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Vpn_reactivate.sh

This is a bash script that I use to check whether a vpn connection is active, reconnect to it if it is lost and stop and restart transmission torrent client accordingly. You can easily modify it, for instance, to kill some other program if your vpn connection is lost. 
#!/bin/bash

##This script checks if a vpn connection is enabled, stops transmission torrent
##client if the vpn connection is lost, restablishes it and restarts transmission.
##The vpn connection has to be configured through Network Manager nm-applet.
##The script runs forever and has to be stoped pressing CTRL-c
##You will need nmcli, transmission and transmission-remote.

##Name of the VPN connection in NetworkManager: (change this accordingly)
IDCONN="Your id connetion as you have in Network Manager"

while [ 1 -gt 0 ]; do
	nmcli con status | grep $IDCONN > /dev/null
	status=$?
	sleep 1s
	if [ $status != 0 ]; then
		transmission-remote -tall --stop
		echo "Reconnecting"
		nmcli con up id $IDCONN
		sleep 5s
		nmcli con status | grep $IDCONN > /dev/null
		status=$?
		sleep 1s
		while [ $status !=0 ]; do
			echo "Reconnecting"
			nmcli con up id $IDCONN
			sleep 5s
			nmcli con status | grep $IDCONN > /dev/null
			status=$?
			sleep 1s
		done
		transmission-remote -tall --start
	fi
done