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The Ultimate Linux Shell Scripting Guide

You're reading from   The Ultimate Linux Shell Scripting Guide Automate, Optimize, and Empower tasks with Linux Shell Scripting

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Product type Paperback
Published in Oct 2024
Publisher Packt
ISBN-13 9781835463574
Length 696 pages
Edition 1st Edition
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Author (1):
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Donald A. Tevault Donald A. Tevault
Author Profile Icon Donald A. Tevault
Donald A. Tevault
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Table of Contents (26) Chapters Close

Preface 1. Getting Started with the Shell 2. Interpreting Commands FREE CHAPTER 3. Understanding Variables and Pipelines 4. Understanding Input/Output Redirection 5. Customizing the Environment 6. Text-Stream Filters – Part 1 7. Text Stream Filters – Part 2 8. Basic Shell Script Construction 9. Filtering Text with grep, sed, and Regular Expressions 10. Understanding Functions 11. Performing Mathematical Operations 12. Automating Scripts with here Documents and expect 13. Scripting with ImageMagick 14. Using awk – Part 1 15. Using awk – Part 2 16. Creating User Interfaces with yad, dialog, and xdialog 17. Using Shell Script Options with getops 18. Shell Scripting for Security Professionals 19. Shell Script Portability 20. Shell Script Security 21. Debugging Shell Scripts 22. Introduction to Z Shell Scripting 23. Using PowerShell on Linux 24. Other Books You May Enjoy
25. Index

Resizing and Customizing Images

Let’s say that I want to downsize my image to 1000x1000 pixels. I would do it like this:

[donnie@fedora script_test]$ convert -resize 1000x1000 S1180001.jpg S1180001_small.jpg
[donnie@fedora script_test]$

By default, the convert command maintains the original aspect ratio of the image. So, the size of my downsized image is actually 1000x563 pixels, as you see here:

[donnie@fedora script_test]$ identify S1180001_small.jpg
S1180001_small.jpg JPEG 1000x563 1000x563+0+0 8-bit sRGB 328914B 0.000u 0:00.000
[donnie@fedora script_test]$

Instead of specifying the size by pixels, you can specify the desired size in terms of a percentage of the original size, like so:

[donnie@fedora script_test]$ convert -resize 20% S1180001.jpg S1180001_small2.jpg
[donnie@fedora script_test]$

Now when I display the image, it will actually fit on my computer screen. Here’s how it looks:

B21693_13_4

Figure 13.4: Goldie, sleeping in my bedroom...

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