An ETL (extract, transform and load) tool. Commonly used to load data from various sources, like databases and log files, into elasticsearch.

# To check validity of a logstash configuration:
logstash --configtest --config logstash_config.conf

# To run logstash using configuration:
sudo logstash --config logstash_config.conf

# To run logstash with the most basic inline configuration string:
sudo logstash -e 'input {} filter {} output {}'