HOW TO INSTALL SPLUNK FREE

First registry on splunk.com
after that try to access: https://www.splunk.com/en_us/download/splunk-enterprise.html

download dpkg file

after that inside of your ubuntu server execute this command:

dpkg -i <your splunk setup>.deb

after to finish, access /opt/splunk

execute: /opt/splunk/bin/splunk start

if finish with successfuly you will receive this message:

To use the Splunk Web interface, point your browser at:

http://<hostname of your server>:8000

HOW TO PURGE FILE ON GRAYLOG SERVER

First execute this command:

For list indice files execute:

curl http://localhost:9200/_cat/indices


after that you just for example:
curl -XDELETE http://localhost:9200/graylog_0