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Bash Cookbook

You're reading from  Bash Cookbook

Product type Book
Published in Jul 2018
Publisher Packt
ISBN-13 9781788629362
Pages 264 pages
Edition 1st Edition
Languages
Authors (2):
Ron Brash Ron Brash
Profile icon Ron Brash
Ganesh Sanjiv Naik Ganesh Sanjiv Naik
Profile icon Ganesh Sanjiv Naik
View More author details
Toc

Table of Contents (15) Chapters close

Title Page
Copyright and Credits
Packt Upsell
Contributors
Preface
1. Crash Course in Bash 2. Acting Like a Typewriter and File Explorer 3. Understanding and Gaining File System Mastery 4. Making a Script Behave Like a Daemon 5. Scripts for System Administration Tasks 6. Scripts for Power Users 7. Writing Bash to Win and Profit 8. Advanced Scripting Techniques 1. Other Books You May Enjoy Index

Striping/altering/sorting/deleting/searching strings with Bash only


So far, we have seen inkling of the power of commands available in Linux, and some of these are among the most powerful: sed and grep. However, while we can easily use these commands together, sed by itself or even using another very useful command called awk, we can leverage Bash itself to shave time and reduce external dependencies in a portable way!

So, how can we do this? Let's begin with a few examples using this Bash syntax:

#!/bin/bash
# Index zero of VARIABLE is the char 'M' & is 14 bytes long
VARIABLE="My test string"
# ${VARIABLE:startingPosition:optionalLength}
echo ${VARIABLE:3:4}

In the preceding example, we can see a special way of calling special substring functionality using ${...} , where VARIABLE is a string variable within your script (or even global), and then the following variable is the :. After the :, there is the startingPosition parameter (remember that strings are just arrays of characters and...

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