How to find the port SQL Server is listing/using using TSQL/Code?

Use below code to programmatically find the port number/s SQL Server Server is listing/using:

DECLARE @port varchar(15), 

@value_name varchar(15), 

@RegistryPath varchar(200) 

IF (charindex('\',@@SERVERNAME)<>0) -- This loop is for named instances 

BEGIN 

SET @RegistryPath = 'SOFTWARE\Microsoft\Microsoft SQL Server\' + 

RIGHT(@@SERVERNAME,LEN(@@SERVERNAME)-CHARINDEX('\',@@SERVERNAME)) + 

'\MSSQLServer\SuperSocketNetLib\Tcp' 

END 

ELSE -- This is for Default Instance 

BEGIN 

SET @RegistryPath = 

'SOFTWARE\Microsoft\MSSQLServer\MSSQLServer\SuperSocketNetLib\Tcp' 

END 

EXEC master..xp_regread 

@rootkey='HKEY_LOCAL_MACHINE' , 

@key=@RegistryPath, 

@value_name='TcpPort', 

@value=@port OUTPUT 

Print 'Port Number of Server '+ @@SERVERNAME + ' is: ' + @port 

Note: This code is tested on SQL 2008 R2 SP2