"Who am I;" is a philosophical question for late night discussions. The Whoami, on the other hand is an extremely useful command of Windows.
When you run the whoami command in a Windows command prompt box without additional commands, you'll see the bare minimum details: the current domain and the username, in the form domain\username (if you're signed in with a local account or a Microsoft account, domain will display your computer name).
Run the Whoami command along with the /? and you will see help showing the options for displaying and formatting additional information about the account of the currently logged-in user.
For best results, use the whoami / all command, and it will display the security ID (SID) for the current user, along with information about team members and privileges.
The /fo list switch changes the default screen from a table (which can be hard to read) to an ordered list.
Use the / fo csv switch to change the appearance of the results to comma-separated values, which you can enter into a spreadsheet.
WHOAMI Parameter list:
/ UPN : displays the user name in User Principal Name (UPN) format.
/ FQDN : displays the user name in Fully Qualified Distinguished Name (FQDN) format.
/ USER : displays information about the logged in user along with the security identifier (SID).
/ GROUPS : displays the group membership for the logged in user, account type, security identifiers (SID) and properties.
/ PRIV : displays the security privileges for the logged in user.
/ LOGONID : displays the logon ID for the logged in user.
/ ALL: Displays user name for the logged in user, groups, security identifiers (SID) and privileges.
/ FO format : output format in TABLE, LIST, CSV values.
/ NH : tells the column header not to appear in the output. Works only for TABLE and CSV formats.
/? : help.