How to Run SQL Script in Command Prompt

sqlcmd -S myServer\instanceName -i C:\myScript.sql

Reference :http://msdn.microsoft.com/en-us/library/ms170572.aspx

How to get SQL Instance Name.

set nocount on

Declare @key Varchar(100), @PortNumber varchar(20)

if charindex('\',CONVERT(char(20), SERVERPROPERTY('servername')),0) <>0

begin

set @key = 'SOFTWARE\MICROSOFT\Microsoft SQL Server\'+@@servicename+'\MSSQLServer\Supersocketnetlib\TCP'

end

else

begin

set @key = 'SOFTWARE\MICROSOFT\MSSQLServer\MSSQLServer\Supersocketnetlib\TCP'

end

EXEC master..xp_regread @rootkey='HKEY_LOCAL_MACHINE', @key=@key,@value_name='Tcpport',@value=@PortNumber OUTPUT

SELECT CONVERT(char(20), SERVERPROPERTY('servername')) ServerName,

CONVERT(char(20), SERVERPROPERTY('InstanceName')) instancename,

CONVERT(char(20), SERVERPROPERTY('MachineName'))

as HOSTNAME, convert(varchar(10),@PortNumber) PortNumber