# Grok custom patterns

**URL:** <https://discuss.elastic.co/t/grok-custom-patterns/169778>\
**Category:** Logstash\
**Created:** [February 25, 2019, 9:21am UTC](https://discuss.elastic.co/t/grok-custom-patterns/169778 "2019-02-25T09:21:01Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Mayurbiw](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/mayurbiw/32/45858_2.png) [@Mayurbiw](https://discuss.elastic.co/u/Mayurbiw)\
**Post date:** [February 25, 2019, 9:21am UTC](https://discuss.elastic.co/t/grok-custom-patterns/169778/1 "2019-02-25T09:21:01Z")

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when I define the grok pattern like this one  
(?someoperation) is the string someoperation is case sensitive or case insensitive. In other words, would it match if a file contains something like someOPERATION ?

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**Author:** ![Badger](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/badger/32/25190_2.png) [@Badger](https://discuss.elastic.co/u/Badger)\
**Post date:** [February 25, 2019, 2:14pm UTC](https://discuss.elastic.co/t/grok-custom-patterns/169778/2 "2019-02-25T14:14:44Z")

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> [@Mayurbiw](#):
>
> In other words, would it match if a file contains something like someOPERATION ?

No, it would not. If you are not capturing the result then you could use

```
(?i:someoperation)

```

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [March 25, 2019, 2:19pm UTC](https://discuss.elastic.co/t/grok-custom-patterns/169778/3 "2019-03-25T14:19:03Z")

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