We have put our best efforts in to making this book's code and content relevant for the larger audience working on GNU/Linux. All the examples covered in the book are based on openSUSE Leap 42.3 Linux distribution with GAWK version 4.1.3 installed. You can use any Linux distribution having GAWK version 4.1.3 or above installed to practice the examples. GAWK is GNU’s open source implementation of AT&T's original AWK.

Only requirement for this book is the GAWK utility. Users can install the Windows variant of GAWK on their system if they want to practice the examples, but we strongly recommend using any Linux distribution for this purpose. For Windows and OS X, those who would like to practice it on a virtual environment can use VMware of Virtualbox to set up their favorite Linux distribution and then use AWK to execute the examples. For beginners, we have covered the installation of AWK programs on popular GNU/Linux distributions using package management and source code.

A basic understanding of GNU/Linux operating systems and familiarity with any text editor such as emacs, vi or nano are required. An understanding of shell scripting will be an added advantage to the reader.

You can download the example code files for this book from your account at www.packtpub.com. If you purchased this book elsewhere, you can visit www.packtpub.com/support and register to have the files emailed directly to you.

You can download the code files by following these steps:

1. Log in or register at www.packtpub.com.
2. Select the SUPPORT tab.
3. Click on Code Downloads & Errata.
4. Enter the name of the book in the Search box and follow the onscreen instructions.

Once the file is downloaded, please make sure that you unzip or extract the folder using the latest version of:

• WinRAR/7-Zip for Windows
• Zipeg/iZip/UnRarX for Mac
• 7-Zip/PeaZip for Linux

The code bundle for the book is also hosted on GitHub at https://github.com/PacktPublishing/Learning-AWK-Programming. In case there's an update to the code, it will be updated on the existing GitHub repository.

We also have other code bundles from our rich catalog of books and videos available at https://github.com/PacktPublishing/. Check them out!

There are a number of text conventions used throughout this book.

CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, path names, dummy URLs, user input, and Twitter handles. Here is an example: "We can check that using the which command, which will return the absolute path of AWK on our system."

Any command-line input or output is written as follows:

[ shiwang@linux ~ ] $ sudo apt-get update -y
[ shiwang@linux ~ ] $ sudo apt-get install gawk -y

Bold: Indicates a new term, an important word, or words that you see onscreen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "It was updated and replaced in the mid-1980s with an enhanced version called New AWK (NAWK)."