# Field name start with

**URL:** <https://discuss.elastic.co/t/field-name-start-with/53513>\
**Category:** Logstash\
**Created:** [June 21, 2016, 1:58pm UTC](https://discuss.elastic.co/t/field-name-start-with/53513 "2016-06-21T13:58:21Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Nizar\_Khalifa](https://avatars.discourse-cdn.com/v4/letter/n/ed655f/32.png) [@Nizar\_Khalifa](https://discuss.elastic.co/u/Nizar_Khalifa)\
**Post date:** [June 21, 2016, 1:58pm UTC](https://discuss.elastic.co/t/field-name-start-with/53513/1 "2016-06-21T13:58:21Z")

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How can i check if a field name (not value) start with some caracter ?

```
{
  params{
    firstname : value1,
    $lastname : value2
  }
}

```

How can i verify if `lastname` field start with `$` ?  
And if yes remove it.

B.R

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<div class="post-metadata">

**Author:** ![magnusbaeck](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/magnusbaeck/32/44943_2.png) [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)\
**Post date:** [June 22, 2016, 11:26am UTC](https://discuss.elastic.co/t/field-name-start-with/53513/2 "2016-06-22T11:26:24Z")

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You mean you want Logstash to go over all field names and strip any leading dollar signs it finds? I suspect you need to write a small Ruby snippet and put in a ruby filter.

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<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:** [July 6, 2017, 4:51am UTC](https://discuss.elastic.co/t/field-name-start-with/53513/3 "2017-07-06T04:51:15Z")

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