Check SQL Express Version or 2008 R2 version

1)If you are not using the default instance, the try then following command:sqlcmd -S MACHINENAME\INSTANCE_NAME

Link (trying to run sqlcmd fails, unable to establish connection?)

2)How to: Identify a SQL Server Express Instance

3)http://www.sqlsecurity.com/faqs-1/sql-server-versions

4) https://gallery.technet.microsoft.com/Determining-the-version-of-62136c05

You can always find out what version number of SQL Server that you are running by executing this T-SQL statement in SQL Server Management Studio:

1
SELECT @@VERSION

http://blog.discountasp.net/microsoft-sql-server-tips-series-incorrect-sql-version/