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)

Saying Hello World the Python way

The code we write in Python should be clear and uncluttered: sparse is better than dense. We will need the shebang on the first line and then the print statement. The print function includes the newline and we do not need semicolons at the end of the line. We can see the edited version of $HOME/bin/hello.py in the following example:

#!/usr/bin/python3
print("Hello World")

We will still need to add the execute permission, but we can run the code as earlier using chmod. This is shown in the following command but we should be a little used to this now:

$ chmod u+x $HOME/bin/hello.py

Finally, we can now execute the code to see our greeting.

Similarly, you can run the file using the Python interpreter from the command line like this:

$ python3 $HOME/bin/hello.py

Or in some Linux distributions, you can run it like this:

$ python36 $HOME/bin...