Book Image

Linux Shell Scripting Cookbook, Second Edition - Second Edition

Book Image

Linux Shell Scripting Cookbook, Second Edition - Second Edition

Overview of this book

The shell remains one of the most powerful tools on a computer system — yet a large number of users are unaware of how much one can accomplish with it. Using a combination of simple commands, we will see how to solve complex problems in day to day computer usage.Linux Shell Scripting Cookbook, Second Edition will take you through useful real-world recipes designed to make your daily life easy when working with the shell. The book shows the reader how to effectively use the shell to accomplish complex tasks with ease.The book discusses basics of using the shell, general commands and proceeds to show the reader how to use them to perform complex tasks with ease.Starting with the basics of the shell, we will learn simple commands with their usages allowing us to perform operations on files of different kind. The book then proceeds to explain text processing, web interaction and concludes with backups, monitoring and other sysadmin tasks.Linux Shell Scripting Cookbook, Second Edition serves as an excellent guide to solving day to day problems using the shell and few powerful commands together to create solutions.
Table of Contents (16 chapters)
Linux Shell Scripting Cookbook
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Creating arbitrary sockets


For defined operations such as file transfer, remote shells, and so on, we have prebuilt tools such as ftp and ssh respectively. However, in some cases you will find the need to do a customized network operation. An example for this might be writing a script which will do something when a remote client connects to your machine. In this recipe, we will create simple network sockets and use them for communication.

Getting ready

To perform these things, we will need to create network sockets which enable us to do data transfer over a TCP/IP network. The easiest way to do this is by using the command netcat (or nc). We need two sockets: one listens for connections and the other connects to this one.

How to do it...

  1. Set up the listening socket using the following:

    nc -l 1234
    

    This will create a listening socket on port 1234 on the local machine.

  2. Connect to the socket using the following:

    nc HOST 1234
    

    If you are running this on the same machine that the listening socket is...