Shrink transaction log file in Sql Server

Command are as follows:

For Sql Server 2005

BACKUP LOG 

[DBNAME] 

WITH TRUNCATE_ONLY

DBCC SHRINKFILE(

[DBNAME]

_log)

For Sql Server 2008

ALTER DATABASE [DBName]
SET RECOVERY SIMPLE;
GO
-- Shrink the truncated log file to 1 MB.
DBCC SHRINKFILE (DBName_log, 1);
GO
-- Reset the database recovery model.
ALTER DATABASE [DBName]
SET RECOVERY FULL;