# Logstash: regex to get part of file name
**URL:** https://discuss.elastic.co/t/logstash-regex-to-get-part-of-file-name/258673
**Category:** Logstash
**Created:** [December 15, 2020, 5:22am UTC](https://discuss.elastic.co/t/logstash-regex-to-get-part-of-file-name/258673 "2020-12-15T05:22:46Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@nameisnotimportant](https://discuss.elastic.co/u/nameisnotimportant)
#### Post date: [December 15, 2020, 5:22am UTC](https://discuss.elastic.co/t/logstash-regex-to-get-part-of-file-name/258673/1 "2020-12-15T05:22:46Z")
Hi,
I am trying to get the date in the file name using following regex, but it still return a-zA-Z character:
Path:
/home/appadmin/Documents/ML/data/pocket\_pmo/activityLogs20201211.csv
> grok { match =\> { "path" =\> "(?\<[@metadata][indexName]\>[^/][\d]\*)....$" } }
> mutate {
> add\_field =\> {"indexname" =\> "%{[@metadata][indexName]}" }
> }
result:
> "indexname" =\> "s20201211"
May i know why the character 's' still there? How do i get only the date ?
Regards.
---
### Author:  [@Badger](https://discuss.elastic.co/u/Badger)
#### Post date: [December 15, 2020, 3:10pm UTC](https://discuss.elastic.co/t/logstash-regex-to-get-part-of-file-name/258673/2 "2020-12-15T15:10:58Z")
> [@nameisnotimportant](#):
>
> May i know why the character 's' still there?
`"(?<[@metadata][indexName]>[^/][\d]*)` captures a single character that is not slash (i.e. the 's'), followed by zero or more digits. You already have the pattern anchored to the end of the string, and I see no reason to include the `[^/]`.
---
### Author:  [@nameisnotimportant](https://discuss.elastic.co/u/nameisnotimportant)
#### Post date: [December 16, 2020, 12:39am UTC](https://discuss.elastic.co/t/logstash-regex-to-get-part-of-file-name/258673/3 "2020-12-16T00:39:52Z")
If i remove [^/] to become the following:
> grok { match =\> { "path" =\> "(?\<[@metadata][indexName]\>[\d]\*)....$" } }
i got the following results:
> "indexname" =\> "%{[@metadata][indexName]}"
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [January 13, 2021, 12:39am UTC](https://discuss.elastic.co/t/logstash-regex-to-get-part-of-file-name/258673/4 "2021-01-13T00:39:53Z")
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