Book Image

Learning Linux Shell Scripting

By : Ganesh Sanjiv Naik
Book Image

Learning Linux Shell Scripting

By: Ganesh Sanjiv Naik

Overview of this book

Linux is the one of the most powerful and universally adopted OSes. Shell is a program that gives the user direct interaction with the operating system. Scripts are collections of commands that are stored in a file. The shell can read this file and act on the commands as if they were typed on the keyboard. Shell scripting is used to automate day-to-day administration, and for testing or product development tasks. This book covers Bash, GNU Bourne Again SHell, preparing you to work in the exciting world of Linux shell scripting. We start with an introduction to the Shell environment and explain basic commands used in Shell. Next we move on to check, kill, and control the execution of processes in Linux OS. Further, we teach you about the filter tools available in Linux and explain standard output and standard errors devices. Then we will ensure you understand Shell’s interpretation of commands and get a firmer grasp so you use them in practice. Next, you’ll experience some real-world essentials such as debugging and perform Shell arithmetic fluently. Then you’ll take a step ahead and learn new and advanced topics in Shell scripting, such as starting up a system and customizing a Linux system. Finally, you’ll get to understand the capabilities of scripting and learn about Grep, Stream Editor, and Awk.
Table of Contents (20 chapters)
Learning Linux Shell Scripting
Credits
About the Author
Acknowledgments
About the Reviewers
www.PacktPub.com
Preface
Index

Pattern matching with the vi editor


For learning pattern matching, we will ensure that the pattern that we will search should be highlighted when the searched pattern is found.

The configuration file for vi is /etc/vimrc.

In the vi editor, give the following command to highlight search:

Sr.

Commands

Description

1

:set hlsearch

This highlights search pattern

2

:se[t] showmode

Show when you are in insert mode

3

:se[t] ic

Ignore case when searching

4

:set noic

Shows case sensitive search

The mentioned user should open the file in vi, press the Esc button so that it goes into command mode and then enter colon followed by these commands.

The following are commands for pattern search and replace:

Sr.

Commands

Description

1

/pat

This searches for the pattern pat and places the cursor where the pattern occurs

2

/

This repeats the last search

3

:%s/old/new/g

Globally, all the occurrences of old will be replaced by new

4

:#,#s/old/new/g

Where #,# should be...