Linux Shell Scripting Tutorial A Beginner's handbook Copyright © 1999-2014 by Satnam Singh Table of Contents Chapter 1: Quick Introduction to Linux What Linux is? Who developed the Linux? How to get Linux? How to Install Linux Where I can use Linux? What Kernel Is? What is Linux Shell? How to use Shell What is Shell Script ? Why to Write Shell Script ? More on Shell... Chapter 2: Getting started with Shell Programming How to write shell script Variables in shell How to define User defined variables (UDV)  Rules for Naming variable name (Both UDV and System Variable) How to print or access value of UDV (User defined variables) echo Command Shell Arithmetic More about Quotes Exit Status The read Statement  Wild cards (Filename Shorthand or meta Characters)  More commands on one command line Command Line Processing Why Command Line arguments required Redirection of Standard output/input i.e. Input - Output redirection Pipes Filter What is Processes Why Process required Linux Command(s) Related with Process Chapter 3: Shells (bash) structured Language Constructs Decision making in shell script ( i.e. if command) test command or [ expr ] if...else...fi Nested ifs Multilevel if-then-else Loops in Shell Scripts for loop Nested for loop while loop The case Statement How to de-bug the shell script? Chapter 4: Advanced Shell Scripting Commands /dev/null - 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-Part I User Interface and dialog utility-Part II Message Box (msgbox) using dialog utility  Confirmation Box (yesno box) using dialog utility Input (inputbox) using dialog utility User Interface using dialog Utility - Putting it all together trap command The shift Command getopts command Chapter 5: Essential Utilities for Power User Preparing for Quick Tour of essential utilities Selecting portion of a file using cut utility Putting lines together using paste utility The join utility Translating range of characters using tr utility Data manipulation using awk utility sed utility - Editing file without using editor Removing duplicate lines from text database file using uniq utility Finding matching pattern using grep utility Chapter 6: Learning expressions with ex Getting started with ex Printing text on-screen Deleting lines Coping lines Searching the words Find and Replace (Substituting regular expression) Replacing word with confirmation from user Finding words Using range of characters in regular expressions Using & as Special replacement character Converting lowercase character to uppercase Chapter 7: awk Revisited Getting Starting with awk Predefined variables of awk  Doing arithmetic with awk User Defined variables in awk Use of printf statement Use of Format Specification Code if condition in awk Loops in awk Real life examples in awk awk miscellaneous sed - Quick Introduction Redirecting the output of sed command How to write sed scripts? More examples of sed Chapter 8: Examples of Shell Scripts Logic Development: Shell script to print given numbers sum of all digit Shell script to print contains of file from given line number to next given number of lines Shell script to say Good morning/Afternoon/Evening as you log in to system Shell script to find whether entered year is Leap or not Sort the given five number in ascending order (use of array) Command line (args) handling: Adding 2 nos. suppiled as command line args Calculating average of given numbers on command line args Finding out biggest number from given three nos suppiled as command line args Shell script to implement getopts statement. Basic math Calculator (case statement) Loops using while & for loop: Print nos. as 5,4,3,2,1 using while loop  Printing the patterns using for loop. Arithmetic in shell scripting: Performing real number calculation in shell script Converting decimal number to hexadecimal number Calculating factorial of given number File handling: Shell script to determine whether given file exist or not. Screen handling/echo command with escape sequence code: Shell script to print "Hello World" message, in Bold, Blink effect, and in different colors like red, brown etc. Background process implementation: Digital clock using shell script User interface and Functions in shell script: Shell script to implements menu based system. System Administration: Getting more information about your working environment through shell script Shell script to gathered useful system information such as CPU, disks, Ram and your environment etc. Shell script to add DNS Entery to BIND Database with default Nameservers, Mail Servers (MX) and host  Integrating awk script with shell script: Script to convert file names from UPPERCASE to lowercase file names or vice versa. Chapter 9: Other Resources Appendix - A : Linux File Server Tutorial (LFST) version b0.1 Rev. 2 Appendix - B : Linux Command Reference (LCR) About the author