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Arbythecoder
Arbythecoder

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Linux Shell Scripting for DevOps: A Beginner's Guide

Introduction

Hello there! Do you remember our last conversation about mastering Git? Now, it's time to delve into a more exciting part of your DevOps journey: Linux shell scripting.

Shell scripting is a powerful tool for automating tasks and managing systems, making it an essential skill for DevOps engineers. This guide provides a basic introduction to Linux shell scripting, with a focus on its applications in the DevOps field. Here, we'll cover essential topics to help you get started.

  • What is Shell Scripting?
  • Writing Your First Shell Script
  • Variables and Data Types
  • Control Flow Statements
  • Functions
  • Error Handling
  • Working with Files and Directories
  • Networking
  • DevOps Applications of Shell Scripting

What is Shell Scripting?

Shell scripting is a form of programming that allows you to automate tasks by creating scripts that the shell interprets and executes. In Linux, the most common shell for scripting is Bash, and that's what we'll focus on in this guide.

How to Write Your First Shell Script

To write your first shell script, you need a text editor. You can use popular editors like vi, Vim, or Nano. Here's how to create a simple "Hello, world!" script:

  1. Open your preferred text editor.

  2. Save a new file with the .sh extension, e.g., hello.sh.

  3. Add the following content to the file:

#!/bin/bash

echo "Hello, world!"
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  1. Save the file.

  2. Make it executable using the following command:

chmod +x hello.sh
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  1. Finally, run the script:
./hello.sh
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The script will execute and print "Hello, world!" to the console.

Variables and Data Types

Shell scripts use variables to store data. These variables can hold various data types, including integers, strings, and Booleans. To declare a variable, use the following syntax:

variable_name=value
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For example, to store the string "welcome to a new world!" in a variable named my_variable, you would write:

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To access a variable's value, simply use its name with a $ prefix. For instance, to print the value of my_variable, you would use:

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Control Flow Statements

Control flow statements are used to manage the order of execution in shell scripts. The most common ones are:

If Statements:

if condition
then
    code_to_execute
fi
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For example:

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For Loops:

for variable_name in list
do
    code_to_execute
done
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Example:

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While Loops:

while condition
do
    code_to_execute
done
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Example:

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Functions

Functions allow you to group code together for improved modularity and readability. Here's how to define a function:

function function_name() {
    # Code to execute
}
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For example:

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To call a function, simply use its name:

greet
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This wraps up our beginner's guide to Linux Shell Scripting for DevOps. Shell scripting is a valuable skill for anyone working in the DevOps field, and with practice and dedication, you can become proficient in automating tasks and managing systems.

Top comments (26)

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darkwiiplayer profile image
𒎏Wii 🏳️‍⚧️

Dunno if this is a me thing, or worth mentioning in the article, but it took me quite a while to get used to not putting spaces around the = when defining variables.

Also, any plans on making a more advanced guide too?

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jihedkdiss profile image
Jihed Kdiss

I did quick research and apparently the preferred way to use = in bash is without spaces unlike many other languages. Even though it's not explicitly mentioned here, you can see that Google themselves have used variable=value so many times in their official code style guide.

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darkwiiplayer profile image
𒎏Wii 🏳️‍⚧️

It's not just preferred, you actually can't put spaces around the =

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arbythecoder profile image
Arbythecoder

Thank you for the observation and thank you for reading 😊

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arbythecoder profile image
Arbythecoder

Well noted, thank you for reading 💪

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arbythecoder profile image
Arbythecoder

it's just for the article's sake but thanks for the observation, well noted .
Yes, I am working on advanced guide too. Thank you for reading 😊

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guinuxbr profile image
Guilherme L. Leite Marques

Nice article. It is a good idea to use fenced code blocks rather than screenshots for accessibility. Screenshots make things more difficult for people who use screen readers. Other than that, fenced code blocks are easy to copy and paste and, therefore, test the proposed code.

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arbythecoder profile image
Arbythecoder

Thank you so much, duly noted.

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jihedkdiss profile image
Jihed Kdiss

This is a good and straightforward tutorial, Good job Arby! However the title is a bit misleading since you didn't mention any DevOps specific commands.

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arbythecoder profile image
Arbythecoder

Thank you so much, I am glad you found it valuable 🙏

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muthukumark98 profile image
MuthuKumar

Awesome explanation 😸 thanks 🙏

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arbythecoder profile image
Arbythecoder

Thank you 👍 I'm glad you find my article valuable

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taijidude profile image
taijidude

Good Stuff. Thank you for sharing.

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icolomina profile image
Nacho Colomina Torregrosa

great !

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pxlmastrxd profile image
Pxlmastr

Can I ask where you download MINGW64? I just can't find where to download it.

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arbythecoder profile image
Arbythecoder
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pxlmastrxd profile image
Pxlmastr

Oh my gosh, thank you so much! You just made my day

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emma32 profile image
emma devid

Great article! Utilizing fenced code blocks instead of screenshots is a smart move for accessibility. Screenshots pose challenges for those using screen readers. Additionally, fenced code blocks are user-friendly, allowing for easy copying, pasting, and testing of the provided code.

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sc0v0ne profile image
sc0v0ne

Simple and amazing !!!

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lucasgrocha profile image
Lucas Rocha

I'm not a DevOps guy, but I loved this!

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arbythecoder profile image
Arbythecoder

I am happy to hear this! Thank you so much

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taqui_786 profile image
TAQUI ⭐

Nice Post

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rijultp profile image
Rijul Rajesh

Nice article, Straight to the point!

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abhixsh profile image
Abishek Haththakage

Awesome explanation!!

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virginiaslifer profile image
VirginiaSlifer

This next step in the DevOps journey promises to be both challenging and rewarding. Tiger exchange