A handy Bash script to monitor your internet connection, log downtimes, and notify you of changes in connectivity status.

Internet-Connectivity-Checker.sh

#!/bin/bash

# Default Configurations
DEFAULT_PING_HOSTS=("8.8.8.8" "1.1.1.1")
DEFAULT_CHECK_INTERVAL=10
DEFAULT_LOG_FILE="$(dirname "$0")/internet_downtime.log"

# Initialize Configurations
PING_HOSTS=("${DEFAULT_PING_HOSTS[@]}")
CHECK_INTERVAL=$DEFAULT_CHECK_INTERVAL
LOG_FILE=$DEFAULT_LOG_FILE

# Parse Command Line Arguments
while getopts "h:i:l:" opt; do
  case $opt in
    h) IFS=',' read -r -a PING_HOSTS <<< "$OPTARG";;
    i) CHECK_INTERVAL="$OPTARG";;
    l) LOG_FILE="$OPTARG";;
    *) echo "Usage: $0 [-h hosts] [-i interval] [-l logfile]"; exit 1;;
  esac
done

# Function Definitions
check_internet() {
    for host in "${PING_HOSTS[@]}"; do
        if /sbin/ping -c 1 "$host" &>/dev/null; then
            return 0
        fi
    done
    return 1
}

log_message() {
    echo "$(date) - $1" | tee -a "$LOG_FILE"
}

send_notification() {
    local message=$1
    if [ "$(uname)" == "Darwin" ]; then
        /usr/bin/osascript -e "Display notification \"$message\" with title \"Connectivity Alert\""
    elif [ "$(expr substr $(uname -s) 1 5)" == "Linux" ]; then
        notify-send "Connectivity Alert" "$message"
    fi
}

handle_exit() {
    log_message "Internet connectivity checker stopped."
    exit 0
}

# Trap SIGINT for graceful termination
trap handle_exit SIGINT

# Main Loop
log_message "Internet connectivity checker started."
notification_sent=0
down_times=0
longest_duration=0
downtime_start=0

while true; do
    if check_internet; then
        if [ "$notification_sent" -eq 1 ]; then
            send_notification "Internet is reconnected"
            notification_sent=0
            downtime_end=$(date +%s)
            duration=$((downtime_end - downtime_start))
            down_times=$((down_times + 1))
            longest_duration=$(($duration > $longest_duration ? $duration : $longest_duration))
        fi
        echo -ne "\rDowntimes: $down_times | Longest Duration: ${longest_duration}s | Status: \033[32mONLINE\033[0m"
    else
        if [ "$notification_sent" -eq 0 ]; then
            send_notification "Internet is disconnected"
            notification_sent=1
            downtime_start=$(date +%s)
            log_message "Internet down"
        fi
        echo -ne "\rDowntimes: $down_times | Longest Duration: ${longest_duration}s | Status: \033[31mOFFLINE\033[0m"
    fi
    sleep "$CHECK_INTERVAL"
done