How to change ESXi host root password using CLI

Log in to the ESXi/ESX host service console, either via SSH or the physical console. 

Note: If you did not log in as root, you must acquire root privileges by running the command: 

 su - 

Enter the current root password when prompted. 

Change the root password by executing: 

 passwd root  

Enter the new root password, and press Enter. Enter the password a second time to verify. You are warned about, but not prevented from using, bad passwords.