#!/usr/bin/perl
# perl script to measure in/out traffic in realtime
# ver: 0.1
# usage: iftraffic.pl <device>
# example: iftraffic.pl eth0
# Notes:
# 1) Numbers are not exact by choice. They are converted to integers. If you are running the script on a heavily
#    loaded system expect a 10-15% deviation
# 2) If you want to have repetitions uncomment line 17 and 32 and comment line 31.
#    Then use it like: iftraffic.pl eth0 10
# 3) You can also change it back to reading the ifconfig output as the original script by uncommenting lines 20,21
#    and commenting lines 22,23
# by kargig [at] void [dot] gr
# original version: http://perlmonks.org/?node_id=635792


my $dev=$ARGV[0];
#my $repetitions=$ARGV[1];

sub get_measures {
	##my $data = `/sbin/ifconfig $dev | grep "RX bytes" | head -n1`;
	##$data =~ /RX bytes\:(\d+) .*TX bytes\:(\d+) .*/;
	my $data = `cat /proc/net/dev | grep "$dev" | head -n1`;
	$data =~ /$dev\:(\d+)\D+\d+\D+\d+\D+\d+\D+\d+\D+\d+\D+\d+\D+\d+\D+(\d+)\D+/;
	my $recv = int($1/1024);
	my $sent= int($2/1024);
	return ($recv,$sent);
}

my @m1 = get_measures;
	
while(1) {
#for (my $time=0;$time<$repetitions;$time++) {
	sleep 1;
	my @m2 = get_measures;

	my @rates = ($m2[0] - $m1[0], $m2[1]-$m1[1]);
	foreach ('received' , ' transmit') {
		printf "$_ rate:%sKB",shift @rates;
	}
	print "\n";
	@m1=@m2;
}