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

Using /proc for gathering information


/proc is an in-memory pseudo filesystem available with the GNU/Linux operating system. It was actually introduced to provide an interface to read several system parameters from the user space. It is very interesting and we can gather lots of information from it. Let's see how to.

How to do it...

If you look at /proc, you will see several files and directories, some of which are already explained in other recipes in this chapter. You can simply cat files in /proc and the subdirectories to get information. All of them are well-formatted text.

There will be a directory in /proc for every process that is running on the system, named after the PID of that process.

Suppose Bash is running with PID 4295 (pgrep bash), /proc/4295 will exist. Each of the directories corresponding to the process will contain a lot of information regarding to that process. Few of the important files in /proc/PID are as follows.

  • environ: This contains environment variables associated...