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Linux Shell Scripting Essentials

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Linux Shell Scripting Essentials

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Linux Shell Scripting Essentials
Nov, 2015 | 282 pages
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Table of Contents (15 chapters)
Linux Shell Scripting Essentials
Linux Shell Scripting Essentials
Credits
Credits
About the Author
About the Author
About the Reviewers
About the Reviewers
www.PacktPub.com
www.PacktPub.com
Preface
Preface
Free Chapter
1
The Beginning of the Scripting Journey
The Beginning of the Scripting Journey
Hello World in shell
Define variables of choice
Builtin shell variables
Operators
Shell expansions
Construct commands using eval
Make bash behave using set
Summary
2
Getting Hands-on with I/O, Redirection Pipes, and Filters
Getting Hands-on with I/O, Redirection Pipes, and Filters
Standard I/O and error streams
Redirecting the standard I/O and error streams
Pipe and pipelines – connecting commands
Regular expressions
Filtering an output using grep
Editing output using sed
Duplicating a stream using tee
Sorting and finding unique text
Character-based translation using tr
Filtering based on lines—head and tail
The Cut-based selection
Summary
3
Effective Script Writing
Effective Script Writing
Exiting from scripts and exit codes
Testing expressions with a test
Using conditional statements with if and else
Indexed arrays and associative arrays
Looping around with for
The select, while, and until loops
Switch to my choice
Passing stdout as a parameter using xargs
Using functions and positional parameters
Alias
pushd and popd
Summary
4
Modularizing and Debugging
Modularizing and Debugging
Modularizing your scripts
Passing command line parameters to script
Debugging your scripts
Command completion
Summary
5
Customizing the Environment
Customizing the Environment
Knowing the default environment
Modifying a shell environment
Using bash startup files
Knowing your history
Task management
Summary
6
Working with Files
Working with Files
Performing basic file operations
Moving and copying files
Comparing files
Finding files
Links to a file
Special files
Temporary files
Permission and ownership
Getting the list of open files
Configuration files
Summary
7
Welcome to the Processes
Welcome to the Processes
Process management
Listing and monitoring processes
Process substitution
Process scheduling priorities
Signals
Traps
Inter-process communication
Summary
8
Scheduling Tasks and Embedding Languages in Scripts
Scheduling Tasks and Embedding Languages in Scripts
Running tasks at a specific time
Cron jobs
Managing the crontab entry
systemd
Embedding languages
Summary
Index
Index

About the Author

Sinny Kumari has been a GNU/Linux user since the beginning of her college days. Her passion is to contribute to free software that benefits millions of people. She is a KDE contributor, KDE e.V. member, Fedora packager, and a Google Summer of Code mentor.

To keep up her passion in open source, she has been working as a software engineer at Red Hat after completing her bachelor's degree in computer science in 2012. As part of her work, she contributes to the Libabigail project that helps with ABI analysis on ELF binaries. She also loves going to technical conferences and sharing her experiences by giving talks. Her blogs about almost all of these activities can be found at http://sinny.io/.

I want to thank my parents who have always supported, encouraged, and provided me with the best education. I would also like to thank my friends and family who were always around me to cheer me up. Special thanks to my friend, Shantanu Tushar, who clarified a few doubts I came across while writing this book. I would also like to thank the reviewers of this book and the entire PacktPub team.

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