Set ip info based on mac addess https://plus.google.com/u/0/108968986881529941950/posts/jd2sKgWjm3k

hackip.sh

#! /usr/bin/env sh

# Set up some shit dependeing on primary mac address

if=en0  # Change this is you don't want to use primary

updateHost() {
  # $1 = ip address
  # $2 = hostname
  # $3 = interface name
  # NB Mac specific

cat <<'EOF'|sudo bash -s  $1 $2  $3
      ipconfig set $3 INFORM $1
      hostname $2
      scutil --set HostName $(hostname)
      scutil --set LocalHostName $(hostname)
EOF
}


mac=$(ifconfig $if | sed -Ene '/^[[:blank:]]ether[[:blank:]]+([0-9a-f:]+)[[:blank:]]*$/s//\1/p')

case $mac in

    aa:bb:cc:49:5e:23) updateHost 192.168.1.51 hostname1 $if ;;

    11.22:33:44:55:66)  updateHost 192.168.1.52 hostname2 $if ;;

     *)  echo Error MAC Address $mac not recognised

esac

echo Mac address is \"$mac\"
echo IP Address is $(ifconfig $if | sed -Ene '/inet (.+)$/s//\1/p')
echo Hostname is $(hostname)
echo Hostname os $(scutil --get HostName)
echo LocaltHostname os $(scutil --get LocalHostName)