OS X connection monitor

README.md

Connection monitor

Note: if you need a simple connection icon, check out BitBar and its internet checker plugin.

This program notifies you when Internet goes down and when it comes back up.

It pings Google's DNS every 4 seconds; when a ping fails it quickly tries a few more times and switches to downtime mode. When Internet is available again, the cycle restarts.

Tools used

• bash
• ping
• osascript (AppleScript, for the OSX notifications)

Notes

Remove lines with osascript to make it compatible outside OS X

Alternatives

http://antirez.com/iconping/

Author

Twitter, more gists, blog

connection-monitor.sh

#!/bin/bash
# Details: https://gist.github.com/bfred-it/7a269ca212faced83e60
# License: WTFPL
# By: Federico Brigante

#config
retries=6
check_interval=4 #seconds
check_interval_hyper=0.2
check_interval_down=0.5
ping_timeout=1 #integers only, ping's fault
offline_message="❌ You are offline"
online_message="✅ You are back online!"

#program
echo $(date +"%T") "Hi. I will notify you when the internet goes down"
while true; do
	status=$retries

	# check connectivity every 4 seconds
	while ! [ "$status" -eq 0 ]; do
		if ! ping -c 1 -t $ping_timeout -q 8.8.8.8 > /dev/null 2>&1; then
			echo $(date +"%T") "Ping timed out"
			# echo $(date +"%T") "You may be offline. Tries left:" $status
			let "status -= 1"
			sleep $check_interval_hyper
		else
			# if ! [[  "$status" -eq $retries ]]; then
			# 	echo 'It was only temporary. You are online'
			# fi
			status=$retries # restore counter
			sleep $check_interval
		fi
	done

	# if it reaches this point, you are offline
	echo $(date +"%T") $offline_message
	offline_since=$(date +"%s")
	osascript -e "display notification \"\" with title  \"$offline_message\""
	while ! ping -c 1 -t $ping_timeout -q 8.8.8.8 > /dev/null 2>&1; do
		sleep $check_interval_down
	done

	# if it reaches this point, you are back online
	online_since=$(date +"%s")
	downtime_duration=$(($online_since-$offline_since))
	echo $(date +"%T") $online_message 'It lasted' $downtime_duration 'seconds'
	osascript -e "display notification \"You were offline for $downtime_duration seconds\" with title \"$online_message\""
done