IP address, MAC address and device name with sed

ipinfo.sh

#!/bin/bash

ifconfig -a | grep -A 3 ^eth | sed -n -e '
  # add first line to hold space
  1h
  # add all other lines to hold space
  1!H
  ${
    # write hold space to pattern space
    g
    # regex replacement: "device: ip address - mac address"
    s/^\(eth[0-9]\).\+\?\(inet \([0-9]\{1,3\}\(\.[0-9]\{1,3\}\)\{3\}\)\).\+\?\(ether \([0-9a-f]\{2\}\(:[0-9a-f]\{2\}\)\{5\}\)\).\+/\1:\t\3\t-\t\6/
    # output replacement
    p
  }'