Why disk management prevents outages in Linux CLI - See It in Action

Why Disk Management Prevents Outages

📖 Scenario: You are a system administrator responsible for keeping a Linux server running smoothly. One important task is to monitor disk usage to prevent the server from running out of space, which can cause outages and stop important services.

🎯 Goal: Build a simple script that checks disk usage on the root partition and alerts if the usage is above a certain threshold. This helps prevent outages by giving early warnings to free up space.

📋 What You'll Learn

Use the df command to get disk usage of the root partition

Create a variable to hold the disk usage percentage as a number

Set a threshold variable for maximum allowed disk usage

Use an if statement to compare usage with the threshold

Print a warning message if usage is above the threshold, otherwise print a safe message

💡 Why This Matters

🌍 Real World

System administrators monitor disk space to avoid server crashes and service interruptions caused by full disks.

💼 Career

Knowing how to automate disk usage checks and alerts is a key skill for Linux system administrators and DevOps engineers.

1

Get disk usage of root partition

Use the df command with -h and / to get disk usage of the root partition. Then create a variable called disk_usage that stores the usage percentage as a string (e.g., '75%'). Use df -h / | tail -1 | awk '{print $5}' to get this value.

Linux CLI

# Use df command to get root partition usage
# Your code here

Need a hint?

Use df -h / to get disk info for root, then extract the fifth column for usage.

2

Set a threshold for disk usage

Create a variable called threshold and set it to 80. This means if disk usage is above 80%, we want to get a warning.

Linux CLI

disk_usage=$(df -h / | tail -1 | awk '{print $5}')
# Set threshold variable to 80
# Your code here

Need a hint?

Just assign the number 80 to the variable threshold.

3

Compare disk usage with threshold

Remove the percent sign from disk_usage and convert it to a number called usage_num. Then use an if statement to check if usage_num is greater than threshold. If yes, set a variable alert_msg to "Warning: Disk usage is above threshold!". Otherwise, set alert_msg to "Disk usage is safe.".

Linux CLI

disk_usage=$(df -h / | tail -1 | awk '{print $5}')
threshold=80
# Remove % sign and convert to number
# Use if statement to compare usage_num and threshold
# Set alert_msg accordingly
# Your code here

Need a hint?

Use ${disk_usage%?} to remove the percent sign. Use if [ "$usage_num" -gt "$threshold" ] for comparison.

4

Print the alert message

Print the value of alert_msg to show the disk usage status.

Linux CLI

disk_usage=$(df -h / | tail -1 | awk '{print $5}')
threshold=80
usage_num=${disk_usage%?}
if [ "$usage_num" -gt "$threshold" ]; then
    alert_msg="Warning: Disk usage is above threshold!"
else
    alert_msg="Disk usage is safe."
fi
# Print the alert message
# Your code here

Need a hint?

Use printf "%s\n" "$alert_msg" or echo "$alert_msg" to print.