Hi Sravan,
The best way to do this is to do a GET on the RESTMAN.
GET 1.0/identityProviders
https://<GatewayName>:9443/restman/1.0/identityProviders
This will give you the id and the Identity provider which you can use in the GMU command line
GatewayMigrationUtility.sh list --host <Gateway_name> --idProvider <provider id> -u admin --plaintextPassword 7layer -type USER
You may have to try a few options before getting your desired result.
Regards
Seenu Mathew