I am trying to find the different kinds of syntax I can give in regex type of query through kibana, but I was not able to find any information on this. I am running logstash and elasticsearch in the backend. Any answer or example will be helpful.
so any regular expressions are valid in grok as well. The regular expression library is Oniguruma.
I took this from the logstash docs online.
Also from [a Google Groups post]: Kibana is a web interface which stay in front of ElasticSearch: to understand the query syntax you have to know something more about Apache Lucene, which is the text search engine used by ElasticSearch.
Here's a small tutorial about the query styles you can use with Lucene and by inheritance with your Kibana web interface:
http://www.lucenetutorial.com/lucene-query-syntax.html This link is dead, I'm not sure but this might be an adequate replacement. (I've saved it into wayback machine as it keeps dying...)
See also the official Lucene Query Syntax documentation.