System Monitoring and Alert Script

#!/bin/bash

# Threshold values for alerts
CPU_THRESHOLD=80     # Percentage
MEMORY_THRESHOLD=80  # Percentage
DISK_THRESHOLD=90    # Percentage
NETWORK_THRESHOLD=100000 # KB/s (Set as needed)

# Email details (Update these with your actual email settings)
EMAIL_TO="your_email@example.com"
EMAIL_SUBJECT="System Alert: Resource Usage Exceeded"

# Function to send an email alert
send_email() {
    local message="$1"
    echo "$message" | mail -s "$EMAIL_SUBJECT" "$EMAIL_TO"
}

# Function to print alert to the current terminal
alert_terminal() {
    local message="$1"
    echo "$message" > /dev/pts/$(who am i | awk '{print $2}')
}

# Monitor CPU usage
check_cpu_usage() {
    local cpu_usage
    cpu_usage=$(top -bn1 | grep "Cpu(s)" | awk '{print $2 + $4}')
    cpu_usage=${cpu_usage%.*} # Remove decimal places

    if (( cpu_usage > CPU_THRESHOLD )); then
        local message="High CPU Usage Alert: $cpu_usage% (Threshold: $CPU_THRESHOLD%)"
        send_email "$message"
        alert_terminal "$message"
    fi
}

# Monitor memory usage
check_memory_usage() {
    local mem_usage
    mem_usage=$(free | grep Mem | awk '{printf "%.0f", $3/$2 * 100.0}')
    
    if (( mem_usage > MEMORY_THRESHOLD )); then
        local message="High Memory Usage Alert: $mem_usage% (Threshold: $MEMORY_THRESHOLD%)"
        send_email "$message"
        alert_terminal "$message"
    fi
}

# Monitor disk usage
check_disk_usage() {
    local disk_usage
    disk_usage=$(df / | tail -1 | awk '{print $5}' | sed 's/%//')

    if (( disk_usage > DISK_THRESHOLD )); then
        local message="High Disk Usage Alert: $disk_usage% (Threshold: $DISK_THRESHOLD%)"
        send_email "$message"
        alert_terminal "$message"
    fi
}

# Monitor network usage
check_network_usage() {
    local rx_bytes tx_bytes total_bytes
    rx_bytes=$(cat /sys/class/net/eth0/statistics/rx_bytes)
    tx_bytes=$(cat /sys/class/net/eth0/statistics/tx_bytes)
    total_bytes=$(( (rx_bytes + tx_bytes) / 1024 )) # Convert to KB/s

    if (( total_bytes > NETWORK_THRESHOLD )); then
        local message="High Network Usage Alert: ${total_bytes}KB/s (Threshold: ${NETWORK_THRESHOLD}KB/s)"
        send_email "$message"
        alert_terminal "$message"
    fi
}

# Main monitoring function
monitor_system() {
    while true; do
        check_cpu_usage
        check_memory_usage
        check_disk_usage
        check_network_usage
        sleep 60 # Check every 60 seconds
    done
}

# Start monitoring
monitor_system