rsync is one of the most advanced file synchronization tools for Linux systems, and its main strength lies in its efficient delta synchronization algorithm. Instead of copying entire files, the program can detect changes in files and transfer only the modified data blocks, or "deltas", over the network. This article introduces the history of the tool, created by Andrew Tridgell in the 1990s, and the theory behind its operation. We discuss in detail the famous rsync algorithm, which compares source and destination files using checksums with minimal network traffic. We cover two main modes of operation: using it securely over an SSH tunnel, and running it in dedicated daemon mode, used on public mirror servers. The article also analyzes the importance of "archive" mode (-a switch), which ensures that permissions, timestamps, and other metadata are preserved intact. We examine the advantages of rsync, such as bandwidth efficiency, flexibility, and the ability to resume interrupted transfers. Finally, we summarize its disadvantages, such as higher resource requirements and the fact that its true effectiveness is revealed during repeated runs.

GParted (GNOME Partition Editor) is a free, open source, and user-friendly graphical partitioning tool that has become the standard partitioning program for Linux systems. This encyclopedia entry provides a detailed introduction to the software's history, purpose, and key milestones in its development, such as the introduction of NTFS and GPT support. The article guides the reader step-by-step, with numerous screenshots, through the most important disk management operations, from creating a partition table to creating, resizing, and moving new partitions, to safely finalizing the operations. A separate chapter covers the portable, bootable version of GParted Live, which also allows you to modify system partitions, and shows you how to start it. The article places special emphasis on security considerations, emphasizing the critical importance of backing up your data before partitioning.

This encyclopedia entry provides a detailed overview of GitHub, the world's leading web-based software development platform, and explains its relationship to the Git version control system behind it. The description presents the history of the platform, which is based on the philosophy of "social coding", and its impact on community development. We discuss in detail the basic building blocks of GitHub, starting from the repository, through the use of branches that enable parallel development, to "Verified" commits authenticated with GPG keys. The article places great emphasis on the "Fork and Pull Request" model that revolutionized open source contribution, and the Issues and Milestones system that helps project planning. We also cover the role of SSH and GPG keys, which are essential for secure work, the operation of GitHub Actions that provide automation, and the Tags and Releases function that closes the software release cycle. Finally, the post analyzes the indispensable role of GitHub in the open source ecosystem.

Git is a modern, distributed version control system that has become the industry standard for software development. Created by Linus Torvalds in 2005 for the needs of the Linux kernel, the tool focuses on speed, data integrity, and support for non-linear workflows. This encyclopedia entry provides a detailed introduction to Git's core concepts, such as its distributed architecture, snapshot-based data model, and workflow between three main states (Working Directory, Repository, and Repository). We cover key terminology such as commit, branch, and remote, and examine how digitally signing with GPG keys increases the credibility of a project. The article clarifies the difference between Git (as a tool) and services that build on it, such as GitHub (as a platform), and summarizes the main advantages of Git that have made it an indispensable foundation for modern software development.

GPG keys are a set of digital tools based on asymmetric cryptography that allows data encryption and digital signatures, based on the OpenPGP standard. Each key consists of a public part that others can use to encrypt for us, and a closely guarded private part that we can use to decrypt and sign. This encyclopedia entry provides a detailed explanation of the structure of a GPG key, from the secure master key, to the subkeys used for everyday tasks, to the fingerprint that proves authenticity. We cover the most important use cases, such as protecting emails, verifying software packages, and signing Git commits. The article introduces GPG's decentralized trust model, the Web of Trust, which is based on mutual trust between users rather than centralized authorities. This comprehensive description provides a theoretical foundation for anyone who wants to understand how GPG keys work and their significance.

Nginx is an open source, high-performance web server that goes far beyond its traditional role. It also functions as a reverse proxy, load balancer, and HTTP cache, making it a cornerstone of modern web infrastructure. Its popularity is due to its unique, event-driven, and asynchronous architecture, which allows it to handle tens of thousands of simultaneous connections with minimal resource consumption. The software was developed by Igor Sysoev to solve the C10k problem, and has received key improvements over its history, such as support for HTTP/2 and dynamic modules. This encyclopedia entry provides a detailed introduction to Nginx's master-worker process model, hierarchical configuration system, and key uses. Finally, we compare it with Apache HTTP Server, highlighting key differences in performance, configuration, and flexibility.

This encyclopedia entry provides a detailed introduction to daemons, the basic background services of Linux and Unix-like systems. The article starts with the mythological origin of the word "daemon" and explains the technical significance of the concept, showing how programs become independent, autonomous processes independent of the user. It deals in detail with the management of daemons in modern Linux distributions using the systemd init system and the systemctl command, illustrating the querying of the status of services, starting and stopping them through practical examples and screenshots. The description also provides insight into the deeper layers of systemd configuration with a detailed analysis of a real sshd.service unit file. The article finally concludes with an introduction to the most common daemons (e.g. sshd, apache2, cron), giving a comprehensive overview of these essential components for system operation.

Xfwm (Xfce Window Manager) is the default window manager for the XFCE desktop environment, responsible for managing, positioning, and decorating windows. Xfwm is a lightweight yet feature-rich window manager that provides optimal performance without demanding too many resources. In this short description, we will go over the main features and configuration options of Xfwm.