Shell Scripting

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  • Topic: Shell script, Shell, Unix shell
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  • Published : August 30, 2010
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Linux Shell Scripting Tutorial

Linux Shell Scripting Tutorial Ver. 1.0
Written by Vivek G Gite

INDEX
q

Introduction
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Kernel Shell How to use Shell Common Linux Command Introduction Why Process required Linux commands related with process Redirectors Pipes Filters Variables in Linux How to define User defined variables Rules for Naming variable name How to print or access value of UDV (User defined variables) How to write shell script How to Run Shell Scripts Quotes in Shell Scripts

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Process
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Redirection of Standard output/input
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q

Shell Programming
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http://www.freeos.com/guides/lsst/index.htm (1 of 2) [17/08/2001 17.41.52]

Linux Shell Scripting Tutorial

r r r r r q

Shell Arithmetic Command Line Processing (Command Line Arguments) Why Command Line arguments required Exit Status Filename Shorthand or meta Characters (i.e. wild cards) echo command Decision making in shell script ( i.e. if command) test command or [ expr ] Loop in shell scripts The case Statement The read Statement /dev/null - Use to send unwanted output of program Local and Global Shell variable (export command) Conditional execution i.e. && and || I/O Redirection and file descriptors Functions User Interface and dialog utility trap command getopts command More examples of Shell Script (Exercise for You :-) © 1998-2000 FreeOS.com (I) Pvt. Ltd. All rights reserved.

Programming Commands
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More Advanced Shell Script Commands
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http://www.freeos.com/guides/lsst/index.htm (2 of 2) [17/08/2001 17.41.52]

Linux Shell Script Tutorial

Introduction

This tutorial is designed for beginners only and This tutorial explains the basics of shell programming by showing some examples of shell programs. Its not help or manual for the shell. While reading this tutorial you can find manual quite useful ( type man bash at $ prompt to see manual pages). Manual contains all necessary information you need, but it won't have that much examples, which makes idea more clear. For that reason, this tutorial contains examples rather than all the features of shell. I assumes you have at least working knowledge of Linux i.e. basic commands like how to create, copy, remove files/directories etc or how to use editor like vi or mcedit and login to your system. Before Starting Linux Shell Script Programming you must know q Kernel q Shell q Process q Redirectors, Pipes, Filters etc.

What's Kernel

Kernel is hart of Linux O/S. It manages resource of Linux O/S. Resources means facilities available in Linux. For eg. Facility to store data, print data on printer, memory, file management etc . Kernel decides who will use this resource, for how long and when. It runs your programs (or set up to execute binary files) It's Memory resident portion of Linux. It performance following task :q I/O management q Process management q Device management q File management q Memory management

What's Linux Shell

Computer understand the language of 0's and 1's called binary language, In early days of computing, instruction are provided using binary language, which is difficult for all of us, to read and write. So in O/s there is special program called Shell. Shell accepts your instruction or commands in English and translate it into computers native binary language. This is what Shell Does for US

http://www.freeos.com/guides/lsst/kershell.htm (1 of 5) [17/08/2001 17.42.02]

Linux Shell Script Tutorial

You type Your command and shell convert it as

It's environment provided for user interaction. Shell is an command language interpreter that executes commands read from the standard input device (keyboard) or from a file. Linux may use one of the following most popular shells (In MS-DOS, Shell name is COMMAND.COM which is also used for same purpose, but it's not as powerful as our Linux Shells are!) Shell Name BASH ( Bourne-Again SHell ) Developed by Brian Fox and Chet...
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