# ACTIONS that mimics a WYSIWYG to Change File Extension or File Name and Extension (2022-2023)

**URL:** https://community.mp3tag.de/t/actions-that-mimics-a-wysiwyg-to-change-file-extension-or-file-name-and-extension-2022-2023/60139
**Category:** General Discussion
**Created:** [February 20, 2023, 10:00pm UTC](https://community.mp3tag.de/t/actions-that-mimics-a-wysiwyg-to-change-file-extension-or-file-name-and-extension-2022-2023/60139 "2023-02-20T22:00:48Z")
**Posts on this page:** 1
**Showing post:** 4

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### Author: ![LyricsLover](https://community.mp3tag.de/letter_avatar_proxy/v4/letter/l/c6cbf5/32.png) [@LyricsLover](https://community.mp3tag.de/u/LyricsLover)
#### Post date: [February 21, 2023, 8:12am UTC](https://community.mp3tag.de/t/actions-that-mimics-a-wysiwyg-to-change-file-extension-or-file-name-and-extension-2022-2023/60139/4 "2023-02-21T08:12:04Z")

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> [@ohrenkino](#):
>
> It could still be that I have simply not grasped what this should be all about.

I also do not see the problem. We can change the filename and/or extension with a regular expression, as already mentioned [here](https://community.mp3tag.de/t/change-file-extension-to-lowercase-regular-expression/59816).

To illustrate it:  
 ![Extension and Filename to lowercase](https://community.mp3tag.de/uploads/default/original/2X/e/e9af0a4432d718a2d505c1a9ff681dcfc849b67a.gif)

Action "Replace with regular expression" to change only the extension to lowercase:  
Field : \_FILENAME  
Regular expression: `\.(.*)$`  
Replace matches with: `.$lower($1)`

Action "Replace with regular expression" to change the filename including the extension to lowercase:  
Field : \_FILENAME  
Regular expression: `(.*)`  
Replace matches with: `$lower($1)`

**Update 22.02.2023, 08.45:**  
As @wneclass2018 stated later in this thread, there is a problem with the above regular expressions, if the filenames include (multiple) dots. Please use the updated versions [in this answer](https://community.mp3tag.de/t/actions-that-mimics-a-wysiwyg-to-change-file-extension-or-file-name-and-extension-2022-2023/60139/10).

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