Linux systems are multi-user environments where many users run programs and share data. Files and directories have three levels of permissions: World, Group, and User.

What is Linux and why it is used?

Linux® is an open source operating system (OS). An operating system is the software that directly manages a system’s hardware and resources, like CPU, memory, and storage. The OS sits between applications and hardware and makes the connections between all of your software and the physical resources that do the work.

What is a Unix environment?

UNIX is an operating system consisting of three important features; a kernel, the shell and a file system. As its name implies, the kernel is at the core of each UNIX system and is loaded in whenever the system is started up – referred to as a boot of the system.