#!/bin/sh


TIME=10

getbytes() {
	IFACE="`cat /proc/net/dev|grep "[[:space:]]*eth0:"|tr ':' ' '|tr -s ' '`"
	IBYTES=`echo $IFACE|cut -f2 -d' '`
	OBYTES=`echo $IFACE|cut -f10 -d' '`
}

getbytes
while true; do
	sleep $TIME
	IBYTESO=$IBYTES
	OBYTESO=$OBYTES
	getbytes
	echo "In: $((($IBYTES-$IBYTESO)/$TIME/1000)) kbytes/s"
	echo "Out: $((($OBYTES-$OBYTESO)/$TIME/1000)) kbytes/s"
#	bc <<CODE
#	scale=1
#	print "\n"
#	print "In:\t", ($IBYTES-$IBYTESO)/$TIME.0/1000, " kbytes/s\n"
#	print "Out:\t", ($OBYTES-$OBYTESO)/$TIME.0/1000, " kbytes/s\n"
#CODE
done