31. Functions in Bash Scripts

Functions allow you to group a block of code and reuse it throughout your script, making the code cleaner, more modular, and easier to debug.

Defining a Function

There are two common ways to define a function:

1. Standard: function_name () { commands; }
2. Keyword: function function_name { commands; } (The first style is often preferred).

bash #!/bin/bash

1. Define the function

create_project_folder () { read -p "Enter folder name: " FOLDER_NAME

if [ -d "$FOLDER_NAME" ]; then
    echo "Error: Folder already exists."
    return 1
fi

mkdir "$FOLDER_NAME"
echo "Folder $FOLDER_NAME created successfully."

}

2. Call the function

create_project_folder

Function Arguments

Functions accept arguments passed at the time of calling. Inside the function:

• $1, $2, etc., refer to the first, second arguments.
• $# is the total number of arguments.
• $* or $@ is the full list of arguments.

Example with Arguments:

bash check_status () { echo "Checking status for user: $1" # Check specific system status using $1 }

Calling the function:

check_status termux_user