# Mutate to concatenate two filed
**URL:** https://discuss.elastic.co/t/mutate-to-concatenate-two-filed/149966
**Category:** Logstash
**Created:** [September 26, 2018, 9:12am UTC](https://discuss.elastic.co/t/mutate-to-concatenate-two-filed/149966 "2018-09-26T09:12:13Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@richagautam](https://discuss.elastic.co/u/richagautam)
#### Post date: [September 26, 2018, 9:12am UTC](https://discuss.elastic.co/t/mutate-to-concatenate-two-filed/149966/1 "2018-09-26T09:12:13Z")
Hi Team,
I am using multiple grok filter to capture specific patterns from the log file.Now i want to concatenate one of the filed of first grok filter with one filed of second grok filter.
```
mutate {
add_field => ["field3", "%{field1} %{field2}"]
```
}
My doubt is that :
1. While doing this do i have to put the check of Path as well, so that mutate should add filed of same file(Path).
2. Logstash excute all filters/configuration file wise file or it parse multiple files at a time?
Thanks
---
### Author:  [@guyboertje](https://discuss.elastic.co/u/guyboertje)
#### Post date: [September 26, 2018, 12:18pm UTC](https://discuss.elastic.co/t/mutate-to-concatenate-two-filed/149966/2 "2018-09-26T12:18:52Z")
The filters are executed sequentially in the order laid out in the config. There is parallel execution with multiple workers, but once a worker thread takes a batch of events from the queue no other threads (workers) act on those events.
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [October 24, 2018, 12:18pm UTC](https://discuss.elastic.co/t/mutate-to-concatenate-two-filed/149966/3 "2018-10-24T12:18:59Z")
This topic was automatically closed 28 days after the last reply. New replies are no longer allowed.