Search icon CANCEL
Arrow left icon
Explore Products
Best Sellers
New Releases
Books
Videos
Audiobooks
Learning Hub
Conferences
Free Learning
Arrow right icon
Arrow up icon
GO TO TOP
Mastering Linux Shell Scripting

You're reading from   Mastering Linux Shell Scripting Master the complexities of Bash shell scripting and unlock the power of shell for your enterprise

Arrow left icon
Product type Paperback
Published in Dec 2015
Publisher
ISBN-13 9781784396978
Length 198 pages
Edition 1st Edition
Tools
Arrow right icon
Author (1):
Arrow left icon
Andrew Mallett Andrew Mallett
Author Profile Icon Andrew Mallett
Andrew Mallett
Arrow right icon
View More author details
Toc

Table of Contents (16) Chapters Close

Preface 1. What and Why of Scripting with Bash FREE CHAPTER 2. Creating Interactive Scripts 3. Conditions Attached 4. Creating Code Snippets 5. Alternative Syntax 6. Iterating with Loops 7. Creating Building Blocks with Functions 8. Introducing sed 9. Automating Apache Virtual Hosts 10. Awk Fundamentals 11. Summarizing Logs with Awk 12. A Better lastlog with Awk 13. Using Perl as a Bash Scripting Alternative 14. Using Python as a Bash Scripting Alternative Index

Formatting output


We have remained faithful to the print command so far, as we have been limited in what we require from the output. If we want to print out, say, the username, UID, and default shell we need to start formatting the output just a little. In this case, we can organize the output in well-shaped columns. Without formatting, the command we use will look similar to the following example where we use commas to separate the field that we want to print:

$ awk ' BEGIN { FS=":" } { print $1,$3,$7 } ' /etc/passwd

We use the BEGIN block here, as we can make use of it to print column headers later.

To understand the problem a little better, we can take a look at the following screenshot that illustrates the uneven column widths:

The issue that we have in the output is that the columns do not align, as the username is of an inconsistent length. To improve on this, we can use the printf function where we can specify the column width. The syntax for the awk statements will be similar to the...

lock icon The rest of the chapter is locked
Register for a free Packt account to unlock a world of extra content!
A free Packt account unlocks extra newsletters, articles, discounted offers, and much more. Start advancing your knowledge today.
Unlock this book and the full library FREE for 7 days
Get unlimited access to 7000+ expert-authored eBooks and videos courses covering every tech area you can think of
Renews at $19.99/month. Cancel anytime