{"action":"closed","issue":{"url":"https://api.github.com/repos/logstash-plugins/logstash-filter-grok/issues/42","labels_url":"https://api.github.com/repos/logstash-plugins/logstash-filter-grok/issues/42/labels{/name}","comments_url":"https://api.github.com/repos/logstash-plugins/logstash-filter-grok/issues/42/comments","events_url":"https://api.github.com/repos/logstash-plugins/logstash-filter-grok/issues/42/events","html_url":"https://github.com/logstash-plugins/logstash-filter-grok/issues/42","id":81120436,"number":42,"title":"\"?:\" meaning in grok","user":{"login":"rakesh91","id":1933540,"avatar_url":"https://avatars.githubusercontent.com/u/1933540?v=3","gravatar_id":"","url":"https://api.github.com/users/rakesh91","html_url":"https://github.com/rakesh91","followers_url":"https://api.github.com/users/rakesh91/followers","following_url":"https://api.github.com/users/rakesh91/following{/other_user}","gists_url":"https://api.github.com/users/rakesh91/gists{/gist_id}","starred_url":"https://api.github.com/users/rakesh91/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/rakesh91/subscriptions","organizations_url":"https://api.github.com/users/rakesh91/orgs","repos_url":"https://api.github.com/users/rakesh91/repos","events_url":"https://api.github.com/users/rakesh91/events{/privacy}","received_events_url":"https://api.github.com/users/rakesh91/received_events","type":"User","site_admin":false},"labels":[],"state":"closed","locked":false,"assignee":null,"milestone":null,"comments":2,"created_at":"2015-05-26T20:21:49Z","updated_at":"2015-06-03T22:15:14Z","closed_at":"2015-06-03T22:15:14Z","body":"Hi,\r\n\"?:\" does this have the same meaning as in regex or grok has special meaning?  I found in logstash grok base pattern apache has\r\n\r\n\"(?:%{WORD:verb} %{NOTSPACE:request}(?: HTTP/%{NUMBER:httpversion})?|%{DATA:rawrequest})\"\r\n\r\nwhat does \"?:\" mean here? I needed it to parse some custom apache logs and wanted to know \"?:\" importance."}}