#!/usr/bin/perl
my %status;
my $file = '/var/nagios/status.dat';
#print TEST;
{
    local $/ = "hoststatus\s{";
    if ( open my $fh, '<', $file ) {
        while ( my $block = <$fh> ) {
            my ($hostname,$status) = $block =~ m!
                host_name: (.*?)
                \n.*?
                scheduled_downtime_depth=(\d+)
            !xms;
            $status{$hostname} = $status;
        #print TEST;
         }
    }
}
for my $host ( keys %status ) {
    print $host,"\n" if $status{$host} == 1;
}