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

Reporting the errors from a crontab file


You may be wondering, if there is an error in a crontab file how does the computer report it? It does this by using the sendmail system, to mail the crontab user.

How to do it...

The following is an example of how errors are reported by cron:

  1. Open a terminal with a user account.

  2. Edit your crontab file by running the following command:

    crontab -e
    
  3. Now let's deliberately cause an error. Scroll to the bottom and add the following line:

    * * * *    date > /baddirectory/date.txt
    
  4. Save the file. Wait until cron runs in the next minute, and then press Enter in your user terminal.

  5. You should see a message saying you have mail. Run the following command:

    mail
    
  6. There should be a mail indicating the error (in this case, file not found). You may delete the message by pressing D and then Q to leave the mail.

  7. To finish, be sure to re-edit your crontab file and remove the bad line we just added.

There's more...

You can also monitor the /var/log/cron file to see what cron...