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

Printing the nth word or column in a file or line


We may have a file having a number of columns, and only a few will actually be useful. For example, in a list of students in an order of their scores, we want to get, for instance, the fourth highest scorer. In this recipe, we will see how to do this.

How to do it...

The most widely-used method is to use awk for doing this task. It can be also done using cut.

  1. To print the fifth column, use the following command:

    $ awk '{ print $5 }' filename
    
  2. We can also print multiple columns and insert our custom string in between columns.

    For example, to print the permission and filename of each file in the current directory, use the following set of commands:

    $ ls -l | awk '{ print $1 " :  " $8 }'
    -rw-r--r-- :  delimited_data.txt
    -rw-r--r-- :  obfuscated.txt
    -rw-r--r-- :  paste1.txt
    -rw-r--r-- :  paste2.txt
    

See also

  • The Using awk for advanced text processing recipe in this chapter explains the awk command

  • The Column-wise cutting of the file with cut recipe in...