WebLogic stopManagedWeblogic.sh script prompts for username and password for shutting down managed server

I faced a similar issue and could resolve it by trying the following:

1. create the directory <domain_home>/servers/<managed_server>/security
2. create boot.properties in the above directory with the below values:
   username=<username>
   password=<password>
   

Now, start/stopManagedWeblogic.sh would work without prompting for credentials.