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)

Using Python to write to files

To add some variety to this chapter, we will now look at printing this data to a file. Again using Python, this is quite a simple and easy way to pick up. We will start by making a copy of our existing args.py. We will copy this to $HOME/bin/file.py. The new file.py should read similar to the following screenshot and have the execute permission set:

You will notice that we have just altered the final lines and instead of print we now open a file. We also see more of the object-orientated nature of Python, whereby it dynamically assigns the write() and close() methods to the object log, as it is seen as an instance of a file. When we open the file, we open it up for the purpose of appending, meaning that we do not overwrite the existing content if it is already there. If the file is not there, we will create a new file. If we use w, we will open...