# What's the meaning of "?\>" in the regular expression

**URL:** <https://discuss.elastic.co/t/whats-the-meaning-of-in-the-regular-expression/157899>\
**Category:** Logstash\
**Created:** [November 22, 2018, 2:54pm UTC](https://discuss.elastic.co/t/whats-the-meaning-of-in-the-regular-expression/157899 "2018-11-22T14:54:56Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![thorzhang](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/thorzhang/32/37996_2.png) [@thorzhang](https://discuss.elastic.co/u/thorzhang)\
**Post date:** [November 22, 2018, 2:54pm UTC](https://discuss.elastic.co/t/whats-the-meaning-of-in-the-regular-expression/157899/1 "2018-11-22T14:54:56Z")

</div>

Below is a regular expression In grok-patterns (url: [https://github.com/logstash-plugins/logstash-patterns-core/blob/master/patterns/grok-patterns](https://github.com/logstash-plugins/logstash-patterns-core/blob/master/patterns/grok-patterns)), I don't know the meanings of "?\>".

YEAR (?\>\d\d){1,2}  
Can anyone help me, Thanks.

---

<div class="post-metadata">

**Author:** ![faulander](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/faulander/32/36344_2.png) [@faulander](https://discuss.elastic.co/u/faulander)\
**Post date:** [November 23, 2018, 10:13am UTC](https://discuss.elastic.co/t/whats-the-meaning-of-in-the-regular-expression/157899/2 "2018-11-23T10:13:10Z")

</div>

This should get you going: [https://www.regular-expressions.info/atomic.html](https://www.regular-expressions.info/atomic.html)

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [December 21, 2018, 10:28am UTC](https://discuss.elastic.co/t/whats-the-meaning-of-in-the-regular-expression/157899/3 "2018-12-21T10:28:15Z")

</div>

This topic was automatically closed 28 days after the last reply. New replies are no longer allowed.