing heavy business logic from an application written in Java that resides in the Tomcat container.

Ethereum has established itself as one of the big players in the cryptocurrency world. It's value has been on a steady rise for well over a year, and it's one of the most widely traded coins in the world.

Ethereum is also an open source technology, and the Ethereum blockchain is powering a whole new wave of web development and web technologies. Even though the initial wave of interest in Ethereum has subsided, it's clearly not too late to get involved.

In a corporate environment it is common to limit Internet access - both for security and accountability. This is often accomplished by using proxy servers that enable access to the Internet after some sort of authentication, while inspect and log all traffic passing trough them. This way the company can, for example find the employee who downloaded the virus that wreak havoc within the corporate system (or at least the employee who's credentials where stolen to do so), or filter the traffic, preventing access to well-known harmful sites to protect employee equipment.

Partitions management is one of the most essentials and dangerous task to perform when working with operating systems. In this tutorial we will focus on the use of GNU parted and see how we can use it to create, resize and delete partitions from the command line interface.

PostgreSQL is a reliable open source database available in many modern distribution's repository. The ease of use, the ability to use extensions and the stability it provides all add to it's popularity. While providing the base functionality, like answering to SQL queries, store inserted data consistently, handling transactions, etc. most mature database solutions provide tools and know-hows on how to tune the database, identify possible bottlenecks, and be able to solve performance problems bound to happen as the system powered by the given solution grows.

Paperwork is a note-taking and archiving alternative to Evernote, Microsoft OneNote, and Google Keep, with the advantage of being FOSS (Free and Open Source Software), meaning it that can be hosted on the user premises, which is a requirement for people and businesses worried about privacy.

Traceroute finds the path network packets take between your computer and a destination. That destination could be a website, server, or another machine on your network. If you can send network packets to it, you can test the path with traceroute. It's a helpful tool for understanding how data flows through a network.

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.