Book Image

Linux Utilities Cookbook

By : James Kent Lewis
Book Image

Linux Utilities Cookbook

By: James Kent Lewis

Overview of this book

<p>Linux is a stable, reliable and extremely powerful operating system. It has been around for many years, however, most people still don't know what it can do and the ways it is superior to other operating systems. Many people want to get started with Linux for greater control and security, but getting started can be time consuming and complicated. <br /><br />A practical, hands-on guide that provides you with a number of clear step-by-step examples to help you solve many of the questions that crop up when using an operating system you may not be familiar with.</p> <p>Presenting solutions to the most common Linux problems in a clear and concise way, this helpful guide starts with spicing up the terminal sessions by command retrieval and line editing, and shell prompt variables. We will then get to know the different desktops (GUIs) available for Linux systems and which is the best fit for you. We will then explore the world of managing files and directories, connectivity, and what to do when it goes wrong. We will also learn a range of skills, from creating and managing user accounts to securing your system, managing and limiting processes, and letting information flow from one process to another using pipes. Later, we will master disk management, working with scripts and automating tasks quickly, and finally, understand the need for a custom kernel and tips on how to build one.</p> <p><br />Based on the author's extensive experience, there is a section on best practices that every Linux user should be familiar with.</p>
Table of Contents (19 chapters)
Linux Utilities Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Removing text from a file


A script can be written to do almost anything you can imagine. The following is one such example.

How to do it...

The following is the listing for a script that can be used to cut the line numbers off the examples. You can then run them as is on your system.

Script 1 – removing line numbers

  1  #!/bin/sh
  2  # removelines 5/1/2013
  3  if [ "$1" = "" ] ; then
  4   echo "Usage: removenumbers filename > newfile"
  5   echo " This script will remove the line numbers from the beginning of the lines"
  6   echo " in filename. It assumes the number field is 5 characters wide."
  7   echo " Use the redirection operator to save the output to a new file."
  8   exit
  9  fi
  10  cat $1 | cut -c 1-5 --complement

How it works…

Let's discuss what the previous given lines do.

  • The first line tells the OS what shell this script is for.

  • Line 2 has a # in the first column. This is called a comment line. Here I have the date the script was written.

  • The $1 variable is the first parameter...