99-hosts

#!/bin/sh  
#
# /etc/NetworkManager/dispatcher.d/99-hosts
#
  
INTERFACE=$1  
STATUS=$2  
  
if [ "x$STATUS" != "xup" ]; then  
  exit 0  
fi  
  
DEFAULT=$(/sbin/ip route | grep ^default | awk '{print $5}')  
  
if [ "x$INTERFACE" != "x$DEFAULT" ]; then  
  exit 0  
fi  
  
hostname=$(hostname)  
alias=$(hotname -a)  
ip=$(/sbin/ip -o -4 addr list $INTERFACE | awk '{print $4}' | cut -d/ -f1)  
  
if [ "x$ip" = "x" -o "x$hostname" = "x" ]; then  
  exit 0  
fi  
  
sed -i -e '/'"$hostname"'/d' /etc/hosts  
sed -i -e '/Added by 99-hosts/d' /etc/hosts  
echo "#Added by 99-hosts" >> /etc/hosts  
echo "$ip $hostname $alias" >> /etc/hosts