USER

The USER command is used to specify the username and real name of a new user.

User Identification
Usage: USER <username> * * :<real name>
<username> The username of the new user.
<real name> The real name of the new user.

This command is used during the initial connection process for server authentication, providing the server with the user's username and real name.

(See section 4.1.3 of RFC 1459, 3.1.3 of RFC 2812)