!/usr/bin/sh

set -u

typeset -i OLD_PACKETS_IN=0
typeset -i OLD_PACKETS_OUT=0
typeset -i OLD_PACKETS_IN_ERR=0
typeset -i OLD_PACKETS_OUT_ERR=0
typeset -i OLD_COLLISSIONS=0
typeset -i IN_BOUND_ERRORS=0
typeset -i NEW_IN_BOUND_ERRORS=0
typeset -i OUT_BOUND_DISCARDS=0
typeset -i NEW_OUT_BOUND_DISCARDS=0

echo " This first entry in this file is the statistics since last boot:"
echo " the other entries are statistics for the previous minute:"

while [ 1=1 ] # Run Foreever
do

  netstat -i    \
    | grep lan0 \
    | read NAME MTU NETWORK ADDRESS IPKTS IERRS OPKTS OERRS COLL

  NEW_PACKETS_IN=$(( $IPKTS - $OLD_PACKETS_IN ))
  OLD_PACKETS_IN=$IPKTS

  NEW_PACKETS_OUT=$(( $OPKTS - $OLD_PACKETS_OUT ))
  OLD_PACKETS_OUT=$OPKTS
  
  NEW_PACKETS_IN_ERR=$(( $IERRS - $OLD_PACKETS_IN_ERR ))
  OLD_PACKETS_IN_ERR=$IERRS
  
  NEW_PACKETS_OUT_ERR=$(( $OERRS - $OLD_PACKETS_OUT_ERR ))
  OLD_PACKETS_OUT_ERR=$OERRS
  
  NEW_COLLISSIONS=$(( $COLL - $OLD_COLLISSIONS ))
  OLD_COLLISSIONS=$COLL
  

  date
  echo Packets in: $NEW_PACKETS_IN
  echo Packet in Errors: $NEW_PACKETS_IN_ERR
  echo Packet out: $NEW_PACKETS_OUT
  echo Packetout Errors: $NEW_PACKETS_OUT_ERR
  echo Collisions: $NEW_COLLISSIONS
  echo IN Bound Errors: $NEW_IN_BOUND_ERRORS
  echo OUT Bound DISCARDS: $NEW_OUT_BOUND_DISCARDS
  echo
  sleep 5

  typeset -i HOUR=$(date +%H)

  if [ $HOUR -eq 18 ]
  then
     exit
  fi
done