How to tell if it is a Physical Server or Virtual Machine - VM? - dmidecode command shows BIOS Info

Follow this lab exercise to understand:
- how to show SMBIOS or BIOS Information
- how to show hardware components details
- how to show configuration of virtual machines
- how to confirm if a server is a VM or a physical server
- how to show Serial Number of your system
- how to take a dump of the current state of your system and use it later post changes made to your system

[@chellenta1175]

Thank you from Russia! I was able to learn a few new useful commands, because many people make videos only commands only for beginners