Below query will help to shrink the log files of all database's in SQL server,
set nocount on
SELECT
'USE [' + d.name + N']' + CHAR(13) + CHAR(10)
+
'DBCC SHRINKFILE (N''' +
mf.name + N''' , 0, TRUNCATEONLY)'
+
CHAR(13) + CHAR(10) + CHAR(13) + CHAR(10)
FROM
sys.master_files mf
JOIN
sys.databases d
ON mf.database_id = d.database_id
WHERE
d.database_id >
4 and mf.type_desc
= 'LOG'
