trap for cleanup on exit in Bash Scripting - Mini Project: Build & Apply

Using trap for Cleanup on Exit in Bash

📖 Scenario: You are writing a bash script that creates a temporary file to store some data. To keep your system clean, you want to make sure this temporary file is deleted automatically when the script finishes or if it is interrupted.

🎯 Goal: Build a bash script that creates a temporary file, sets up a trap to delete this file when the script exits, and then prints a message confirming the cleanup.

📋 What You'll Learn

Create a variable tempfile with the value /tmp/mytempfile.txt

Set up a trap command to delete $tempfile on script exit

Create the temporary file using touch

Print Cleanup done! after the file is deleted

💡 Why This Matters

🌍 Real World

Scripts often create temporary files or resources that must be cleaned up to avoid clutter or security risks. Using trap ensures cleanup happens even if the script is interrupted.

💼 Career

Knowing how to use trap for cleanup is important for system administrators, DevOps engineers, and anyone writing reliable shell scripts that manage temporary resources.

1

Create the temporary file variable

Create a variable called tempfile and set it to the string /tmp/mytempfile.txt.

Bash Scripting

# Create a variable called tempfile with the value /tmp/mytempfile.txt
# Your code here

Need a hint?

Use tempfile=/tmp/mytempfile.txt to assign the path.

2

Set up the trap for cleanup

Add a trap command that runs rm -f "$tempfile" and then echo "Cleanup done!" when the script exits.

Bash Scripting

tempfile=/tmp/mytempfile.txt
# Set up trap to remove tempfile and print message on exit
# Your code here

Need a hint?

Use trap 'rm -f "$tempfile"; echo "Cleanup done!"' EXIT to run commands on exit.

3

Create the temporary file

Use the touch command to create the file at the path stored in tempfile.

Bash Scripting

tempfile=/tmp/mytempfile.txt
trap 'rm -f "$tempfile"; echo "Cleanup done!"' EXIT
# Create the tempfile using touch
# Your code here

Need a hint?

Use touch "$tempfile" to create the file.

4

Test the cleanup on exit

Run the script and observe that when it finishes, it prints Cleanup done! and the temporary file is deleted.

Bash Scripting

tempfile=/tmp/mytempfile.txt
trap 'rm -f "$tempfile"; echo "Cleanup done!"' EXIT
touch "$tempfile"
# Run the script and check output
# Your code here

Need a hint?

Run the script normally. The message Cleanup done! should appear when it exits.