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
About the Author
About the Reviewer

Using echo with options

So far, in this book we have been able to see that the echo command is very useful and is going to be in many of our scripts, if not all. We have also seen that this is both a built-in command as well as a command file. When running the echo command, the built-in command will be used unless we state the full path to the file. We can test this with the following command:

$ test -a echo

To gain help on the built-in command, we can use man bash and search for echo; however, the echo command is identical to the internal command so I will recommend that you use man echo in most cases in order to display command options.

The basic use of echo that we have seen so far will produce a text output and a new line. This is often the desired response so we don't have to be concerned that the next prompt will append to the end of the echoed text. The new line separates the script output from the next shell prompt. If we do not supply any text string to print, echo will print only...