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
About the Authors
About the Reviewers

Replacing a pattern with text in all the files in a directory

There will be numerous occasions when we will need to replace a particular text with a new text in every file in a directory. An example would be changing a common URI everywhere in a website's source directory. Using the shell for this is one of the quickest methods out there.

How to do it...

From what we have learnt up to now, we can first use find to locate the files we want to perform the text replacement on. Then, we can use sed to do the actual replacement.

Let's say we want to replace the text Copyright with the word Copyleft in all .cpp files:

$ find . -name *.cpp -print0 |  xargs -I{} -0 sed -i 's/Copyright/Copyleft/g' {}

How it works...

We use find on the current directory to find all the files of .cpp, and use print0 to print a null-separated list of files (recall that this helps, if the filenames have spaces in them). We then pipe this list to xargs, which will pass these files to sed, which in turn will make the modifications...