#!/usr/bin/perl
# Provided by Mike Beresford

# Predeclare variables
my $count = 0;
my $predict = 0;
my $diff = 0.0;
my $real;

# Infinite loop of pinging
while(1) {
    # Read in hostname to ping
    $host = $ARGV[0];

    # Ping, count=1 the host and parse out the reply string
    $real = `ping -c 1 $host | grep time=`;

    # Replace all the junk we don't want with nothing
    $real =~ s/.*ttl=[0-9]* time=//;
    $real =~ s/ ms\n//;

    # Find difference between predicted and actual values
    $diff = $predict - $real;

    # Print out vital info
    printf("(%d) real: %.3f\tpredicted: %.3f\t\tdiff: %.3f\n", $count, $real, $predict, $diff);

    $predict = $real;

    $count++;
    # Prevent ping floods
    sleep(1);
}