🐚 Bash Function Syntax & Examples

Bash functions allow you to group reusable logic in shell scripts. Below are clear examples and explanations to help you understand how to define and use them effectively.

🔧 Defining a Function

You can define a Bash function in two main ways:

Option 1: Classic Syntax

function_name () {
    # commands
}

Option 2: With the `function` Keyword

function function_name () {
    # commands
}

💡 Both syntaxes are valid. The use of the function keyword is optional and mostly stylistic.

📥 Passing Arguments

Bash functions accept arguments just like scripts. These are accessed via $1, $2, etc.

Example: Single Argument

func1() {
    echo "Arg: $1"
}

func1 "Test"

Output:

Arg: Test

➕ Multiple Arguments & Calculation

You can perform operations using passed arguments, like arithmetic:

summery() {
    local sum=$(( $1 + $2 ))
    echo $sum
}

summery 5 7

Output:

📌 local ensures sum is scoped within the function.

✅ Best Practices

Use local to avoid polluting the global scope.
Quote variables when dealing with strings.
Use descriptive names for clarity.

🧪 Try It Yourself

Add these examples to a .sh file and run it with:

bash script.sh

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