ShellCheck for static analysis in Bash Scripting - Mini Project: Build & Apply

ShellCheck for Static Analysis

📖 Scenario: You are a system administrator who wants to write a safe and error-free Bash script to automate a simple task. You will learn how to use ShellCheck, a tool that helps find mistakes in your Bash scripts before running them.

🎯 Goal: Create a Bash script that prints a greeting message. Then, use ShellCheck to find and fix a common mistake in the script. Finally, run the fixed script to see the correct output.

📋 What You'll Learn

Create a Bash script file named greet.sh with a greeting message.

Add a variable called name with the value World.

Use ShellCheck to find a warning about quoting the variable.

Fix the script by adding quotes around the variable.

Run the fixed script and print the greeting message.

💡 Why This Matters

🌍 Real World

System administrators and developers use ShellCheck to catch errors in Bash scripts before running them, saving time and avoiding bugs.

💼 Career

Knowing how to use ShellCheck is valuable for anyone writing or maintaining shell scripts in IT, DevOps, and software development roles.

1

Create the initial Bash script

Create a file named greet.sh and write a Bash script that sets a variable called name to World and prints Hello, $name! without quotes around $name.

Bash Scripting

# Create a variable called name with value World
# Print Hello, $name! without quotes around $name

Need a hint?

Remember to write the variable assignment without spaces around the equals sign. Use echo to print the message.

2

Run ShellCheck to find warnings

Run shellcheck greet.sh in the terminal to check the script. Add a comment in the script that says # shellcheck disable=SC2086 above the echo line to temporarily disable the warning about unquoted variables.

Bash Scripting

name=World

# Add a shellcheck disable comment above the echo line
# Your code here

echo Hello, $name!

Need a hint?

Use the exact comment # shellcheck disable=SC2086 on the line before echo.

3

Fix the script by quoting the variable

Remove the shellcheck disable comment. Edit the echo line to add double quotes around $name like echo "Hello, $name!" to fix the warning properly.

Bash Scripting

name=World

# Remove the disable comment and add quotes around $name
# Your code here

echo "Hello, $name!"

Need a hint?

Put double quotes around $name inside the echo command to prevent word splitting.

4

Run the fixed script and print output

Run the fixed script ./greet.sh in the terminal and print the output. Write a command to run the script and a command to print the output.

Bash Scripting

# Run the script and print the output
# Your code here

Need a hint?

Make sure the script has execute permission with chmod +x greet.sh before running it.