# How does permalink normalization with regex work?
**URL:** https://meta.discourse.org/t/how-does-permalink-normalization-with-regex-work/354671
**Category:** Support
**Created:** [February 26, 2025, 5:36pm UTC](https://meta.discourse.org/t/how-does-permalink-normalization-with-regex-work/354671 "2025-02-26T17:36:46Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@SubStrider](https://meta.discourse.org/u/SubStrider)
#### Post date: [February 26, 2025, 5:36pm UTC](https://meta.discourse.org/t/how-does-permalink-normalization-with-regex-work/354671/1 "2025-02-26T17:36:46Z")
I went to this setting Admin \> Permalinks \> Settings
Which says it will apply the regex before matching the permalink.
I have an old xenforo forum URL which is
[http://localhost/threads/xyz-abc-is-ghp.223846/](http://localhost/threads/xyz-abc-is-ghp.223846/)
And the new discourse URL is
[http://localhost/t/xyz-abc-is-ghp/274528](http://localhost/t/xyz-abc-is-ghp/274528)
When I enter the xenforo URL in the browser without the slug like the following then it is redirecting fine but not with it.
[http://localhost/threads/223846/](http://localhost/threads/223846/)
So I tried to use the following regex to strip the slug out but it seems to be doing nothing. Am I missing a step or is this not how its to be done?
/^(/threads/)[^.]+.(\d+)/?$/+/\1\2
---
### Author:  [@pfaffman](https://meta.discourse.org/u/pfaffman)
#### Post date: [February 26, 2025, 9:01pm UTC](https://meta.discourse.org/t/how-does-permalink-normalization-with-regex-work/354671/2 "2025-02-26T21:01:51Z")
You don’t need a `\2`. And you need a `\` before the period that you’ure searching for. You’ve got only one thing in parentheses. Maybe something like
```plaintext
/^(/threads/)[^.]+\.(\d+)/?$/threads/\1
```
---
### Author:  [@SubStrider](https://meta.discourse.org/u/SubStrider)
#### Post date: [February 27, 2025, 9:57am UTC](https://meta.discourse.org/t/how-does-permalink-normalization-with-regex-work/354671/3 "2025-02-27T09:57:48Z")
`/threads\/[^.]+\.([0-9]+)\/?/threads/\1`
this worked
---
### Author:  [@lilstranded](https://meta.discourse.org/u/lilstranded)
#### Post date: [March 11, 2025, 6:37pm UTC](https://meta.discourse.org/t/how-does-permalink-normalization-with-regex-work/354671/4 "2025-03-11T18:37:10Z")
> [@SubStrider](#):
>
> `/threads\/[^.]+\.([0-9]+)\/?/threads/\1`
Hey, im in the same situation and this worked for me! 🍻
But when the URL (xenforo URL) has inner pages like for example"[https://website](https://website)[.]com/threads/thread-slug/ **page-3**" then again ill get the " Oops! That page doesn’t exist or is private." error page. Any fix for this?
---
### Author:  [@system](https://meta.discourse.org/u/system)
#### Post date: [April 10, 2025, 6:37pm UTC](https://meta.discourse.org/t/how-does-permalink-normalization-with-regex-work/354671/5 "2025-04-10T18:37:26Z")
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