Shell Programming and Scripting

Hello,

I am new to shell scripting. I want to optimize my one of the script.
I have one file and i want to remove selected zones for domains from that file.In this file i have almost 3500 zones for domains.Sample data for the file....

named.backup
-------------------------------------------------------------
zone "britshoponline.co.uk" {
type master;
file "/var/named/britshoponline.co.uk.db";
};

zone "skateboardstickers.net" {
type master;
file "/var/named/skateboardstickers.net.db";
};

zone "kalibrantas.or.id" {
type master;
file "/var/named/kalibrantas.or.id.db";
};

zone "mf-host.com" {
type master;
file "/var/named/mf-host.com.db";
};

zone "googlepatch.com" {
type master;
file "/var/named/googlepatch.com.db";
};
--------------------------------------------------------

list.conf contains 2 records..
vebosoft.com
kalibrantas.or.id

---------------------------------------------------------
AWK script (namedscript.awk) ..
BEGIN{
}

{
zone = $1
sedcmd = "sed '/" zone "/,+4d' named.backup > named.backup.test"
printf "Command: %s\n", sedcmd
system(sedcmd)
system("mv named.backup.test named.backup")
}
END{
}
--------------------------------------------------------------
My command for executing the script:
awk -f namedscript.awk list.conf
--------------------------------------------------------------
In the above code it's possible to remove "system("mv named.backup.test named.backup")" command. But i dont; know i how to do it.

Please help me..
Thanks in Advance