Linux refers to an open-source, Unix-like operating system kernel that serves as the core component of various Linux-based operating systems (OS). The Linux kernel was initially created by Linus Torvalds in 1991 and has since been developed collaboratively by a large community of developers worldwide. The term "Linux" is often used more broadly to refer to complete operating systems, known as Linux distributions or distros, which combine the Linux kernel with additional software and utilities to create a functional and user-friendly computing environment. .

1. Multiuser Capability
• Linux is designed to support multiple users, allowing several users to log in and use the system simultaneously, each with their own user account and personalized environment.
2. Security Features
• Linux has robust security features, including user permissions, file system encryption, and a comprehensive set of tools to secure the system against malware and unauthorized access.
3. File Systems
• Linux supports a variety of file systems, including ext4, Btrfs, XFS, and more. Each file system has its own features and advantages, providing flexibility for different use cases.