Script security best practices in Bash Scripting - Mini Project: Build & Apply

Script security best practices

📖 Scenario: You are creating a simple Bash script to manage user backups on a shared server. To keep the server safe, you want to follow script security best practices.

🎯 Goal: Build a Bash script step-by-step that uses secure coding practices like setting safe permissions, avoiding running as root, and validating inputs.

📋 What You'll Learn

Create a variable with a backup directory path

Add a variable to hold the username to backup

Use a conditional to check if the user exists

Print a secure message confirming the backup

💡 Why This Matters

🌍 Real World

System administrators often write scripts to automate backups and user management. Following security best practices prevents accidental damage or security breaches.

💼 Career

Knowing how to write secure Bash scripts is essential for roles like DevOps engineers, system administrators, and security analysts.

1

Create the backup directory variable

Create a variable called backup_dir and set it to /home/backups.

Bash Scripting

# Create a variable called backup_dir and set it to /home/backups
# Your code here

Need a hint?

Use double quotes around the path string for safety.

2

Add the username variable

Create a variable called username and set it to guest.

Bash Scripting

backup_dir="/home/backups"
# Create a variable called username and set it to guest
# Your code here

Need a hint?

Use double quotes around the username string.

3

Check if the user exists

Use an if statement with id -u $username to check if the user exists. If the user exists, print User exists, else print User does not exist.

Bash Scripting

backup_dir="/home/backups"
username="guest"
# Use if statement to check if user exists
# Your code here

Need a hint?

Use id -u $username and redirect errors to /dev/null to check user existence.

4

Print a secure backup confirmation

Print a message using echo that says Backup for user guest will be stored in /home/backups using the variables username and backup_dir.

Bash Scripting

backup_dir="/home/backups"
username="guest"
if id -u "$username" >/dev/null 2>&1; then
    echo "User exists"
else
    echo "User does not exist"
fi
# Print backup confirmation message
# Your code here

Need a hint?

Use echo with variables inside double quotes for safe output.