UNIX 3 :- SHELL (User Interface)

1. In UNIX the user interact with the system through a command interpreter called the shell.
2. The user key in the words and the shell interprets it as a command to be executed.
3. A command may already exist in the system or can be written by the user. 

The power of UNIX lies in combining these commands just like you combine the words of  English to generate a meaningful sentence.


Common shells in UNIX are :-

1.  C Shell          -    csh               -           commonly used by general users.
2. Bourne shell   -      sh               -           Commonly used by system administrators.
3. Korn Shell      -     ksh               - 
4. Bash Shell      -                         -