Monitor Disk Usage and Alert on High Consumption

#!/bin/bash

# Configuration
THRESHOLD=90 # Percentage threshold for disk usage
PARTITION="/"  # The disk partition to monitor (e.g., '/', '/var', '/home')
ALERT_EMAIL="[email protected]" # Email address to send alerts
HOST_NAME=$(hostname)

# Check if 'mail' command is available
if ! command -v mail &> /dev/null
then
    echo "'mail' command not found. Please install mailutils (e.g., sudo apt install mailutils)."
    exit 1
fi

# Get current disk usage percentage for the specified partition
USAGE=$(df -h "$PARTITION" | awk 'NR==2 {print $5}' | sed 's/%//')

echo "Checking disk usage for $PARTITION on $HOST_NAME... Current usage: $USAGE%"

# Compare usage with threshold
if (( USAGE > THRESHOLD )); then
    SUBJECT="Disk Space Alert on $HOST_NAME - $PARTITION at $USAGE%"
    BODY="Disk usage on $HOST_NAME for partition $PARTITION has exceeded the threshold of $THRESHOLD%. Current usage: $USAGE%."
    
    echo "$BODY"
    echo "Sending alert email to $ALERT_EMAIL..."
    
    # Send email
    echo "$BODY" | mail -s "$SUBJECT" "$ALERT_EMAIL"
    
    if [ $? -eq 0 ]; then
        echo "Alert email sent successfully."
    else
        echo "Failed to send alert email. Check mail configuration."
    fi
else
    echo "Disk usage is within acceptable limits."
fi