I wrote this dumb script a long time ago, it depends on nothing but Perl and Linux≥2.6:
#!/usr/bin/perl
use strict;
use warnings;
use POSIX qw(strftime);
use Time::HiRes qw(gettimeofday usleep);
my $dev = @ARGV ? shift : 'eth0';
my $dir = "/sys/class/net/$dev/statistics";
my %stats = do {
opendir +(my $dh), $dir;
local @_ = readdir $dh;
closedir $dh;
map +($_, []), grep !/^\.\.?$/, @_;
};
if (-t STDOUT) {
while (1) {
print "\033[H\033[J", run();
my ($time, $us) = gettimeofday();
my ($sec, $min, $hour) = localtime $time;
{
local $| = 1;
printf '%-31.31s: %02d:%02d:%02d.%06d%8s%8s%8s%8s',
$dev, $hour, $min, $sec, $us, qw(1s 5s 15s 60s)
}
usleep($us ? 1000000 - $us : 1000000);
}
}
else {print run()}
sub run {
map {
chomp (my ($stat) = slurp("$dir/$_"));
my $line = sprintf '%-31.31s:%16.16s', $_, $stat;
$line .= sprintf '%8.8s', int (($stat - $stats{$_}->[0]) / 1)
if @{$stats{$_}} > 0;
$line .= sprintf '%8.8s', int (($stat - $stats{$_}->[4]) / 5)
if @{$stats{$_}} > 4;
$line .= sprintf '%8.8s', int (($stat - $stats{$_}->[14]) / 15)
if @{$stats{$_}} > 14;
$line .= sprintf '%8.8s', int (($stat - $stats{$_}->[59]) / 60)
if @{$stats{$_}} > 59;
unshift @{$stats{$_}}, $stat;
pop @{$stats{$_}} if @{$stats{$_}} > 60;
"$line\n";
} sort keys %stats;
}
sub slurp {
local @ARGV = @_;
local @_ = <>;
@_;
}
It just reads from /sys/class/net/$dev/statistics
every second, and prints out the current numbers and the average rate of change:
$ ./net_stats.pl eth0
rx_bytes : 74457040115259 4369093 4797875 4206554 364088
rx_packets : 91215713193 23120 23502 23234 17616
...
tx_bytes : 90798990376725 8117924 7047762 7472650 319330
tx_packets : 93139479736 23401 22953 23216 23171
...
eth0 : 15:22:09.002216 1s 5s 15s 60s
^ current reading ^-------- averages ---------^