# Variable in gsub

**URL:** <https://discuss.elastic.co/t/variable-in-gsub/44051>\
**Category:** Logstash\
**Created:** [March 10, 2016, 4:11pm UTC](https://discuss.elastic.co/t/variable-in-gsub/44051 "2016-03-10T16:11:44Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![deepmind](https://avatars.discourse-cdn.com/v4/letter/d/71e660/32.png) [@deepmind](https://discuss.elastic.co/u/deepmind)\
**Post date:** [March 10, 2016, 4:11pm UTC](https://discuss.elastic.co/t/variable-in-gsub/44051/1 "2016-03-10T16:11:45Z")

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Hi,

Multiline concat my device logs but does not remove unusefull informations.

exemple:  
`<134>Mar 03 11:39:57 SHK-NSW-CORE CLI(67) Data: USERCMD: <gmenage> <10.1.16.1> [no ip interface lololol] <ERROR: No such interfa<134>Mar 03 11:39:57 SHK-NSW-CORE CLI(67) Data: [Count.]ce - lololol.>`

I tryed to use GSUB to clean my multiline output:  
`gsub=>["message","%{ALE_MULTILINE_BASE}", ""]`

with  
`ALE_BASE <%{POSINT:syslog_pri}>%{ALE_TIMESTAMP:@timestamp}%{SPACE}%{SYSLOGHOST:hostname}%{SPACE}%{SYSLOGPROG:message_program}\(%{DATA:message_thread_id}\)%{SPACE}Data:%{SPACE}`

But it looks like gsub does not accept `%{ALE_MULTILINE_BASE}` as a variable.

Do you have an idea?

/opt/logstash/bin/logstash --version  
logstash 2.1.1

Thank you in advance.

Regards

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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:** [March 10, 2016, 6:14pm UTC](https://discuss.elastic.co/t/variable-in-gsub/44051/2 "2016-03-10T18:14:12Z")

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The mutate filter's gsub option doesn't support grok patterns.

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**Author:** ![deepmind](https://avatars.discourse-cdn.com/v4/letter/d/71e660/32.png) [@deepmind](https://discuss.elastic.co/u/deepmind)\
**Post date:** [March 11, 2016, 7:50am UTC](https://discuss.elastic.co/t/variable-in-gsub/44051/3 "2016-03-11T07:50:03Z")

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☹

Ok, thank you for the answer.

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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:** [July 6, 2017, 5:07am UTC](https://discuss.elastic.co/t/variable-in-gsub/44051/4 "2017-07-06T05:07:26Z")

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