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 (16 chapters)
15
Index

Summary

This marks the end of the chapter and I am sure that you might have found this useful. Especially for those making a start with bash scripting, this chapter must have built a firm foundation on which you can build your knowledge.

We began by ensuring that bash is secure and not susceptible to embedded functions shell-shock. With bash secured, we considered the execution hierarchy where aliases, functions, and so on are checked before the command; knowing this can help us plan a good naming structure and a path to locate the scripts.

Soon we were writing simple scripts with static content but we saw how easy it was to add flexibility using arguments. The exit code from the script can be read with the $? variable and we can create a command line list using || and &&, which depends on the success or failure of the preceding command in the list.

Finally, we closed the chapter by looking at debugging the script. Its not really required when the script is trivial, but it will be useful later when complexity is added.

In the next chapter, we will be creating interactive scripts that read the user's input during script execution.