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

Perl arrays

Something that we can make use of in Perl is an array. These arrays are variables that are created from lists; put simply, they are basically multi-valued variables. If we were to use a container analogy to describe a variable, it will be either a cup or a placeholder for one value. An array will be analogous to a crate. We can describe the crate with a single name but we have to include additional naming elements to access each slot within the crate. A crate can hold more than a single item, just like an array.

We saw that by using bash scripting we can pass command line arguments in the script. The arguments were using their own variable name, $1, $2, and so on. This also clashed with the name of the program, to a degree, because of the fact that it was $0. Even though they may appear similar, there is no logical relationship between $0 and $1. The $0 variable is the name of the script and $1 is the first argument. When we look at this in Perl, we can start to see some of the...