Nikto is a, non-stealth, web vulnerability scanner. So don’t think the NSA doesn’t know you are using it. This tool is easy to get some quick results, so I especially recommend it to beginners.
The real charm of nikto is that most positive results come with the layman’s description and a link. (Read the contents of these links to become better at life.)
You can initiate your first scan with this command

nikto -h <IP or Host name>

Lets see what we get!