Hack 3 Find and Replace Registry Keys from a Command Line

Using the Regfind utility, you can easily search the Registry for a value, regardless of the key, and replace it.

Regfind (from the Windows 2000 Server Resource Kit) can be an invaluable tool when you need change a Registry key that you know the value for but when do not necessarily know the full path. Recently tasked with changing the hardcoded DNS server IP on all the servers in our organization, I was pleasantly surprised when I located this gem. The problem with trying to change the DNS server entry in the Registry is that all the IP parameters are broken up by a hashed ID. The ID references several things, but most of them have to do with the network card. Regfind allows you to search a set of subkeys in the Registry for a specific value and, when found, replace it. Another real beauty of this program is that it will work remotely; all you need to do is supply it with a list of machines and let it go. Using a list of computer names (generated from SMS, Server Manager, or AD Users and Computers), combined with two batch files, you can make sweeping changes in a dynamic environment.

The Code

Here's an example of how to change the DNS server entry on all servers in your organization. First, create a batch file called Regchange2.bat with the following syntax:

regfind -m \\%1 -p HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\parameters "OLDIP" -r "NEWIP"

You will obviously want to replace OLDIP with the old DNS server IP and replace NEWIP with the new DNS server IP.

Now, create a second batch file called regchange1.bat with the following syntax:

for /F %%A in (servers.txt) do (call regchange2.bat %%A)

This searches the servers.txt file for computer names and passes them to the regchange2.bat file as a command-line argument.

Now you need to create a list file for your batch files to use. Create a listing of servers that need to have their DNS IP's changed and save that list as servers.txt. An SMS report or a copy/paste from the server manager will suffice, or you can create the file manually if you like.