User–group – environment settings

You will want to run Splunk as the splunk user, and the installation rpm should have created the splunk user and group, but let's check to make sure: typing the command cut -d: -f1 /etc/passwd will display a list of local users. If splunk isn't in the list, create this user and group with the adduser splunk and groupadd splunk commands.

You should be able to change the user to splunk: su - splunk. Then, ensure that the $SPLUNK_HOME
environment variable is set: cd $SPLUNK_HOME

Typing pwd should reveal that you're now in the /opt/splunk directory.