Delete from a specific character to the end

Sorry for the bad English ...
When exporting a file, I want it deleted from the file name from a character / example to the end of the file name.
That is, the file names:
001 Algebra / Eighth Grade Lesson
002 Engineering Class / 5th Grade
003 Accounting Lesson / 6th Grades
I want it deleted after the check /
And the result will be:
001 Algebra
002 Engineering Class
003 Accounting Lesson
What should I define?
By the way, do not want to rename the file, only in the export file.
Thanks!!

Try Converter>Filename-Filename
Source mask: %1 / %2
Target: %1

Thank you very much for the response.
I do not want to rename the file, just know what code to write in the export file.
As a follow-up to this:

$filename(M1036-1.tts,utf-8) $loop(%year%,1) $cutLeft(%_filename%,4) $replace(%track%,01,1,02,2,03,3,04,4,05,5,06,6,07,7,08,8,09,9).
$loopend()

Thank you!

You want this part to be changed to something that only write the file names until the first / character?

try
$regexp(%whatever%,\s*/.*,)

could be shortened to
$num(%track%,1)

Excellent!!!
I thank you very much!!!