at command for one-time jobs in Linux CLI - Mini Project: Build & Apply

Schedule a One-Time Job Using the at Command

📖 Scenario: You want to run a simple task on your Linux system just once at a specific time. For example, you want to display a message after 1 minute.

🎯 Goal: Learn how to use the at command to schedule a one-time job that runs a command at a specified time.

📋 What You'll Learn

Create a file with a command to run

Schedule the command to run using at

Verify the scheduled job

Check the output of the job

💡 Why This Matters

🌍 Real World

System administrators often need to run tasks once at a specific time, like backups or notifications.

💼 Career

Knowing how to use the <code>at</code> command is useful for automating one-time maintenance or alert tasks in Linux environments.

1

Create a file with the command to run

Create a file called message.sh that contains the command echo "Hello from at command!" > ~/at_output.txt.

Linux CLI

# Create the file message.sh with the echo command
# Your code here

Need a hint?

Use echo with redirection > to create the file.

2

Schedule the command to run using at

Schedule the script message.sh to run 1 minute from now using the at command. Use at now + 1 minute and provide the command bash ~/message.sh to at.

Linux CLI

echo "echo \"Hello from at command!\" > ~/at_output.txt" > message.sh
# Schedule the message.sh script to run 1 minute from now
# Your code here

Need a hint?

Use a here document << EOF to pass commands to at.

3

Verify the scheduled job

Use the atq command to list the scheduled jobs and confirm your job is queued.

Linux CLI

echo "echo \"Hello from at command!\" > ~/at_output.txt" > message.sh
at now + 1 minute << EOF
bash ~/message.sh
EOF
# List scheduled jobs with atq
# Your code here

Need a hint?

Just type atq to see the queue of jobs.

4

Check the output of the job

After 1 minute, use cat ~/at_output.txt to display the message written by the scheduled job.

Linux CLI

echo "echo \"Hello from at command!\" > ~/at_output.txt" > message.sh
at now + 1 minute << EOF
bash ~/message.sh
EOF
atq
# Display the contents of at_output.txt
# Your code here

Need a hint?

Use cat ~/at_output.txt to see the message.