Book Image

Linux Shell Scripting Cookbook - Third Edition

By : Clif Flynt, Sarath Lakshman, Shantanu Tushar
Book Image

Linux Shell Scripting Cookbook - Third Edition

By: Clif Flynt, Sarath Lakshman, Shantanu Tushar

Overview of this book

The shell is the most powerful tool your computer provides. Despite having it at their fingertips, many users are unaware of how much the shell can accomplish. Using the shell, you can generate databases and web pages from sets of files, automate monotonous admin tasks such as system backups, monitor your system's health and activity, identify network bottlenecks and system resource hogs, and more. This book will show you how to do all this and much more. This book, now in its third edition, describes the exciting new features in the newest Linux distributions to help you accomplish more than you imagine. It shows how to use simple commands to automate complex tasks, automate web interactions, download videos, set up containers and cloud servers, and even get free SSL certificates. Starting with the basics of the shell, you will learn simple commands and how to apply them to real-world issues. From there, you'll learn text processing, web interactions, network and system monitoring, and system tuning. Software engineers will learn how to examine system applications, how to use modern software management tools such as git and fossil for their own work, and how to submit patches to open-source projects. Finally, you'll learn how to set up Linux Containers and Virtual machines and even run your own Cloud server with a free SSL Certificate from letsencrypt.org.
Table of Contents (14 chapters)

Monitoring remote disk usage health

Disks fill up and sometimes wear out. Even RAIDed storage systems can fail if you don't replace a faulty drive before the others fail. Monitoring the health of the storage systems is part of an administrator's job.

The job gets easier when an automated script checks the devices on the network and generates a one-line report, the date, IP address of the machine, device, capacity of device, used space, free space, percentage usage, and alert status. If the disk usage is under 80 percent, the drive status is reported as SAFE. If the drive is getting full and needs attention, the status is reported as ALERT.

Getting ready

The script uses SSH to log in to remote systems, collect disk usage statistics, and write them to a log...