Function libraries (sourcing scripts) in Bash Scripting - Mini Project: Build & Apply

Using Function Libraries by Sourcing Scripts in Bash

📖 Scenario: You are working on a bash script project where you want to reuse some useful functions stored in a separate file. This helps keep your scripts clean and organized, just like having a toolbox with tools ready to use.

🎯 Goal: Learn how to create a bash function library in one script file and then use source to include those functions in another script. Finally, call the functions to see their output.

📋 What You'll Learn

Create a bash script file named functions.sh with two simple functions.

Create a main bash script named main.sh that sources functions.sh.

Call the sourced functions from main.sh and print their outputs.

💡 Why This Matters

🌍 Real World

In real projects, you often keep reusable bash functions in separate files. This helps you avoid rewriting code and keeps your scripts clean.

💼 Career

Knowing how to source scripts and use function libraries is important for system administrators, DevOps engineers, and anyone automating tasks with bash.

1

Create the function library script

Create a bash script file named functions.sh that defines two functions: greet which prints "Hello, friend!" and farewell which prints "Goodbye, friend!". Write the exact function definitions with these names and messages.

Bash Scripting

# Define the greet and farewell functions here
# Your code here

Need a hint?

Use the syntax function_name() { commands } to define functions in bash.

2

Create the main script and source the function library

Create a bash script file named main.sh. Inside it, use source ./functions.sh to include the functions from functions.sh. This will let you use the functions defined there.

Bash Scripting

# Source the functions.sh file here
# Your code here

Need a hint?

Use source ./functions.sh or . ./functions.sh to include the functions.

3

Call the sourced functions in the main script

In main.sh, after sourcing functions.sh, call the functions greet and farewell by writing their names on separate lines.

Bash Scripting

source ./functions.sh

# Call greet and farewell functions below
# Your code here

Need a hint?

Simply write the function names greet and farewell on separate lines to call them.

4

Run the main script and see the output

Run the main.sh script in your terminal. It should print the greeting and farewell messages from the sourced functions. Write a bash main.sh command and observe the output.

Bash Scripting

# Run the script in terminal and observe output
# Your code here

Need a hint?

Use the command bash main.sh in your terminal to run the script.