Purging the old Transaction Log files

Hi,

In one of our DR Servers we have configured Custom Logshipping. In the folder where the .TRN files are getting copied there is a script to purge the files which are older than one day. Following is the code for the same.

@Echo Off
if exist filelist del filelist
date /t > rundate
for /f "tokens=2* delims= " %%i in (rundate) do set rundate=%%i
for %%i IN (*.trn) do echo >> filelist %%i %%~ti
for /f "tokens=1,2* delims= " %%i in (filelist) do if not %rundate% equ %%j del %%i
:pause
:Exit

Instead of removing the files older than 1 day, I need to keep 3 days transaction logs.

Being a novice I don't have much idea how to accomlish it. Can anybody help me with this?

Many thanks in advance,

Sandhya

Is it dos batch file? What's log backup file naming convention?