Book Image

Linux Shell Scripting Bootcamp

By : James K Lewis
Book Image

Linux Shell Scripting Bootcamp

By: James K Lewis

Overview of this book

Linux Shell Scripting Bootcamp is all about learning the essentials of script creation, validating parameters, and checking for the existence of files and other items needed by the script. We will use scripts to explore iterative operations using loops and learn different types of loop statements, with their differences. Along with this, we will also create a numbered backup script for backup files. Further, you will get well-versed with how variables work on a Linux system and how they relate to scripts. You’ll also learn how to create and call subroutines in a script and create interactive scripts. The most important archive commands, zip and tar, are also discussed for performing backups. Later, you will dive deeper by understanding the use of wget and curl scripts and the use of checksum and file encryption in further chapters. Finally, you will learn how to debug scripts and scripting best practices that will enable you to write a great code every time! By the end of the book, you will be able to write shell scripts that can dig data from the web and process it efficiently.
Table of Contents (19 chapters)
Linux Shell Scripting Bootcamp
About the Author
About the Reviewer
Customer Feedback

Progress indicator

Here is another cursor movement script that also calculates the low and high of the $RANDOM Bash variable. It might not look all that cool to everyone but it does show some more of the concepts we have covered in this book. I was also somewhat curious as to what the range of that random number generator was.

Chapter 10 - Script 1

# 6/11/2017
# Chapter 10 - Script 1

# Subroutines
trap catchCtrlC INT          # Initialize the trap

# Subroutines
 loop=0                      # end the loop

 tput clear

movestr()                    # move cursor to row, col, display string
 tput cup $1 $2
 echo -n "$3"

# Code
if [ "$1" = "--help" ] ; then
 echo "Usage: script1 or script1 --help "
 echo " Shows the low and high count of the Bash RANDOM variable."
 echo " Press Ctrl-C to end."
 exit 255



echo "Chapter 10 - Script 1"
echo "Calculating RANDOM low and high .....