Writing the result set of a stored procedure directly int a textfile from within the stored procedure

I want to use a stored procedure to write out the summary of a an income table into a text file.

I have created a stored procedure that takes two integer arguments (month and year) and print out the result on SSMS. I don't want to go through the manual option of exporting result to text. Below is the structure of the stored procedure (I am using adventureworks database here as an illustration, but my stored procedure is exactly of the same structure):

create proc monthlySummary(@month int, @year int) as
begin
	set nocount on
	declare
	@monthSTR nvarchar(2), @yearSTR nvarchar(4), @selectList nvarchar(200)
	set @monthSTR = CONVERT(nvarchar(2),@month)
	set @yearSTR = CONVERT (nvarchar(4), @year)
	set @selectList = 'SELECT*FROM AdventureWorks.Sales.SalesOrderDetail WHERE DATEPART(MONTH, ModifiedDate)= '
	+@monthSTR + 'AND '+ 'DATEPART(YEAR, ModifiedDate)='+@yearSTR
	

	EXEC sp_executesql @selectList
end

I want the result to be written out directly on a text file instead of being displayed on SSMS.

Another solution is to use SQLCMD as in the following:

SQLCMD -S server -d database -E -Q "EXEC dbo.monthlySummary" -o out.txt

It connects to the server, executes the query and creates the txt file. File formats (header, column separator,.. ) can be customized with command line switches -w -h -s.

hope this helps.