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)

The HTTPD log file format

When working with any file, the first task is to become familiar with the file schema. In simple terms, we need to know what is represented by each field and what is used to delimit the fields. We will be working with the access log file from an Apache HTTPD web server. The location of the log file can be controlled from the httpd.conf file. The default log file location on a Debian-based system is /var/log/apache2/access.log; other systems may use the httpd directory in place of apache2.

The log file is already in the code bundle, so you can download it and use it directly.

Using the tail command, we can display the end of the log file. Although, to be fair, the use of cat will do just as well with this file, as it will have just a few lines:

$ tail /var/log/apache2/access.log  

The output of the command and the contents of the file are shown in the...