MS SQL Server Log cleanup

Server SET NOCOUNT on
DECLARE @LogicalFileName sysname, @MaxMinutes int, @NewSize int
Use grades-the name of the database to manipulate
SELECT @LogicalFileName = ' Grades_log ',--log file name
@MaxMinutes =--Limit on time allowed to wrap log.
@NewSize = 1-the size of the log file you want to set (M)

--Setup/initialize
DECLARE @OriginalSize int
SELECT @OriginalSize = size from sysfiles WHERE name = @LogicalFileName

SELECT ' Original Size of ' + db_name () + ' LOG is ' +
CONVERT (VARCHAR, @OriginalSize) + ' 8K pages or ' +
CONVERT (VARCHAR (@OriginalSize *8/1024)) + ' MB '
From Sysfiles
WHERE name = @LogicalFileName

CREATE TABLE Dummytrans (dummycolumn char (8000) NOT NULL)
DECLARE @Counter INT, @StartTime DATETIME, @TruncLog VARCHAR (255)

SELECT @StartTime = GETDATE (), @TruncLog = ' BACKUP LOG ' + db_name () + ' with Truncate_only '
DBCC shrinkfile (@LogicalFileName, @NewSize)
EXEC (@TruncLog)
--Wrap the log if necessary.
While @MaxMinutes > DATEDIFF (MI, @StartTime, GETDATE ())--time has not expired
and @OriginalSize = (SELECT size from sysfiles WHERE name = @LogicalFileName)
and (@OriginalSize * 8/1024) > @NewSize

BEGIN--Outer loop.
SELECT @Counter = 0
while (@Counter < @OriginalSize/16) and (@Counter < 50000))
BEGIN--Update
INSERT Dummytrans VALUES (' Fill Log ')
DELETE Dummytrans
SELECT @Counter = @Counter + 1
End
EXEC (@TruncLog)
End

SELECT ' Final Size ' + db_name () + ' LOG is ' +
CONVERT (VARCHAR (), size) + ' 8K pages or ' +
CONVERT (VARCHAR (), (size*8/1024)) + ' MB '
From Sysfiles
WHERE name = @LogicalFileName

DROP TABLE Dummytrans
SET NOCOUNT off