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)

Further filtering to display users by UID

We have been able to build our skills with AWK, piece by piece, and what we have learned has been useful. We can take these tiny steps and add them to start creating something a little more usable. Perhaps we want to print just standard users; these are usually users higher than 500 or 1,000 depending on your particular distribution.

On the Linux Mint distribution that I am using for this book, standard users start with UID 1000. The UID is the third field. This is really a simple matter of using the value of the third field as the range operator. We can see this in the following example:

$ awk -F":" '$3 > 999 ' /etc/passwd  

We can show users whose UID is 101 or lower with the following command:

$ awk -F":" '$3 < 101 ' /etc/passwd

These just give you an idea of some of the possibilities available...