Here is a very simple script to identify the startup parameter in SQL Server using T-SQL.
SELECT registry_key, value_name, value_data FROM sys.dm_server_registry WHERE registry_key LIKE N'%MSSQLServer\Parameters';
If you are aware of any other methods, I request you to share for other’s benefits.
EDIT: (On 22nd Aug 2016)
One of my colleague executed the above script and reported me back that he is getting the below error:
Msg 208, Level 16, State 1, Line 9 Invalid object name 'sys.dm_server_registry'.
The issue was that the version of his SQL Server was SQL Server 2008R2 (RTM).
This is a new DMV introduced from service pack (SP1) and available only for later versions of SQL Server 2008R2(SP1).