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Learning Linux Shell Scripting

You're reading from   Learning Linux Shell Scripting Leverage the power of shell scripts to solve real-world problems

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Product type Paperback
Published in May 2018
Publisher Packt
ISBN-13 9781788993197
Length 332 pages
Edition 2nd Edition
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Author (1):
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Ganesh Sanjiv Naik Ganesh Sanjiv Naik
Author Profile Icon Ganesh Sanjiv Naik
Ganesh Sanjiv Naik
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Table of Contents (17) Chapters Close

Preface 1. Getting Started and Working with Shell Scripting FREE CHAPTER 2. Drilling Deep into Process Management, Job Control, and Automation 3. Using Text Processing and Filters in Your Scripts 4. Working with Commands 5. Exploring Expressions and Variables 6. Neat Tricks with Shell Scripting 7. Performing Arithmetic Operations in Shell Scripts 8. Automating Decision-Making in Scripts 9. Automating Repetitive Tasks 10. Working with Functions 11. Using Advanced Functionality in Scripts 12. System Startup and Customizing a Linux System 13. Pattern Matching and Regular Expressions with sed and awk 14. Taking Backup and Embedding Other Languages in Shell Scripts 15. Database Administration Using Shell Scripts 16. Other Books You May Enjoy

Understanding signals and traps

Two types of interrupts exist in the Linux operating system: hardware interrupts and software interrupts. Software interrupts are called signals or traps. Software interrupts are used for inter-process synchronizations.

Signals are used to notify us about a certain event occurrence or to initiate a certain activity.

We use software signals many times. For example, if any command does not respond after being typed, then you might have entered Ctrl + C. This sends a SIGINT signal to the process, and the process is terminated. In certain situations, we may want the program to perform a certain activity instead of terminating it using Ctrl + C. In such cases, we can use the trap command to ignore a signal or to associate our desired function with that signal.

In operating systems, software interrupts or signals are generated when the process attempts...

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