#!/bin/sh

# Ce script donne la volumétrie d'une interface réseau à intervalle régulier
# (se base sur /proc/net/dev)

FICHIER_PROC=/proc/net/dev
INTERFACE="eth0"
DELAI="10"

OLD_VOLUME_IN=0
OLD_VOLUME_OUT=0
VOLUME_IN=0
VOLUME_OUT=0

while true ; do
	VOLUME_IN=$( cat "$FICHIER_PROC" | grep "$INTERFACE:" | sed 's/^[[:space:]]*eth0:\([[:digit:]]\+\)[[:space:]]\+.*/\1/' )
	VOLUME_OUT=$( cat "$FICHIER_PROC" | grep "$INTERFACE:" | sed 's/^[[:space:]]*eth0:\([[:digit:]]\+[[:space:]]\+\)\{8\}\([[:digit:]]\+\)[[:space:]]\+.*/\2/' )

	if [ "$OLD_VOLUME_IN" -eq "0" ] ; then
		echo "Please wait..."
	else
		printf "%s: %10d o/s reception, %10d o/s emission\n" "$INTERFACE" $(( ( $VOLUME_IN - $OLD_VOLUME_IN ) / $DELAI )) $(( ( $VOLUME_OUT - $OLD_VOLUME_OUT ) / $DELAI ))
	fi

	OLD_VOLUME_IN=$VOLUME_IN
	OLD_VOLUME_OUT=$VOLUME_OUT

	sleep "$DELAI"
done