i think i need to provide something that written inside a loop to replace the lines of the zone with space like

s///;
[download]

That statement doesn't do anything other than substituting nothing with nothing, which isn't anything you could call something.

Sample named.conf:

options {
        listen-on port 53 { 127.0.0.1; };
        // listen-on-v6 port 53 { ::1; };
        directory       "/var/named";
        dump-file       "/var/named/data/cache_dump.db";
        statistics-file "/var/named/data/named_stats.txt";
        memstatistics-file "/var/named/data/named_mem_stats.txt";
        allow-query     { localhost; };
        forwarders {
            2.3.4.5;
        };
        recursion yes;
};

logging {
        channel default_debug {
                file "data/named.run";
                severity dynamic;
        };
};

zone "." IN {
        type hint;
        file "named.ca";
};

zone "foo.bar.de" {
    type master;
    file "foo-bar";
    allow-transfer {
        1.2.3.4;
        1.2.3.5;
    };
};  
zone "quux.info" {
    type forward;
    forwarders {
        3.4.5.6;
        4.5.6.7;
    };  
};  
zone "blah-fasel.de" {
    type forward;
    forwarders {
        5.6.7.8;
    };  
};  
zone "10.in-addr.arpa" {
    type forward;
    forwarders {
        1.2.3.4;
        2.3.4.5;
        3.4.5.6;
    };  
};  
include "/etc/named.rfc1912.zones";
[download]

The following script is used to delete a zone:

#!/usr/bin/perl -w 

use strict;

print "please enter the domain name: ";

chomp (my $targetdomain = <STDIN>);

my $file = "named.conf"; # copied to my home folder

rename $file, "$file.bak" or die "Can't rename file '$file': $!\n";

open my $in, '<', "$file.bak" or die "Can't read file '$file': $!\n";
open my $out, '>', $file or die "Can't write file '$file': $!\n";

my $comment = 0;
my $block   = 0;

while(<$in>) {
    if (/^zone\s+"$targetdomain"/) {
        $comment++;
        $block += () = /(\{)/g;
        # print $out '// '.$_;
        next;
    }
    if($comment) {
        $block += () = /(\{)/g;
        s!^!// ! if $comment or $block;
        $block -= () = /(\})/g;
        unless ($block) {
            $comment = 0;
            next;
        }
    }
    print $out $_ unless $comment;
}
[download]

We delete the zone "quux.info" using that script, named 'zonedel.pl':

qwurx [shmem] ~ > perl zonedel.pl
please enter the domain name: quux.info
[download]

The zone file (named.conf) is now:

options {
        listen-on port 53 { 127.0.0.1; };
        // listen-on-v6 port 53 { ::1; };
        directory       "/var/named";
        dump-file       "/var/named/data/cache_dump.db";
        statistics-file "/var/named/data/named_stats.txt";
        memstatistics-file "/var/named/data/named_mem_stats.txt";
        allow-query     { localhost; };
        forwarders {
            2.3.4.5;
        };
        recursion yes;
};

logging {
        channel default_debug {
                file "data/named.run";
                severity dynamic;
        };
};

zone "." IN {
        type hint;
        file "named.ca";
};

zone "foo.bar.de" {
    type master;
    file "foo-bar";
    allow-transfer {
        1.2.3.4;
        1.2.3.5;
    };
};
zone "blah-fasel.de" {
    type forward;
    forwarders {
        5.6.7.8;
    };
};
zone "10.in-addr.arpa" {
    type forward;
    forwarders {
        1.2.3.4;
        2.3.4.5;
        3.4.5.6;
    };
};
include "/etc/named.rfc1912.zones";
[download]

Running 'diff -uNw named.conf named.conf.bak' shows:

--- named.conf  2007-11-11 00:25:18.000000000 +0100
+++ named.conf.bak      2007-11-11 00:18:17.000000000 +0100
@@ -46,6 +46,13 @@
        1.2.3.5;
     };
 };
+zone "quux.info" {
+    type forward;
+    forwarders {
+       3.4.5.6;
+       4.5.6.7;
+    };
+};
 zone "blah-fasel.de" {
     type forward;
     forwarders {
[download]

Please let me know if that solution doesn't work for you. In that case, please provide a full set of files as I have done.

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}