# /opt/logstash/bin/logstash -v
+---------------------------------------------------------+
| An unexpected error occurred. This is probably a bug.   |
| You can find help with this problem in a few places:    |
|                                                         |
| * chat: #logstash IRC channel on freenode irc.          |
|     IRC via the web: http://goo.gl/TI4Ro                |
| * email: logstash-users@googlegroups.com                |
| * bug system: https://logstash.jira.com/                |
|                                                         |
+---------------------------------------------------------+
The error reported is:
  undefined method `+' for nil:NilClass