my-docs/Linux/Bash Script/05-Variables.md

🧮 Bash Variables

In Bash scripting, variables are used to store values like text or numbers. They allow scripts to be dynamic and reusable.

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✍️ Defining Variables

Variables are created without spaces around the = sign:

user="ali"
age=21

• user is assigned the value "ali".
• age is assigned the value 21.

✅ Tip: No let or var is needed like in other programming languages.

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📢 Using Variables

You can access variables by prefixing them with $:

user="radin"
echo "Welcome, $user"

Output:

Welcome, radin

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🧪 Full Script Example

Here's a complete Bash script using variables:

#!/bin/bash

user="mmd"
age=25

echo "$user is $age years old."

Output:

mmd is 25 years old.

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📌 Notes

• Variable names are case-sensitive (User and user are different).
• Avoid spaces around = when assigning.
• Enclose variable values in quotes if they contain spaces.

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✅ Summary

Task	Syntax
Define variable	name="value"
Use variable	$name
Print value	echo "$name"
With script	Use #!/bin/bash at the top