#!/usr/bin/perl
use strict;
use warnings;

open my $cmd, '-|', '/usr/sbin/ntpq', '-p' or die "Cannot open pipe from ntpq because: $!";

while ( <$cmd> ) {
    my $offset = ( split )[ 8 ];
    print "$offset\n" if /^\*/;
    }

close $cmd or warn $! ? "Error closing ntpq pipe: $!"
                      : "Exit status $? from ntpq";