1#!/bin/sh
2
3if [ "$1" = "" ]; then
4	echo "Please provide one of the following interfaces as a parameter: (ie. ./iftop.sh eth0)"
5	grep -v lo /proc/net/dev | grep -v Inter | grep -v face | awk '{print $1}' | tr -d ':'
6	exit 1
7fi
8
9LASTRX=$(grep "$1" /proc/net/dev | awk '{print $2}')
10LASTTX=$(grep "$1" /proc/net/dev | awk '{print $10}')
11printf "%9s %12s %12s\n" "Interface" "Received" "Transmitted"
12echo "------------------------------------"
13LINES=0
14while :; do
15	sleep 1
16	LINES=$((LINES+1))
17	RX=$(grep "$1" /proc/net/dev | awk '{print $2}')
18	TX=$(grep "$1" /proc/net/dev | awk '{print $10}')
19
20	RXDIFF=$(($RX-$LASTRX))
21	TXDIFF=$(($TX-$LASTTX))
22
23	LASTRX=$RX
24	LASTTX=$TX
25
26	if [ $RXDIFF -gt $((1024*1024*1024)) ]; then
27		RXMOD="GB/s"
28		RXDIFF=$((RXDIFF/1024/1024/1024))
29	elif [ $RXDIFF -gt $((1024*12024)) ]; then
30		RXMOD="MB/s"
31		RXDIFF=$((RXDIFF/1024/1024))
32	elif [ $RXDIFF -gt 1024 ]; then
33		RXMOD="KB/s"
34		RXDIFF=$((RXDIFF/1024))
35	else
36		RXMOD="Bytes/s"
37	fi
38
39	if [ $TXDIFF -gt $((1024*1024*1024)) ]; then
40		TXMOD="GB/s"
41		TXDIFF=$((TXDIFF/1024/1024/1024))
42	elif [ $TXDIFF -gt $((1024*12024)) ]; then
43		TXMOD="MB/s"
44		TXDIFF=$((TXDIFF/1024/1024))
45	elif [ $TXDIFF -gt 1024 ]; then
46		TXMOD="KB/s"
47		TXDIFF=$((TXDIFF/1024))
48	else
49		TXMOD="Bytes/s"
50	fi
51
52	if [ $LINES -eq 20 ]; then
53		echo
54		printf "%9s %12s %12s\n" "int" "Received" "Transmitted"
55		echo "------------------------------------"
56		LINES=0
57	fi
58
59	printf "%9s %4s %7s %4s %7s\n" $1 $RXDIFF $RXMOD $TXDIFF $TXMOD
60
61done