For Users

• download logstash 1.4.2
• upgrade/release notes
• view changelog
• contrib plugins
• package repositories
• configuration file overview
• conditionals
• referring to fields [like][this]
• using the %{fieldname} syntax
• the life of an event in logstash
• command-line flags

For Developers

• writing your own plugins

Tutorials and Use Cases

• Getting started with Logstash - New to Logstash? Start here!
• Metrics from logs - take metrics from logs and ship them to graphite, ganglia, and more.
• Just enough RabbitMQ knowledge for Logstash - Get a quick primer on RabbitMQ and how to use it in Logstash!

books and articles

• The Logstash Book - An introductory Logstash book.

plugin documentation