Different Login Shell Types

 Different Login Shell Types (Bourne, Korn, C)

There are three major login shells:

1. The Bourne shell (sh)
   1. The original UNIX shell
   2. Now viewed as "limited" in its capabilities as a login shell
2. The C shell (csh)
   1. Named after the C programming language
   2. Created at the University of California/Berkeley (UCB)
   3. Commonly used as a login shell
3. The Korn shell (ksh)
   1. From AT&T
   2. Supports all Bourne shell commands
   3. Supports many C shell commands
   4. Adds new features    

What is shell

In short we can say shell is the program which communicate between the unix OS and the user. it works as a interpreter.

Shell Scripting

Types of commands :
Basic Commands
Coplex commands
Compund commands