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Bash Cookbook

You're reading from   Bash Cookbook Leverage Bash scripting to automate daily tasks and improve productivity

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Product type Paperback
Published in Jul 2018
Publisher Packt
ISBN-13 9781788629362
Length 264 pages
Edition 1st Edition
Languages
Tools
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Authors (2):
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Ganesh Sanjiv Naik Ganesh Sanjiv Naik
Author Profile Icon Ganesh Sanjiv Naik
Ganesh Sanjiv Naik
Ron Brash Ron Brash
Author Profile Icon Ron Brash
Ron Brash
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Table of Contents (10) Chapters Close

Preface 1. Crash Course in Bash FREE CHAPTER 2. Acting Like a Typewriter and File Explorer 3. Understanding and Gaining File System Mastery 4. Making a Script Behave Like a Daemon 5. Scripts for System Administration Tasks 6. Scripts for Power Users 7. Writing Bash to Win and Profit 8. Advanced Scripting Techniques 9. Other Books You May Enjoy

Running a program continuously (forever) using looping constructs or recursion


So far, this cookbook has mostly shown scripts that serve a single purpose and exit upon task completion. This is great for single use scripts, but what about if we wanted to have scripts execute multiple scripts through a menu, or perform tasks in the background automatically forever without being executed each time by scheduling processes (like cron)? This recipe introduces a few ways for a script to run forever until it is killed or exits.

Getting ready

Besides having a terminal open, we need to remember a few concepts:

  • Recursive functions combined with a prompt (for example, the read command) can result in a script that loops based on user input
  • Looping constructs such as for, while, and until can be executed in such a way that a condition is never met and cannot exit

Therefore, a loop or something that causes a loop will force a program to run for an indefinite period of time until an exit event occurs.

Note

In...

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