Book Image

Mastering Linux Shell Scripting

By : Andrew Mallett
Book Image

Mastering Linux Shell Scripting

By: Andrew Mallett

Overview of this book

Shell scripting is a quick method to prototype a complex application or a problem by automating tasks when working on Linux-based systems. Using both simple one-line commands and command sequences complex problems can be solved with ease, from text processing to backing up sysadmin tools. In this book, you’ll discover everything you need to know to master shell scripting and make informed choices about the elements you employ. 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. Implement functions and edit files using the Stream Editor, script in Perl, program in Python – as well as complete coverage of other scripting languages to ensure you can choose the best tool for your project.
Table of Contents (21 chapters)
Mastering Linux Shell Scripting
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Controlling the visibility of entered text


Even though we have limited the input to a single character, we do get to see the text on the screen. In the same way, if we type the name we get to see the entered text before we hit Enter. In this case, it is just untidy but if we were entering sensitive data, such as a pin or a password, we should hide the text. We can use the silent option or -s to achieve this. A simple edit in the script will set this in place:

#!/bin/bash
read -p "May I ask your name: " name
echo "Hello $name"
read -sn1 -p "Press any key to exit"
echo
exit 0

Now, when we use a key to continue, it will not be displayed on the screen. We can see the behavior of the script in the following screenshot: