SQL basics.

Getting started notes on ELK (Elasticsearch, Logstash, Kibana).

References on how to setup nagios with check_mk plugin with omd package.

Setup nagios core on ubuntu 12.04 (precise 32) with root user.

How to config logstash email output plugin to send email alert.

Logstash getting started simple guide covering installation and a simple example.

Some git commands and tips

An example of using apache Ant to create a zip file and keep the root directory.

Execute linux/unix command in java.

Sample entrance code of rabbitmq java client.