Linux, What is a shell?, command interpreter environment

Home
E-mail Us
Oracle Articles
New Oracle Articles

Oracle Training
Oracle Tips
Oracle Forum
Class Catalog

Remote DBA
Oracle Tuning
Emergency 911
RAC Support
Apps Support
Analysis
Design
Implementation
Oracle Support

SQL Tuning
Security
Oracle UNIX
Oracle Linux
Monitoring
Remote support
Remote plans
Remote services
Application Server
Applications
Oracle Forms
Oracle Portal
App Upgrades
SQL Server
Oracle Concepts
Software Support
Remote Support
Development
Implementation

Consulting Staff
Consulting Prices
Help Wanted!

Oracle Posters
Oracle Books
Oracle Scripts
Ion
Excel-DB

Don Burleson Blog

Oracle Tips by Burleson

What is a shell?

A shell provides a command interpreter environment for giving instructions to the Linux kernel via English-like commands. There are a number of different shell environments available in Linux. In order to determine which shell environments are available on your version of Linux, issue the following command:

Determining available shells

$ cat /etc/shells

/bin/sh

/bin/bash

/sbin/nologin

/bin/bash2

/bin/ash

/bin/bsh

/bin/ksh

/bin/tcsh

/bin/csh

/bin/zsh

$

We can see that we have several shells available on this server such as sh (Bourne shell), bash (Bourne Again shell), ksh (Korn shell), and csh (C-shell) among others. In Linux the default shell is normally the bash shell.

To determine what your default shell is currently set to, run the following command:

Determining your default shell

$ echo $SHELL

/bin/bash

As predicted, the bash shell is our current default.

As we mentioned, the shell is a command language interpreter that executes commands read from the standard input device (keyboard) or from a plain text file.

A shell can be compared to the Microsoft Windows command prompt, which also executes commands issued from the keyboard or from text (.bat) files. However, the shell environment is much more robust and feature-rich than its Windows counterpart.

The above book excerpt is from:

Easy Linux Commands
Working Examples of Linux Command Syntax

ISBN: 0-9759135-0-6

Terry Clark

http://www.rampant-books.com/book_2005_1_linux_commands.htm

��