Unix and Linux are related, but they are not the same thing. Unix is a family of operating systems with a long commercial and academic history. Linux is a Unix-like operating system kernel commonly used with GNU tools and modern distributions.
Unix
Unix systems influenced many operating system ideas: multi-user design, permissions, shells, small command-line tools and a hierarchical filesystem. Traditional Unix systems were often tied to specific vendors and hardware platforms.
Linux
Linux is the kernel used by distributions such as Debian, Ubuntu, Fedora, Red Hat Enterprise Linux and Arch. A Linux distribution combines the kernel with system tools, package management, libraries and applications.
The practical difference
- Linux is widely available as open source software.
- Unix-like commands and concepts are common across both worlds.
- Administration skills often transfer, but commands, package managers and service tools can differ.
- Modern Linux systems are common on servers, desktops, cloud platforms and embedded systems.
For a beginner, it is enough to remember that Linux behaves like a Unix-style system, but the exact tools depend on the distribution.