Hello.

Another with flip-flop 

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

my ($buff,$hostname,$address);
my $criteria="DMZ|CRIT";
while(<DATA>){
        #flip-flop. while /begin/ to /end/ condition, you enter the if
+ block
        #and line number is set to $num.
        if(my $num = /define\s+host\{/ .. /\s*\}/ ){
                $buff ='' if($num==1); #for regex match keep text to $
+buff
                $buff .=$_;

                if( /\s*host_name\s+(.*)/ ){ #get hostname
                        $hostname=$1;
                }
                if( /\s*address\s+(.*?)/ ){  #get address
                        $address= $1;
                }

                #E0 shows end of Block. if $buff has $criteria, print
                if ($num =~ /E0/ && $buff =~ /$criteria/s ){
                        print "$address $hostname is in $criteria \n";
                }
        }

}
__DATA__
same data with yours...

[download]
For flip-flop, please see this thread, which is very similar case with yours, and Grandfather's meditation for flip-flop and Range Operators at PerlOp.

One another approach with grep. But this may not work well, I am sure. 

egrep -A 2 -B 5 "hostgroups.*(CRIT|DMZ)" your_config_file

[download]

In reply to Re: split file on blank lines and match blocks by remiah
in thread split file on blank lines and match blocks by raggmopp

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