Network Addresses

#!/bin/bash

# Get the list of network devices and their corresponding interfaces in
# service order priority.  The sed commands at the end first extracts
# the names of the devices and their corresponding interface names,
# then removes illegal characters and replace them with "_".
devlist="$(networksetup -listnetworkserviceorder | grep Hardware | \
    sed -e 's/^(H.*rt: \(.*\), Device: \(.*\))/\1/' \
        -e 's/[()\*#]//g' -e 's/[ -]/_/g')"

iflist="$(networksetup -listnetworkserviceorder | grep Hardware | \
    sed -e 's/^(H.*rt: \(.*\), Device: \(.*\))/\1=\2/' \
        -e 's/[()\*#]//g' -e 's/[ -]/_/g')"

for iface in ${iflist}; do
    # skip FireWire and PPTP
    if [ $iface != "FireWire=fw0" -a $iface != "PPTP=" ]; then
        eval export ${iface}
    fi
done

RED_FG="\033[31m"
NORMAL="\033[0m"

# The original tip could be implemented inside a for loop like this:
# (the bang in the environment variable does an indirect lookup)
for dev in ${devlist}; do
    # skip FireWire and PPTP
    if [ $dev != "FireWire" -a $dev != "PPTP" ]; then
        echo -n "${dev} on ${!dev}: "
        IP=$(ifconfig -m ${!dev} | grep "inet " | awk '{print $2'})
        echo -e "${IP:-${RED_FG}INACTIVE${NORMAL}}"
    fi
done

TIMEOUT=10

EXTERNAL_IP=$(curl --connect-timeout $TIMEOUT -s http://checkip.dyndns.com/ \
    | cut -d ':' -f2 | sed -e 's#</body></html>##g')

# external IP address
echo External IP: ${EXTERNAL_IP:-${TIMEOUT} second timeout encountered}