duckdns.org

duck.sh

#!/bin/sh

## Sample run:
## chmod 700 ~/Dropbox/apps/_running_/duck.sh
## crontab -e
## */5 * * * * ~/Dropbox/apps/_running_/duck.sh ingcma utun1 >/dev/null 2>&1

NAME=$1
IFACE=$2
TOKEN=<ENTER-TOKEN>
#TOKEN=$3

LOG=$HOME/.duckdns.log

usage(){
    echo "Usage: $0 domain-hostname interface"
    exit 1
}

( test -z "$NAME" || test -z "$IFACE" ) && usage

#Linux: IP=$(/sbin/ifconfig ${IFACE} | grep 'inet addr' | sed -e 's/:/ /' | awk '{print $3}')
#Mac OS X
IP=$(/sbin/ifconfig ${IFACE} | grep 'inet' | tail -n 1 | sed -e 's/:/ /' | awk '{print $2}')

test -z "$IP"
if [[ $? -eq 0 ]]; then
    echo "Unable to get valid IP, quitting.";
    exit 0
fi

FILE="/tmp/duckdns.${IFACE}.${NAME}"

if [ -e $FILE ]; then
    read LASTIP < $FILE
    if [ "$IP" = "$LASTIP" ]; then
        echo "IP: $IP hasn't changed, early exit.";
        exit 0
    fi
fi

echo $IP > $FILE
echo "Setting ${NAME} to '${IP}' (from iface ${IFACE})"
echo url="https://www.duckdns.org/update?domains=${NAME}&token=${TOKEN}&ip=${IP}" | curl -o $LOG -k -K -