Book Image

Mastering Linux Shell Scripting - Second Edition

By : Mokhtar Ebrahim, Andrew Mallett
5 (1)
Book Image

Mastering Linux Shell Scripting - Second Edition

5 (1)
By: Mokhtar Ebrahim, Andrew Mallett

Overview of this book

In this book, you’ll discover everything you need to know to master shell scripting and make informed choices about the elements you employ. Grab your favorite editor and start writing your best Bash scripts step by step. Get to grips with the fundamentals of creating and running a script in normal mode, and in debug mode. Learn about various conditional statements' code snippets, and realize the power of repetition and loops in your shell script. You will also learn to write complex shell scripts. This book will also deep dive into file system administration, directories, and system administration like networking, process management, user authentications, and package installation and regular expressions. Towards the end of the book, you will learn how to use Python as a BASH Scripting alternative. By the end of this book, you will know shell scripts at the snap of your fingers and will be able to automate and communicate with your system with keyboard expressions.
Table of Contents (17 chapters)

Questions

  1. What is the output of the following command?
$ awk '
BEGIN{
var="I love AWK tool"
print $var 
}'

  1. Assume you have the following file:
13
15
22
18
35
27

Then you run the following command against this file:

$ awk '{if ($1 > 30) print $2}' myfile 

How many numbers will be printed?

  1. Assume that you have the following file:
135 325 142
215 325 152
147 254 327

And you run the following command:

$ awk '{
total = 0
i = 1
while (i < 3)
{
total += $i
i++
}
mean = total / 3
print "Mean value:",mean  
}' myfile

What is wrong with the previous code?

  1. How many lines will be printed from the following command?
$ awk -F":" '$3 < 1 ' /etc/passwd