#! /usr/bin/env bash
for network in $(cat /proc/net/dev | grep ':' | cut -d: -f1 | awk '{ print $1 }'); do
if [ "$network" != "lo" ]
then
echo $(/sbin/ifconfig $network | grep 'inet addr:' | cut -d: -f2 | awk '{ print $1}')
fi
done
Clearly you could modify the if condition to fit your needs.