who and its cross-references

who

who [<nick>]
 Gives information about who I think the nick is (or who I think you
 are), including whether the nick is registered, whether it is
 associated with a username and if so who, and whether the current
 user of the nick has identified themselves to me.
 See `help register'.

register

register            register your nick (or make it secure)
register delete     delete your nick registration
register insecure   register your nick insecurely
 I only store settings for registered nicks.  For `insecure' nicks
 anyone who currently holds that nick can change its settings (see
 `help set', including securing it to their username.  `secure'
 nicks can only have their settings changed by the user to which they
 are registered, after identifying themselves (see `help identify').