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)
2
Part I: The Linux Command Line
13
Part II: Shell Scripting Basics
20
Part III: Advanced Shell Scripting
28
Part IV: Creating Practical Scripts
32
End User License Agreement

Pipes

Sometimes, you need to send the output of one command to the input of another command. This is possible using redirection, but somewhat clunky:

$ rpm -qa > rpm.list
$ sort < rpm.list
abrt-1.1.14-1.fc14.i686
abrt-addon-ccpp-1.1.14-1.fc14.i686
abrt-addon-kerneloops-1.1.14-1.fc14.i686
abrt-addon-python-1.1.14-1.fc14.i686
abrt-desktop-1.1.14-1.fc14.i686
abrt-gui-1.1.14-1.fc14.i686
abrt-libs-1.1.14-1.fc14.i686
abrt-plugin-bugzilla-1.1.14-1.fc14.i686
abrt-plugin-logger-1.1.14-1.fc14.i686
abrt-plugin-runapp-1.1.14-1.fc14.i686
acl-2.2.49-8.fc14.i686
[...]

The rpm command manages the software packages installed on systems using the Red Hat Package Management system (RPM), such as the Fedora system as shown. When used with the -qa parameters, it produces a list of the existing packages installed, but not necessarily in any specific order. If you're looking for a specific package or group of packages, it can be difficult to find it using the output of the rpm command.

Using the...