This bash script gets your devices local IPv4 and sets it to your zzzz.io domains. (My usecase: I carry around a Raspberry Pi for web development, and can set multiple domains in one line so I can continue testing no matter what network or device I'm on.)

zzzz-localip.sh

#!/bin/bash
# Get your token from zzzz.io
ZZZZ_TOKEN="YOUR-TOKEN-HERE"

# Your domains as a list.
domains=("DOMAIN1" "DOMAIN2")

# Let the code do its thing.
LOCALIP="$(ifconfig wlan0 | grep "inet addr" | cut -d ':' -f 2 | cut -d ' ' -f 1)"
echo "Local IP: $LOCALIP"
for DOMAIN in "${domains[@]}"
do
        curl "https://zzzz.io/api/v1/update/$DOMAIN/?token=$ZZZZ_TOKEN&ip=$LOCALIP"
        echo " $DOMAIN"
done