Bash Empty Function [A Complete Guide]

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The bash function serves as a cornerstone in the world of bash scripting. Within the framework of bash function, the concept of empty functions emerges as an important foundation. This seemingly void construct serves as a placeholder within scripts awaiting future functionalities. This article will dive into the bash empty function and describe its purpose and utility in script organization and modularity.

What is Bash Empty Function?

A bash empty function is a function definition in a bash script that lacks any executable code within its body. Essentially, it is a function declaration without any operations to perform. It serves as a placeholder or a template for defining functions that may not have any functionality at the moment but need to be outlined within the script structure.

How to Use Bash Empty Function?

In bash scripting, an empty function is utilized as a structural placeholder for future implementation. To use an empty function first you need to declare the function with an empty body usually with a colon which serves as a null command indicating a no operation (do nothing) or a placeholder. It is often used in situations where syntax requires a command but no action is needed which is perfect for the empty function. Then, call the empty function where needed. The following is the basic syntax of the bash empty function:

empty_function() {


empty_function(){ :; }

The syntax of the bash empty function is similar to the traditional function definition. It consists of the function name followed by optional empty parentheses and curly braces. The colon(:) within the curly braces serves as a placeholder, indicating that the function body is empty. It can also be represented as a one-liner function definition as shown in the second syntax above.

A Practical Example of Using Bash Empty Function

Empty function is mainly used in bash script for modularity, maintaining proper structure, and future functionality expansion of the script. The below example properly demonstrates it. The following bash script is designed to perform several functions including empty functions using a modular approach:


# Function to greet the user
greet_user() {
  echo "Hello, $1!"

# Function to display current date and time
show_date_time() {
  echo "Current date and time: $(date)"

# Empty function 
show_next_appointment() {

# Another empty placeholder function 
create_new_appointment() { :; }

# Main function to execute script logic
main() {
  # Check if a name is provided for greeting
  greet_user $1

  # Display the current date and time

  # Call the placeholder functions

# Error handling
if [ "$#" -ne 1 ]; then
  echo "Usage: $0 <name>"
  exit 1

# Call the main function to start the script
main "$@"

The bash script starts by defining two functions. The greet_user() function greets the user with the name provided as an argument. And the show_date_time() displays the current date and time using the date command. Additionally, it contains two empty placeholder functions: show_next_appointment() and create_new_appointment(). These functions serve as placeholders for future implementation or functionality expansion.

The main() function coordinates the script’s execution. It first ensures that the correct number of arguments is provided. After that, it greets the user with the provided name and then displays the current date and time. Then it calls the empty placeholders functions.

The script also includes an error-handling feature. If the correct number of arguments is not provided it displays a usage message and exits the script.

Finally, by calling the main function at the end of the script, the whole script is executed in an ordered manner.

while executing a script with empty function, it is executed as a null command

Here, after executing the script, the system echoes the output of the first two functions, and then it executes the empty function with the null command.

Why Empty Function is Needed in Bash?

Bash empty functions serve as placeholders or markers within scripts, providing several key benefits, such as:

  1. Structural Organization: Empty functions help in structuring Bash scripts by delineating logical sections or modules. They provide a clear outline of the script’s components, making it easier for developers to understand and navigate the codebase.
  2. Modular Design: By defining empty functions for different functionalities, users can adopt a modular design approach. Each function represents a specific task or feature, promoting code reusability and maintainability.
  3. Future Expansion: Empty functions serve as placeholders for future implementation. Developers can outline the structure of their scripts and leave room for adding functionality later. This approach facilitates agile development and accommodates changes in project requirements.
  4. Readability and Maintenance: Well-organized scripts with clearly defined empty functions are easier to read, understand, and maintain. They encourage best practices in coding and contribute to the overall readability of the script.


To sum it up, bash empty functions play a pivotal role in script development, serving as markers for future functionalities and promoting modular design. I hope this article helps you understand the basics of the bash empty function and its utilization.

People Also Ask

What is a function in bash scripting?

In bash scripting, a function is a named block of code that performs a specific task. It allows users to organize and modularize their scripts by grouping related commands together. Functions can make your code reusable and easier to maintain. It can accept parameters, process data, and return results. It enhances the flexibility and efficiency of the script.

Can an empty function be called in bash scripting?

Yes, an empty function can be called in bash scripting. Even though an empty function does not contain any executable code within its body it can still be invoked like any other function in bash. Calling an empty function simply executes the function declaration without performing any operations. It is often used as a placeholder for future functionality.

How do you define an empty function in bash?

To define an empty function in bash you use the standard function declaration syntax but without any executable code inside the function body. In simple terms, you specify the function name followed by empty parentheses and curly braces. Within the curly braces, you place a colon(:) which serves as a null command indicating that the function has no operations to perform.

Can the empty function improve script readability?

Yes, the empty function can improve the script readability. It provides a clear structure and indicates where certain functionalities are intended to be added in the future. It helps organize the script into logical sections and makes it easier for users to understand the overall flow. Using the empty function user can plan for future expansions or modifications without cluttering the script with unnecessary code.

Are there any best practices for using the bash empty function?

Yes, there are several best practices for using the bash empty function effectively. First, it is crucial to use descriptive names for empty functions to indicate their intended purpose or future functionality. This enhances code readability and understanding. Secondly, ensure that empty functions are strategically placed within the script to maintain logical organization and modularity. Thirdly document the purpose of each empty function using comments to provide clarity to other users.

What is the purpose of the bash empty function?

The purpose of the bash empty function is to serve as a structural placeholder within a script. It lacks executable code but outlines where functions with future functionality can be implemented. Essentially, it serves as a marker or template for defining functions that may not have specific operations at the moment but need inclusion in the script’s structure.

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Ridoy Chandra Shil

Hello everyone. I am Ridoy Chandra Shil, currently working as a Linux Content Developer Executive at SOFTEKO. I am a Biomedical Engineering graduate from Bangladesh University of Engineering and Technology. I am a science and tech enthusiast. In my free time, I read articles about new tech and watch documentaries on science-related topics. I am also a big fan of “The Big Bang Theory”. Read Full Bio

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