# Some Regex Issues

**URL:** https://community.mp3tag.de/t/some-regex-issues/10638
**Category:** Support
**Created:** [August 12, 2010, 1:58pm UTC](https://community.mp3tag.de/t/some-regex-issues/10638 "2010-08-12T13:58:41Z")
**Posts on this page:** 1
**Showing post:** 2

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### Author: ![DetlevD](https://community.mp3tag.de/user_avatar/community.mp3tag.de/detlevd/32/123_2.png) [@DetlevD](https://community.mp3tag.de/u/DetlevD)
#### Post date: [August 12, 2010, 2:30pm UTC](https://community.mp3tag.de/t/some-regex-issues/10638/2 "2010-08-12T14:30:59Z")

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> [@Phixion](#):
>
> ... I'm using this to capitalize letters after certain characters:  
> FIELD: _ALL  
> CASE CONVERSION: Mixed  
> WORDS BEGIN FROM/AFTER ANY OF: (-_.[
> 
> The problem is this also names my files .Mp3 rather than .mp3, I need a way to tell it to not capitalize .mp3. ...

You can add an action that will re-lower the file extension using a formula like this:  
\_FILENAME\_EXT \<== $lower(%\_FILENAME\_EXT%)  
... but I do not know how to do it in detail .. the summer abstinence put me totally away from Mp3tag scripting.

Hmm, maybe this way works ...  
_Actiontype 4:_ **Replace with regular expression**  
_Field:_ **\_FILENAME**  
_Regular expression:_ **..\*$**  
_Replace matches with:_ **\L$0**

[\_] Case sensitive comparison

> [@Phixion](#):
>
> ... I also need a way to search for _exactly_ what I type in the filter (case sensitive), at the moment it seems to throw a bunch of results back regardless of the case I use in the search. ...

[Filter expressions](https://community.mp3tag.de/t/10080/4)

DD.20100812.1858.CEST

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_[View the full topic](https://community.mp3tag.de/t/some-regex-issues/10638)._