Why cron automates recurring tasks in Linux CLI - See It in Action

Why cron automates recurring tasks

📖 Scenario: You are managing a small server that needs to perform regular backups every day. Doing this manually is tiring and easy to forget. You want to use a tool that runs commands automatically at set times.

🎯 Goal: Learn how to use cron to automate a simple recurring task that runs every minute for demonstration. You will create a cron job that writes the current date and time to a file repeatedly.

📋 What You'll Learn

Create a text file to store output

Write a cron job command that runs every minute

Use the correct cron syntax for timing

Verify the cron job runs and appends output

💡 Why This Matters

🌍 Real World

Automating tasks like backups, system updates, or report generation saves time and avoids forgetting important jobs.

💼 Career

System administrators and developers use cron to schedule scripts and commands to run automatically, improving efficiency and reliability.

1

DATA SETUP: Create a file to store output

Create an empty file called /tmp/cron_test.log using the touch command.

Linux CLI

# Use touch to create /tmp/cron_test.log
# Your code here

Need a hint?

Use touch to create an empty file if it does not exist.

2

CONFIGURATION: Write the cron job command

Write a cron job line that runs every minute and appends the current date and time to /tmp/cron_test.log. Use the command date >> /tmp/cron_test.log.

Linux CLI

touch /tmp/cron_test.log
# Write the cron job line below
# Your code here

Need a hint?

The cron timing * * * * * means every minute.

3

CORE LOGIC: Add the cron job to the crontab

Add the cron job line * * * * * date >> /tmp/cron_test.log to your user crontab using crontab -l | { cat; echo "* * * * * date >> /tmp/cron_test.log"; } | crontab -.

Linux CLI

touch /tmp/cron_test.log
* * * * * date >> /tmp/cron_test.log
# Add the cron job to crontab below
# Your code here

Need a hint?

This command appends the new cron job to your existing crontab.

4

OUTPUT: Check the output file for new entries

Use tail -n 3 /tmp/cron_test.log to display the last three lines of the file and verify the cron job is running.

Linux CLI

touch /tmp/cron_test.log
* * * * * date >> /tmp/cron_test.log
crontab -l | { cat; echo "* * * * * date >> /tmp/cron_test.log"; } | crontab -
# Check the last 3 lines of /tmp/cron_test.log
# Your code here

Need a hint?

The output should show recent date and time entries, one per minute.