LINUX/UNIX has three most important parts. They are Kernel, Shell and File System
Figure: Layers of Linux
- Kernel is the heart of the operating system.
- It is the low level core of the System that is the interface between applications and H/W.
- Manage Memory, I/O devices, allocates the time between user and process,inter process communication, sets process priority
The shell is a program that sits on the as an interface between users and kernel It is a command interpreter and also has programming capability of its own.
- Shell Types
- Bourne Shell (sh) (First shell by Stephen Bourne)
- C Shell(sh)
- Korn Shell (ksh)
- Bourne Again Shell(bash)
- Linux treats everything as a file including hardware devices. Arranged as a directory hierarchy.
- The top level directory is known as ―root (/).