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Mastering Bash

You're reading from   Mastering Bash A Step-by-Step Guide to working with Bash Programming and Shell Scripting

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Product type Paperback
Published in Jun 2017
Publisher Packt
ISBN-13 9781784396879
Length 502 pages
Edition 1st Edition
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Author (1):
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Giorgio Zarrelli Giorgio Zarrelli
Author Profile Icon Giorgio Zarrelli
Giorgio Zarrelli
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Table of Contents (15) Chapters Close

Preface 1. Let's Start Programming 2. Operators FREE CHAPTER 3. Testing 4. Quoting and Escaping 5. Menus, Arrays, and Functions 6. Iterations 7. Plug into the Real World 8. We Want to Chat 9. Subshells, Signals, and Job Controls 10. Lets Make a Process Chat 11. Living as a Daemon 12. Remote Connections over SSH 13. Its Time for a Timer 14. Time for Safety

Operators

What we have looked at so far is tinkering with values returned from variable expansions and descriptors used in a tricky way. So, something nice, but we could not do much more, since we do not have a way to actually relate values, compare or even modify at our will.

Here is where the operators come in to play, and we will see how to modify the value of a variable so that it will hold a value and, over time, modify to gather new information. So, let's start from something simple, from basic math then move on to something more complex.

One last thing we have to bear in mind before proceeding is that the operators follow an order of precedence:

  • The compound logical operators -a, -o, and && have a low precedence
  • The arithmetic operators have the following precedence:
    • Multiply
    • Divide
    • Add
    • Subtract
  • The evaluation of operators with equal precedence is from...
You have been reading a chapter from
Mastering Bash
Published in: Jun 2017
Publisher: Packt
ISBN-13: 9781784396879
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