#!/usr/bin/perl -w
use strict;
use Sys::Statistics::Linux;

my $log_file = '/tmp/netstats.yml';
my $sleep = 1;

my $lxs = Sys::Statistics::Linux->new(
    netstats => { init => 1, initfile => $log_file, },
);

while( 1 ) {
    my $stat = $lxs->get( $sleep );
    my $netstats_ppp0 = $stat->{netstats}{ppp0};
    my $bytes_per_second = $netstats_ppp0->{ttbyt};
    print $bytes_per_second, "\n";
}