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

Verifying backups

I have already spoken about backups at least twice in this book and this will be the last time I promise. Create your backup scripts and make sure they run when they are supposed to. But one thing I have not talked about yet is verification of the backups. You might have 10 teraquads of backups lying around somewhere, but do they actually work? When was the last time you checked?

When using the tar command it will report at the end of the run if it encountered any issues making the archive. In general if it doesn't show anything amiss the backup is probably good. Using tar with the -t (tell) option, or actually extracting it on the local or remote machine, is also a good way to determine if the archive was made successfully.


Note: A somewhat common mistake when using tar is to include a file in the backup that is currently being updated.

Here is a rather obvious example:

guest1 /home # tar cvzf guest1.gz guest1/ | tee /home/guest1/temp/mainlogs`date '+%Y%m%d'`.gz

The tar...