Question

What is the shell? What shell program is present in all versions of UNIX? What is a shell prompt?

Thank you.

Answer 1

Shell:

The shell is the utility that processes your requests. When you type in a command at your terminal, the shell interprets the command and calls the program that you want. To do anything in the system, we should give the shell a command. If the command requires a utility, the shell requests that the kernel execute the utility.

       There are two major parts to a shell.The first is the interpreter.The second part of

the shell is aprogramming capability that allows you to write a shell (command) script

Three type of shell

1)C Shell

-The C shell, developed in Berkeley by Bill Jo

2)Bourne Shell

-The Bourne shell, developed by Steve Bourne

3) Korn Shell

-The Korn shell, developed by David Korn

This three re famous shells which are available in Unix variants.

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the follwing shell Progran used to all unix version in system

#!/bin/bash

$ cat /etc/*-release

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shell Prompt

The Shell prompt, $, which is called command prompt, is issued by the shell.

you can type a command. The shell reads your input after you press Enter. It determines the command you want executed by looking at the first word of your input

examples

$ ls

It will show all list of files in current Directory

$cd user

used into change directory