Book Image

Linux Command Line and Shell Scripting Bible - Third Edition

By : Richard Blum, Christine Bresnahan
Book Image

Linux Command Line and Shell Scripting Bible - Third Edition

By: Richard Blum, Christine Bresnahan

Overview of this book

The Linux command line enables you to type specific shell commands directly into the system to manipulate files and query system resources. Command line statements can be combined into short programs called shell scripts, a practice increasing in popularity due to its usefulness in automation. Linux is a robust system with tremendous potential, and Linux Command Line and Shell Scripting Bible opens the door to new possibilities. Linux Command Line and Shell Scripting Bible is your essential Linux guide. It contains new functional examples that are fully updated to align with the latest Linux features. Beginning with command line fundamentals, the book moves into shell scripting and shows you the practical application of commands in automating frequently performed functions. This book is a complete guide providing detailed instruction and expert advice working within this aspect of Linux. Whether used as a tutorial or as a quick reference, this book contains information that every Linux user should know.
Table of Contents (34 chapters)
Part I: The Linux Command Line
Part II: Shell Scripting Basics
Part III: Advanced Shell Scripting
Part IV: Creating Practical Scripts
End User License Agreement

Placing sed Commands in Scripts

Now that you've seen the various parts of the sed editor, it's time to put them together and use them in your shell scripts. This section demonstrates some of the features that you should know about when using the sed editor in your bash shell scripts.

Using wrappers

You may have noticed that trying to implement a sed editor script can be cumbersome, especially if the script is long. Instead of having to retype the entire script each time you want to use it, you can place the sed editor command in a shell script wrapper. The wrapper acts as a go-between for the sed editor script and the command line.

Once inside the shell script, you can use normal shell variables and parameters with your sed editor scripts. Here's an example of using the command line parameter variable as the input to a sed script:

$ cat
# Shell wrapper for sed editor script.
#               to reverse text file lines.
sed -n '{ 1!G ; h ; ...