Book Image

Linux Shell Scripting Bootcamp

By : James K Lewis
Book Image

Linux Shell Scripting Bootcamp

By: James K Lewis

Overview of this book

Linux Shell Scripting Bootcamp is all about learning the essentials of script creation, validating parameters, and checking for the existence of files and other items needed by the script. We will use scripts to explore iterative operations using loops and learn different types of loop statements, with their differences. Along with this, we will also create a numbered backup script for backup files. Further, you will get well-versed with how variables work on a Linux system and how they relate to scripts. You’ll also learn how to create and call subroutines in a script and create interactive scripts. The most important archive commands, zip and tar, are also discussed for performing backups. Later, you will dive deeper by understanding the use of wget and curl scripts and the use of checksum and file encryption in further chapters. Finally, you will learn how to debug scripts and scripting best practices that will enable you to write a great code every time! By the end of the book, you will be able to write shell scripts that can dig data from the web and process it efficiently.
Table of Contents (19 chapters)
Linux Shell Scripting Bootcamp
About the Author
About the Reviewer
Customer Feedback

wget and recursion

The wget program can also be used to download the contents of an entire website by using the recursive (-r) option.

For an example look at the following screenshot:

The no verbose (-nv) option was used to limit the output. After the wget command completed the more command was used to view the contents of the log. Depending on the number of files the output might be very long.

When using wget you may run into unexpected issues. It may not get any files, or it may get some but not all of them. It might even fail without any reasonable error message. If this happens check the man page (man wget) very carefully. There may be an option that can help get you through the problem. In particular look at the following.

Run wget --version on your system. It will display a detailed listing of the options and features and also how wget was compiled.

Here is an example taken from my system running CentOS 6.8 64-bit: