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)

Gathering system I/O usage with dstat

Knowing what services are running may not tell you which services are slowing down your system. The top command (discussed in Chapter 9, Put on the Monitor's Cap) will tell you about CPU usage and how much time is spent waiting for IO, but it might not tell you enough to track down a task that's overloading the system.

Tracking I/O and context switches can help trace a problem to its source.

The dstat utility can point you to a potential bottleneck.

Getting ready

The dstat application is not commonly installed. It will need to be installed with your package manager. It requires Python 2.2, which is installed by default on modern Linux systems:

    # apt-get install dstat
    # yum install dstat
...