# How to make custom Logstash start parameters / arguments
**URL:** https://discuss.elastic.co/t/how-to-make-custom-logstash-start-parameters-arguments/65165
**Category:** Logstash
**Created:** [November 7, 2016, 5:57am UTC](https://discuss.elastic.co/t/how-to-make-custom-logstash-start-parameters-arguments/65165 "2016-11-07T05:57:12Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@elasticheart](https://discuss.elastic.co/u/elasticheart)
#### Post date: [November 7, 2016, 5:57am UTC](https://discuss.elastic.co/t/how-to-make-custom-logstash-start-parameters-arguments/65165/1 "2016-11-07T05:57:13Z")
Hi,
Logstash takes a lot of file parameters while starting like;
```
--path.settings=/logstash-5.0.0/config/
```
I want to pass something like, for example, I have a jdbc input in logstash and how can I pass it through command line argument when I start logstash like;
```
--dbname=my_log_db
```
Is this possible?
---
### Author:  [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)
#### Post date: [November 7, 2016, 7:58am UTC](https://discuss.elastic.co/t/how-to-make-custom-logstash-start-parameters-arguments/65165/2 "2016-11-07T07:58:45Z")
I don't think so, but you can reference environment variables: [https://www.elastic.co/guide/en/logstash/current/environment-variables.html](https://www.elastic.co/guide/en/logstash/current/environment-variables.html)
---
### Author:  [@elasticheart](https://discuss.elastic.co/u/elasticheart)
#### Post date: [November 8, 2016, 5:45am UTC](https://discuss.elastic.co/t/how-to-make-custom-logstash-start-parameters-arguments/65165/3 "2016-11-08T05:45:52Z")
Ok.. So, could you tell me how logstash is identifying these parameters, or in which ruby file these are defined?
---
### Author:  [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)
#### Post date: [November 8, 2016, 6:43am UTC](https://discuss.elastic.co/t/how-to-make-custom-logstash-start-parameters-arguments/65165/4 "2016-11-08T06:43:18Z")
I don't understand your question. Are you asking where you should set the values of the environment variables?
---
### Author:  [@elasticheart](https://discuss.elastic.co/u/elasticheart)
#### Post date: [November 9, 2016, 6:18am UTC](https://discuss.elastic.co/t/how-to-make-custom-logstash-start-parameters-arguments/65165/5 "2016-11-09T06:18:14Z")
Hi, I meant, not environment variables, but the command line flags. Hows logstash recognizing it, or which ruby file is responsible for parsing the command line flags?
---
### Author:  [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)
#### Post date: [November 9, 2016, 6:41am UTC](https://discuss.elastic.co/t/how-to-make-custom-logstash-start-parameters-arguments/65165/6 "2016-11-09T06:41:56Z")
You're probably looking for [runner.rb](https://github.com/elastic/logstash/blob/master/logstash-core/lib/logstash/runner.rb).
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [December 7, 2016, 6:42am UTC](https://discuss.elastic.co/t/how-to-make-custom-logstash-start-parameters-arguments/65165/7 "2016-12-07T06:42:06Z")
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