🚀 Day 5 of My DevOps Journey: Bash Scripting (Beginner to Advanced)

Today was all about automation. I dove deep into Bash scripting, one of the most fundamental skills in any DevOps engineer’s toolkit. From creating simple scripts to understanding logic, loops, and functions — I now feel confident writing scripts to automate tasks on Linux systems.

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🧠 What is Bash Scripting?

Bash scripting lets you write a sequence of Linux commands in a file and execute them all at once. It's used to:

• Automate repetitive tasks

• Create backups, alerts, monitoring tools

• Configure and manage environments

Scripts are saved as .sh files and run using the Bash shell.

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✅ Step 1: My First Bash Script

I created and ran my first script:

touch hello.sh
chmod +x hello.sh

Inside hello.sh:

#!/bin/bash
echo "Hello, DevOps World!"

Then executed it:

./hello.sh

This printed: Hello, DevOps World!

The line #!/bin/bash is a shebang that tells Linux to use the Bash interpreter.

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✅ Step 2: Variables in Bash

#!/bin/bash
name="ritesh"
echo "Welcome, $name!"

🧠 Bash variables are declared without spaces and accessed using $.

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✅ Step 3: Accepting User Input

#!/bin/bash
echo "Enter your name:"
read name
echo "Hello, $name!"

The read command takes user input and stores it in a variable.

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✅ Step 4: Conditions with If/Else

#!/bin/bash
echo "Enter a number:"
read num

if [ "$num" -gt 10 ]; then
  echo "Greater than 10"
else
  echo "10 or less"
fi

Here, -gt means “greater than”. We also use square brackets [] to evaluate conditions.

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✅ Step 5: Using Loops

➕ For Loop

for i in 1 2 3 4 5
do
  echo "Count: $i"
done

🔁 While Loop

i=1
while [ $i -le 5 ]
do
  echo "Step $i"
  ((i++))
done

🧠 Loops help execute code repeatedly until a condition is met.

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✅ Step 6: Functions in Bash

greet() {
  echo "Hi $1, welcome to scripting!"
}
greet ritesh

Functions help keep code modular and reusable. $1 accesses the first argument passed.

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✅ Step 7: Arguments and Script Parameters

#!/bin/bash
echo "Script name: $0"
echo "First argument: $1"

Run this using:

./myscript.sh devops

🧠 $0 is the script name, $1, $2, etc., are the passed arguments.

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✅ Step 8: Error Handling with Exit Codes

mkdir /tmp/myfolder || {
  echo "Failed to create folder"
  exit 1
}

This is a way to stop the script if something fails. || means “if the command fails, do the following.”

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🔧 Mini Project Ideas (Next Practice)

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📘 Key Bash Commands Summary

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✨ Reflection

“Today, I moved from typing commands manually to scripting them like a DevOps engineer. Bash scripting feels like giving Linux superpowers.”

With this knowledge, I'm ready to write automation scripts and build small tools for my own Linux system.

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🔗 GitHub Journal: https://github.com/ritesh355/devops-journal
🔗 Connect: https://linkedin.com/in/ritesh-singh-092b84340

#devops #linux #bash #shellscripting #automation #selftaught #100DaysOfDevOps #learninginpublic