"bat file" to run SQL log file shrink task - sql-server

Question

I have a SQL2012 DB that has a log file growing very rapidly. I have a 3rd party program doing full database backups so I'm not worried about that.
I have the command to run in the SQL manager to shrink the log file and that is working but it's a very manual task.
I'm trying to create a script that I can schedule to run every 2 weeks but a BAT file won't work it seems as after the sqlcmd -S servername\instancename -E command is run it just goes to 1> and stops. I need to run the USE and DBCC commands but not sure how to achieve this.
I have tried looking online but nowhere can I find a way to make a double click script to run this DBCC SHRINKFILE task.
So using sqlcmd, I can do this:
USE DBNAME
GO
DBCC SHRINKFILE (DBNAME_20070302091322_Log, 1);
GO
Running manually the file shrinks to below 10mb and that is correct. I need to just automate this task.

Answer 1

I have a SQL2012 DB that has a log file growing very rapidly
In this case you must verify the database recovery model and log_reuse_wait_desc which you can identity with following command:
Select name, recovery_model_desc, log_reuse_wait_desc
from sys.databases
If Recovery model set to FULL:
As mentioned in the comments, you must schedule LOG BACKUP at the backup tool that you are using for Full Backups, even you perform DBCC SHRINKFILE it would't shrink the size due to active portion in the log file, you must perform appropriate action bases on log_reuse_wait_desc status before running DBCC SHRINKFILE command. You can verify it
looking at message section once DBCC command you executed.
For more details on LOG FILE/CHECKPOINTS/log_reuse_wait..
If Recovery model set to Simple:
Once you decided to go with Simple recovery model, shrink the file manually, but keep enough room for SQL Engine to perform log operations depending on transaction workload. Shrinking the log file to lower size means putting unnecessary overload on the server as the SQL Engine try to increase it again when there is no enough space available for the transaction workload/throughput.
You do not have schedule LOG backup in simple recovery model, as the log file checkpoints would be automatically added and based on checkpoint log would be truncated.

Answer 2

So looks like with your help i managed to get it working.
I have a BAT with the -i option where the DBCC command is.
here is that bat
sqlcmd -S sqlserver\instance -E -d databasename -i c:\test.sql -o c:\out.txt
here is hte test.sql
USE databasename
GO
DBCC SHRINKFILE (DBLOGFILENAME_Log, 1);
GO
tested and its working.