updated twodns updater, which only calls the API if current external ip is different from the one stored in current_ip.txt

ddns_updater_v2.sh

# !/bin/sh

path="/usr/local/bin/twodns/"

# create file if it doesn't exist
if ! test -f $path"current_ip.txt"; then
	echo "empty" > $path"current_ip.txt"
fi

ip_address=`cat /usr/local/bin/twodns/current_ip.txt`
my_ext_ip=$(curl -sS http://ipv4.icanhazip.com)
log=$path"ddns_updater.log.txt"

# echo "n$(date -u) IP in file " $ip_address " external IP " $my_ext_ip >> $log

if [ $ip_address = $my_ext_ip ]
then
	echo "\n$(date) ip adresses are equal, not updating" >> $log
else
	# update ip in file and online
	echo "$my_ext_ip" > $path"current_ip.txt"

	echo "\n\n\n===== \
	   \n$(date) \
	   \nUpdating IP to: $my_ext_ip \n" >> $log
	curl -isSX PUT \
	   -u "[email protected]:YOUR_API_TOKEN" \
	   -H "Content-Type: application/json" \
	   --data '{"ip_address":"'$my_ext_ip'", "activate_wildcard": "false"}' \
	   https://api.twodns.de/hosts/YOUR_HOSTNAME.dynvpn.de >> $log
	exit
fi

this script is based on https://gist.github.com/oliveratgithub/a50a3d6bcb1e030ed06e

changes

• updated URL for obtaining ipv4 address (old URL doesn't work anymore)
• highlighted the areas where user data needs to be placed
• added check for previous IP address, not updating to TwoDNS if current public IP equals stored IP
• check if current_ip.txt exists, create the file if it doesn't exist

• added path reference for improved file/log handling. Note: the path needs to be updated in 2 lines in case the script is used in a different location (this needs to be improved)
• remove -u after date calls to make log timestamps in sync with current timezone